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Sample records for oxygen premix sedation

  1. Conscious sedation with inhaled 50% nitrous oxide/oxygen premix in photodynamic therapy sessions for vulvar lichen sclerosus treatment.

    Science.gov (United States)

    Cabete, Joana; Campos, Sara; Lestre, Sara

    2015-01-01

    Photodynamic therapy has been described as an effective therapeutic option in selected cases of anogenital lichen sclerosus that are refractory to first-line treatments. However, procedure-related pain is a limiting factor in patient adherence to treatment. The authors report the case of a 75-year-old woman with highly symptomatic vulvar lichen sclerosus, successfully treated with photodynamic therapy. An inhaled 50% nitrous oxide/oxygen premix was administered during sessions, producing a pain-relieving, anxiolytic, and sedative effect without loss of consciousness. This ready-to-use gas mixture may be a well-tolerated and accepted alternative to classical anesthetics in Photodynamic therapy, facilitating patients' adherence to illumination of pain-prone areas.

  2. Ion measurements in premixed methane-oxygen flames

    KAUST Repository

    Alquaity, Awad; Hourani, Nadim; Chahine, May; Selim, Hatem; Sarathy, Mani; Farooq, Aamir

    2014-01-01

    Mass Spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane-oxygen-argon burner-stabilized flames. Lean, stoichiometric and rich flames at atmospheric pressure are used to study the dependence of ion chemistry

  3. Ion measurements in premixed methane-oxygen flames

    KAUST Repository

    Alquaity, Awad

    2014-07-25

    Ions are formed as a result of chemi-ionization processes in combustion systems. Recently, there has been an increasing interest in understanding flame ion chemistry due to the possible application of external electric fields to reduce emissions and improve combustion efficiency by active control of combustion process. In order to predict the effect of external electric fields on combustion plasma, it is critical to gain a good understanding of the flame ion chemistry. In this work, a Molecular Beam Mass Spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane-oxygen-argon burner-stabilized flames. Lean, stoichiometric and rich flames at atmospheric pressure are used to study the dependence of ion chemistry on equivalence ratio of premixed flames. The relative ion concentration profiles are compared qualitatively with previous methane-oxygen studies and show good agreement. The relative ion concentration data obtained in the present study can be used to validate and improve ion chemistry models for methane-oxygen flames.

  4. Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad; Han, Jie; Chahine, May; Selim, Hatem; Belhi, Memdouh; Sarathy, Mani; Bisetti, Fabrizio; Farooq, Aamir

    2016-01-01

    chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon

  5. Supplementary Material for: Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad B. S.; Han, Jie; Chahine, May; Selim, Hatem; Belhi, Memdouh; Sarathy, Mani; Bisetti, Fabrizio; Farooq, Aamir

    2017-01-01

    chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon

  6. [Sedation with 50 % nitrous oxide/oxygen in paediatric dentistry].

    Science.gov (United States)

    Atash, R; Vanden Abbeele, A

    2008-09-01

    The management of paediatric dentistry treatment is essentially based on behaviour management but some behaviour troubles or mental retardation may hinder this kind of treatment at the dental office without any premedication. This often leads the dentist to change his treatment planning even if this may compromise the quality of treatment . Conscious sedation techniques enable stress and pain control during the active treatment phase and represent a useful alternative to general anaesthesia which cannot be used on a routine based level. Conscious sedation by the inhalation of nitrous oxide and oxygen (MEOPA) represents a good choice, as well as by its harmlessness as by its fast reversibility. MEOPA is a precious help in our practice, provided that its administration is totally under central and all contra-indication are respected. However sedation by inhalation should in no case be systematized and its goal must remain the progressive rehabilitation of the patient in a circuit of traditional ambulatory care.

  7. Investigating the effects of critical phenomena in premixed methane-oxygen flames at cryogenic conditions

    Science.gov (United States)

    Gopal, Abishek; Yellapantula, Shashank; Larsson, Johan

    2017-11-01

    Methane is increasingly becoming viable as a rocket fuel in the latest generation of launch vehicles. In liquid rocket engines, fuel and oxidizer are injected under cryogenic conditions into the combustion chamber. At high pressures, typical of rocket combustion chambers, the propellants exist in supercritical states where the ideal gas thermodynamics are no longer valid. We investigate the effects of real-gas thermodynamics on transcritical laminar premixed methane-oxygen flames. The effect of the real-gas cubic equations of state and high-pressure transport properties on flame dynamics is presented. We also study real-gas effects on the extinction limits of the methane-oxygen flame.

  8. Soot Formation in Laminar Premixed Methane/Oxygen Flames at Atmospheric Pressure

    Science.gov (United States)

    Xu, F.; Lin, K.-C.; Faeth, G. M.

    1998-01-01

    Flame structure and soot formation were studied within soot-containing laminar premixed mc1hane/oxygen flames at atmospheric pressure. The following measurements were made: soot volume fractions by laser extinction, soot temperatures by multiline emission, gas temperatures (where soot was absent) by corrected fine-wire thermocouples, soot structure by thermophoretic sampling and transmission electron microscope (TEM), major gas species concentrations by sampling and gas chromatography, and gas velocities by laser velocimetry. Present measurements of gas species concentrations were in reasonably good agreement with earlier measurements due to Ramer et al. as well as predictions based on the detailed mechanisms of Frenklach and co-workers and Leung and Lindstedt: the predictions also suggest that H atom concentrations are in local thermodynamic equilibrium throughout the soot formation region. Using this information, it was found that measured soot surface growth rates could be correlated successfully by predictions based on the hydrogen-abstraction/carbon-addition (HACA) mechanisms of both Frenklach and co-workers and Colket and Hall, extending an earlier assessment of these mechanisms for premixed ethylene/air flames to conditions having larger H/C ratios and acetylene concentrations. Measured primary soot particle nucleation rates were somewhat lower than the earlier observations for laminar premixed ethylene/air flames and were significantly lower than corresponding rates in laminar diffusion flames. for reasons that still must be explained.

  9. Evaluation of nitrous oxide-oxygen and triclofos sodium as conscious sedative agents

    Directory of Open Access Journals (Sweden)

    Priya Subramaniam

    2017-01-01

    Full Text Available Background: Conscious sedation is used in the pediatric dentistry to reduce fear and anxiety in children and promote favorable treatment outcomes. To achieve them, the primary clinical need is for a well-tolerated, effective, and expedient analgesic and sedative agent that is safe to use. Aim: The aim of the present study was to evaluate the efficacy of nitrous oxide-oxygen and triclofos sodium as conscious sedative agents in 5–10-year-old children. Methodology: Sixty children aged 5–10 years showing anxious, uncooperative, and apprehensive behavior were randomly divided and assigned into two groups (Groups A and B such that Group A received 40% nitrous oxide-60% oxygen and Group B received triclofos sodium in the dose of 70 mg/kg body weight, given 30 min before the treatment procedure. During the whole course of sedation procedure, the response of the child was assessed using Houpt's behavior rating scale. The acceptance of route of drug administration by the patient and parent was also assessed. Data obtained were statistically evaluated using the Mann–Whitney U-test and Chi-square test. Results: Children sedated with triclofos sodium were significantly more drowsy and disoriented compared to those sedated with nitrous oxide. The overall behavior of children in both the groups was similar. Good parental acceptance was observed for both the routes of administration. Patients accepted the oral route significantly better than inhalation route. Conclusion: Both nitrous oxide-oxygen and triclofos sodium were observed to be effective sedative agents, for successful and safe use in 5–10-year-old dental patients. Patients showed a good acceptance of the oral route compared to the inhalation route for sedation.

  10. Identification of combustion intermediates in low-pressure premixed pyridine/oxygen/argon flames.

    Science.gov (United States)

    Tian, Zhenyu; Li, Yuyang; Zhang, Taichang; Zhu, Aiguo; Qi, Fei

    2008-12-25

    Combustion intermediates of two low-pressure premixed pyridine/oxygen flames with respective equivalence ratios of 0.56 (C/O/N = 1:4.83:0.20) and 2.10 (C/O/N = 1:1.29:0.20) have been identified with tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry techniques. About 80 intermediates in the rich flame and 60 intermediates in the lean flame, including nitrogenous, oxygenated, and hydrocarbon intermediates, have been identified by measurements of photoionization mass spectra and photoionization efficiency spectra. Some radicals and new nitrogenous intermediates are identified in the present work. The experimental results are useful for studying the conversion of volatile nitrogen compounds and understanding the formation mechanism of NO(x) in flames of nitrogenous fuels.

  11. Supplementary Material for: Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad B. S.

    2017-01-01

    Cations and anions are formed as a result of chemi-ionization processes in combustion systems. Electric fields can be applied to reduce emissions and improve combustion efficiency by active control of the combustion process. Detailed flame ion chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon burner-stabilized atmospheric flames. Lean and stoichiometric flames are considered to assess the dependence of ion chemistry on flame stoichiometry. Relative ion concentration profiles are compared with numerical simulations using various temperature profiles, and good qualitative agreement was observed for the stoichiometric flame. However, for the lean flame, numerical simulations misrepresent the spatial distribution of selected ions greatly. Three modifications are suggested to enhance the ion mechanism and improve the agreement between experiments and simulations. The first two modifications comprise the addition of anion detachment reactions to increase anion recombination at low temperatures. The third modification involves restoring a detachment reaction to its original irreversible form. To our knowledge, this work presents the first detailed measurements of cations and flame temperature in canonical methane–oxygen-argon atmospheric flat flames. The positive ion profiles reported here may be useful to validate and improve ion chemistry models for methane-oxygen flames.

  12. Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad

    2016-08-22

    Cations and anions are formed as a result of chemi-ionization processes in combustion systems. Electric fields can be applied to reduce emissions and improve combustion efficiency by active control of the combustion process. Detailed flame ion chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon burner-stabilized atmospheric flames. Lean and stoichiometric flames are considered to assess the dependence of ion chemistry on flame stoichiometry. Relative ion concentration profiles are compared with numerical simulations using various temperature profiles, and good qualitative agreement was observed for the stoichiometric flame. However, for the lean flame, numerical simulations misrepresent the spatial distribution of selected ions greatly. Three modifications are suggested to enhance the ion mechanism and improve the agreement between experiments and simulations. The first two modifications comprise the addition of anion detachment reactions to increase anion recombination at low temperatures. The third modification involves restoring a detachment reaction to its original irreversible form. To our knowledge, this work presents the first detailed measurements of cations and flame temperature in canonical methane–oxygen-argon atmospheric flat flames. The positive ion profiles reported here may be useful to validate and improve ion chemistry models for methane-oxygen flames.

  13. [Sedation with intravenous midazolam during upper gastrointestinal endoscopy--changes in hemodynamics, oxygen saturation and memory].

    Science.gov (United States)

    Mizuno, Ju; Matsuki, Michiko; Gouda, Yoshinori; Nishiyama, Tomoki; Hanaoka, Kazuo

    2003-09-01

    Cardiorespiratory adverse effects are often observed in patients undergoing upper gastrointestinal endoscopy with sedation. In this study, we examined hemodynamics, oxygen saturation and memory during upper gastrointestinal endoscopy under sedation with intravenous midazolam. Eight healthy outpatients without any obvious complications received intravenous midazolam 5 mg for sedation for upper gastrointestinal endoscopy. Blood pressure, heart rate and percutaneous arterial oxygen saturation (SpO2) were measured before, during and after endoscopy. After the arousal by intravenous flumazenil, we inquired the patients about the level of memory during the endoscopy. Blood pressure decreased significantly two minutes after midazolam administration, but increased significantly after the insertion of an endoscope which was not different from the control value. Heart rate increased significantly one and three minutes after the insertion of the endoscope. SpO2 decreased significantly after midazolam administration and stayed at around 95%. No patients remembered the procedure. Sedation with intravenous midazolam during upper gastrointestinal endoscopy is useful to control the cardiovascular responses, and to obtain amnesia. However, a decrease in SpO2 should be watched carefully.

  14. An experimental and kinetic investigation of premixed furan/oxygen/argon flames.

    Science.gov (United States)

    Tian, Zhenyu; Yuan, Tao; Fournet, Rene; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Zhang, Kuiwen; Qi, Fei

    2011-04-01

    The detailed chemical structures of three low-pressure (35 Torr) premixed laminar furan/oxygen/argon flames with equivalence ratios of 1.4, 1.8 and 2.2 have been investigated by using tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry. About 40 combustion species including hydrocarbons and oxygenated intermediates have been identified by measurements of photoionization efficiency spectra. Mole fraction profiles of the flame species including reactants, intermediates and products have been determined by scanning burner position with some selected photon energies near ionization thresholds. Flame temperatures have been measured by a Pt-6%Rh/Pt-30%Rh thermocouple. A new mechanism involving 206 species and 1368 reactions has been proposed whose predictions are in reasonable agreement with measured species profiles for the three investigated flames. Rate-of-production and sensitivity analyses have been performed to track the key reaction paths governing furan consumption for different equivalence ratios. Both experimental and modeling results indicate that few aromatics could be formed in these flames. Furthermore, the current model has been validated against previous pyrolysis results of the literature obtained behind shock waves and the agreement is reasonable as well.

  15. The effect of neuromuscular blockade on oxygen consumption in sedated and mechanically ventilated pediatric patients after cardiac surgery.

    NARCIS (Netherlands)

    Lemson, J.; Driessen, J.J.; Hoeven, J.G. van der

    2008-01-01

    OBJECTIVE: To measure the effect of intense neuromuscular blockade (NMB) on oxygen consumption (VO(2)) in deeply sedated and mechanically ventilated children on the first day after complex congenital cardiac surgery. DESIGN: Prospective clinical interventional study. SETTING: Pediatric intensive

  16. Simulated use of premixed 0.25% isoflurane in 50% nitrous oxide and 50% oxygen.

    Science.gov (United States)

    Ross, J A; Tunstall, M E

    2002-12-01

    Isoflurane (0.25%) in premixed nitrous oxide and oxygen, 50/50, v/v (IN(2)O), has been suggested for pain relief in labour. Possible phase separation of the mixture was studied during simulated administration. A sinusoidal pump set at stroke volume of 2 litres and a rate of 20-22 bpm and cycling for 1 min in three was used to simulate breathing during the painful contractions of labour. The temperature inside a 10-litre capacity cylinder did not drecrease sufficiently to cause separation of the gas mixture. Temperature in the demand valve decreased to -15.5 degrees C and this caused a small amount of liquid formation within the valve. Accordingly, the inspired concentration during the first breath of mixture in a cycle could be transiently as high as 0.55%. The concentration observed at the patient connection after the first breath varied between 0.17 and 0.28%. The system delivered a clinically acceptable performance although further development to avoid liquid condensation is needed.

  17. The safety and efficacy of intranasal midazolam sedation combined with inhalation sedation with nitrous oxide and oxygen in paediatric dental patients as an alternative to general anaesthesia.

    Science.gov (United States)

    Wood, Michael

    2010-01-01

    Conscious Decision' was published in 2000 by the Department of Health, effectively ending the provision of dental general anaesthesia (DGA) outside the hospital environment. Other aspects of dental anxiety and behavioural management and sedation techniques were encouraged before the decision to refer for a DGA was reached. Although some anxious children may be managed with relative analgesia (RA), some may require different sedation techniques for dentists to accomplish dental treatment. Little evidence has been published in the UK to support the use of alternative sedation techniques in children. This paper presents another option using an alternative conscious sedation technique. to determine whether a combination of intranasal midazolam (IN) and inhalation sedation with nitrous oxide and oxygen is a safe and practical alternative to DGA. A prospective clinical audit of 100 cases was carried out on children referred to a centre for DGA. 100 children between 3 and 13 years of age who were referred for DGA were treated using this technique. Sedation was performed by intranasal midazolam followed by titrating a mixture of nitrous oxide and oxygen. A range of dental procedures was carried out while the children were sedated. Parents were present during the dental treatment. Data related to the patient, dentistry and treatment as well as sedation variables were collected at the treatment visit and a telephonic post-operative assessment from the parents was completed a week later. It was found that 96% of the required dental treatment was completed successfully using this technique, with parents finding this technique acceptable in 93% of cases. 50% of children found the intranasal administration of the midazolam acceptable. There was no clinically relevant oxygen desaturation during the procedure. Patients were haemodynamically stable and verbal contact was maintained throughout the procedure. In selected cases this technique provides a safe and effective alternative

  18. An equivalence study comparing nitrous oxide and oxygen with low-dose sevoflurane and oxygen as inhalation sedation agents in dentistry for adults.

    Science.gov (United States)

    Allen, M; Thompson, S

    2014-11-01

    The aim of this study was to examine whether sevoflurane in oxygen was equivalent to near equipotent concentrations of nitrous oxide in oxygen when used as an inhalation sedation agent in terms of patient and user acceptability. Forty anxious dental patients referred to the sedation suite at Cardiff University School of Dentistry received either nitrous oxide to a maximum concentration of 40% or sevoflurane to a maximum concentration of 0.3% for a routine maxillary plastic restoration with articaine infiltration local analgesia. The inhalation sedation agent to be administered was chosen by a random number allocator. Measurements of blood pressure, oxygen saturation, heart rate, respiratory rate and bispectral index were recorded every 5 minutes. At the end of the treatment episode the patient, the operator and an observer who was unaware of the agent used, recorded their impressions about the episode by completing questionnaires. In the doses used in this study, sevoflurane was found to be as effective as an inhalation sedation agent as the standard dose of nitrous oxide used in normal inhalation sedation in the treatment of adult anxious dental patients. Sevoflurane in low concentrations is equivalent in effect to near equipotent concentrations of nitrous oxide. This would suggest that further research, perhaps with slightly higher concentrations of sevoflurane, is needed. If sevoflurane was shown to be acceptable at slightly higher concentrations, there is scope to explore the development of equipment specifically designed to deliver sevoflurane as an inhalation sedation agent in future.

  19. An experimental study of the structure of laminar premixed flames of ethanol/methane/oxygen/argon

    Science.gov (United States)

    Tran, L.S.; Glaude, P.A.; Battin-Leclerc, F.

    2013-01-01

    The structures of three laminar premixed stoichiometric flames at low pressure (6.7 kPa): a pure methane flame, a pure ethanol flame and a methane flame doped by 30% of ethanol, have been investigated and compared. The results consist of concentration profiles of methane, ethanol, O2, Ar, CO, CO2, H2O, H2, C2H6, C2H4, C2H2, C3H8, C3H6, p-C3H4, a-C3H4, CH2O, CH3HCO, measured as a function of the height above the burner by probe sampling followed by on-line gas chromatography analyses. Flame temperature profiles have been also obtained using a PtRh (6%)-PtRh (30%) type B thermocouple. The similarities and differences between the three flames were analyzed. The results show that, in these three flames, the concentration of the C2 intermediates is much larger than that of the C3 species. In general, mole fraction of all intermediate species in the pure ethanol flame is the largest, followed by the doped flame, and finally the pure methane flame. PMID:24092946

  20. Practices and opinions on nitrous oxide/oxygen sedation from dentists licensed to perform relative analgesia in Brazil

    Directory of Open Access Journals (Sweden)

    Daher Anelise

    2012-07-01

    Full Text Available Abstract Background Relative analgesia (RA, defined as the use of inhalation sedation with nitrous oxide and oxygen, is one of the most common pharmacological behavior management techniques used to provide sedation and analgesia for dental patients. This study aimed to assess RA licensed Brazilian dentists’ practices and opinions about nitrous oxide/oxygen sedation in the dental setting. Methods A cross sectional national survey was conducted with 281 dentists who were certified to perform RA, using an electronically mailed self-administered questionnaire containing closed questions about their practices and opinions regarding RA. Practice and opinion were individually analyzed by descriptive statistics. Non-parametric tests assessed the relationships between RA practice and independent variables. To test the interplay between practices and opinions, a k-means clusters analysis was used to divide the group for statistical comparisons. Results The response rate was 45.2%. Women made up 64.6% of the respondents, the mean age was 39.1 years (SD = 9.8, and the mean time since graduation in dentistry was 16 years (SD = 9.7. Seventy-seven percent of respondents reported the use of RA in clinical practice, most of them ‘sometimes’ (53.5%, and focusing more on adult patients. Patients with certain physical or mental deficiencies were indications associated with RA practice. ‘Equipment acquisition’ (p  Conclusion Most of the RA licensed Brazilian dentists interviewed currently use RA. Current practice of RA and frequency of use determined the degree of favorable opinion about this inhalation sedation among this group of respondents.

  1. Influence of the depth of sedation on regional cerebral oxygen saturation monitoring in neurosurgery of supratentorial gliomas

    Directory of Open Access Journals (Sweden)

    ZHANG Kai⁃ying

    2012-12-01

    Full Text Available Objective To investigate the influence on regional cerebral oxygen saturation (rScO2 of sedation depth during anesthesia induction and maintenance in supratentorial glioma resections. Methods Thirty patients with Ⅰ - Ⅱ supratentorial glioma (graded by American Society of Anesthesiologists underwent elective supratentorial glioma resection were included in this study. Rocuronium, sufentanil and propofol were used for anesthesia induction. After trachea cannula, total intravenous anesthesia (TIVA was maintained with plasma concentration of propofol 2.80-3.20 μg/ml and remifentanil 0.10-0.20 μg/(kg·min. Thirty groups of rScO2, bispectral index (BIS, mean arterial pressure (MAP and heart rate (HR were recorded continuously till the incision. Results During anesthesia induction, BIS decreased along with the infusion of anesthetics, and there was significant negative correlation between BIS and rScO2 (r = ⁃0.803, P = 0.001. During anesthesia maintenance, rScO2 and BIS were not significantly related (r = 0.147, P = 0.396. Conclusion The rScO2 monitoring can reflect the influence of sedation depth on cerebral oxygen delivery and consumption balance during supratentorial glioma resection under TIVA.

  2. Comparison of oral midazolam with a combination of oral midazolam and nitrous oxide-oxygen inhalation in the effectiveness of dental sedation for young children

    Directory of Open Access Journals (Sweden)

    Al-Zahrani A

    2009-03-01

    Full Text Available Aim: To compare the effectiveness of 0.6 mg/kg oral midazolam sedation alone and a combination of 0.6 mg/kg oral midazolam plus nitrous oxide-oxygen inhalation sedation, in controlling the behavior of uncooperative children during dental treatment. Study Design: The study had a crossover design where the same patient received two different sedation regimens, that is, oral midazolam 0.6 mg/kg and oral midazolam 0.6 mg/kg with nitrous oxide-oxygen inhalation during two dental treatment visits. Materials and Methods: Thirty children (17 males and 13 females were randomly selected for the study, with a mean age of 55.07 (± 9.29 months, ranging from 48 - 72 months. A scoring system suggested by Houpt et al. (1985 was utilized for assessment of the children′s behavior. Results : There was no significant (p > 0.05 difference in the overall behavior assessment between the two sedation regimens, that is, oral midazolam alone and oral midazolam plus nitrous oxide-oxygen. However, the combination of midazolam and nitrous oxide-oxygen showed significantly (p < 0.05 superior results as compared to midazolam alone, in terms of controlling movement and crying during local anesthesia administration and restorative procedures. Conclusion: Compared to oral midazolam alone, a combination of oral midazolam and nitrous oxide inhalation sedation appears to provide more comfort to pediatric dental patients and operators during critical stages of dental treatment.

  3. [Clinical trail on the effect of nitrous oxide/oxygen inhalation sedation on the treatment of acute pulpitis].

    Science.gov (United States)

    Zhou, Xin-wen; Wang, Li-xin; Liu, Xi-yun

    2013-12-01

    To evaluate the effectiveness and safety of nitrous oxide/oxygen inhalation sedation in the treatment of acute pulpitis. The study population comprised 72 patients of acute pulpitis treated from September 2012 to March 2013. They were randomly divided into 2 groups, which included experimental group (37 cases) and control group (35 cases). Venham clinical anxiety, cooperative behavior level and WHO clinical pain level evaluation were conducted for the patients. Wilcoxon and Chi-square test were used respectively for statistical analysis with SPSS 14.0 software package. In the experimental group, 86.5% cases behaved comfortable, while in the control group the rate was only 42.9%. 94.6% of the patients in the experimental group felt painless after therapy. The proportion of that in the control group was 68.6%. There was significant difference between the 2 groups (Ppulpitis, while the long-term clinical result still needs further investigation.

  4. Comparative evaluation of stress levels before, during, and after periodontal surgical procedures with and without nitrous oxide-oxygen inhalation sedation

    Directory of Open Access Journals (Sweden)

    Gurkirat Sandhu

    2017-01-01

    Full Text Available Context: Periodontal surgical procedures produce varying degree of stress in all patients. Nitrous oxide-oxygen inhalation sedation is very effective for adult patients with mild-to-moderate anxiety due to dental procedures and needle phobia. Aim: The present study was designed to perform periodontal surgical procedures under nitrous oxide-oxygen inhalation sedation and assess whether this technique actually reduces stress physiologically, in comparison to local anesthesia alone (LA during lengthy periodontal surgical procedures. Settings and Design: This was a randomized, split-mouth, cross-over study. Materials and Methods: A total of 16 patients were selected for this randomized, split-mouth, cross-over study. One surgical session (SS was performed under local anesthesia aided by nitrous oxide-oxygen inhalation sedation, and the other SS was performed on the contralateral quadrant under LA. For each session, blood samples to measure and evaluate serum cortisol levels were obtained, and vital parameters including blood pressure, heart rate, respiratory rate, and arterial blood oxygen saturation were monitored before, during, and after periodontal surgical procedures. Statistical Analysis Used: Paired t-test and repeated measure ANOVA. Results: The findings of the present study revealed a statistically significant decrease in serum cortisol levels, blood pressure and pulse rate and a statistically significant increase in respiratory rate and arterial blood oxygen saturation during periodontal surgical procedures under nitrous oxide inhalation sedation. Conclusion: Nitrous oxide-oxygen inhalation sedation for periodontal surgical procedures is capable of reducing stress physiologically, in comparison to LA during lengthy periodontal surgical procedures.

  5. An experimental study on the effects of swirling oxidizer flow and diameter of fuel nozzle on behaviour and light emittance of propane-oxygen non-premixed flame

    Directory of Open Access Journals (Sweden)

    Javareshkian Alireza

    2017-01-01

    Full Text Available In this study, the stability and the light emittance of non-premixed propane-oxygen flames have been experimentally evaluated with respect to swirling oxidizer flow and variations in fuel nozzle diameter. Hence, three types of the vanes with the swirl angles of 30°, 45°, and 60° have been chosen for producing the desired swirling flows. The main aims of this study are to determine the flame behaviour, light emittance, and also considering the effect of variation in fuel nozzle diameter on combustion phenomena such as flame length, flame shape, and soot free length parameter. The investigation into the flame phenomenology was comprised of variations of the oxidizer and fuel flow velocities (respective Reynolds numbers and the fuel nozzle diameter. The results showed that the swirl effect could change the flame luminosity and this way could reduce or increase the maximum value of the flame light emittance in the combustion zone. Therefore, investigation into the flame light emittance can give a good clue for studying the mixing quality of reactants, the flame phenomenology (blue flame or sooty flame, localized extinction, and the combustion intensity in non-premixed flames.

  6. Study on the Enhancement Effect of Dielectric Barrier Discharge on the Premixed Methane/Oxygen/Helium Flame Velocity

    International Nuclear Information System (INIS)

    Mu Haibao; Yu Lin; Li Ping; Zhang Guanjun; Tang Chenglong; Wang Jinhua

    2015-01-01

    Recently, plasma-assisted combustion has become a potentially applicable technology in many combustion scenarios. In this paper, a dielectric barrier discharge (DBD) plasma generator is designed to explore the effect of plasma on the CH4 oxidation process, and several properties of combustion are considered. First, in the presence or absence of plasma discharge, physical appearance of the flame is examined and analyzed. Second, the flame propagation velocity is calculated by the flame front extracted from the imaging data with the Bunsen burner method. Finally, the main molecular components and their intensity variation in the flame and the plasma zones are identified with an emission spectrograph to analyze the effect of active species on the combustion process. We also discuss the possible kinetic regime of plasma-assisted combustion. Experimental results imply that plasma discharge applied to the premixed CH4/O2/He mixture significantly raises the flame speed with equivalence ratios ranging from 0.85 to 1.10, with the flame speed improved by 17% to 35%. It can be seen that plasma can improve methane oxidation efficiency in the premixed fuel/oxidizer, especially at a low equivalence ratio. (paper)

  7. Effect of oxygenated fuel on premixed lean diesel combustion; Kihaku yokongo diesel nensho ni oyobosu gansanso nenryo kongo keiyu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, S.; Miyamoto, T.; Harada, A.; Akagawa, H.; Tsujimura, K. [New ACE Institute Co. Ltd., Tokyo (Japan)

    1998-05-01

    Because injection timing in diesel engines is early in a premixed lean diesel combustion system using early fuel injection, ignition timing is determined by ignitability of the fuel used. The conventional diesel fuel, which has good ignitability, causes excessively early ignition, thus aggravating fuel consumption. In order to reduce cylinder temperature with an aim of delaying ignition timing to improve the fuel consumption, attempts are being made on using low cetane fuels to reduce CO2 gas supply or compression ratio, and to vary ignitability of the fuels. The present study investigated ignition timing control and properties of exhausts by mixing different types of oxygenated fuels into light oil. Mixing the oxygenated fuels into light oil proved that the ignition timing can be controlled, and mixing such low cetane fuels as ethanol and MTBE achieved improvement in fuel consumption. Trial use of the oxygenated fuels aggravated CO concentration, which is caused because the cylinder temperature was reduced. Numerical calculations suggest that use of fuels with faster evaporation speed and lower cetane number is effective in improving the fuel consumption and the exhausts. 12 refs., 9 figs., 2 tabs.

  8. Chemical structures and theoretical models of lean premixed ...

    African Journals Online (AJOL)

    To better understand the chemistry involved in the lean-fuel combustion, the chemical structure of lean premixed propene-oxygen-nitrogen flames stabilized on a flat-flame burner at atmospheric pressure was determined experimentally. The species mole fraction profiles were also computed by the Premix code and three ...

  9. Nitric Oxide and Oxygen Air-Contamination Effects on Extinction Limits of Non-Premixed Hydrocarbon-Air Flames for a HIFiRE Scramjet

    Science.gov (United States)

    Pellett, Gerald L.; Dawson, Lucy C.; Vaden, Sarah N.; Wilson, Lloyd G.

    2009-01-01

    Unique nitric oxide (NO) and oxygen air-contamination effects on the extinction Flame Strength (FS) of non-premixed hydrocarbon (HC) vs. air flames are characterized for 7 gaseous HCs, using a new idealized 9.3 mm straight-tube Opposed Jet Burner (OJB) at 1 atm. FS represents a laminar strain-induced extinction limit based on cross-section-average air jet velocity, Uair, that sustains combustion of a counter jet of gaseous fuel just before extinction. Besides ethane, propane, butane, and propylene, the HCs include ethylene, methane, and a 64 mole-% ethylene / 36 % methane mixture, the writer s previously recommended gaseous surrogate fuel for HIFiRE scramjet tests. The HC vs. clean air part of the work is an extension of a May 2008 JANNAF paper that characterized surrogates for the HIFiRE project that should mimic the flameholding of reformed (thermally- or catalytically-cracked) endothermic JP-like fuels. The new FS data for 7 HCs vs. clean air are thus consolidated with the previously validated data, normalized to absolute (local) axial-input strain rates, and co-plotted on a dual kinetically dominated reactivity scale. Excellent agreement with the prior data is obtained for all 7 fuels. Detailed comparisons are also made with recently published (Univ. Va) numerical results for ethylene extinction. A 2009-revised ethylene kinetic model (Univ. Southern Cal) led to predicted limits within approx. 5 % (compared to 45 %, earlier) of this writer s 2008 (and present) ethylene FSs, and also with recent independent data (Univ. Va) obtained on a new OJB system. These +/- 5 % agreements, and a hoped-for "near-identically-performing" reduced kinetics model, would greatly enhance the capability for accurate numerical simulations of surrogate HC flameholding in scramjets. The measured air-contamination effects on normalized FS extinction limits are projected to assess ongoing Arc-Heater-induced "facility test effects" of NO production (e.g., 3 mole-%) and resultant oxygen

  10. ASAP ECMO: Antibiotic, Sedative and Analgesic Pharmacokinetics during Extracorporeal Membrane Oxygenation: a multi-centre study to optimise drug therapy during ECMO

    Directory of Open Access Journals (Sweden)

    Shekar Kiran

    2012-11-01

    Full Text Available Abstract Background Given the expanding scope of extracorporeal membrane oxygenation (ECMO and its variable impact on drug pharmacokinetics as observed in neonatal studies, it is imperative that the effects of the device on the drugs commonly prescribed in the intensive care unit (ICU are further investigated. Currently, there are no data to confirm the appropriateness of standard drug dosing in adult patients on ECMO. Ineffective drug regimens in these critically ill patients can seriously worsen patient outcomes. This study was designed to describe the pharmacokinetics of the commonly used antibiotic, analgesic and sedative drugs in adult patients receiving ECMO. Methods/Design This is a multi-centre, open-label, descriptive pharmacokinetic (PK study. Eligible patients will be adults treated with ECMO for severe cardiac and/or respiratory failure at five Intensive Care Units in Australia and New Zealand. Patients will receive the study drugs as part of their routine management. Blood samples will be taken from indwelling catheters to investigate plasma concentrations of several antibiotics (ceftriaxone, meropenem, vancomycin, ciprofloxacin, gentamicin, piperacillin-tazobactum, ticarcillin-clavulunate, linezolid, fluconazole, voriconazole, caspofungin, oseltamivir, sedatives and analgesics (midazolam, morphine, fentanyl, propofol, dexmedetomidine, thiopentone. The PK of each drug will be characterised to determine the variability of PK in these patients and to develop dosing guidelines for prescription during ECMO. Discussion The evidence-based dosing algorithms generated from this analysis can be evaluated in later clinical studies. This knowledge is vitally important for optimising pharmacotherapy in these most severely ill patients to maximise the opportunity for therapeutic success and minimise the risk of therapeutic failure. Trial registration ACTRN12612000559819

  11. Experiments for the premixing phase (PREMIX); Experimente zur Vorvermischungsphase (PREMIX)

    Energy Technology Data Exchange (ETDEWEB)

    Cherdron, W.; Huber, F.; Kaiser, A.; Schuetz, W.; Steinbrueck, M.; Will, H.

    1995-08-01

    In the PREMIX experiment, the premixing phenomena are studied by means of real high temperature melt jets. Jet fragmentation as well as (coarse) fragmentation of melt drops are being investigated. The objective is to avoid as far as possible a fine fragmentation and thus to help prevent explosions. Therefore water is used close to boiling temperature. The pressure can be varied in a relevant range up to nearly 10 bar. The melt is created by a thermite reaction after which most of the iron is separated from the melt. In this way a predominantly oxide melt with temperatures of about 2700 K is produced. Preliminary experiments showed as a surprising result that melt jets can penetrate into the water as far as nearly 1 m depth before a violant evaporation comes about. (orig.)

  12. Gas turbine premixing systems

    Science.gov (United States)

    Kraemer, Gilbert Otto; Varatharajan, Balachandar; Evulet, Andrei Tristan; Yilmaz, Ertan; Lacy, Benjamin Paul

    2013-12-31

    Methods and systems are provided for premixing combustion fuel and air within gas turbines. In one embodiment, a combustor includes an upstream mixing panel configured to direct compressed air and combustion fuel through premixing zone to form a fuel-air mixture. The combustor includes a downstream mixing panel configured to mix additional combustion fuel with the fule-air mixture to form a combustion mixture.

  13. Detection of Respiratory Adverse Events in Pediatric Dental Patients Sedated With 0.75mg/Kg of Midazolam and Oxygen by Continuous Pretracheal Auscultation: A Prospective Randomized Controlled Trial.

    Science.gov (United States)

    Somri, Mostafa; Matter, Ibrahim; Hadjittofi, Christopher; Hoash, Naser; Moaddi, Bian; Kharouba, Johnny; Parisinos, Constantinos A; Peretz, Benjamin

    Sedation is becoming more commonplace for pediatric patients undergoing minor procedures. Fortunately, electronic monitors have contributed to a reduction in the associated respiratory adverse events (RAEs). To test the hypothesis that adding the pretracheal stethoscope (PTS) to standard monitoring methods (SMMs) may improve RAE detection in sedated pediatric dental patients, the frequency of RAEs detected by SMMs (i.e. visual observation, capnography, and pulse oximetry) was compared to that detected by SMMs alongside continuous PTS auscultation. A prospective, randomised, controlled trial was performed with 100 pediatric patient participants of ASA≤2, who were scheduled to receive dental treatment under 0.75 mg/kg and oxygen. Patients were randomised into Groups A (n=50; SMMs) and B (n=50; SMMs+PTS). Inclusion criteria were behavioral management problems and intolerance to dental treatment despite behavioral management techniques or nitrous oxide administration. Exclusion criteria were high-risk conditions for RAEs, altered mental status, gastrointestinal disorders, parental refusal of conscious sedation and failure of previous conscious sedation. An anesthesist was present throughout the dental treatments. RAEs were detected in 10 (20%) and 22(44%) Group A and B patients respectively (p=0.01). The majority of RAEs within Group B were detected by PTS auscultation (n=19). Capnography produced 13 and 15 false-positive results in Groups A and B respectively, whereas the PTS produced 4(8%) false-positive results in Group B (p=0.009). PTS was found to be useful for detecting RAEs during pediatric dental sedation with 0.75mg/kg midazolam and oxygen, in the presence of an anesthesist.

  14. Experiments for the premixing phase (PREMIX)

    International Nuclear Information System (INIS)

    Cherdron, W.; Huber, F.; Kaiser, A.; Schuetz, W.; Steinbrueck, M.; Will, H.

    1995-01-01

    In the PREMIX experiment, the premixing phenomena are studied by means of real high temperature melt jets. Jet fragmentation as well as (coarse) fragmentation of melt drops are being investigated. The objective is to avoid as far as possible a fine fragmentation and thus to help prevent explosions. Therefore water is used close to boiling temperature. The pressure can be varied in a relevant range up to nearly 10 bar. The melt is created by a thermite reaction after which most of the iron is separated from the melt. In this way a predominantly oxide melt with temperatures of about 2700 K is produced. Preliminary experiments showed as a surprising result that melt jets can penetrate into the water as far as nearly 1 m depth before a violant evaporation comes about. (orig.)

  15. Premixed direct injection nozzle

    Science.gov (United States)

    Zuo, Baifang [Simpsonville, SC; Johnson, Thomas Edward [Greer, SC; Lacy, Benjamin Paul [Greer, SC; Ziminsky, Willy Steve [Simpsonville, SC

    2011-02-15

    An injection nozzle having a main body portion with an outer peripheral wall is disclosed. The nozzle includes a plurality of fuel/air mixing tubes disposed within the main body portion and a fuel flow passage fluidly connected to the plurality of fuel/air mixing tubes. Fuel and air are partially premixed inside the plurality of the tubes. A second body portion, having an outer peripheral wall extending between a first end and an opposite second end, is connected to the main body portion. The partially premixed fuel and air mixture from the first body portion gets further mixed inside the second body portion. The second body portion converges from the first end toward said second end. The second body portion also includes cooling passages that extend along all the walls around the second body to provide thermal damage resistance for occasional flame flash back into the second body.

  16. Inhalation Conscious Sedation with Nitrous Oxide and Oxygen as Alternative to General Anesthesia in Precooperative, Fearful, and Disabled Pediatric Dental Patients: A Large Survey on 688 Working Sessions

    Science.gov (United States)

    Galeotti, Angela; Garret Bernardin, Annelyse; D'Antò, Vincenzo; Viarani, Valeria; Cassabgi, Giorgio

    2016-01-01

    Aim. To evaluate the effectiveness and the tolerability of the nitrous oxide sedation for dental treatment on a large pediatric sample constituting precooperative, fearful, and disabled patients. Methods. 472 noncooperating patients (aged 4 to 17) were treated under conscious sedation. The following data were calculated: average age; gender distribution; success/failure; adverse effects; number of treatments; kind of dental procedure undertaken; number of dental procedures for each working session; number of working sessions for each patient; differences between males and females and between healthy and disabled patients in relation to success; success in relation to age; and level of cooperation using Venham score. Results. 688 conscious sedations were carried out. The success was 86.3%. Adverse effects occurred in 2.5%. 1317 dental procedures were performed. In relation to the success, there was a statistically significant difference between healthy and disabled patients. Sex and age were not significant factors for the success. Venham score was higher at the first contact with the dentist than during the treatment. Conclusions. Inhalation conscious sedation represented an effective and safe method to obtain cooperation, even in very young patients, and it could reduce the number of pediatric patients referred to hospitals for general anesthesia. PMID:27747238

  17. Inhalation Conscious Sedation with Nitrous Oxide and Oxygen as Alternative to General Anesthesia in Precooperative, Fearful, and Disabled Pediatric Dental Patients: A Large Survey on 688 Working Sessions

    Directory of Open Access Journals (Sweden)

    Angela Galeotti

    2016-01-01

    Full Text Available Aim. To evaluate the effectiveness and the tolerability of the nitrous oxide sedation for dental treatment on a large pediatric sample constituting precooperative, fearful, and disabled patients. Methods. 472 noncooperating patients (aged 4 to 17 were treated under conscious sedation. The following data were calculated: average age; gender distribution; success/failure; adverse effects; number of treatments; kind of dental procedure undertaken; number of dental procedures for each working session; number of working sessions for each patient; differences between males and females and between healthy and disabled patients in relation to success; success in relation to age; and level of cooperation using Venham score. Results. 688 conscious sedations were carried out. The success was 86.3%. Adverse effects occurred in 2.5%. 1317 dental procedures were performed. In relation to the success, there was a statistically significant difference between healthy and disabled patients. Sex and age were not significant factors for the success. Venham score was higher at the first contact with the dentist than during the treatment. Conclusions. Inhalation conscious sedation represented an effective and safe method to obtain cooperation, even in very young patients, and it could reduce the number of pediatric patients referred to hospitals for general anesthesia.

  18. Sedation with nitrous oxide compared with no sedation during catheterization for urologic imaging in children

    International Nuclear Information System (INIS)

    Zier, Judith L.; Kvam, Kathryn A.; Kurachek, Stephen C.; Finkelstein, Marsha

    2007-01-01

    Various strategies to mitigate children's distress during voiding cystourethrography (VCUG) have been described. Sedation with nitrous oxide is comparable to that with oral midazolam for VCUG, but a side-by-side comparison of nitrous oxide sedation and routine care is lacking. The effects of sedation/analgesia using 70% nitrous oxide and routine care for VCUG and radionuclide cystography (RNC) were compared. A sample of 204 children 4-18 years of age scheduled for VCUG or RNC with sedation or routine care were enrolled in this prospective study. Nitrous oxide/oxygen (70%/30%) was administered during urethral catheterization to children in the sedated group. The outcomes recorded included observed distress using the Brief Behavioral Distress Score, self-reported pain, and time in department. The study included 204 patients (99 nonsedated, 105 sedated) with a median age of 6.3 years (range 4.0-15.2 years). Distress and pain scores were greater in nonsedated than in sedated patients (P < 0.001). Time in department was longer in the sedated group (90 min vs. 30 min); however, time from entry to catheterization in a non-imaging area accounted for most of the difference. There was no difference in radiologic imaging time. Sedation with nitrous oxide is effective in reducing distress and pain during catheterization for VCUG or RNC in children. (orig.)

  19. Dynamic-Stability Characteristics of Premixed Methane Oxy-Combustion

    KAUST Repository

    Shroll, Andrew P.; Shanbhogue, Santosh J.; Ghoniem, Ahmed F.

    2012-01-01

    This work explores the dynamic stability characteristics of premixed CH 4/O 2/CO 2 mixtures in a 50 kW swirl stabilized combustor. In all cases, the methane-oxygen mixture is stoichiometric, with different dilution levels of carbon dioxide used

  20. Procedural sedation analgesia

    Directory of Open Access Journals (Sweden)

    Sheta Saad

    2010-01-01

    Full Text Available The number of noninvasive and minimally invasive procedures performed outside of the operating room has grown exponentially over the last several decades. Sedation, analgesia, or both may be needed for many of these interventional or diagnostic procedures. Individualized care is important when determining if a patient requires procedural sedation analgesia (PSA. The patient might need an anti-anxiety drug, pain medicine, immobilization, simple reassurance, or a combination of these interventions. The goals of PSA in four different multidisciplinary practices namely; emergency, dentistry, radiology and gastrointestinal endoscopy are discussed in this review article. Some procedures are painful, others painless. Therefore, goals of PSA vary widely. Sedation management can range from minimal sedation, to the extent of minimal anesthesia. Procedural sedation in emergency department (ED usually requires combinations of multiple agents to reach desired effects of analgesia plus anxiolysis. However, in dental practice, moderate sedation analgesia (known to the dentists as conscious sedation is usually what is required. It is usually most effective with the combined use of local anesthesia. The mainstay of success for painless imaging is absolute immobility. Immobility can be achieved by deep sedation or minimal anesthesia. On the other hand, moderate sedation, deep sedation, minimal anesthesia and conventional general anesthesia can be all utilized for management of gastrointestinal endoscopy.

  1. Large eddy simulation of premixed and non-premixed combustion

    OpenAIRE

    Malalasekera, W; Ibrahim, SS; Masri, AR; Sadasivuni, SK; Gubba, SR

    2010-01-01

    This paper summarises the authors experience in using the Large Eddy Simulation (LES) technique for the modelling of premixed and non-premixed combustion. The paper describes the application of LES based combustion modelling technique to two well defined experimental configurations where high quality data is available for validation. The large eddy simulation technique for the modelling flow and turbulence is based on the solution of governing equations for continuity and momentum in a struct...

  2. Premixed direct injection disk

    Science.gov (United States)

    York, William David; Ziminsky, Willy Steve; Johnson, Thomas Edward; Lacy, Benjamin; Zuo, Baifang; Uhm, Jong Ho

    2013-04-23

    A fuel/air mixing disk for use in a fuel/air mixing combustor assembly is provided. The disk includes a first face, a second face, and at least one fuel plenum disposed therebetween. A plurality of fuel/air mixing tubes extend through the pre-mixing disk, each mixing tube including an outer tube wall extending axially along a tube axis and in fluid communication with the at least one fuel plenum. At least a portion of the plurality of fuel/air mixing tubes further includes at least one fuel injection hole have a fuel injection hole diameter extending through said outer tube wall, the fuel injection hole having an injection angle relative to the tube axis. The invention provides good fuel air mixing with low combustion generated NOx and low flow pressure loss translating to a high gas turbine efficiency, that is durable, and resistant to flame holding and flash back.

  3. Development of rapid mixing fuel nozzle for premixed combustion

    International Nuclear Information System (INIS)

    Katsuki, Masashi; Chung, Jin Do; Kim, Jang Woo; Hwang, Seung Min; Kim, Seung Mo; Ahn, Chul Ju

    2009-01-01

    Combustion in high-preheat and low oxygen concentration atmosphere is one of the attractive measures to reduce nitric oxide emission as well as greenhouse gases from combustion devices, and it is expected to be a key technology for the industrial applications in heating devices and furnaces. Before proceeding to the practical applications, we need to elucidate combustion characteristics of non-premixed and premixed flames in high-preheat and low oxygen concentration conditions from scientific point of view. For the purpose, we have developed a special mixing nozzle to create a homogeneous mixture of fuel and air by rapid mixing, and applied this rapidmixing nozzle to a Bunsen-type burner to observe combustion characteristics of the rapid-mixture. As a result, the combustion of rapid-mixture exhibited the same flame structure and combustion characteristics as the perfectly prepared premixed flame, even though the mixing time of the rapid-mixing nozzle was extremely short as a few milliseconds. Therefore, the rapid-mixing nozzle in this paper can be used to create preheated premixed flames as far as the mixing time is shorter than the ignition delay time of the fuel

  4. Safety of Conscious Sedation In Interventional Radiology

    International Nuclear Information System (INIS)

    Arepally, Aravind; Oechsle, Denise; Kirkwood, Sharon; Savader, Scott J.

    2001-01-01

    Purpose: To identify rates of adverse events associated with the use of conscious sedation in interventional radiology.Methods: In a 5-month period, prospective data were collected on patients undergoing conscious sedation for interventional radiology procedures (n = 594). Adverse events were categorized as respiratory, sedative, or major adverse events. Respiratory adverse events were those that required oral airway placement, ambu bag, or jaw thrust. Sedation adverse events were unresponsiveness, oxygen saturation less than 90%, use of flumazenil/naloxone, or agitation. Major adverse events were hypotension, intubation, CPR, or cardiac arrest. The frequency of adverse events for the five most common radiology procedures were determined.Results: The five most common procedures (total n = 541) were biliary tube placement/exchange (n = 182), tunneled catheter placement (n 135), diagnostic arteriography (n = 125), vascular interventions (n = 52), and other catheter insertions (n = 46). Rates for respiratory, sedation, and major adverse events were 4.7%, 4.2%, and 2.0%, respectively. The most frequent major adverse event was hypotension (2.0%). Biliary procedures had the highest rate of total adverse events (p < .05) and respiratory adverse events (p < .05).Conclusion: The frequency of adverse events is low with the use of conscious sedation during interventional procedures. The highest rates occurred during biliary interventions

  5. Analgesic efficacy of equimolar 50% nitrous oxide/oxygen gas premix (Kalinox®) as compared with a 5% eutectic mixture of lidocaine/prilocaine (EMLA®) in chronic leg ulcer debridement.

    Science.gov (United States)

    Traber, Juerg; Held, Ulrike; Signer, Maria; Huebner, Tobias; Arndt, Stefan; Neff, Thomas A

    2017-08-01

    Chronic foot and leg ulcers are a common health problem worldwide. A mainstay of chronic ulcer therapy is sharp mechanical wound debridement requiring potent analgesia. In this prospective, controlled, single-centre, crossover design study, patients were assigned to either the administration of topical analgesia with 5% lidocaine/prilocaine cream or the inhalation of an analgesic 50% N 2 O/O 2 gas premix. Primary outcome parameter was level of pain at maximum wound depth during debridement as measured by a visual analogue scale. Secondary outcomes included level of pain after debridement, overall duration of treatment session, duration and completeness of debridement, and the patient's subjective perception of analgesic quality during debridement. Pain level increased from 0·60/0·94 (first/second debridement; baseline) to 1·76/2·50 (debridement) with 5% lidocaine/prilocaine and from 1·00/1·35 (baseline) to 3·95/3·29 (debridement) with 50% N 2 O/O 2 gas premix. Patient satisfaction was 90·48%/94·44% (first/second debridement) with topical 5% lidocaine/prilocaine analgesia and 90·48%/76·47% with the inhalation of 50% N 2 O/O 2 gas premix. Debridement was completed in a significantly higher percentage of 85·71%/88·89% (first/second debridement) with 5% lidocaine/prilocaine than with 50% N 2 O/O 2 gas premix (42·86%/58·82%) (odds ratio 6·7; P = 0·001). This study provides sound evidence that analgesia with topically administered 5% lidocaine/prilocaine cream is superior to the use of inhaled 50% N 2 O/O 2 gas premix in chronic leg ulcer debridement. © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  6. THE EFFECTS OF EQUIVALENCE RATIO ON THE FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND SOOT IN PREMIXED ETHANE FLAMES. (R825412)

    Science.gov (United States)

    AbstractThe formation of polycyclic aromatic hydrocarbons (PAH) and soot has been investigated in atmospheric-pressure, laminar, ethane/oxygen/argon premixed flames as a function of mixture equivalence ratio. Mole fraction profiles of major products, trace aromatics, ...

  7. Sedation in Pediatric Esophagogastroduodenoscopy

    Directory of Open Access Journals (Sweden)

    Seak Hee Oh

    2018-03-01

    Full Text Available Pediatric esophagogastroduodenoscopy (EGD has become an established diagnostic and therapeutic modality in pediatric gastroenterology. Effective sedation strategies have been adopted to improve patient tolerance during pediatric EGD. For children, safety is a fundamental consideration during this procedure as they are at a higher risk of severe adverse events from procedural sedation compared to adults. Therefore, a detailed risk evaluation is required prior to the procedure, and practitioners should be aware of the benefits and risks associated with sedation regimens during pediatric EGD. In addition, pediatric advanced life support by endoscopists or immediate intervention by anesthesiologists should be available in the event that severe adverse events occur during pediatric EGD.

  8. Procedural sedation analgesia

    OpenAIRE

    Sheta, Saad A

    2010-01-01

    The number of noninvasive and minimally invasive procedures performed outside of the operating room has grown exponentially over the last several decades. Sedation, analgesia, or both may be needed for many of these interventional or diagnostic procedures. Individualized care is important when determining if a patient requires procedural sedation analgesia (PSA). The patient might need an anti-anxiety drug, pain medicine, immobilization, simple reassurance, or a combination of these interve...

  9. Laryngospasm With Apparent Aspiration During Sedation With Nitrous Oxide.

    Science.gov (United States)

    Babl, Franz E; Grindlay, Joanne; Barrett, Michael Joseph

    2015-11-01

    Nitrous oxide and oxygen mixture has become increasingly popular for the procedural sedation and analgesia of children in the emergency department. In general, nitrous oxide is regarded as a very safe agent according to large case series. We report a case of single-agent nitrous oxide sedation of a child, complicated by laryngospasm and radiographically confirmed bilateral upper lobe pulmonary opacities. Although rarely reported with parenteral sedative agents, laryngospasm and apparent aspiration has not been previously reported in isolated nitrous oxide sedation. This case highlights that, similar to other sedative agents, nitrous oxide administration also needs to be conducted by staff and in settings in which airway emergencies can be appropriately managed. Copyright © 2015 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  10. Effects of music on sedation depth and sedative use during pediatric dental procedures.

    Science.gov (United States)

    Ozkalayci, Ozlem; Araz, Coskun; Cehreli, Sevi Burcak; Tirali, Resmiye Ebru; Kayhan, Zeynep

    2016-11-01

    The study aimed to investigate the effects of listening to music or providing sound isolation on the depth of sedation and need for sedatives in pediatric dental patients. Prospective, randomized, and controlled study. Tertiary, university hospital. In total, 180 pediatric patients, American Society of Anesthesiologists physical status I and II, who were scheduled for dental procedures of tooth extraction, filling, amputation, and root treatment. Patients were categorized into 3 groups: music, isolation, and control. During the procedures, the patients in the music group listened to Vivaldi's The Four Seasons violin concertos by sound-isolating headphones, whereas the patients in the isolation group wore the headphones but did not listen to music. All patients were sedated by 0.1 mg/kg midazolam and 1 mg/kg propofol. During the procedure, an additional 0.5 mg/kg propofol was administered as required. Bispectral index was used for quantifying the depth of sedation, and total dosage of the propofol was used for sedative requirements. The patients' heart rates, oxygen saturations, and Observer's Assessment of Alertness and Sedation Scale and bispectral index scores, which were monitored during the operation, were similar among the groups. In terms of the amount of propofol used, the groups were similar. Prolonged postoperative recovery cases were found to be significantly frequent in the control group, according to the recovery duration measurements (P = .004). Listening to music or providing sound isolation during pediatric dental interventions did not alter the sedation level, amount of medication, and hemodynamic variables significantly. This result might be due to the deep sedation levels reached during the procedures. However, listening to music and providing sound isolation might have contributed in shortening the postoperative recovery duration of the patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Extinction of laminar partially premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Suresh K. [Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 842 W. Taylor Street, Room 2039, MC-251, Chicago, IL 60607-7022 (United States)

    2009-12-15

    Flame extinction represents one of the classical phenomena in combustion science. It is important to a variety of combustion systems in transportation and power generation applications. Flame extinguishment studies are also motivated from the consideration of fire safety and suppression. Such studies have generally considered non-premixed and premixed flames, although fires can often originate in a partially premixed mode, i.e., fuel and oxidizer are partially premixed as they are transported to the reaction zone. Several recent investigations have considered this scenario and focused on the extinction of partially premixed flames (PPFs). Such flames have been described as hybrid flames possessing characteristics of both premixed and non-premixed flames. This paper provides a review of studies dealing with the extinction of PPFs, which represent a broad family of flames, including double, triple (tribrachial), and edge flames. Theoretical, numerical and experimental studies dealing with the extinction of such flames in coflow and counterflow configurations are discussed. Since these flames contain both premixed and non-premixed burning zones, a brief review of the dilution-induced extinction of premixed and non-premixed flames is also provided. For the coflow configuration, processes associated with flame liftoff and blowout are described. Since lifted non-premixed jet flames often contain a partially premixed or an edge-flame structure prior to blowout, the review also considers such flames. While the perspective of this review is broad focusing on the fundamental aspects of flame extinction and blowout, results mostly consider flame extinction caused by the addition of a flame suppressant, with relevance to fire suppression on earth and in space environment. With respect to the latter, the effect of gravity on the extinction of PPFs is discussed. Future research needs are identified. (author)

  12. An experimental and kinetic modeling study of premixed nitroethane flames at low pressure

    DEFF Research Database (Denmark)

    Zhang, Kuiwen; Zhang, Lidong; Xie, Mingfeng

    2013-01-01

    An experimental and kinetic modeling study is reported on three premixed nitroethane/oxygen/argon flames at low pressure (4.655kPa) with the equivalence ratios (Φ) of 1.0, 1.5 and 2.0. Over 30 flame species were identified with tunable synchrotron vacuum ultraviolet photoionization mass spectrome......An experimental and kinetic modeling study is reported on three premixed nitroethane/oxygen/argon flames at low pressure (4.655kPa) with the equivalence ratios (Φ) of 1.0, 1.5 and 2.0. Over 30 flame species were identified with tunable synchrotron vacuum ultraviolet photoionization mass...

  13. The PediSedate device, a novel approach to pediatric sedation that provides distraction and inhaled nitrous oxide: clinical evaluation in a large case series.

    Science.gov (United States)

    Denman, William T; Tuason, Pacifico M; Ahmed, Mohammed I; Brennen, Loralie M; Cepeda, M Soledad; Carr, Daniel B

    2007-02-01

    Pediatric sedation is of paramount importance but can be challenging. Fear and anticipatory anxiety before invasive procedures often lead to uncooperativeness. A novel device (PediSedate) provides sedation through a combination of inhaled nitrous oxide and distraction (video game). We evaluated the acceptability and safety of the PediSedate device in children. We enrolled children between 3 and 9 years old who were scheduled to undergo surgical procedures that required general inhalational anesthesia. After the device was applied, he/she played a video game while listening to the audio portion of the game through the earphones. Nitrous oxide in oxygen was administered via the nasal piece of the headset starting at 50% and increasing to 70%, in 10% increments every 8 min. Treatment failures, vital signs, arterial oxygen saturation, depth of sedation, airway patency, side effects, acceptance of the device and parental satisfaction were all evaluated. Of 100 children included, treatment failure occurred in 18% mainly because of poor tolerance of the device. At least 96% of the children who completed the study exhibited an excellent degree of sedation, 22% had side effects, and none experienced serious airway obstruction. Nausea and vomiting were the most common side effects and no patients had hemodynamic instability. The PediSedate device combines nonpharmacologic with pharmacologic methods of sedation. Most of the children we evaluated were able to tolerate the PediSedate device and achieved an adequate degree of sedation.

  14. [General practitioner and palliative sedation].

    Science.gov (United States)

    Schweitzer, Bart

    2014-01-01

    Recent publications in Dutch national newspapers on palliative sedation have raised concerns about its use in general practice. There is now evidence that there is no significant increase in the incidence of palliative sedation. Euthanasia requests were pending in 20.8% of the cases in which palliative sedation was performed, but the general practitioners could clearly justify why they made this choice. This is important because it indicates that they are aware of a sharp distinction between euthanasia and palliative sedation. Although the decision to perform palliative sedation was discussed with almost all cancer patients, patient involvement was less present in non-cancer conditions. This may be related to different disease trajectories, but it also indicates that attention should be devoted to earlier identification of patients in need of palliative care. The findings confirm that the practice of palliative sedation by general practitioners largely reflects the recommendations of the Dutch National Guideline on Palliative Sedation.

  15. Palliative sedation in nursing anesthesia.

    Science.gov (United States)

    Wolf, Michael T

    2013-04-01

    Palliative sedation is a technique of providing a sedative for end-of-life care to patients with intractable pain. The literature discusses the techniques and use of palliative sedation. Numerous articles have been written regarding the issues surrounding its use, but no literature has discussed the prescription or administration of palliative sedation by a nurse anesthetist. By understanding the concept and ethics involved in its use and providing nursing care that is theory based, the author argues that the involvement of nursing anesthesia is appropriate and within the scope of practice. Few other healthcare disciplines can provide the patient care and empirical knowledge that is imperative in the care of the dying patient. This article discusses the concept and ethics of palliative sedation and presents a case of providing palliative sedation to a terminally ill patient by an experienced nurse anesthetist. Palliative sedation should be understood, embraced, and utilized as an area of expertise suited for nursing anesthesia.

  16. Flashback resistant pre-mixer assembly

    Science.gov (United States)

    Laster, Walter R [Oviedo, FL; Gambacorta, Domenico [Oviedo, FL

    2012-02-14

    A pre-mixer assembly associated with a fuel supply system for mixing of air and fuel upstream from a main combustion zone in a gas turbine engine. The pre-mixer assembly includes a swirler assembly disposed about a fuel injector of the fuel supply system and a pre-mixer transition member. The swirler assembly includes a forward end defining an air inlet and an opposed aft end. The pre-mixer transition member has a forward end affixed to the aft end of the swirler assembly and an opposed aft end defining an outlet of the pre-mixer assembly. The aft end of the pre-mixer transition member is spaced from a base plate such that a gap is formed between the aft end of the pre-mixer transition member and the base plate for permitting a flow of purge air therethrough to increase a velocity of the air/fuel mixture exiting the pre-mixer assembly.

  17. An experimental and kinetic modeling study of premixed nitromethane flames at low pressure

    DEFF Research Database (Denmark)

    Zhang, Kuiwen; Li, Yuyang; Yuan, Tao

    2011-01-01

    An experimental and modeling study is reported on three premixed nitromethane/oxygen/argon flames at low pressure (4.655kPa) with equivalence ratios (ϕ) of 1.0, 1.5 and 2.0. Flame species were identified with tunable synchrotron vacuum ultraviolet photoionization. The mole fraction profiles of more...

  18. Palliative Sedation at Home

    Science.gov (United States)

    Barathi, B

    2012-01-01

    Patients with advanced cancer often suffer from multiple intractable physical symptoms. Though majority of the symptoms can be controlled, in some of the patients these symptoms remain refractory and uncontrolled till the end. Palliative sedation (PS) is one of the ways to relieve intractable suffering of the dying cancer patients. The main concern while using PS is its life-shortening effect. This case report describes the feasibility of administering PS in Indian home settings. PMID:22837615

  19. Palliative sedation at home

    Directory of Open Access Journals (Sweden)

    B Barathi

    2015-04-01

    Full Text Available Patients with advanced cancer often suffer from multiple intractable physical symptoms. Though majority of the symptoms can be controlled, in some of the patients these symptoms remain refractory and uncontrolled till the end. Palliative sedation (PS is one of the ways to relieve intractable suffering of the dying cancer patients. The main concern while using PS is its life-shortening effect. This case report describes the feasibility of administering PS in Indian home settings.

  20. On the regimes of premixing

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, S.; Theofanous, T.G.; Yuen, W.W. [California Univ., Santa Barbara, CA (United States). Center for Risk Studies and Safety

    1998-01-01

    The conditions of the MAGICO-2000 experiment are extended to more broadly investigate the regimes of premixing, and the corresponding internal structures of mixing zones. With the help of the data and numerical simulations using the computer code PM-ALPHA, we can distinguish extremes of behavior dominated by inertia and thermal effects - we name these the inertia and thermal regimes, respectively. This is an important distinction that should guide future experiments aimed at code verification in this area. Interesting intermediate behaviors are also delineated and discussed. (author)

  1. Current sedation and monitoring practice for colonoscopy: an International Observational Study (EPAGE)

    DEFF Research Database (Denmark)

    Froehlich, F; Harris, JK; Wietlisbach, V

    2006-01-01

    centers. Oxygen desaturation (LT /= 85 %) occurred in 5 % of patients, of whom 80 % were moderately sedated. On average, three staff members were involved in procedures. An anesthesiologist was present during 27 % of colonoscopies, and during 85 % of colonoscopies using deep sedation. CONCLUSIONS...

  2. A Review of Palliative Sedation.

    Science.gov (United States)

    Bobb, Barton

    2016-09-01

    Palliative sedation has become a standard practice to treat refractory symptoms at end-of-life. Dyspnea and delirium are the two most commonly treated symptoms. The medications used in palliative sedation are usually benzodiazepines, barbiturates, antipsychotics, and/or anesthetics. Some ethical considerations remain, especially surrounding the use of palliative sedation in psychological distress and existential suffering. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Therapeutics and Sedation in Dentistry

    OpenAIRE

    Young, Earle R.

    1988-01-01

    Sedation can help to overcome the fear that prevents many Canadians from accepting dental treatment. This article discusses the indications and contraindications for oral, intramuscular, and inhalation sedation as used by the general dental practitioner for both adult and child patients, with a note on the growing number of specialist dental anesthetists who provide intravenous out-patient sedation. Local anesthesia is discussed with reference to allergic reactions, malignant hyperthermia, an...

  4. Computational aspects of premixing modelling

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, D.F. [Sydney Univ., NSW (Australia). Dept. of Chemical Engineering; Witt, P.J.

    1998-01-01

    In the steam explosion research field there is currently considerable effort being devoted to the modelling of premixing. Practically all models are based on the multiphase flow equations which treat the mixture as an interpenetrating continuum. Solution of these equations is non-trivial and a wide range of solution procedures are in use. This paper addresses some numerical aspects of this problem. In particular, we examine the effect of the differencing scheme for the convective terms and show that use of hybrid differencing can cause qualitatively wrong solutions in some situations. Calculations are performed for the Oxford tests, the BNL tests, a MAGICO test and to investigate various sensitivities of the solution. In addition, we show that use of a staggered grid can result in a significant error which leads to poor predictions of `melt` front motion. A correction is given which leads to excellent convergence to the analytic solution. Finally, we discuss the issues facing premixing model developers and highlight the fact that model validation is hampered more by the complexity of the process than by numerical issues. (author)

  5. Optimization of Premix Powders for Tableting Use.

    Science.gov (United States)

    Todo, Hiroaki; Sato, Kazuki; Takayama, Kozo; Sugibayashi, Kenji

    2018-05-08

    Direct compression is a popular choice as it provides the simplest way to prepare the tablet. It can be easily adopted when the active pharmaceutical ingredient (API) is unstable in water or to thermal drying. An optimal formulation of preliminary mixed powders (premix powders) is beneficial if prepared in advance for tableting use. The aim of this study was to find the optimal formulation of the premix powders composed of lactose (LAC), cornstarch (CS), and microcrystalline cellulose (MCC) by using statistical techniques. Based on the "Quality by Design" concept, a (3,3)-simplex lattice design consisting of three components, LAC, CS, and MCC was employed to prepare the model premix powders. Response surface method incorporating a thin-plate spline interpolation (RSM-S) was applied for estimation of the optimum premix powders for tableting use. The effect of tablet shape identified by the surface curvature on the optimization was investigated. The optimum premix powder was effective when the premix was applied to a small quantity of API, although the function of premix was limited in the case of the formulation of large amount of API. Statistical techniques are valuable to exploit new functions of well-known materials such as LAC, CS, and MCC.

  6. Palliative Sedation: Reliability and Validity of Sedation Scales

    NARCIS (Netherlands)

    Arevalo Romero, J.; Brinkkemper, T.; van der Heide, A.; Rietjens, J.A.; Ribbe, M.W.; Deliens, L.; Loer, S.A.; Zuurmond, W.W.A.; Perez, R.S.G.M.

    2012-01-01

    Context: Observer-based sedation scales have been used to provide a measurable estimate of the comfort of nonalert patients in palliative sedation. However, their usefulness and appropriateness in this setting has not been demonstrated. Objectives: To study the reliability and validity of

  7. Comparison of propofol deep sedation versus moderate sedation during endosonography.

    Science.gov (United States)

    Nayar, D S; Guthrie, W G; Goodman, A; Lee, Y; Feuerman, M; Scheinberg, L; Gress, F G

    2010-09-01

    The purposes of this study are: (1) to prospectively evaluate clinically relevant outcomes including sedation-related complications for endoscopic ultrasound (EUS) procedures performed with the use of propofol deep sedation administered by monitored anesthesia care (MAC), and (2) to compare these results with a historical case-control cohort of EUS procedures performed using moderate sedation provided by the gastrointestinal (GI) endoscopist. Patients referred for EUS between January 1, 2001 and December 31, 2002 were enrolled. Complication rates for EUS using MAC sedation were observed and also compared with a historical case-control cohort of EUS patients who received meperidine/midazolam for moderate sedation, administered by the GI endoscopist. Logistic regression analysis was used to isolate possible predictors of complications. A total of 1,000 patients underwent EUS with propofol sedation during the period from January 1, 2001 through December 31, 2002 (mean age 64 years, 53% female). The distribution of EUS indications based on the primary area of interest was: 170 gastroduodenal, 92 anorectal, 508 pancreaticohepatobiliary, 183 esophageal, and 47 mediastinal. The primary endpoint of the study was development of sedation-related complications occurring during a performed procedure. A total of six patients experienced complications: duodenal perforation (one), hypotension (one), aspiration pneumonia (one), and apnea requiring endotracheal intubation (three). The complication rate with propofol was 0.60%, compared with 1% for the historical case-control (meperidine/midazolam moderate sedation) group. There does not appear to be a significant difference between complication rates for propofol deep sedation with MAC and meperidine/midazolam administered for moderate sedation.

  8. Palliative sedation: reliability and validity of sedation scales.

    Science.gov (United States)

    Arevalo, Jimmy J; Brinkkemper, Tijn; van der Heide, Agnes; Rietjens, Judith A; Ribbe, Miel; Deliens, Luc; Loer, Stephan A; Zuurmond, Wouter W A; Perez, Roberto S G M

    2012-11-01

    Observer-based sedation scales have been used to provide a measurable estimate of the comfort of nonalert patients in palliative sedation. However, their usefulness and appropriateness in this setting has not been demonstrated. To study the reliability and validity of observer-based sedation scales in palliative sedation. A prospective evaluation of 54 patients under intermittent or continuous sedation with four sedation scales was performed by 52 nurses. Included scales were the Minnesota Sedation Assessment Tool (MSAT), Richmond Agitation-Sedation Scale (RASS), Vancouver Interaction and Calmness Scale (VICS), and a sedation score proposed in the Guideline for Palliative Sedation of the Royal Dutch Medical Association (KNMG). Inter-rater reliability was tested with the intraclass correlation coefficient (ICC) and Cohen's kappa coefficient. Correlations between the scales using Spearman's rho tested concurrent validity. We also examined construct, discriminative, and evaluative validity. In addition, nurses completed a user-friendliness survey. Overall moderate to high inter-rater reliability was found for the VICS interaction subscale (ICC = 0.85), RASS (ICC = 0.73), and KNMG (ICC = 0.71). The largest correlation between scales was found for the RASS and KNMG (rho = 0.836). All scales showed discriminative and evaluative validity, except for the MSAT motor subscale and VICS calmness subscale. Finally, the RASS was less time consuming, clearer, and easier to use than the MSAT and VICS. The RASS and KNMG scales stand as the most reliable and valid among the evaluated scales. In addition, the RASS was less time consuming, clearer, and easier to use than the MSAT and VICS. Further research is needed to evaluate the impact of the scales on better symptom control and patient comfort. Copyright © 2012 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

  9. Safe sedation in general practice

    African Journals Online (AJOL)

    anxiolysis, amnesia, sedation or pain control? ∙ What will the effect of the drugs be on the airway, spontaneous breathing and cardiovascular system? The patient. As more procedures are performed OOR, the operator has retained the opportunity to evaluate patients pre-operatively. However, the sedation provider usually ...

  10. The impact of a standardised intramuscular sedation protocol for acute behavioural disturbance in the emergency department

    Directory of Open Access Journals (Sweden)

    Downes Michael A

    2010-06-01

    Full Text Available Abstract Background Acute behavioural disturbance (ABD is an increasing problem in emergency departments. This study aimed to determine the impact of a structured intramuscular (IM sedation protocol on the duration of ABD in the emergency department. Methods A historical control study was undertaken comparing 58 patients who required physical restraint and parenteral sedation with the structured IM sedation protocol, to 73 historical controls treated predominantly by intravenous sedation, according to individual clinician preference. The primary outcome was the duration of the ABD defined as the time security staff were required. Secondary outcomes were the requirement for additional sedation, drug related-adverse effects and patient and staff injuries. Results The median duration of the ABD in patients with the new sedation protocol was 21 minutes (IQR: 15 to 35 minutes; Range: 5 to 78 minutes compared to a median duration of 30 minutes (IQR: 15 to 50 minutes; Range: 5 to 135 minutes in the historical controls which was significantly different (p = 0.03. With IM sedation only 27 of 58 patients (47%; 95% CI: 34% to 60% required further sedation compared to 64 of 73 historical controls (88%; 95%CI: 77% to 94%. There were six (10% drug-related adverse events with the new IM protocol [oxygen desaturation (5, oxygen desaturation/airway obstruction (1] compared to 10 (14% in the historical controls [oxygen desaturation (5, hypoventilation (4 and aspiration (1]. Injuries to staff occurred with three patients using the new sedation protocol and in seven of the historical controls. Two patients were injured during the new protocol and two of the historical controls. Conclusion The use of a standardised IM sedation protocol was simple, more effective and as safe for management of ABD compared to predominantly intravenous sedation.

  11. Premixed autoignition in compressible turbulence

    Science.gov (United States)

    Konduri, Aditya; Kolla, Hemanth; Krisman, Alexander; Chen, Jacqueline

    2016-11-01

    Prediction of chemical ignition delay in an autoignition process is critical in combustion systems like compression ignition engines and gas turbines. Often, ignition delay times measured in simple homogeneous experiments or homogeneous calculations are not representative of actual autoignition processes in complex turbulent flows. This is due the presence of turbulent mixing which results in fluctuations in thermodynamic properties as well as chemical composition. In the present study the effect of fluctuations of thermodynamic variables on the ignition delay is quantified with direct numerical simulations of compressible isotropic turbulence. A premixed syngas-air mixture is used to remove the effects of inhomogeneity in the chemical composition. Preliminary results show a significant spatial variation in the ignition delay time. We analyze the topology of autoignition kernels and identify the influence of extreme events resulting from compressibility and intermittency. The dependence of ignition delay time on Reynolds and turbulent Mach numbers is also quantified. Supported by Basic Energy Sciences, Dept of Energy, United States.

  12. Pediatric procedural sedation and analgesia

    Directory of Open Access Journals (Sweden)

    Meredith James

    2008-01-01

    Full Text Available Procedural sedation and analgesia (PSA is an evolving field in pediatric emergency medicine. As new drugs breach the boundaries of anesthesia in the Pediatric Emergency Department, parents, patients, and physicians are finding new and more satisfactory methods of sedation. Short acting, rapid onset agents with little or no lingering effects and improved safety profiles are replacing archaic regimens. This article discusses the warning signs and areas of a patient′s medical history that are particularly pertinent to procedural sedation and the drugs used. The necessary equipment is detailed to provide the groundwork for implementing safe sedation in children. It is important for practitioners to familiarize themselves with a select few of the PSA drugs, rather than the entire list of sedatives. Those agents most relevant to PSA in the pediatric emergency department are presented.

  13. Palliative sedation for intolerable suffering.

    Science.gov (United States)

    Maltoni, Marco; Scarpi, Emanuela; Nanni, Oriana

    2014-07-01

    The purpose of this review is to provide an update on palliative sedation in palliative and end-of-life care. Palliative sedation is the medical procedure used to deal with refractory symptoms in advanced cancer patients when all other specific approaches have failed. Palliative sedation, in the strictest sense of the term, is a proportionate (proportionate palliative sedation, PPS) and intrinsically variable procedure used on an individual basis to relieve refractory symptoms in terminally ill patients, without the intention of hastening death. Completely separate from any other end-of-life decision and not intended to hasten death, palliative sedation has been shown not to have a detrimental impact on survival. To maintain palliative sedation as a legitimate clinical procedure from any ethical or clinical point of view, it must be limited to the restricted area for which it was conceived, that is, relief from refractory suffering as deemed necessary by a patient and by an experienced palliative care team. In this way, there is no risk of associating palliative sedation with other end-of-life decisions. Close collaboration is needed between oncologists and palliative care physicians for this clinical procedure.

  14. Early structure of LPG partially premixed conically stabilized flames

    KAUST Repository

    Elbaz, Ayman M.

    2013-01-01

    This paper presents experimental investigation of LPG partially premixed turbulent flames stabilized within a conical nozzle burner under constant degree of partial premixing. The stability limits and mean flame structure are presented based

  15. Thermal Radiation Properties of Turbulent Lean Premixed Methane Air Flames

    National Research Council Canada - National Science Library

    Ji, Jun; Sivathanu, Y. R; Gore, J. P

    2000-01-01

    ... of turbulent premixed flames. Reduced cooling airflows in lean premixed combustors, miniaturization of combustors, and the possible use of radiation sensors in combustion control schemes are some of the practical reasons...

  16. Optimum Drug Combinations for the Sedation of Growing Boars Prior to Castration

    Science.gov (United States)

    Lehmann, Heidi S.; Blache, Dominique; Drynan, Eleanor; Tshewang, Pema; Blignaut, David J. C.; Musk, Gabrielle C.

    2017-01-01

    Simple Summary Pigs are notoriously challenging patients. They are difficult to handle so the use of predictable and safe sedation techniques is required for husbandry and surgical procedures. Various combinations of sedative and analgesic drugs have been previously investigated in this species, though the combination of midazolam and detomidine with either butorphanol or morphine has not been reported for sedation in pigs. The use of these combinations was investigated in the context of adequate sedation to allow castration of boars with the aid of local anaesthetic infiltration. The combination of midazolam, detomidine with butorphanol provided a more reliable sedation combination than that including morphine. It is proposed that this combination of drugs would be useful for sedation during painful husbandry procedures in pigs. Abstract Juvenile male pigs were sedated for castration. Eight five-month old boars were sedated twice (two weeks apart) with a combination of detomidine (0.1 mg/kg), midazolam (0.2 mg/kg) and either butorphanol (0.2 mg/kg) (Group MDB, n = 8) or morphine (0.2 mg/kg) (Group MDM, n = 8) intramuscularly. The boars were positioned in lateral recumbency and lidocaine (200 mg total) was injected into the testicle and scrotal skin. Castration of a single testicle was performed on two occasions. Sedation and reaction (to positioning and surgery) scores, pulse rate, respiratory rate, haemoglobin oxygen saturation, body temperature, arterial blood gas parameters and the times to immobility and then recovery were recorded. Atipamezole was administered if spontaneous recovery was not evident within 60 min of sedative administration. Data were compared with either a paired-sample t-test or a Wilcoxon-Signed Rank Test. There was no difference in sedation score, body temperature, respiratory rate and haemoglobin oxygen saturation between MDB and MDM. Mild hypoxaemia was noted in both groups. There was less reaction to castration after MDB. The pulse rate

  17. Intranasal sedatives in pediatric dentistry

    Science.gov (United States)

    AlSarheed, Maha A.

    2016-01-01

    Objectives: To identify the intranasal (IN) sedatives used to achieve conscious sedation during dental procedures amongst children. Methods: A literature review was conducted by identifying relevant studies through searches on Medline. Search included IN of midazolam, ketamine, sufentanil, dexmedetomidine, clonidine, haloperidol and loranzepam. Studies included were conducted amongst individuals below 18 years, published in English, and were not restricted by year. Exclusion criteria were articles that did not focus on pediatric dentistry. Results: Twenty studies were included. The most commonly used sedatives were midazolam, followed by ketamine and sufentanil. Onset of action for IN midazolam was 5-15 minutes (min), however, IN ketamine was faster (mean 5.74 min), while both IN sufentanil (mean 20 min) and IN dexmedetomidine (mean 25 min) were slow in comparison. Midazolam was effective for modifying behavior in mild to moderately anxious children, however, for more invasive or prolonged procedures, stronger sedatives, such as IN ketamine, IN sufentanil were recommended. In addition, ketamine fared better in overall success rate (89%) when compared with IN midazolam (69%). Intranasal dexmedetomidine was only used as pre-medication amongst children. While its’ onset of action is longer when compared with IN midazolam, it produced deeper sedation at the time of separation from the parent and at the time of anesthesia induction. Conclusion: Intranasal midazolam, ketamine and sufentanil are effective and safe for conscious sedation, while intranasal midazolam, dexmedetomidine and sufentanil have proven to be effective premedications. PMID:27570849

  18. A retrospective study of deep sedation with concomitant administration of sedative agents in children undergoing surgical removal of a mesiodens.

    Science.gov (United States)

    Lee, Soo Jeong; Baek, Kwangwoo

    2015-12-01

    Pediatric dentists face challenges when young patients require a mesiodens extraction. General anesthesia may be a burden to the child as well as the parent due to dental fears and costs. The aim of this study was to evaluate oral and intravenous sedation in the outpatient setting as a safe and effective means of managing patients who require a mesiodens extraction. Records were reviewed retrospectively to find patients who underwent a mesiodens removal procedure from January 2013 to September 2014 in the Department of Pediatric Dentistry at Ajou University Hospital (Suwon, Gyeonggi-do, Republic of Korea). A total of 81 patients (62 male and 19 female) between 4 and 11 years of age (mean [± SD] 81.6 ± 14.1 months) were studied, with a mean weight of 22.9 ± 3.3 kg (16 kg to 30 kg). Vital signs, sedation drug dosage, and sedation time were studied. Mean doses of 63.7 ± 2.5 mg/kg chloral hydrate and 1.36 ± 0.22 mg/kg hydroxyzine were used for oral sedation. Nitrous oxide/oxygen was administrated for 40.0 ± 2.1 min. The mean dose of midazolam administered intravenously was 0.14 ± 0.06 mg/kg (2.38 ± 0.97 times). In all cases, the mesiodens was removed successfully. Intravenous sedation combined with oral sedation and nitrous oxide/oxygen inhalation can be an alternative to general anesthesia when administrated and monitored properly.

  19. Colorimetric determination of selenium in mineral premixes .

    Science.gov (United States)

    Hurlbut, J A; Burkepile, R G; Geisler, C A; Kijak, P J; Rummel, N G

    1997-01-01

    A method is described for determination of sodium selenite or sodium selenate in mineral-based premixes. It is based on the formation of intense-yellow piazselenol by Se(IV) and 3,3'-diaminobenzidine. Mineral premixes typically contain calcium carbonate as a base material and magnesium carbonate, silicon dioxide, and iron(III) oxide as minor components or additives. In this method, the premix is digested briefly in nitric acid, diluted with water, and filtered to remove any Iron(III) oxide. Ethylenediaminetetraacetic acid and HCl are added to the filtrate, which is heated to near boiling for 1 h to convert any selenate to selenite. After heating, the solution is buffered between pH 2 and 3 with NaOH and formic acid and treated with NH2OH and EDTA; any Se present forms a complex with 3,3'-diaminobenzidine at 60 degrees C. The solution is made basic with NH4OH, and the piazselenol is extracted into toluene. The absorbance of the complex in dried toluene is measured at 420 nm. The method was validated independently by 2 laboratories. Samples analyzed included calcium carbonate fortified with 100, 200, and 300 micrograms Se in the form of sodium selenite or sodium selenate, a calcium carbonate premix containing sodium selenite, a calcium carbonate premix containing sodium selenate, and a commercial premix; 5 replicates of each sample type were analyzed by each laboratory. Average recoveries ranged from 89 to 109% with coefficients of variation from 1.2 to 13.6%.

  20. Chaos in an imperfectly premixed model combustor.

    Science.gov (United States)

    Kabiraj, Lipika; Saurabh, Aditya; Karimi, Nader; Sailor, Anna; Mastorakos, Epaminondas; Dowling, Ann P; Paschereit, Christian O

    2015-02-01

    This article reports nonlinear bifurcations observed in a laboratory scale, turbulent combustor operating under imperfectly premixed mode with global equivalence ratio as the control parameter. The results indicate that the dynamics of thermoacoustic instability correspond to quasi-periodic bifurcation to low-dimensional, deterministic chaos, a route that is common to a variety of dissipative nonlinear systems. The results support the recent identification of bifurcation scenarios in a laminar premixed flame combustor (Kabiraj et al., Chaos: Interdiscip. J. Nonlinear Sci. 22, 023129 (2012)) and extend the observation to a practically relevant combustor configuration.

  1. Anxiety in Children Undergoing VCUG: Sedation or No Sedation?

    Directory of Open Access Journals (Sweden)

    David W. Herd

    2008-01-01

    Full Text Available Background. Voiding cystourethrograms are distressing for children and parents. Nonpharmacological methods reduce distress. Pharmacological interventions for VCUG focus on sedation as well as analgesia, anxiolysis, and amnesia. Sedation has cost, time, and safety issues. Which agents and route should we use? Are we sure that sedation does not influence the ability to diagnose vesicoureteric reflux? Methods. Literature search of Medline, EMBASE, and the Cochrane Database. Review of comparative studies found. Results. Seven comparative studies including two randomised controlled trials were reviewed. Midazolam given orally (0.5-0.6 mg/kg or intranasally (0.2 mg/kg is effective with no apparent effect on voiding dynamics. Insufficient evidence to recommend other sedating agents was found. Deeper sedating agents may interfere with voiding dynamics. Conclusion. Midazolam reduces the VCUG distress, causes amnesia, and does not appear to interfere with voiding dynamics. Midazolam combined with simple analgesia is an effective method to reduce distress to children undergoing VCUG.

  2. Factors associated with patient-reported procedural memory following emergency department procedural sedation with ketamine and propofol: A prospective cohort of 563 patients.

    Science.gov (United States)

    Greer, Andrew; Treston, Greg

    2018-04-01

    To describe the proportion of patients reporting procedural memory following procedural sedation and analgesia (PSA) with ketamine and propofol (KP) administered premixed together (ketofol) or individually (sequential KP) in ED attendees. Identify any clinical or demographic variables associated with procedural memory. This was a convenience sample of 563 patients who received KP PSA as per the departmental protocol. A standardised script was used to assess for procedural memory. This was categorised as 'any' and 'unpleasant' prior to discharge (immediate memory) and at telephone follow up (delayed memory). A total of 318 patients had sequential KP and 249 premixed 1:1 ketofol. For sequential KP compared to ketofol, the proportion reporting any memory was as follows: 3.5% versus 3.3% immediate, 4.4% versus 5.5% delayed and 5.4% versus 7.4% for the sum of these. For unpleasant memory, the proportion was as follows: 1.6% versus 2.9% immediate, 1.7% versus 4.7% delayed and 2.2% versus 6.9% all unpleasant memory (odds ratio [OR] 3.3, 95% confidence interval [CI] 1.4-8.1). Memory was associated with male sex (OR 4, 95% CI 1.5-10.5), opiates (OR 3, 95% CI 1.7-7.5), a Wisconsin Sedation Scale score ≥3 (moderate sedation) (OR 4.3, 95% CI 1.1-18.2) and propofol dose 0.75 mg/kg (13% versus 3%) (OR 6, 95% CI 1.7-21). The ketofol group had 5% (95% CI 0.1-10) more respiratory events requiring intervention. Procedural memory was uncommon for both mix types; however, a greater proportion of the premixed ketofol group had unpleasant memory. Associations with sex, opiates, moderate sedation and propofol dose were identified, and respiratory adverse events were more common in the premixed ketofol group. © 2017 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  3. Intravenous ketamine is as effective as midazolam/fentanyl for procedural sedation and analgesia in the emergency department.

    Science.gov (United States)

    Jamal, S M; Fathil, S M; Nidzwani, M M; Ismail, A K; Yatim, F M

    2011-08-01

    The study compared the effectiveness of ketamine and midazolam/fentanyl as procedural sedation and analgesia agents for reduction of fractures and dislocated joints. Forty-one adult patients were enrolled by convenience sampling. They were randomized to receive ketamine or midazolam/fentanyl. Depth of sedation, pain score, procedural outcome and memory of the procedure were documented. The ketamine group had deeper sedation, but there was no statistical difference in other variables between the two groups. Three patients in the midazolam/fentanyl group had oxygen desaturation. More adverse effects were associated with ketamine. Intravenous ketamine is as effective as midazolam/fentanyl for procedural sedation.

  4. Cognitive Effects and Sedation.

    Science.gov (United States)

    Dhingra, Lara; Ahmed, Ebtesam; Shin, Jae; Scharaga, Elyssa; Magun, Maximilian

    2015-10-01

    Cognitive effects and sedation (CES) are prevalent in chronic nonmalignant pain populations receiving long-term opioid therapy and are among the most common reasons patients discontinue opioid use. In this narrative review, we describe the phenomenology, epidemiology, mechanisms, assessment, and management of opioid-related CES. We reviewed the empirical and theoretical literature on CES in opioid-treated populations with chronic pain. Data on long-term opioid therapy (≥ 3 months in duration) in chronic nonmalignant pain patients were sought. The phenomenology of CES includes: inattention, concentration difficulties, memory deficits, psychomotor dysfunction, perceptual distortions, and executive dysfunction and somnolence, sleep disorders, and lethargy. Deficits may be caused by unrelieved pain or opioid therapy alone, or from a combination of these and other factors. Mechanisms include central nervous system effects, for example, direct toxic effects on neurons resulting in decreased consciousness; direct effects on processing and reaction resulting in cognitive or psychomotor impairment, and inhibitory effects on cholinergic activity. Pharmacological management approaches may include opioid dose reduction and rotation or psychostimulant use. Nonpharmacological approaches may include cognitive-behavioral therapy, mindfulness-based stress reduction, acupuncture, exercise, and yoga. The most prevalent CES include: memory deficits (73-81%), sleep disturbance (35-57%), and fatigue (10%). At its most severe, extreme cognitive dysfunction can result in frank delirium and decreased alertness can result in coma. Emotional distress, sleep disorders, and other comorbidities and treatments can worsen CES, particularly among the elderly. Conclusions about the neuropsychological domains affected by opioids are limited due to the heterogeneity of studies and methodological issues. Wiley Periodicals, Inc.

  5. No-sedation during mechanical ventilation

    DEFF Research Database (Denmark)

    Laerkner, Eva; Stroem, Thomas; Toft, Palle

    2016-01-01

    BACKGROUND: Evidence is growing that less or no-sedation is possible and beneficial for patients during mechanical ventilation. AIM: To investigate if there was a difference in patient consciousness and nursing workload comparing a group of patients receiving no-sedation with a group of sedated...... patients with daily wake up, and also to estimate economic consequences of a no-sedation strategy. DESIGN AND METHODS: Data were collected during a prospective trial of 140 mechanically ventilated patients randomized to either no-sedation or to sedation with daily wake up. From day 1 to 7 in the intensive...

  6. Sedation and Anesthesia in Pediatric and Congenital Cardiac Catheterization: A Prospective Multicenter Experience.

    Science.gov (United States)

    Lin, C Huie; Desai, Sanyukta; Nicolas, Ramzi; Gauvreau, Kimberlee; Foerster, Susan; Sharma, Anshuman; Armsby, Laurie; Marshall, Audrey C; Odegard, Kirsten; DiNardo, James; Vincent, Julie; El-Said, Howaida; Spaeth, James; Goldstein, Bryan; Holzer, Ralf; Kreutzer, Jackie; Balzer, David; Bergersen, Lisa

    2015-10-01

    Sedation/anesthesia is critical to cardiac catheterization in the pediatric/congenital heart patient. We sought to identify current sedation/anesthesia practices, the serious adverse event rate related to airway, sedation, or anesthesia, and the rate of intra-procedural conversion from procedural sedation to the use of assisted ventilation or an artificial airway. Data from 13,611 patients who underwent catheterization at eight institutions were prospectively collected from 2007 to 2010. Ninety-four (0.69 %) serious sedation/airway-related adverse events occurred; events were more likely to occur in smaller patients (anesthesia, LMA, or tracheostomy, whereas 4232 (31 %) were managed with procedural sedation without an artificial airway, of which 75 (1.77 %) patients were converted to assisted ventilation/general anesthesia. Young age (risk procedure (category 4, OR 10.1, 95 % CI 6.5-15.6, p pediatric/congenital patients was associated with a low rate of serious sedation/airway-related adverse events. Smaller patients with non-cardiac comorbidities or low mixed venous oxygen saturation may be at higher risk. Patients under 1 year of age, undergoing high-risk procedures, or requiring continuous pressor/inotrope support may be at higher risk of requiring conversion from procedural sedation to assisted ventilation/general anesthesia.

  7. Simulation of lean premixed turbulent combustion

    International Nuclear Information System (INIS)

    Bell, J; Day, M; Almgren, A; Lijewski, M; Rendleman, C; Cheng, R; Shepherd, I

    2006-01-01

    There is considerable technological interest in developing new fuel-flexible combustion systems that can burn fuels such as hydrogen or syngas. Lean premixed systems have the potential to burn these types of fuels with high efficiency and low NOx emissions due to reduced burnt gas temperatures. Although traditional Scientific approaches based on theory and laboratory experiment have played essential roles in developing our current understanding of premixed combustion, they are unable to meet the challenges of designing fuel-flexible lean premixed combustion devices. Computation, with its ability to deal with complexity and its unlimited access to data, has the potential for addressing these challenges. Realizing this potential requires the ability to perform high fidelity simulations of turbulent lean premixed flames under realistic conditions. In this paper, we examine the specialized mathematical structure of these combustion problems and discuss simulation approaches that exploit this structure. Using these ideas we can dramatically reduce computational cost, making it possible to perform high-fidelity simulations of realistic flames. We illustrate this methodology by considering ultra-lean hydrogen flames and discuss how this type of simulation is changing the way researchers study combustion

  8. Premixed combustion on ceramic foam burners

    NARCIS (Netherlands)

    Bouma, P.H.; Goey, de L.P.H.

    1999-01-01

    Combustion of a lean premixed methane–air mixture stabilized on a ceramic foam burner has been studied. The stabilization of the flame in the radiant mode has been simulated using a one-dimensional numerical model for a burner stabilized flat-flame, taking into account the heat transfer between the

  9. Capnography monitoring during procedural sedation and analgesia: a systematic review protocol

    OpenAIRE

    Conway, Aaron; Douglas, Clint; Sutherland, Joanna

    2015-01-01

    Background An important potential clinical benefit of using capnography monitoring during procedural sedation and analgesia (PSA) is that this technology could improve patient safety by reducing serious sedation-related adverse events, such as death or permanent neurological disability, which are caused by inadequate oxygenation. The hypothesis is that earlier identification of respiratory depression using capnography leads to a change in clinical management that prevents hypoxaemia. As inade...

  10. Sedation with alfentanil and propofol for rhizotomies

    African Journals Online (AJOL)

    M Jansen van Rensburg

    Deep sedation can be avoided by maximising analgesia, and keeping patients ..... sedation and memory effects of propofol, midazolam, isoflurane, and alfentanil in healthy ... electroencephalogram predicts conscious processing of information.

  11. The impact of obesity on pediatric procedural sedation-related outcomes: results from the Pediatric Sedation Research Consortium.

    Science.gov (United States)

    Scherrer, Patricia D; Mallory, Michael D; Cravero, Joseph P; Lowrie, Lia; Hertzog, James H; Berkenbosch, John W

    2015-07-01

    To evaluate the impact of obesity on adverse events and required interventions during pediatric procedural sedation. The Pediatric Sedation Research Consortium database of prospectively collected procedural sedation encounters was queried to identify patients for whom body mass index (BMI) could be calculated. Obesity was defined as BMI ≥95th percentile for age and gender. Sedation-related outcomes, adverse events, and therapeutic interventions were compared between obese and nonobese patients. For analysis, 28,792 records were eligible. A total of 5,153 patients (17.9%) were obese; they were predominantly male and older and had a higher median American Society of Anesthesiologists Physical Status classification (P obese patients (odds ratio [OR] 1.49, 95% confidence interval [1.31, 1.70]). Respiratory events (airway obstruction OR 1.94 [1.54, 2.44], oxygen desaturation OR 1.99 [1.50, 2.63], secretions OR 1.48 [1.01, 2.15], laryngospasm OR 2.30 [1.30, 4.05]), inability to complete the associated procedure (OR 1.96 [1.16, 3.30]), and prolonged recovery (OR 2.66 [1.26, 5.59]) were increased in obese patients. Obese patients more frequently required airway intervention including repositioning, suctioning, jaw thrust, airway adjuncts, and bag-valve-mask ventilation. Multivariate regression analysis demonstrated obesity to be independently associated with minor and moderate but not major adverse events. Obesity is an independent risk factor for adverse respiratory events during procedural sedation and is associated with an increased frequency of airway interventions, suggesting that additional vigilance and expertise are required when sedating these patients. © 2015 John Wiley & Sons Ltd.

  12. Administration order of midazolam/fentanyl for moderate dental sedation.

    Science.gov (United States)

    Lobb, Douglas; Clarke, Alix; Lai, Hollis

    2018-02-01

    The purpose of this study is to investigate the effects of administration order when a sedative drug (midazolam) and an opioid analgesic drug (fentanyl) is applied for moderate intravenous (IV) sedation in dentistry. A retrospective chart review was conducted in one dental clinic during its transition from a midazolam-first to a fentanyl-first protocol for dental procedures requiring moderate IV sedation. Physiological parameters, drug administration times, patient recovery times, drug dosages, and patient recall and satisfaction were investigated for differences. A total of 76 charts (40 midazolam-first and 36 fentanyl-first administrations), were used in the analysis. Administering midazolam first resulted in an average 4.38 min (52%) decrease in administration times (P 0.05). Oxygen saturation levels did not drop below 90% for either group; however, 5 cases in the fentanyl-first group fell to between 90% and 92%, compared with 0 cases in the midazolam-first group. The administration order of fentanyl and midazolam may have different effects on patients and the sedation procedure. Findings from this study should be used to facilitate discussion among dental practitioners and to guide additional research investigating this topic.

  13. Sedating children in South Africa

    African Journals Online (AJOL)

    bRed Cross War Memorial Children's Hospital, Cape Town, South Africa. cSedation and Pain ... As the authors indicate, there is increasing pressure from practitioners, funders and patients or parents for procedures to take place outside the ...

  14. Pembakaran Premixed Minyak Nabati Pada Bunsen Burner Type Silinder

    OpenAIRE

    La Muhaya, Syamsul Bahri; Wardana, ING; Widhiyanuriyawan, Denny

    2015-01-01

    In the premixed combustion wave propagation combustion occurs is called the flame front. Premixed flame will propagate at the speed of moving towards the reactants unique. If the speed of the reactants is equal to the speed of propagation of fire, the fire (reaction zone) will be stationary. It is necessary to follow up on the influence of equivalence ratio (φ) varied with laminar flame speed (SL) in the premixed combustion of vegetable oil (virgin coconut oil, jatropha and cotton seeds). Res...

  15. Conscious sedation for endoscopic and non-endoscopic interventional gastrointestinal procedures: meeting patients' expectations, missing the standard

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, P.; Laasch, H.-U.; Wilbraham, L.; Marriott, A.; England, R.E.; Martin, D.F. E-mail: derrick.martin@smtr.nhs.uk

    2004-02-01

    AIM: To assess the level of sedation, patient satisfaction and frequency of unplanned events with conscious sedation for interventional procedures. MATERIALS AND METHODS: One hundred and seventeen patients were assessed prospectively before, during and after procedures. Blood pressure, pulse, oxygen saturation and sedation level were monitored and patients followed up after 24 h. Sedation was scored after drugs were given in accordance with an established protocol. Doses were recorded, as were patients' weight, age and ASA grade and any unplanned events and their management. RESULTS: Seventy-six of the 117 patients (65%) had no unplanned event, 20 (17.1%) became agitated, 15 (12.8%) hypotensive, three (2.6%) hypoxic and three (2.6%) had more than one response. Twelve patients required active management. Fifty-two (44.4%) had a sedation level of {<=}3 (responsive to verbal commands), but 39 (33.3%) reached level 6. Median doses were midazolam 6 mg (1-20 mg) and pethidine 50 mg (12.5-100 mg). Ninety-three percent were satisfied with their sedation. No adverse effects were observed after 24 h. CONCLUSION: Despite using a sedation protocol, unplanned events occurred in 35% (95% CI=27-44%) of patients, although not all required active management. The sedation levels reached in some exceeded guidelines. Unplanned events were commoner with increased sedation level. Patient satisfaction was high and no permanent damage was observed.

  16. Conscious sedation for endoscopic and non-endoscopic interventional gastrointestinal procedures: meeting patients' expectations, missing the standard

    International Nuclear Information System (INIS)

    Marriott, P.; Laasch, H.-U.; Wilbraham, L.; Marriott, A.; England, R.E.; Martin, D.F.

    2004-01-01

    AIM: To assess the level of sedation, patient satisfaction and frequency of unplanned events with conscious sedation for interventional procedures. MATERIALS AND METHODS: One hundred and seventeen patients were assessed prospectively before, during and after procedures. Blood pressure, pulse, oxygen saturation and sedation level were monitored and patients followed up after 24 h. Sedation was scored after drugs were given in accordance with an established protocol. Doses were recorded, as were patients' weight, age and ASA grade and any unplanned events and their management. RESULTS: Seventy-six of the 117 patients (65%) had no unplanned event, 20 (17.1%) became agitated, 15 (12.8%) hypotensive, three (2.6%) hypoxic and three (2.6%) had more than one response. Twelve patients required active management. Fifty-two (44.4%) had a sedation level of ≤3 (responsive to verbal commands), but 39 (33.3%) reached level 6. Median doses were midazolam 6 mg (1-20 mg) and pethidine 50 mg (12.5-100 mg). Ninety-three percent were satisfied with their sedation. No adverse effects were observed after 24 h. CONCLUSION: Despite using a sedation protocol, unplanned events occurred in 35% (95% CI=27-44%) of patients, although not all required active management. The sedation levels reached in some exceeded guidelines. Unplanned events were commoner with increased sedation level. Patient satisfaction was high and no permanent damage was observed

  17. Gravity Effects Observed In Partially Premixed Flames

    Science.gov (United States)

    Puri, Ishwar K.; Aggarwal, Suresh K.; Lock, Andrew J.; Gauguly, Ranjan; Hegde, Uday

    2003-01-01

    Partially premixed flames (PPFs) contain a rich premixed fuel air mixture in a pocket or stream, and, for complete combustion to occur, they require the transport of oxidizer from an appropriately oxidizer-rich (or fuel-lean) mixture that is present in another pocket or stream. Partial oxidation reactions occur in fuel-rich portions of the mixture and any remaining unburned fuel and/or intermediate species are consumed in the oxidizer-rich portions. Partial premixing, therefore, represents that condition when the equivalence ratio (phi) in one portion of the flowfield is greater than unity, and in another section its value is less than unity. In general, for combustion to occur efficiently, the global equivalence ratio is in the range fuel-lean to stoichiometric. These flames can be established by design by placing a fuel-rich mixture in contact with a fuel-lean mixture, but they also occur otherwise in many practical systems, which include nonpremixed lifted flames, turbulent nonpremixed combustion, spray flames, and unwanted fires. Other practical applications of PPFs are reported elsewhere. Although extensive experimental studies have been conducted on premixed and nonpremixed flames under microgravity, there is a absence of previous experimental work on burner stabilized PPFs in this regard. Previous numerical studies by our group employing a detailed numerical model showed gravity effects to be significant on the PPF structure. We report on the results of microgravity experiments conducted on two-dimensional (established on a Wolfhard-Parker slot burner) and axisymmetric flames (on a coannular burner) that were investigated in a self-contained multipurpose rig. Thermocouple and radiometer data were also used to characterize the thermal transport in the flame.

  18. Comparative study of non-premixed and partially-premixed combustion simulations in a realistic Tay model combustor

    OpenAIRE

    Zhang, K.; Ghobadian, A.; Nouri, J. M.

    2017-01-01

    A comparative study of two combustion models based on non-premixed assumption and partially premixed assumptions using the overall models of Zimont Turbulent Flame Speed Closure Method (ZTFSC) and Extended Coherent Flamelet Method (ECFM) are conducted through Reynolds stress turbulence modelling of Tay model gas turbine combustor for the first time. The Tay model combustor retains all essential features of a realistic gas turbine combustor. It is seen that the non-premixed combustion model fa...

  19. Sedation and monitoring for gastrointestinal endoscopy.

    Science.gov (United States)

    Amornyotin, Somchai

    2013-02-16

    The safe sedation of patients for diagnostic or therapeutic procedures requires a combination of properly trained physicians and suitable facilities. Additionally, appropriate selection and preparation of patients, suitable sedative technique, application of drugs, adequate monitoring, and proper recovery of patients is essential. The goal of procedural sedation is the safe and effective control of pain and anxiety as well as to provide an appropriate degree of memory loss or decreased awareness. Sedation practices for gastrointestinal endoscopy (GIE) vary widely. The majority of GIE patients are ambulatory cases. Most of this procedure requires a short time. So, short acting, rapid onset drugs with little adverse effects and improved safety profiles are commonly used. The present review focuses on commonly used regimens and monitoring practices in GIE sedation. This article is to discuss the decision making process used to determine appropriate pre-sedation assessment, monitoring, drug selection, dose of sedative agents, sedation endpoint and post-sedation care. It also reviews the current status of sedation and monitoring for GIE procedures in Thailand.

  20. Palliative sedation and ethical dilemma

    Directory of Open Access Journals (Sweden)

    Juri Salamah

    2018-01-01

    Full Text Available Palliative sedation is a unique concern for the patient as well as the family. It is a difficult serious ethical dilemma for the physicians to handle. The conflicting ethical principles of autonomy, beneficence and nonmaleficence in continuing versus discontinuing all supportive devices raise concerns among health professionals whether this is euthanasia (physician-assisted suicide or is just prolonging the patient's unnecessary suffering.

  1. Quantification of extinction mechanism in counterflow premixed flames

    KAUST Repository

    Choi, Sangkyu; Cho, Eunseong; Chung, Suk-Ho

    2014-01-01

    The extinction mechanisms of stretched premixed flames have been investigated numerically for the fuels of CH4, C3H8, H2, CO and for the mixture fuels of CH4+H2 and CO+H2 by adopting symmetric double premixed flames in a counterflow configuration

  2. Sedation-related complications in gastrointestinal endoscopy

    OpenAIRE

    Amornyotin, Somchai

    2013-01-01

    Sedation practices for gastrointestinal endoscopic (GIE) procedures vary widely in different countries depending on health system regulations and local circumstances. The goal of procedural sedation is the safe and effective control of pain and anxiety, as well as to provide an appropriate degree of memory loss or decreased awareness. Sedation-related complications in gastrointestinal endoscopy, once occurred, can lead to significant morbidity and occasional mortality in patients. The risk fa...

  3. Sedation and monitoring for gastrointestinal endoscopy

    OpenAIRE

    Amornyotin, Somchai

    2013-01-01

    The safe sedation of patients for diagnostic or therapeutic procedures requires a combination of properly trained physicians and suitable facilities. Additionally, appropriate selection and preparation of patients, suitable sedative technique, application of drugs, adequate monitoring, and proper recovery of patients is essential. The goal of procedural sedation is the safe and effective control of pain and anxiety as well as to provide an appropriate degree of memory loss or decreased awaren...

  4. Pediatric dental sedation: challenges and opportunities

    OpenAIRE

    Nelson, Travis; Xu,Zheng

    2015-01-01

    Travis M Nelson, Zheng Xu Department of Pediatric Dentistry, University of Washington, Seattle, WA, USA Abstract: High levels of dental caries, challenging child behavior, and parent expectations support a need for sedation in pediatric dentistry. This paper reviews modern developments in pediatric sedation with a focus on implementing techniques to enhance success and patient safety. In recent years, sedation for dental procedures has been implicated in a disproportionate number of cases th...

  5. Pediatric dental sedation: challenges and opportunities

    Directory of Open Access Journals (Sweden)

    Nelson TM

    2015-08-01

    Full Text Available Travis M Nelson, Zheng Xu Department of Pediatric Dentistry, University of Washington, Seattle, WA, USA Abstract: High levels of dental caries, challenging child behavior, and parent expectations support a need for sedation in pediatric dentistry. This paper reviews modern developments in pediatric sedation with a focus on implementing techniques to enhance success and patient safety. In recent years, sedation for dental procedures has been implicated in a disproportionate number of cases that resulted in death or permanent neurologic damage. The youngest children and those with more complicated medical backgrounds appear to be at greatest risk. To reduce complications, practitioners and regulatory bodies have supported a renewed focus on health care quality and safety. Implementation of high fidelity simulation training and improvements in patient monitoring, including end-tidal carbon dioxide, are becoming recognized as a new standard for sedated patients in dental offices and health care facilities. Safe and appropriate case selection and appropriate dosing for overweight children is also paramount. Oral sedation has been the mainstay of pediatric dental sedation; however, today practitioners are administering modern drugs in new ways with high levels of success. Employing contemporary transmucosal administration devices increases patient acceptance and sedation predictability. While recently there have been many positive developments in sedation technology, it is now thought that medications used in sedation and anesthesia may have adverse effects on the developing brain. The evidence for this is not definitive, but we suggest that practitioners recognize this developing area and counsel patients accordingly. Finally, there is a clear trend of increased use of ambulatory anesthesia services for pediatric dentistry. Today, parents and practitioners have become accustomed to children receiving general anesthesia in the outpatient setting. As a

  6. Sedation-related complications in gastrointestinal endoscopy.

    Science.gov (United States)

    Amornyotin, Somchai

    2013-11-16

    Sedation practices for gastrointestinal endoscopic (GIE) procedures vary widely in different countries depending on health system regulations and local circumstances. The goal of procedural sedation is the safe and effective control of pain and anxiety, as well as to provide an appropriate degree of memory loss or decreased awareness. Sedation-related complications in gastrointestinal endoscopy, once occurred, can lead to significant morbidity and occasional mortality in patients. The risk factors of these complications include the type, dose and mode of administration of sedative agents, as well as the patient's age and underlying medical diseases. Complications attributed to moderate and deep sedation levels are more often associated with cardiovascular and respiratory systems. However, sedation-related complications during GIE procedures are commonly transient and of a mild degree. The risk for these complications while providing any level of sedation is greatest when caring for patients already medically compromised. Significant unwanted complications can generally be prevented by careful pre-procedure assessment and preparation, appropriate monitoring and support, as well as post-procedure management. Additionally, physicians must be prepared to manage these complications. This article will review sedation-related complications during moderate and deep sedation for GIE procedures and also address their appropriate management.

  7. Pediatric neuro MRI. Tricks to minimize sedation

    Energy Technology Data Exchange (ETDEWEB)

    Barkovich, Matthew J.; Desikan, Rahul S. [University of California, San Francisco, Department of Radiology and Diagnostic Imaging, San Francisco, CA (United States); Xu, Duan; Barkovich, A.J. [University of California, San Francisco, Department of Radiology and Diagnostic Imaging, San Francisco, CA (United States); UCSF-Benioff Children' s Hospital, Department of Radiology, San Francisco, CA (United States); Williams, Cassandra [UCSF-Benioff Children' s Hospital, Department of Radiology, San Francisco, CA (United States)

    2018-01-15

    Magnetic resonance imaging (MRI) is the workhorse modality in pediatric neuroimaging because it provides excellent soft-tissue contrast without ionizing radiation. Until recently, studies were uninterpretable without sedation; however, given development of shorter sequences, sequences that correct for motion, and studies showing the potentially deleterious effects of sedation on immature laboratory animals, it is prudent to minimize sedation when possible. This manuscript provides basic guidelines for performing pediatric neuro MRI without sedation by both modifying technical factors to reduce scan time and noise, and using a multi-disciplinary team to coordinate imaging with the patient's biorhythms. (orig.)

  8. Premixed and non-premixed generated manifolds in large-eddy simulation of Sandia flame D and F

    NARCIS (Netherlands)

    Vreman, A.W.; Albrecht, B.A.; Oijen, van J.A.; Goey, de L.P.H.; Bastiaans, R.J.M.

    2008-01-01

    Premixed and nonpremixed flamelet-generated manifolds have been constructed and applied to large-eddy simulation of the piloted partially premixed turbulent flames Sandia Flame D and F. In both manifolds the chemistry is parameterized as a function of the mixture fraction and a progress variable.

  9. Methane combustion in catalytic premixed burners

    International Nuclear Information System (INIS)

    Cerri, I.; Saracco, G.; Specchia, V.

    1999-01-01

    Catalytic premixed burners for domestic boiler applications were developed with the aim of achieving a power modularity from 10 to 100% and pollutant emissions limited to NO x 2 , where the combustion took place entirely inside the burner heating it to incandescence and allowing a decrease in the flame temperature and NO x emissions. Such results were confirmed through further tests carried out in a commercial industrial-scale boiler equipped with the conical panels. All the results, by varying the excess air and the heat power employed, are presented and discussed [it

  10. A NEW DOUBLE-SLIT CURVED WALL-JET (CWJ) BURNER FOR STABILIZING TURBULENT PREMIXED AND NON-PREMIXED FLAMES

    KAUST Repository

    Mansour, Morkous S.; Chung, Suk-Ho

    2015-01-01

    Mixing characteristics in the cold flow of non-premixed cases were first examined using acetone fluorescence technique, indicating substantial transport between the fuel and air by exhibiting appreciable premixing conditions.PIV measurements revealed that velocity gradients in the shear layers at the boundaries of the annularjets generate the turbulence, enhanced with the collisions in the interaction jet, IJ,region. Turbulent mean and rms velocities were influenced significantly by Re and high rms turbulent velocities are generated within the recirculation zone improving the flame stabilization in this burner.Premixed and non-premixed flames with high equivalence ratio were found to be more resistant to local extinction and exhibited a more corrugated and folded nature, particularly at high Re. For flames with low equivalence ratio, the processes of local quenching at IJ region and of re-ignition within merged jet region maintained these flames further downstream particularly for non-premixed methane flame, revealing a strong intermittency.

  11. Premixing hydrogen burners for surface refinement of glass; Vormischende Wasserstoffbrenner zur Oberflaechenbearbeitung von Glas

    Energy Technology Data Exchange (ETDEWEB)

    Goerisch, Matthias [Linde AG, Linde Gas Deutschland, Nuernberg (Germany)

    2013-02-15

    As a result, inter alia, of unceasing globalisation, European glass producers in practically all sectors - flat glass, container glass, crystal glass and special glasses - are faced with ever tougher competition from Asia. In the 2012 to 2015 period and beyond, the principal focuses in the manufacture of glass products will again be on reducing overall production costs and increasing process efficiency wherever possible, on greater productivity and on enhanced product (surface) quality. To meet these challenges in the field of surface refinement and flame polishing of glass products as efficiently as possible, Linde AG/Linde Gases Division has developed premixing Hydropox {sup registered} burner technology for hydrogen/oxygen fuels. (orig.)

  12. Use of high-flow nasal cannula in obese patients receiving colonoscopy under intravenous propofol sedation: A case series

    Directory of Open Access Journals (Sweden)

    Chi Chan Lee

    Full Text Available Intravenous sedation during colonoscopy has become the standard practice in the United States given its higher patient satisfaction and procedural quality. This practice is not free of side effects as a significant proportion of patients undergoing this procedure tend to have respiratory depression and desaturation events. Obesity, as it relates to higher levels of body mass index (BMI has a positive correlation with the incidence of hypoxemia. During colonoscopy High flow nasal cannula (HFNC may potentially improve oxygen performance in patients receiving colonoscopy under intravenous sedation. Here we present 3 cases of patients undergoing adjunctive oxygen therapy with HFNC during colonoscopy with intravenous sedation. We found patients to have lower number of desaturation events and were satisfied with their experience. Keywords: High BMI (body mass index, HFNC (high-flow nasal cannula, Colonoscopy, Intravenous sedation, Obesity

  13. Sedation practice in Nordic and non-Nordic ICUs

    DEFF Research Database (Denmark)

    Egerod, Ingrid; Albarran, John W; Ring, Mette

    2013-01-01

    A trend towards lighter sedation has been evident in many intensive care units (ICUs). The aims of the survey were to describe sedation practice in European ICUs and to compare sedation practice in Nordic and non-Nordic countries....

  14. Efficacy of two types of palliative sedation therapy defined using intervention protocols: proportional vs. deep sedation.

    Science.gov (United States)

    Imai, Kengo; Morita, Tatsuya; Yokomichi, Naosuke; Mori, Masanori; Naito, Akemi Shirado; Tsukuura, Hiroaki; Yamauchi, Toshihiro; Kawaguchi, Takashi; Fukuta, Kaori; Inoue, Satoshi

    2018-06-01

    This study investigated the effect of two types of palliative sedation defined using intervention protocols: proportional and deep sedation. We retrospectively analyzed prospectively recorded data of consecutive cancer patients who received the continuous infusion of midazolam in a palliative care unit. Attending physicians chose the sedation protocol based on each patient's wish, symptom severity, prognosis, and refractoriness of suffering. The primary endpoint was a treatment goal achievement at 4 h: in proportional sedation, the achievement of symptom relief (Support Team Assessment Schedule (STAS) ≤ 1) and absence of agitation (modified Richmond Agitation-Sedation Scale (RASS) ≤ 0) and in deep sedation, the achievement of deep sedation (RASS ≤ - 4). Secondary endpoints included mean scores of STAS and RASS, deep sedation as a result, and adverse events. Among 398 patients who died during the period, 32 received proportional and 18 received deep sedation. The treatment goal achievement rate was 68.8% (22/32, 95% confidence interval 52.7-84.9) in the proportional sedation group vs. 83.3% (15/18, 66.1-100) in the deep sedation group. STAS decreased from 3.8 to 0.8 with proportional sedation at 4 h vs. 3.7 to 0.3 with deep sedation; RASS decreased from + 1.2 to - 1.7 vs. + 1.4 to - 3.7, respectively. Deep sedation was needed as a result in 31.3% (10/32) of the proportional sedation group. No fatal events that were considered as probably or definitely related to the intervention occurred. The two types of intervention protocol well reflected the treatment intention and expected outcomes. Further, large-scale cohort studies are promising.

  15. Pediatric dental sedation: challenges and opportunities.

    Science.gov (United States)

    Nelson, Travis M; Xu, Zheng

    2015-01-01

    High levels of dental caries, challenging child behavior, and parent expectations support a need for sedation in pediatric dentistry. This paper reviews modern developments in pediatric sedation with a focus on implementing techniques to enhance success and patient safety. In recent years, sedation for dental procedures has been implicated in a disproportionate number of cases that resulted in death or permanent neurologic damage. The youngest children and those with more complicated medical backgrounds appear to be at greatest risk. To reduce complications, practitioners and regulatory bodies have supported a renewed focus on health care quality and safety. Implementation of high fidelity simulation training and improvements in patient monitoring, including end-tidal carbon dioxide, are becoming recognized as a new standard for sedated patients in dental offices and health care facilities. Safe and appropriate case selection and appropriate dosing for overweight children is also paramount. Oral sedation has been the mainstay of pediatric dental sedation; however, today practitioners are administering modern drugs in new ways with high levels of success. Employing contemporary transmucosal administration devices increases patient acceptance and sedation predictability. While recently there have been many positive developments in sedation technology, it is now thought that medications used in sedation and anesthesia may have adverse effects on the developing brain. The evidence for this is not definitive, but we suggest that practitioners recognize this developing area and counsel patients accordingly. Finally, there is a clear trend of increased use of ambulatory anesthesia services for pediatric dentistry. Today, parents and practitioners have become accustomed to children receiving general anesthesia in the outpatient setting. As a result of these changes, it is possible that dental providers will abandon the practice of personally administering large amounts of

  16. Turbulent piloted partially-premixed flames with varying levels of O2/N2: stability limits and PDF calculations

    Science.gov (United States)

    Juddoo, Mrinal; Masri, Assaad R.; Pope, Stephen B.

    2011-12-01

    This paper reports measured stability limits and PDF calculations of piloted, turbulent flames of compressed natural gas (CNG) partially-premixed with either pure oxygen, or with varying levels of O2/N2. Stability limits are presented for flames of CNG fuel premixed with up to 20% oxygen as well as CNG-O2-N2 fuel where the O2 content is varied from 8 to 22% by volume. Calculations are presented for (i) Sydney flame B [Masri et al. 1988] which uses pure CNG as well as flames B15 to B25 where the CNG is partially-premixed with 15-25% oxygen by volume, respectively and (ii) Sandia methane-air (1:3 by volume) flame E [Barlow et al. 2005] as well as new flames E15 and E25 that are partially-premixed with 'reconstituted air' where the O2 content in nitrogen is 15 and 25% by volume, respectively. The calculations solve a transported PDF of composition using a particle-based Monte Carlo method and employ the EMST mixing model as well as detailed chemical kinetics. The addition of oxygen to the fuel increases stability, shortens the flames, broadens the reaction zone, and shifts the stoichiometric mixture fraction towards the inner side of the jet. It is found that for pure CNG flames where the reaction zone is narrow (∼0.1 in mixture fraction space), the PDF calculations fail to reproduce the correct level of local extinction on approach to blow-off. A broadening in the reaction zone up to about 0.25 in mixture fraction space is needed for the PDF/EMST approach to be able to capture these finite-rate chemistry effects. It is also found that for the same level of partial premixing, increasing the O2/N2 ratio increases the maximum levels of CO and NO but shifts the peak to richer mixture fractions. Over the range of oxygenation investigated here, stability limits have shown to improve almost linearly with increasing oxygen levels in the fuel and with increasing the contribution of release rate from the pilot.

  17. The Effect of Intravenous Dexmedetomidine on Spinal Block and Sedation

    Directory of Open Access Journals (Sweden)

    Abdurrahman Ekici

    2015-03-01

    Material and Methods: Our randomised, double-blind study was applied to ASA I-III, 18-75 years old 50 patients scheduled for transurethral surgery. The patients were divided into two groups and spinal anesthesia with 5% levobupivacaine 12.5 mg was administered to all patients. Intravenous dexmedetomidine was received 1 and micro;g/kg for loading dose before 0.5 and micro;g/kg/hour infusion to Group D (n=25. Saline infusion was given 1 and micro;g/kg for loading dose before 0.5 and micro;g/kg/hour infusion to Group S (n=25. Systolic, diastolic and mean arterial pressure, heart rate, peripheral oxygen saturation values, pain and sedation score, the level and duration of motor and sensorial block, recovery and patient comfort score and side effects were recorded. Results: Time to reach maximum block level and duration of spinal anesthesia were longer in Group D than Group S. Sedation scores were significantly higher in Group D than Group S intraoperatively (except 1th minute and postoperatively 10th and 15th minutes. The incidence of side effects, postoperative recovery and patient comfort values were similar between the groups. Conclusion: We found that dexmedetomidine prolongs duration of motor block, provides safe and effective sedation without increasing the incidence of side effect in the patients under spinal anesthesia. [Cukurova Med J 2015; 40(1.000: 55-62

  18. Multidimensional flamelet-generated manifolds for partially premixed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Phuc-Danh; Vervisch, Luc; Subramanian, Vallinayagam; Domingo, Pascale [CORIA - CNRS and INSA de Rouen, Technopole du Madrillet, BP 8, 76801 Saint-Etienne-du-Rouvray (France)

    2010-01-15

    Flamelet-generated manifolds have been restricted so far to premixed or diffusion flame archetypes, even though the resulting tables have been applied to nonpremixed and partially premixed flame simulations. By using a projection of the full set of mass conservation species balance equations into a restricted subset of the composition space, unsteady multidimensional flamelet governing equations are derived from first principles, under given hypotheses. During the projection, as in usual one-dimensional flamelets, the tangential strain rate of scalar isosurfaces is expressed in the form of the scalar dissipation rates of the control parameters of the multidimensional flamelet-generated manifold (MFM), which is tested in its five-dimensional form for partially premixed combustion, with two composition space directions and three scalar dissipation rates. It is shown that strain-rate-induced effects can hardly be fully neglected in chemistry tabulation of partially premixed combustion, because of fluxes across iso-equivalence-ratio and iso-progress-of-reaction surfaces. This is illustrated by comparing the 5D flamelet-generated manifold with one-dimensional premixed flame and unsteady strained diffusion flame composition space trajectories. The formal links between the asymptotic behavior of MFM and stratified flame, weakly varying partially premixed front, triple-flame, premixed and nonpremixed edge flames are also evidenced. (author)

  19. Dynamic-Stability Characteristics of Premixed Methane Oxy-Combustion

    KAUST Repository

    Shroll, Andrew P.

    2012-01-01

    This work explores the dynamic stability characteristics of premixed CH 4/O 2/CO 2 mixtures in a 50 kW swirl stabilized combustor. In all cases, the methane-oxygen mixture is stoichiometric, with different dilution levels of carbon dioxide used to control the flame temperature (T ad). For the highest T ad\\'s, the combustor is unstable at the first harmonic of the combustor\\'s natural frequency. As the temperature is reduced, the combustor jumps to fundamental mode and then to a low-frequency mode whose value is well below the combustor\\'s natural frequency, before eventually reaching blowoff. Similar to the case of CH 4/air mixtures, the transition from one mode to another is predominantly a function of the T ad of the reactive mixture, despite significant differences in laminar burning velocity and/or strained flame consumption speed between air and oxy-fuel mixtures for a given T ad. High speed images support this finding by revealing similar vortex breakdown modes and thus similar turbulent flame geometries that change as a function of flame temperature. Copyright © 2012 American Society of Mechanical Engineers.

  20. The sedative and analgesic potentials of dexmedtomidine ...

    African Journals Online (AJOL)

    Venous access was secured thirty minutes later, the fluid was connected to the cannula and was set to flow at daily fluid maintenance rate of 90mlkgday-1. Neither sedation nor analgesia was achieved with 20μgkg-1. Slight to moderate sedative effect was achieved at 40μg/kg with significant reduction in heart, pulse and ...

  1. Palliative Sedation in Patients With Cancer.

    Science.gov (United States)

    Maltoni, Marco; Setola, Elisabetta

    2015-10-01

    Palliative sedation involves the use of sedative medication to relieve refractory symptoms in patients by reducing their level of consciousness. Although it is considered an acceptable clinical practice from most ethical points of view, palliative sedation is still a widely debated procedure and merits better understanding. The relevant medical literature pertaining to palliative sedation was analyzed and reviewed from various technical, relational, and bioethical perspectives. Proportionate palliative sedation is considered to be the most clinically appropriate modality for performing palliative sedation. However, guidelines must be followed to ensure that it is performed correctly. Benzodiazepines represent the first therapeutic option and careful monitoring of dosages is essential to avoid oversedation or undersedation. Proportionate palliative sedation is used to manage and relieve refractory symptoms in patients with cancer during their last days or hours of life. Evidence suggests that its use has no detrimental effect on survival. A different decision-making process is used to manage the withdrawal of hydration than the process used to determine whether proportionate palliative sedation is appropriate. Communication between patients, their relatives, and the health care staff is important during this medical intervention.

  2. Sedation in the ICU Less is more

    DEFF Research Database (Denmark)

    Strom, T.

    2012-01-01

    . The intervention group received only bolus doses of morphine or haloperidol if delirium was suspected. The control group received standard infusion of sedatives to RAMSAY 3-4 and sedatives were interrupted on a daily basis. Both groups received morphine as intravenous bolus doses (2.5 to 5 mg). The primary outcome...

  3. Nurse-administered propofol sedation for endoscopy

    DEFF Research Database (Denmark)

    Jensen, J T; Vilmann, P; Horsted, T

    2011-01-01

    The aim of the present study was to perform a risk analysis during the implementation phase of nurse-administered propofol sedation (NAPS) and to validate our structured training program.......The aim of the present study was to perform a risk analysis during the implementation phase of nurse-administered propofol sedation (NAPS) and to validate our structured training program....

  4. Sedation practice among Nigerian radiology residents

    African Journals Online (AJOL)

    Background: Providing safe and effective sedation to patients, especially those with multiple medical problems, can be ... This study aimed to determine knowledge, attitude and practice of Nigerian radiology ..... works. Conclusion. Sedation and resuscitation are an integral part of radiology .... An evaluation of a virtual reality.

  5. Visual cortex reactivity in sedated children examined with perfusion MRI (FAIR)

    DEFF Research Database (Denmark)

    Born, A P; Rostrup, E; Miranda, M J

    2002-01-01

    that it is caused by a relatively greater increase of oxygen consumption compared to rCBF (regional cerebral blood flow) increase. We studied the rCBF changes during visual stimulation in four sedated children, aged 4-71 months, and four alert adults, with an arterial water spin labeling technique (FAIR) and BOLD f...

  6. A randomized controlled trial to compare fentanyl-propofol and ketamine-propofol combination for procedural sedation and analgesia in laparoscopic tubal ligation

    Directory of Open Access Journals (Sweden)

    Ranju Singh

    2013-01-01

    Full Text Available Background: Procedural sedation and analgesia is widely being used for female laparoscopic sterilization using combinations of different drugs at varying doses. This study compared the combination of fentanyl and propofol, and ketamine and propofol in patients undergoing outpatient laparoscopic tubal ligation, with respect to their hemodynamic effects, postoperative recovery characteristics, duration of hospital stay, adverse effects, and patient comfort and acceptability. Settings and Design: Randomized, double blind. Methods: Patients were assigned to receive premixed injection of either fentanyl 1.5 μg/kg + propofol 2 mg/kg (Group PF, n0=50 or ketamine 0.5 mg/kg + propofol 2 mg/kg (Group PK, n=50. Hemodynamic data, peripheral oxygen saturation, and respiratory rate were recorded perioperatively. Recovery time, time to discharge, and comfort score were noted. Statistical Analysis: Chi-square (χ2 test was used for categorical data. Student′s t-test was used for quantitative variables for comparison between the two groups. For intragroup comparison, paired t-test was used. SPSS 14.0 was used for analysis. Results: Although the heart rate was comparable, blood pressures were consistently higher in group PK. Postoperative nausea and vomiting and delay in voiding were more frequent in group PK ( P<0.05. The time to reach Aldrete score ≥8 was significantly longer in group PK (11.14±3.29 min in group PF vs. 17.3±6.32 min in group PK, P<0.01. The time to discharge was significantly longer in group PK (105.8±13.07 min in group PF vs.138.18±13.20 min in group PK, P<0.01. Patient comfort and acceptability was better in group PF, P<0.01. Conclusion: As compared to ketamine-propofol, fentanyl-propofol combination is associated with faster recovery, earlier discharge, and better patient acceptability.

  7. [Sedation with nitrous oxide in daily practice].

    Science.gov (United States)

    Martens, Luc C; Marks, Luc A

    2003-01-01

    Conscious sedation is recommended, together with behaviour management techniques, to facilitate treatment of dental fear or dental phobia patients. In this article the authors focus on inhalation sedation by means of nitrous oxide. The procedures and indications are explained and illustrated with clinical cases. On the strength of the literature and their own experience the authors reach the conclusion that Inhalation sedation is a kind of pharmacological behaviour management and an important additional tool to increase patient cooperation. Inhalation sedation can only be performed by trained practitioners under internationally accepted safety conditions. Inhalation sedation has a future in Belgium providing the appropriate law is adapted. This technique deserves a place in the dental curriculum.

  8. Cultural changes in ICU sedation management

    DEFF Research Database (Denmark)

    Egerod, Ingrid

    2009-01-01

    The aim of this study was to explore physicians' views and perceptions of sedation, and offer a new approach to the understanding of issues of sedation. I used a qualitative, descriptive, and explorative multicenter design. Data were generated by seven key-informant interviews using...... a semistructured interview guide. One experienced doctor was selected at each of the seven largest intensive care units in Denmark. Interpretational analysis was performed by comprehensive overview, individual case analysis, cross-case analysis, and integrated thematic analysis and identification of emerging...... provide an understanding of contextual issues of sedation, safety, and comfort, and suggest that a cultural change in sedation strategies might reduce the duration of sedation and mechanical ventilation while containing cost and improving the well-being of the patients....

  9. Palliative sedation versus euthanasia: an ethical assessment.

    Science.gov (United States)

    ten Have, Henk; Welie, Jos V M

    2014-01-01

    The aim of this article was to review the ethical debate concerning palliative sedation. Although recent guidelines articulate the differences between palliative sedation and euthanasia, the ethical controversies remain. The dominant view is that euthanasia and palliative sedation are morally distinct practices. However, ambiguous moral experiences and considerable practice variation call this view into question. When heterogeneous sedative practices are all labeled as palliative sedation, there is the risk that palliative sedation is expanded to include practices that are actually intended to bring about the patients' death. This troublesome expansion is fostered by an expansive use of the concept of intention such that this decisive ethical concept is no longer restricted to signify the aim in guiding the action. In this article, it is argued that intention should be used in a restricted way. The significance of intention is related to other ethical parameters to demarcate the practice of palliative sedation: terminality, refractory symptoms, proportionality, and separation from other end-of-life decisions. These additional parameters, although not without ethical and practical problems, together formulate a framework to ethically distinguish a more narrowly defined practice of palliative sedation from practices that are tantamount to euthanasia. Finally, the article raises the question as to what impact palliative sedation might have on the practice of palliative care itself. The increasing interest in palliative sedation may reemphasize characteristics of health care that initially encouraged the emergence of palliative care in the first place: the focus on therapy rather than care, the physical dimension rather than the whole person, the individual rather than the community, and the primacy of intervention rather than receptiveness and presence. Copyright © 2014 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

  10. Propofol sedation in children: sleep trumps amnesia☆

    Science.gov (United States)

    Veselis, Robert; Kelhoffer, Eric; Mehta, Meghana; Root, James C.; Robinson, Fay; Mason, Keira P.

    2017-01-01

    Objective Detailed assessments of the effects of propofol on memory in children are lacking. We assessed the feasibility of measuring memory during propofol infusion, as commonly performed in sedation for MRI scanning. In addition, we determined the onset of memory loss in relation to the onset of sedation measured by verbal responsiveness. Materials and methods Children scheduled for sedation for MRI received a 10-min infusion of propofol (3 mg/kg) as they viewed and named 100 simple line drawings, one shown every five seconds, until they were no longer responsive (encoding). A control group receiving no sedation for MRI underwent similar tasks. Sedation was measured as any verbal response, regardless of correctness. After recovery from sedation, recognition memory was tested, with correct yes/no recognitions matched to sedation responses during encoding (subsequent memory paradigm). Results Of the 48 children who received propofol, 30 could complete all study tasks (6.2 ± 1.6 years, 16 males). Individual responses could be modeled in all 30 children. On average, there was a 50% probability of no verbal response 3.1 min after the start of infusion, with 50% memory loss at 2.7 min. Children receiving propofol recognized 65 ± 16% of the pictures seen, whereas the control group recognized 93 ± 5%. Conclusion Measurement of memory and sedation is possible in verbal children receiving propofol by infusion in a clinical setting. Despite propofol being an amnestic agent, there was little or no amnestic effect of propofol while the child was verbally responsive. It is important for sedation providers to realize that propofol sedation does not always produce amnesia while the child is responsive. ClinicalTrials.gov number NCT02278003. PMID:27938911

  11. Propofol sedation in children: sleep trumps amnesia.

    Science.gov (United States)

    Veselis, Robert; Kelhoffer, Eric; Mehta, Meghana; Root, James C; Robinson, Fay; Mason, Keira P

    Detailed assessments of the effects of propofol on memory in children are lacking. We assessed the feasibility of measuring memory during propofol infusion, as commonly performed in sedation for MRI scanning. In addition, we determined the onset of memory loss in relation to the onset of sedation measured by verbal responsiveness. Children scheduled for sedation for MRI received a 10-min infusion of propofol (3 mg/kg) as they viewed and named 100 simple line drawings, one shown every five seconds, until they were no longer responsive (encoding). A control group receiving no sedation for MRI underwent similar tasks. Sedation was measured as any verbal response, regardless of correctness. After recovery from sedation, recognition memory was tested, with correct yes/no recognitions matched to sedation responses during encoding (subsequent memory paradigm). Of the 48 children who received propofol, 30 could complete all study tasks (6.2 ± 1.6 years, 16 males). Individual responses could be modeled in all 30 children. On average, there was a 50% probability of no verbal response 3.1 min after the start of infusion, with 50% memory loss at 2.7 min. Children receiving propofol recognized 65 ± 16% of the pictures seen, whereas the control group recognized 93 ± 5%. Measurement of memory and sedation is possible in verbal children receiving propofol by infusion in a clinical setting. Despite propofol being an amnestic agent, there was little or no amnestic effect of propofol while the child was verbally responsive. It is important for sedation providers to realize that propofol sedation does not always produce amnesia while the child is responsive. CLINICALTRIALS. NCT02278003. Copyright © 2016. Published by Elsevier B.V.

  12. Predictive factors of oxygen desaturation of patients submitted to endoscopic retrograde cholangiopancreatography under conscious sedation Fatores preditivos de dessaturação de oxigênio de pacientes submetidos a colangiopancreatografia endoscópica retrógrada sob sedação consciente

    Directory of Open Access Journals (Sweden)

    Suzana Müller

    2004-09-01

    Full Text Available BACKGROUND AND AIMS: Hypoxemia can occur during endoscopic retrograde cholangiopancreatography probably induced by the analgesia and sedation done. Moreover the patient’s prone position difficults the adequate ventilation. The hypoxemia and hypoventilation may not be noticed by nursing staff. A transversal study was used to investigate possible predictive factors of oxygen desaturation in sedated patients with midazolam associated to meperidine undergoing endoscopic retrograde cholangiopancreatography. PATIENTS AND METHODS: A total of 186 patients were monitored with continuous pulse oximetry. Poisson regression was used to measure the independent effect of each factor adjusted for effects of each of the other factors. The variables studied were: age, gender, hematocrit and hemoglobin levels, scopolamine use, diagnostic or therapeutic exam, American Society of Anesthesiologists Scores (ASA, duration time of exam, sedative used midazolam in the average of 0.07 mg/kg and analgesic drug meperidine in the average of 0.7 mg/kg that was titrated according patient’s reaction. RESULTS: No desaturation was found in 113 (60.8% patients, mild desaturation (SpO2 60 years old and ASA score III. The duration of exam was barely significant for desaturation. CONCLUSIONS:The variables of age of 60 years old or more, and ASA III score are identified as increased risk for desaturation for patients who undergo endoscopic retrograde cholangiopancreatography under conscious sedation. Long time of exam suggests the patient oxygen desaturate. Such patients require very close monitoring to desaturation and hypoventilation by the assistants and nursing staff alerting to respiratory depression. The use of pulse oximeter and asking for deep breaths during the exam helps to diminish such risks.RACIONAL: A hipoxemia pode ocorrer durante a colangiopancreatografia endoscópica retrógrada, provavelmente induzida pela analgesia e sedação realizadas, além da posição do

  13. Sedation for pediatric radiological procedures: analysis of potential causes of sedation failure and paradoxical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Karian, V.E.; Burrows, P.E.; Connor, L. [Dept. of Radiology, Children' s Hospital, Boston, MA (United States); Zurakowski, D. [Dept. of Biostatistics, Children' s Hospital, Boston, MA (United States); Mason, K.P. [Dept. of Anesthesiology, Children' s Hospital, Boston, MA (United States)

    1999-11-01

    Background. Sedation for diagnostic imaging and interventional radiologic procedures in pediatrics has greatly increased over the past decade. With appropriate patient selection and monitoring, serious adverse effects are infrequent, but failure to sedate and paradoxical reactions do occur. Objective. The purpose of this study was to determine, among patients undergoing sedation for radiologic procedures, the incidence of sedation failure and paradoxical reaction to pentobarbital and to identify potentially correctable causes. Materials and methods. Records of 1665 patients who were sedated in the radiology department from 1 November 1997 to 1 July 1998 were reviewed. Patients failing sedation or experiencing paradoxical reaction were compared with respect to sex, age group, diagnosis, scan type, time of day, NPO status, use of IV contrast and type of sedation agent using the Fisher exact test, Pearson chi-square, analysis of variance (ANOVA), the Student t-test, and logistic regression. Results. Data analysis revealed a sedation failure rate of 1 % and paradoxical reaction rate of 1.2 %. Stepwise multiple logistic regression revealed that the only significant independent multivariate predictor of failure was the need for the administration of a combination of pentobarbital, fentanyl, and midazolam IV. Conclusion. The low rate of sedation failure and paradoxical reactions to pentobarbital was near optimal and probably cannot be improved with the currently available sedatives. (orig.)

  14. Sedation for pediatric radiological procedures: analysis of potential causes of sedation failure and paradoxical reactions

    International Nuclear Information System (INIS)

    Karian, V.E.; Burrows, P.E.; Connor, L.; Zurakowski, D.; Mason, K.P.

    1999-01-01

    Background. Sedation for diagnostic imaging and interventional radiologic procedures in pediatrics has greatly increased over the past decade. With appropriate patient selection and monitoring, serious adverse effects are infrequent, but failure to sedate and paradoxical reactions do occur. Objective. The purpose of this study was to determine, among patients undergoing sedation for radiologic procedures, the incidence of sedation failure and paradoxical reaction to pentobarbital and to identify potentially correctable causes. Materials and methods. Records of 1665 patients who were sedated in the radiology department from 1 November 1997 to 1 July 1998 were reviewed. Patients failing sedation or experiencing paradoxical reaction were compared with respect to sex, age group, diagnosis, scan type, time of day, NPO status, use of IV contrast and type of sedation agent using the Fisher exact test, Pearson chi-square, analysis of variance (ANOVA), the Student t-test, and logistic regression. Results. Data analysis revealed a sedation failure rate of 1 % and paradoxical reaction rate of 1.2 %. Stepwise multiple logistic regression revealed that the only significant independent multivariate predictor of failure was the need for the administration of a combination of pentobarbital, fentanyl, and midazolam IV. Conclusion. The low rate of sedation failure and paradoxical reactions to pentobarbital was near optimal and probably cannot be improved with the currently available sedatives. (orig.)

  15. Cardiovascular, respiratory and sedative effects of intramuscular alfaxalone, butorphanol and dexmedetomidine compared with ketamine, butorphanol and dexmedetomidine in healthy cats.

    Science.gov (United States)

    Cremer, Jeannette; Riccó, Carolina H

    2017-11-01

    Objectives The aim of the study was to evaluate the cardiorespiratory effects, quality of sedation and recovery of intramuscular alfaxalone-dexmedetomidine-butorphanol (ADB) and ketamine-dexmedetomidine-butorphanol (KDB), in cats. Methods Nine adult, healthy cats (6.63 ± 1.42 kg) were enrolled in a blinded, randomized, crossover experimental design. Cats were sedated twice intramuscularly, once with ADB (alfaxalone 1 mg/kg, dexmedetomidine 0.005 mg/kg, butorphanol 0.2 mg/kg), and once with KDB (ketamine 5 mg/kg, dexmedetomidine 0.005 mg/kg, butorphanol 0.2 mg/kg), in random order. Data collected included heart rate (HR), arterial blood pressure and blood gas analysis, respiratory rate, and sedation score. Analysis of variance with Bonferroni post-hoc correction was used for parametric data, and a Wilcoxon signed rank test was used for non-parametric data. Significance was set at P <0.05. Results Total sedation time was shorter for ADB (90.71 ± 15.12 mins vs 147.00 ± 47.75 mins). Peak sedation was observed within 15 mins in both groups. Quality of recovery was excellent in both groups. HR decreased over time in both groups. Diastolic and mean arterial pressure decreased over time for ADB, becoming significant after 30 mins. All cardiovascular variables were within the clinically acceptable range in both groups. Arterial partial pressure of oxygen was significantly decreased from baseline for KDB at all time points (73 ± 2.5 mmHg [9.7 ± 0.3 kPa] vs ADB 83 ± 2.6 mmHg [11 ± 0.3 kPa]). Hypoventilation was not observed. Conclusions and relevance Both protocols produced acceptable cardiovascular stability. Sedation and recovery quality were good, albeit sedation was shorter with ADB. Although oxygenation was better maintained in the ADB group, all sedated cats should receive oxygen supplementation.

  16. Implementation of Premixed Equilibrium Chemistry Capability in OVERFLOW

    Science.gov (United States)

    Olsen, Mike E.; Liu, Yen; Vinokur, M.; Olsen, Tom

    2004-01-01

    An implementation of premixed equilibrium chemistry has been completed for the OVERFLOW code, a chimera capable, complex geometry flow code widely used to predict transonic flowfields. The implementation builds on the computational efficiency and geometric generality of the solver.

  17. Crossed-Plane Imaging of Premixed Turbulent Combustion Processes

    National Research Council Canada - National Science Library

    Gouldin, F

    2003-01-01

    .... Rayleigh scattering from premixed flames can be used for temperature imaging, and we have developed crossed-plane Rayleigh imaging in order to measure with high-resolution instantaneous temperature...

  18. Flamelet Surface Density and Burning Rate Integral in Premixed Combustion

    National Research Council Canada - National Science Library

    Gouldin, F

    1999-01-01

    We have developed, tested and applied in V-flames and a spark ignition engine a new experimental method, crossed-plane laser imaging, for measuring flamelet surface normals in premixed turbulent flames...

  19. Palliative pharmacological sedation for terminally ill adults.

    Science.gov (United States)

    Beller, Elaine M; van Driel, Mieke L; McGregor, Leanne; Truong, Shani; Mitchell, Geoffrey

    2015-01-02

    Terminally ill people experience a variety of symptoms in the last hours and days of life, including delirium, agitation, anxiety, terminal restlessness, dyspnoea, pain, vomiting, and psychological and physical distress. In the terminal phase of life, these symptoms may become refractory, and unable to be controlled by supportive and palliative therapies specifically targeted to these symptoms. Palliative sedation therapy is one potential solution to providing relief from these refractory symptoms. Sedation in terminally ill people is intended to provide relief from refractory symptoms that are not controlled by other methods. Sedative drugs such as benzodiazepines are titrated to achieve the desired level of sedation; the level of sedation can be easily maintained and the effect is reversible. To assess the evidence for the benefit of palliative pharmacological sedation on quality of life, survival, and specific refractory symptoms in terminally ill adults during their last few days of life. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 11), MEDLINE (1946 to November 2014), and EMBASE (1974 to December 2014), using search terms representing the sedative drug names and classes, disease stage, and study designs. We included randomised controlled trials (RCTs), quasi-RCTs, non-RCTs, and observational studies (e.g. before-and-after, interrupted-time-series) with quantitative outcomes. We excluded studies with only qualitative outcomes or that had no comparison (i.e. no control group or no within-group comparison) (e.g. single arm case series). Two review authors independently screened titles and abstracts of citations, and full text of potentially eligible studies. Two review authors independently carried out data extraction using standard data extraction forms. A third review author acted as arbiter for both stages. We carried out no meta-analyses due to insufficient data for pooling on any outcome; therefore, we reported

  20. Deep sedation during pneumatic reduction of intussusception.

    Science.gov (United States)

    Ilivitzki, Anat; Shtark, Luda Glozman; Arish, Karin; Engel, Ahuva

    2012-05-01

    Pneumatic reduction of intussusception under fluoroscopic guidance is a routine procedure. The unsedated child may resist the procedure, which may lengthen its duration and increase the radiation dose. We use deep sedation during the procedure to overcome these difficulties. The purpose of this study was to summarize our experience with deep sedation during fluoroscopic reduction of intussusception and assess the added value and complication rate of deep sedation. All children with intussusception who underwent pneumatic reduction in our hospital between January 2004 and June 2011 were included in this retrospective study. Anesthetists sedated the children using propofol. The fluoroscopic studies, ultrasound (US) studies and the childrens' charts were reviewed. One hundred thirty-one attempted reductions were performed in 119 children, of which 121 (92%) were successful and 10 (8%) failed. Two perforations (1.5%) occurred during attempted reduction. Average fluoroscopic time was 1.5 minutes. No complication to sedation was recorded. Deep sedation with propofol did not add any complication to the pneumatic reduction. The fluoroscopic time was short. The success rate of reduction was high,raising the possibility that sedation is beneficial, possibly by smooth muscle relaxation.

  1. Euthanasia and palliative sedation in Belgium.

    Science.gov (United States)

    Cohen-Almagor, Raphael; Ely, E Wesley

    2018-01-04

    The aim of this article is to use data from Belgium to analyse distinctions between palliative sedation and euthanasia. There is a need to reduce confusion and improve communication related to patient management at the end of life specifically regarding the rapidly expanding area of patient care that incorporates a spectrum of nuanced yet overlapping terms such as palliative care, sedation, palliative sedation, continued sedation, continued sedation until death, terminal sedation, voluntary euthanasia and involuntary euthanasia. Some physicians and nurses mistakenly think that relieving suffering at the end of life by heavily sedating patients is a form of euthanasia, when indeed it is merely responding to the ordinary and proportionate needs of the patient. Concerns are raised about abuse in the form of deliberate involuntary euthanasia, obfuscation and disregard for the processes sustaining the management of refractory suffering at the end of life. Some suggestions designed to improve patient management and prevent potential abuse are offered. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  2. [Sedation with midazolam for ambulatory pediatric dentistry].

    Science.gov (United States)

    Shavlokhova, E A; Ostreĭkov, I F; Korolenkova, M V

    2014-01-01

    To improve the quality of dental treatment in children by using combined anaesthesia technique including local anaesthesia and conscious sedation, and to assess the effectiveness of conscious sedation for younger children undergoing dental treatment. The study included 208 children aged 14-88 months who received dental treatment for tooth decay and its complication under combined anaesthesia. Midazolam was used as sedative medication. Sedation level was assessed by visual scale and BIS-monitoring. ANI-monitoring was also used for pain sensitiveness evaluation. Results All 208 children were successfully treated under combined anaesthesia which showed satisfactory sedation rates both by visual scale and and BIS-monitoring values. While mean patient age was 39 months 20.6% were younger than 24 months. These data are extremely valuable as according to literature review conscious sedation in early infancy remains controversial. Our results proved conscious sedation to be effective in younger children undergoing dental treatment thus representing important alternative for general anaesthesia and providing a basis for later behavior management.

  3. The indicator of sedation need (IOSN).

    Science.gov (United States)

    Coulthard, Paul

    2013-01-01

    Conscious sedation in dentistry is usually indicated because a patient's anxiety can prohibit the necessary dental treatment being undertaken. It may also be indicated because of unpleasant or lengthy treatment or to prevent exacerbation of a patient's medical or behavioural condition by anxiety. The indicator of sedation need (IOSN) tool has been developed to help support dentists in their clinical decision-making and uses information about a patient's anxiety, medical and behavioural status and treatment complexity. The IOSN has been used to measure sedation need and has shown that 5.1% of patients attending general dental practices have a high need of conscious sedation. IOSN has also been used to investigate the need for conscious sedation in the general population among dental practice attenders and those who don't attend. The proportion was found to be 6.7%. Some patients require conscious sedation in order to access dental care. The indicator of sedation need (IOSN) tool helps in the decision-making process.

  4. Aerodynamic features of flames in premixed gases

    Science.gov (United States)

    Oppenheim, A. K.

    1984-01-01

    A variety of experimentally established flame phenomena in premixed gases are interpreted by relating them to basic aerodynamic properties of the flow field. On this basis the essential mechanism of some well known characteristic features of flames stabilized in the wake of a bluff-body or propagating in ducts are revealed. Elementary components of the flame propagation process are shown to be: rotary motion, self-advancement, and expansion. Their consequences are analyzed under a most strict set of idealizations that permit the flow field to be treated as potential in character, while the flame is modelled as a Stefan-like interface capable of exerting a feed-back effect upon the flow field. The results provide an insight into the fundamental fluid-mechanical reasons for the experimentally observed distortions of the flame front, rationalizing in particular its ability to sustain relatively high flow velocities at amazingly low normal burning speeds.

  5. Extinction of counterflow premixed laminar flames

    International Nuclear Information System (INIS)

    Smooke, M.D.; Giovangigli, V.

    1987-01-01

    Problems in combustion and heat and mass transfer often depend upon one or more physical/chemical parameters. In many cases the combustion scientist is interested in knowing how the solution will behave if one or more of these parameters is varied. For some parameter regimes the governing equations can produce multiple solutions and the branches of the solution curve are linked via singular points. It is at these singular points, however that the system exhibits special behavior. To be able to predict the solution structure in the neighborhood of these points, the authors employ a phase-space, pseudo arclength, continuation method that utilizes Newton-like iterations and adaptive gridding techniques. The authors apply the method in the solution of counterflow premixed laminar flames

  6. Oral Sedation in the Dental Office.

    Science.gov (United States)

    Sebastiani, Francesco R; Dym, Harry; Wolf, Joshua

    2016-04-01

    This article highlights the commonly used medications used in dentistry and oral surgery. General dentists and specialists must be knowledgeable about the pharmacology of the drugs currently available along with their risks and benefits. Enteral sedation is a useful adjunct for the treatment of anxious adult and pediatric patients. When enteral sedation is used within the standards of care, the interests of the public and the dental profession are served through a cost-effective, effective service that can be widely available. Oral sedation enables dentists to provide dental care to millions of individuals who otherwise would have unmet dental needs. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Fully Premixed Low Emission, High Pressure Multi-Fuel Burner

    Science.gov (United States)

    Nguyen, Quang-Viet (Inventor)

    2012-01-01

    A low-emissions high-pressure multi-fuel burner includes a fuel inlet, for receiving a fuel, an oxidizer inlet, for receiving an oxidizer gas, an injector plate, having a plurality of nozzles that are aligned with premix face of the injector plate, the plurality of nozzles in communication with the fuel and oxidizer inlets and each nozzle providing flow for one of the fuel and the oxidizer gas and an impingement-cooled face, parallel to the premix face of the injector plate and forming a micro-premix chamber between the impingement-cooled face and the in injector face. The fuel and the oxidizer gas are mixed in the micro-premix chamber through impingement-enhanced mixing of flows of the fuel and the oxidizer gas. The burner can be used for low-emissions fuel-lean fully-premixed, or fuel-rich fully-premixed hydrogen-air combustion, or for combustion with other gases such as methane or other hydrocarbons, or even liquid fuels.

  8. Sedation for procedures outside the operating room in children

    International Nuclear Information System (INIS)

    Molina Rodriguez, Ericka

    2014-01-01

    Sedation is defined in the pediatric population. An adequate preoperative assessment is established in patients subjected to a sedation. Fundamental characteristics of drugs used during a sedation are determined. Recommendations about surveillance and monitoring are established in a patient sedated. Principal characteristics of sedation are defined in patients exposed to radiological diagnostic and therapeutic procedures. Considerations in sedation are identified for procedures in the laboratory of digestive endoscopy. Alternatives of sedation are mentioned for oncological patients subjected to invasive procedures. Working conditions and specifications of anesthesia are determined in the cardiac catheterization room [es

  9. Changes to the bispectral index and regional cerebral blood flow in a sedative state, caused by midazolam administration

    International Nuclear Information System (INIS)

    Ikeda, Junko

    2006-01-01

    Psychosedation, as used in the field of dentistry, is intended to provide trouble-free dental care while maintaining a proper level of sedation. One drug used in psychosedation is midazolam, which is known to have a strong amnestic effect. In the current research, I sought to clarify whether the bispectral index (BIS) using electroencephalogram (EEG) analysis can be used for assessment of optimal sedation in psychosedation, and what effects midazolam has on the cerebrum's mechanism of memory. The subjects were 17 healthy adult volunteers. Intravenous sedation involved a single administration of 0.06 mg/kg midazolam, or 6 mg/kg/h propofol, administered for 5 minutes and then continuously administered for 25 minutes at 3 mg/kg/h. For nitrous oxide inhalation sedation, 10-30% nitrous oxide was used. Clinical sedation and the BIS were measured in a variety of circumstances. To examine the effects of midazolam on the central nervous system, changes in brain oxygen consumption in visual memory tasks were assessed through observing changes in areas of brain activation using 3T fMRI. With intravenous sedation using midazolam or propofol, the BIS decreased immediately after drug administration, and the BIS at which optimal sedation was clinically determined was about 65. In contrast, no decrease in the BIS was noted with nitrous oxide inhalation sedation. In observing areas of brain activation by fMRI, the oxygen consumption mainly of visual cortices in the occipital lobe increased as a result of stimulation by visual memory tasks. Regardless of the amnestic effect midazolam produced in subjects, it did not suppress activation of the visual cortices in the occipital lobe. In intravenous sedation using midazolam or propofol, the BIS is effective in determining optimal sedation, and appropriate perioperative management can be performed using the BIS. However, in nitrous oxide inhalation sedation it appears that the BIS cannot be used to monitor levels of sedation. Amnestic

  10. Experience with the Large Eddy Simulation (LES) Technique for the Modelling of Premixed and Non-premixed Combustion

    OpenAIRE

    Malalasekera, W; Ibrahim, SS; Masri, AR; Gubba, SR; Sadasivuni, SK

    2013-01-01

    Compared to RANS based combustion modelling, the Large Eddy Simulation (LES) technique has recently emerged as a more accurate and very adaptable technique in terms of handling complex turbulent interactions in combustion modelling problems. In this paper application of LES based combustion modelling technique and the validation of models in non-premixed and premixed situations are considered. Two well defined experimental configurations where high quality data are available for validation is...

  11. Comparison of Dexmedetomidine and Midazolam in Sedation for Percutaneous Drainage of Hepatic Hydatid Cysts.

    Science.gov (United States)

    Bavullu, Emine Nilgün; Aksoy, Esra; Abdullayev, Ruslan; Göğüş, Nermin; Dede, Doğan

    2013-12-01

    Hydatid cyst still continues to be a public health problem. The basic treatment for the disease is surgery, but ultrasound-guided percutaneous drainage has become an important treatment alternative. Agents preferred for sedation during drainage performed under local anaesthesia must also preserve respiration and hemodynamic stability while providing adequate sedation. We compared the sedative properties of midazolam, which has a short duration of action, and a selective α2 adrenergic receptor agonist, dexmedetomidine, and the intraoperative complications. After approval by the clinical trials ethics committee, 40 patients with similar demographic data were randomized into two groups. All patients received 10 mg metoclopramide and 45.5 mg pheniramine before the procedure. Then, midazolam (0.07 mg kg(-1) IV bolus followed by 0.01 mg kg(-1) h(-1) infusion) was administered to Group 1, and dexmedetomidine (1 μg kg(-1) loading dose in 10 minutes, followed by 0.2 μg kg(-1) h(-1) continuous infusion) was administered to Group 2 for sedation. Just before the surgical procedure, all patients received IV propofol in a subhypnotic dose of 0.5 mg kg(-1); the dose was repeated if adequate sedation could not be achieved. Observer's assessment of alertness/sedation (OAA/S) scale and Bispectral index (BIS) were used to evaluate the sedation level during the procedure. Heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), peripheral oxygen saturation (SpO2) and end-tidal carbon dioxide pressure (ETCO2) were monitored before and after induction and every 5 minutes thereafter. Propofol requirement was noted for each group. Sedation in the dexmedetomidine group was as effective and adequate as that observed in the midazolam group. BIS values were significantly lower in the dexmedetomidine group, especially after 10 minutes and thereafter. RR, SpO2, and ETCO2 were similar in both groups, whereas clinically insignificant decreases in HR and MAP were observed in the

  12. Volatile Components of the Essential Oil of Artemisia montana and Their Sedative Effects.

    Science.gov (United States)

    Kunihiro, Kento; Myoda, Takao; Tajima, Noriaki; Gotoh, Kotaro; Kaneshima, Tai; Someya, Takao; Toeda, Kazuki; Fujimori, Takane; Nishizawa, Makoto

    2017-08-01

    The sedative effects of volatile components in the essential oil of Artemisia montana ("Yomogi") were investigated and measured using gas chromatography-mass spectrometry (GC-MS). Major components identified included 1,8-cineol, camphor, borneol, α-piperitone, and caryophyllene oxide. Among them, 1,8-cineol exhibited the highest flavor dilution (FD) value in an aroma extract dilution analysis (AEDA), followed by borneol, o-cymene, β-thujone, and bornyl acetate. The sedative effects of yomogi oil aroma were evaluated by sensory testing, analysis of salivary α-amylase activity, and measurement of relative fluctuation of oxygenated hemoglobin concentration in the brain using near-infrared spectroscopy (NIRS). All results indicated the stress-reducing effects of the essential oil following nasal exposure, and according to the NIRS analysis, 1,8-cineol is likely responsible for the sedative effects of yomogi oil.

  13. Downbeat Nystagmus Induced by Sedation in Lasik

    Directory of Open Access Journals (Sweden)

    Miguel Paciuc-Beja

    2012-01-01

    Full Text Available Nystagmus was elicited during lasik under sedation in two patients that were treated for depression. Nystagmus was not present before or after surgery. Nystagmus can be pharmacologically induced and can be a hazard to refractive surgery.

  14. Clonidine Sedation Effects in Children During Electroencephalography

    Directory of Open Access Journals (Sweden)

    Mohammad Barzegar

    2017-10-01

    Full Text Available It is very important to have proper management in children with Seizure. Electroencephalography (EEG as a diagnostic instrument has a key role in determining the management method of seizure in children. Because of poor cooperation of some children (especially children with attention deficit hyperactivity disorders and developmental disorders in performing EEG, it is the best choice to sedate children before EEG. The aim of present study is to evaluate the sedation efficacy of clonidine in children before EEG. In a randomized clinical trial, 45 children age 2 to 12 with seizure, who referred to Children Hospital of Tabriz University of Medical Sciences and candidate for EEG, were studied. Sedation before EEG induced by 0.5 to 2.0 mg clonidine orally. Sedation score (0 to 5 measured by using eyes condition, response to voice, and response to touch. Successful sedation, EEG performing, and hemodynamic stability were evaluated during sedation. Of all patients, 40 patients (88.88% were sedated successfully, and EEG was performed for all of the children. Mean onset time of clonidine effect was 35.47±13.56 minutes and mean time of that the patients’ level of consciousness back to the level before administrating of clonidine was 77.55±26.87 minutes. Hemodynamic states of all patients were stable during the study, and there were no significant changes in vital sign of patients. In conclusion, clonidine can be considered as a safe alternative medication for sedation for EEG, which is fortunately associated with no significant change in vital signs, which may complicate overall status of patients.

  15. Premixer Design for High Hydrogen Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Benjamin P. Lacy; Keith R. McManus; Balachandar Varatharajan; Biswadip Shome

    2005-12-16

    This 21-month project translated DLN technology to the unique properties of high hydrogen content IGCC fuels, and yielded designs in preparation for a future testing and validation phase. Fundamental flame characterization, mixing, and flame property measurement experiments were conducted to tailor computational design tools and criteria to create a framework for predicting nozzle operability (e.g., flame stabilization, emissions, resistance to flashback/flame-holding and auto-ignition). This framework was then used to establish, rank, and evaluate potential solutions to the operability challenges of IGCC combustion. The leading contenders were studied and developed with the most promising concepts evaluated via computational fluid dynamics (CFD) modeling and using the design rules generated by the fundamental experiments, as well as using GE's combustion design tools and practices. Finally, the project scoped the necessary steps required to carry the design through mechanical and durability review, testing, and validation, towards full demonstration of this revolutionary technology. This project was carried out in three linked tasks with the following results. (1) Develop conceptual designs of premixer and down-select the promising options. This task defined the ''gap'' between existing design capabilities and the targeted range of IGCC fuel compositions and evaluated the current capability of DLN pre-mixer designs when operated at similar conditions. Two concepts (1) swirl based and (2) multiple point lean direct injection based premixers were selected via a QFD from 13 potential design concepts. (2) Carry out CFD on chosen options (1 or 2) to evaluate operability risks. This task developed the leading options down-selected in Task 1. Both a GE15 swozzle based premixer and a lean direct injection concept were examined by performing a detailed CFD study wherein the aerodynamics of the design, together with the chemical kinetics of the

  16. Nurse-administered propofol sedation for endoscopy

    DEFF Research Database (Denmark)

    Jensen, J T; Vilmann, P; Horsted, T

    2011-01-01

    BACKGROUND AND STUDY AIMS: The aim of the present study was to perform a risk analysis during the implementation phase of nurse-administered propofol sedation (NAPS) and to validate our structured training program. PATIENTS AND METHODS: A structured training program was developed both for endosco......BACKGROUND AND STUDY AIMS: The aim of the present study was to perform a risk analysis during the implementation phase of nurse-administered propofol sedation (NAPS) and to validate our structured training program. PATIENTS AND METHODS: A structured training program was developed both...... pressure was recorded in 451 patients (26%). Independent risk factors were type of intervention and level of experience of the staff performing the sedation. CONCLUSION: These results were obtained after development of a structured training program both for endoscopists and nurses using propofol...... for sedation, and can be used as basis for further comparison. NAPS for endoscopic procedures is safe when performed by personnel properly trained in airway handling and sedation with propofol, and has considerable advantages compared with conventional sedation for endoscopy....

  17. Analgesia, sedation, and memory of intensive care.

    Science.gov (United States)

    Capuzzo, M; Pinamonti, A; Cingolani, E; Grassi, L; Bianconi, M; Contu, P; Gritti, G; Alvisi, R

    2001-09-01

    The purpose of this article was to investigate the relationship between analgesia, sedation, and memory of intensive care. One hundred fifty-two adult, cooperative intensive care unit (ICU) patients were interviewed 6 months after hospital discharge about their memory of intensive care. The patient was considered to be cooperative when he/she was aware of self and environment at the interview. The patients were grouped as follows: A (45 patients) substantially no sedation, B (85) morphine, and C (22) morphine and other sedatives. The patients having no memory of intensive care were 38%, 34%, and 23% respectively, in the three groups. They were less ill, according to SAPS II (P memories was not different among the three groups. Females reported at least one emotional memory more frequently than males (odds ratio 4.17; 95% CI 10.97-1.59). The patients receiving sedatives in the ICU are not comparable with those receiving only opiates or nothing, due to the different clinical condition. The lack of memory of intensive care is present in one third of patients and is influenced more by length of stay in ICU than by the sedation received. Sedation does not influence the incidence of factual, sensation, and emotional memories of ICU admitted patients. Females have higher incidences of emotional memories than males. Copyright 2001 by W.B. Saunders Company

  18. Speak Up: Anesthesia and Sedation

    Science.gov (United States)

    ... and you may be given oxygen. You may sleep until the drugs wear off. Tell your doctor or anesthesia professional about • General health issues and any recent changes • Allergies to medicines, ...

  19. Palliative sedation, not slow euthanasia: a prospective, longitudinal study of sedation in Flemish palliative care units.

    Science.gov (United States)

    Claessens, Patricia; Menten, Johan; Schotsmans, Paul; Broeckaert, Bert

    2011-01-01

    Palliative sedation remains a much debated and controversial issue. The limited literature on the topic often fails to answer ethical questions concerning this practice. The aim of this study was to describe the characteristics of patients who are being sedated for refractory symptoms in palliative care units (PCUs) from the time of admission until the day of death. A prospective, longitudinal, descriptive design was used to assess data in eight PCUs. The total sample consisted of 266 patients. Information on demographics, medication, food and fluid intake, decision making, level of consciousness, and symptom experience were gathered by nurses and researchers three times a week. If patients received palliative sedation, extra information was gathered. Of all included patients (n=266), 7.5% received palliative sedation. Sedation started, on average, 2.5 days before death and for half of these patients, the form of sedation changed over time. At the start of sedation, patients were in the end stage of their illness and needed total care. Patients were fully conscious and had very limited oral food or fluid intake. Only three patients received artificial fluids at the start of sedation. Patients reported, on average, two refractory symptoms, the most important ones being pain, fatigue, depression, drowsiness, and loss of feeling of well-being. In all cases, the patient gave consent to start palliative sedation because of increased suffering. This study revealed that palliative sedation is only administered in exceptional cases where refractory suffering is evident and for those patients who are close to the ends of their lives. Moreover, this study supports the argument that palliative sedation has no life-shortening effect. Copyright © 2011 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

  20. Sedation and Analgesia in Burn

    Directory of Open Access Journals (Sweden)

    Özkan Akıncı

    2011-07-01

    Full Text Available Burn injury is one of the most serious injuries that mankind may face. In addition to serious inflammation, excessive fluid loss, presence of hemodynamic instability due to intercurrent factors such as debridements, infections and organ failure, very different levels and intensities of pain, psychological problems such as traumatic stress disorder, depression, delirium at different levels that occur in patient with severe burn are the factors which make it difficult to provide the patient comfort. In addition to a mild to moderate level of baseline permanent pain in burn patients, which is due to tissue damage, there is procedural pain as well, which occurs by treatments such as grafting and dressings, that are severe, short-term burst style 'breakthrough' pain. Movement and tactile stimuli are also seen in burn injury as an effect to sensitize the peripheral and central nervous system. Even though many burn centers have established protocols to struggle with the pain, studies show that pain relief still inadequate in burn patients. Therefore, the treatment of burn pain and the prevention of possible emergence of future psychiatric problems suc as post-traumatic stress disorder, the sedative and anxiolytic agents should be used as a recommendation according to the needs and hemodynamic status of individual patient. (Journal of the Turkish Society Intensive Care 2011; 9 Suppl: 26-30

  1. Safe Driving After Propofol Sedation.

    Science.gov (United States)

    Summerlin-Grady, Lee; Austin, Paul N; Gabaldon, Dion A

    2017-10-01

    Propofol is a short-acting medication with fast cognitive and psychomotor recovery. However, patients are usually instructed not to drive a motor vehicle for 24 hours after receiving propofol. The purpose of this article was to review the evidence examining when it is safe to drive after receiving propofol for sedation for diagnostic and surgical procedures. This is a systematic review of the literature. A search of the literature was conducted using Google Scholar, PubMed, and the Cochrane Library for the time period 1990 to 2015. Two randomized controlled trials and two observational studies met the inclusion criteria. Using a simulator, investigators examined driving ability of subjects who received modest doses (about 100 mg) of propofol for endoscopic procedures and surveyed subjects who drove immediately after discharge. There were methodological concerns with the studies such as small sample sizes, modest doses of propofol, and three of the four studies were done in Japan by the same group of investigators limiting generalizability. This limited research suggests that it may be safe for patients to drive sooner than 24 hours after receiving propofol. However, large multicenter trials using heterogenous samples using a range of propofol doses are needed to support an evidence-based revision to the current discharge guidelines for patients receiving propofol. Copyright © 2016 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.

  2. Turbulent Premixed Flame Propagation in Microgravity

    Science.gov (United States)

    Menon, S.; Disseau, M.; Chakravarthy, V. K.; Jagoda, J.

    1997-01-01

    A facility in which turbulent Couette flow could be generated in a microgravity environment was designed and built. To fit into the NASA Lewis drop tower the device had to be very compact. This means that edge effects and flow re-circulation were expected to affect the flow. The flow was thoroughly investigated using LDV and was found to be largely two dimensional away from the edges with constant turbulence intensities in the core. Slight flow asymmetries are introduced by the non symmetric re-circulation of the fluid outside the test region. Belt flutter problems were remedied by adding a pair of guide plates to the belt. In general, the flow field was found to be quite similar to previously investigated Couette flows. However, turbulence levels and associated shear stresses were higher. This is probably due to the confined re-circulation zone reintroducing turbulence into the test section. An estimate of the length scales in the flow showed that the measurements were able to resolve nearly all the length scales of interest. Using a new LES method for subgrid combustion it has been demonstrated that the new procedure is computational feasible even on workstation type environment. It is found that this model is capable of capturing the propagation of the premixed names by resolving the flame in the LES grid within 2-3 grid points. In contrast, conventional LES results in numerical smearing of the flame and completely inaccurate estimate of the turbulent propagation speed. Preliminary study suggests that there is observable effect of buoyancy in the 1g environment suggesting the need for microgravity experiments of the upcoming experimental combustion studies. With the cold flow properties characterized, an identical hot flow facility is under construction. It is assumed that the turbulence properties ahead of the flame in this new device will closely match the results obtained here. This is required since the hot facility will not enable LDV measurements. The

  3. Proposed Guideline Revisions for Dental Sedation and General Anesthesia: Why Target the Safest Level of Sedation?

    Science.gov (United States)

    Dionne, Raymond A

    2016-09-01

    Recently proposed revisions to the American Dental Association's Guidelines for the Use of Sedation and General Anesthesia by Dentists, aimed at improving safety in dental offices, differentiate between levels of sedation based on drug-induced changes in physiologic and behavioral states. However, the author of this op-ed is concerned the proposed revisions may have far-reaching and unintended consequences.

  4. A NEW DOUBLE-SLIT CURVED WALL-JET (CWJ) BURNER FOR STABILIZING TURBULENT PREMIXED AND NON-PREMIXED FLAMES

    KAUST Repository

    Mansour, Morkous S.

    2015-06-30

    A novel double-slit curved wall-jet (CWJ) burner was proposed and employed, which utilizes the Coanda effect by supplying fuel and air as annular-inward jets over a curved surface. We investigated the stabilization characteristics and structure of methane/air, and propane/air turbulent premixed and non-premixed flames with varying global equivalence ratio, , and Reynolds number, Re. Simultaneous time-resolved measurements of particle image velocimetry and planar laser-induced fluorescence of OH radicals were conducted. The burner showed potential for stable operation for methane flames with relatively large fuel loading and overall rich conditions. These have a non-sooting nature. However, propane flames exhibit stable mode for a wider range of equivalence ratio and Re. Mixing characteristics in the cold flow of non-premixed cases were first examined using acetone fluorescence technique, indicating substantial transport between the fuel and air by exhibiting appreciable premixing conditions.PIV measurements revealed that velocity gradients in the shear layers at the boundaries of the annularjets generate the turbulence, enhanced with the collisions in the interaction jet, IJ,region. Turbulent mean and rms velocities were influenced significantly by Re and high rms turbulent velocities are generated within the recirculation zone improving the flame stabilization in this burner.Premixed and non-premixed flames with high equivalence ratio were found to be more resistant to local extinction and exhibited a more corrugated and folded nature, particularly at high Re. For flames with low equivalence ratio, the processes of local quenching at IJ region and of re-ignition within merged jet region maintained these flames further downstream particularly for non-premixed methane flame, revealing a strong intermittency.

  5. The role of sedation tests in identifying sedative drug effects in healthy volunteers and their power to dissociate sedative-related impairments from memory dysfunctions

    NARCIS (Netherlands)

    Wezenberg, E.; Sabbe, B.G.C.; Hulstijn, W.; Ruigt, G.S.F.; Verkes, R.J.

    2007-01-01

    The study investigated whether four specified drugs would show similar patterns on tests considered to measure sedation. In addition, their drug-effect patterns on sedation and memory performance were compared to determine whether the sedative effects could be differentiated from the memory effects.

  6. The role of sedation tests in identifying sedative drug effects in healthy volunteers and their power to dissociate sedative-related impairments from memory dysfunctions.

    NARCIS (Netherlands)

    Wezenberg, E.; Sabbe, B.G.C.; Hulstijn, W.; Ruigt, G.S.F.; Verkes, R.J.

    2007-01-01

    The study investigated whether four specified drugs would show similar patterns on tests considered to measure sedation. In addition, their drug-effect patterns on sedation and memory performance were compared to determine whether the sedative effects could be differentiated from the memory

  7. Experiments for the premixing phase (QUEOS)

    International Nuclear Information System (INIS)

    Meyer, L.; Huber, R.; Haessler, M.; Kirstahler, M.; Kuhn, D.; Rehme, K.; Schumacher, G.; Schwall, M.; Wachter, E.; Woerner, G.

    1995-01-01

    Experiments are performed with solid spheres at high temperatures to establish a data base for the premixing phase of a steam explosion, which will be used for code improvement and validation. The hot spheres (T≤2600 K) are being dropped into saturated water at 1 bar pressure. The objective of the experiments is to obtain data on the cooling rate of the spheres, their distribution in the water, the amount of generated steam and its distribution with respect to the spheres. The spheres have a diameter of 4.2 mm, 4.8 mm and 10 mm, respectively, depending on the material used. Molybdenum coated with Rhenium to inhibit oxidation and ZrO 2 are used. The experimental parameters are the mass flow of the spheres, their density and their temperature. The QUEOS test facility has been set up and tested. A series of first tests has been performed with cold spheres and spheres at 1000 C. The main results are the distribution of the spheres during the fall through the water and their distribution at the bottom of the water vessel. A large air bubble is being entrained into the water in both the cold and hot tests. (orig./HP)

  8. Numerical simulation of premixed turbulent methane combustion

    International Nuclear Information System (INIS)

    Bell, John B.; Day, Marcus S.; Grcar, Joseph F.

    2001-01-01

    In this paper we study the behavior of a premixed turbulent methane flame in three dimensions using numerical simulation. The simulations are performed using an adaptive time-dependent low Mach number combustion algorithm based on a second-order projection formulation that conserves both species mass and total enthalpy. The species and enthalpy equations are treated using an operator-split approach that incorporates stiff integration techniques for modeling detailed chemical kinetics. The methodology also incorporates a mixture model for differential diffusion. For the simulations presented here, methane chemistry and transport are modeled using the DRM-19 (19-species, 84-reaction) mechanism derived from the GRIMech-1.2 mechanism along with its associated thermodynamics and transport databases. We consider a lean flame with equivalence ratio 0.8 for two different levels of turbulent intensity. For each case we examine the basic structure of the flame including turbulent flame speed and flame surface area. The results indicate that flame wrinkling is the dominant factor leading to the increased turbulent flame speed. Joint probability distributions are computed to establish a correlation between heat release and curvature. We also investigate the effect of turbulent flame interaction on the flame chemistry. We identify specific flame intermediates that are sensitive to turbulence and explore various correlations between these species and local flame curvature. We identify different mechanisms by which turbulence modulates the chemistry of the flame

  9. Soot Formation in Freely-Propagating Laminar Premixed Flames

    Science.gov (United States)

    Lin, K.-C.; Hassan, M. I.; Faeth, G. M.

    1997-01-01

    Soot formation within hydrocarbon-fueled flames is an important unresolved problem of combustion science. Thus, the present study is considering soot formation in freely-propagating laminar premixed flames, exploiting the microgravity environment to simplify measurements at the high-pressure conditions of interest for many practical applications. The findings of the investigation are relevant to reducing emissions of soot and continuum radiation from combustion processes, to improving terrestrial and spacecraft fire safety, and to developing methods of computational combustion, among others. Laminar premixed flames are attractive for studying soot formation because they are simple one-dimensional flows that are computationally tractable for detailed numerical simulations. Nevertheless, studying soot-containing burner-stabilized laminar premixed flames is problematical: spatial resolution and residence times are limited at the pressures of interest for practical applications, flame structure is sensitive to minor burner construction details so that experimental reproducibility is not very good, consistent burner behavior over the lengthy test programs needed to measure soot formation properties is hard to achieve, and burners have poor durability. Fortunately, many of these problems are mitigated for soot-containing, freely-propagating laminar premixed flames. The present investigation seeks to extend work in this laboratory for various soot processes in flames by observing soot formation in freely-propagating laminar premixed flames. Measurements are being made at both Normal Gravity (NG) and MicroGravity (MG), using a short-drop free-fall facility to provide MG conditions.

  10. Nitrous Oxide-Oxygen Sedation: USAF Dental Guidelines.

    Science.gov (United States)

    1981-11-01

    the patient with a history of a seizure disorder that is controlled by anticonvulsives . The patient probably at the highest risk of developing...Refusal by patient (be sure to get parent’s pert;,ission for all pediatric patients). 2. Nasal obstruction. 3. O.per respiratory tract infection. 4

  11. A simple one-step chemistry model for partially premixed hydrocarbon combustion

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Tarrazo, Eduardo [Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Sanchez, Antonio L. [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, Leganes 28911 (Spain); Linan, Amable [ETSI Aeronauticos, Pl. Cardenal Cisneros 3, Madrid 28040 (Spain); Williams, Forman A. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States)

    2006-10-15

    This work explores the applicability of one-step irreversible Arrhenius kinetics with unity reaction order to the numerical description of partially premixed hydrocarbon combustion. Computations of planar premixed flames are used in the selection of the three model parameters: the heat of reaction q, the activation temperature T{sub a}, and the preexponential factor B. It is seen that changes in q with equivalence ratio f need to be introduced in fuel-rich combustion to describe the effect of partial fuel oxidation on the amount of heat released, leading to a universal linear variation q(f) for f>1 for all hydrocarbons. The model also employs a variable activation temperature T{sub a}(f) to mimic changes in the underlying chemistry in rich and very lean flames. The resulting chemistry description is able to reproduce propagation velocities of diluted and undiluted flames accurately over the whole flammability limit. Furthermore, computations of methane-air counterflow diffusion flames are used to test the proposed chemistry under nonpremixed conditions. The model not only predicts the critical strain rate at extinction accurately but also gives near-extinction flames with oxygen leakage, thereby overcoming known predictive limitations of one-step Arrhenius kinetics. (author)

  12. Sedation and Monitoring in the Pediatric Patient during Gastrointestinal Endoscopy.

    Science.gov (United States)

    Chung, Hyun Kee; Lightdale, Jenifer R

    2016-07-01

    Sedation is a fundamental component of pediatric gastrointestinal procedures. The 2 main types of sedation for pediatric endoscopy remain general anesthesia and procedural sedation. Although anesthesiologist-administered sedation protocols are more common, there is no ideal regimen for endoscopy in children. This article discusses specific levels of sedation for endoscopy as well as various regimens that can be used to achieve each. Risks and considerations that may be specific to performing gastrointestinal procedures in children are reviewed. Finally, potential future directions for sedation and monitoring that may change the practice of pediatric gastroenterology and ultimately patient outcomes are examined. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Sedation for pediatric diagnostic imaging: use of pediatric and nursing resources as an alternative to a radiology department sedation team

    International Nuclear Information System (INIS)

    Ruess, Lynne; O'Connor, Stephen C.; Mikita, Cecilia P.; Creamer, Kevin M.

    2002-01-01

    Objective. To develop a pathway to provide safe, effective, and efficient sedation for pediatric diagnostic imaging studies using non-radiology personnel. Materials and methods. A multidisciplinary team considered manpower and training requirements and national sedation standards before designing a sedation pathway, which included scheduling, pre-sedation history and physical, medication protocols, and monitoring. Oral and IV medication protocols were developed based on patient age and weight. Sedation delays were defined as >15 min (IV) or >30 min (PO) from start of sedation to start of imaging. A sedation failure resulted in an incomplete diagnostic imaging study. Failure rates of 124 sedations before and 388 sedations after the pathway were compared.Results. The sedation failure rate for 7 months prior to pathway initiation was 15% (19/124). In the first 25 months after pathway initiation, failures were significantly reduced to 1.5% (6/388) (P 55 min). Deviation from the recommended medication protocol accounted for most of the 115 delays. Only minor adverse events were seen (12/388, 3.1%).Conclusion. Implementing a pediatric sedation pathway significantly decreases the sedation failure rate. Pediatric residents and nurses can safely, effectively and efficiently sedate pediatric patients for routine diagnostic imaging procedures without the need for a radiology department sedation team in a department with a small-to-moderate volume of pediatric patients. (orig.)

  14. [AWAKE CRANIOTOMY: IN SEARCH FOR OPTIMAL SEDATION].

    Science.gov (United States)

    Kulikova, A S; Sel'kov, D A; Kobyakov, G L; Shmigel'skiy, A V; Lubnin, A Yu

    2015-01-01

    Awake craniotomy is a "gold standard"for intraoperative brain language mapping. One of the main anesthetic challenge of awake craniotomy is providing of optimal sedation for initial stages of intervention. The goal of this study was comparison of different technics of anesthesia for awake craniotomy. Materials and methods: 162 operations were divided in 4 groups: 76 cases with propofol sedation (2-4mg/kg/h) without airway protection; 11 cases with propofol sedation (4-5 mg/kg/h) with MV via LMA; 36 cases of xenon anesthesia; and 39 cases with dexmedetomidine sedation without airway protection. Results and discussion: brain language mapping was successful in 90% of cases. There was no difference between groups in successfulness of brain mapping. However in the first group respiratory complications were more frequent. Three other technics were more safer Xenon anesthesia was associated with ultrafast awakening for mapping (5±1 min). Dexmedetomidine sedation provided high hemodynamic and respiratory stability during the procedure.

  15. Rectal Sedation with Thiopental in Children

    International Nuclear Information System (INIS)

    Granados, Ana Maria; Levy, Wilma; Badiel, Marisol; Cruz Libreros, Alejandro; Toro Gutierrez, Juan Sebastian

    2012-01-01

    Objective: to determine the effectiveness of a rectal sedation protocol with sodium thiopental in children undergoing diagnostic imaging studies in a level-four-complexity health care facility. Materials and Methods: this case series observational study was developed between the months of January and March 2004 in the Fundacion clinica Valle del Lili. All pediatric patients between the ages of three months and eight years of age who underwent an imaging study were included. A dose of 25-40 mg/kg of sodium thiopental was administered rectally. Successful sedation was defined as one that allowed the successful completion of the study with the least number of motion artifacts. The features of the sedation and the adverse effects were evaluated. Results: the study population included 103 children with a median age of two years. The imaging studies were successfully concluded in 97% of the patients. The average total time until complete awakening was 2.9 hours. With respect to the interruption of sedation, we found statistically significant differences between the children who were kept awake the night before the procedure and those who were not. The most common adverse effect was diarrhea, which was recorded in 13 patients. Five of the patients required a supplemental dose of the sedative. There were two cases of increased salivation and one of vomiting, yet they resolved spontaneously. Conclusions: this rectal sodium thiopental protocol is a safe and effective procedure for the completion of diagnostic imaging studies in the pediatric population at our health care center.

  16. Anaesthesia and Sedation for the Autistic Patient.

    Science.gov (United States)

    Sacoor, Sarah

    2017-01-01

    Autism is a disability that affects how a person communicates and relates to the world around them. Patients on the autistic spectrum may be referred to a Special Care Dentistry service to be managed under sedation or general anaesthetic, as their visit to the dentist can be stressful and disruptive to their routine. As it is a spectrum disorder, each patient needs to be assessed individually in order to determine whether sedation or general anaesthetic would be appropriate for them. Some autistic patients may have good verbal communication and mild learning difficulties, and may be able to tolerate treatment under local anaesthetic with behavioural management alone. On the other end of the spectrum, patients with severe autism and learning difficulties may not permit the dentist to even examine them and will require a general anaesthetic. There will also be patients on the autistic spectrum who are suitable for conscious sedation depending on their level of learning difficulty and cooperation. Oral and transmucosal sedation can also be useful for providing presedation to a patient to facilitate venous access. In order to minimise distress to the patient, it is important that adequate sedation, anaesthesia and analgesia are achieved both perioperatively and post-operatively.

  17. Ketamine-propofol sedation in circumcision

    Directory of Open Access Journals (Sweden)

    Handan Gulec

    2015-10-01

    Full Text Available ABSTRACTBACKGROUND AND OBJECTIVE: To compare the therapeutic effects of ketamine alone or ketamine plus propofol on analgesia, sedation, recovery time, side effects in premedicated children with midazolam-ketamine-atropin who are prepared circumcision operation.METHODS: 60 American Society of Anaesthesiologists physical status I-II children, aged between 3 and 9 years, undergoing circumcision operations under sedation were recruited according to a randomize and double-blind institutional review board-approved protocol. Patients were randomized into two groups via sealed envelope assignment. Both groups were administered a mixture of midazolam 0.05 mg/kg + ketamine 3 mg/kg + atropine 0.02 mg/kg intramuscularly in the presence of parents in the pre-operative holding area. Patients were induced with propofol-ketamine in Group I or ketamine alone in Group II.RESULTS: In the between-group comparisons, age, weight, initial systolic blood pressure, a difference in terms of the initial pulse rate was observed (p > 0.050. Initial diastolic blood pressure and subsequent serial measurements of 5, 10, 15, 20th min, systolic blood pressure, diastolic blood pressure and pulse rate in ketamine group were significantly higher (p < 0.050.CONCLUSION: Propofol-ketamine (Ketofol provided better sedation quality and hemodynamy than ketamine alone in pediatric circumcision operations. We did not observe significant complications during sedation in these two groups. Therefore, ketofol appears to be an effective and safe sedation method for circumcision operation.

  18. Intramuscular injection of alfaxalone in combination with butorphanol for sedation in cats.

    Science.gov (United States)

    Deutsch, Julia; Jolliffe, Colette; Archer, Emma; Leece, Elizabeth A

    2017-07-01

    To assess quality of sedation following intramuscular (IM) injection of two doses of alfaxalone in combination with butorphanol in cats. Prospective, randomized, 'blinded' clinical study. A total of 38 cats undergoing diagnostic imaging or noninvasive procedures. Cats were allocated randomly to be administered butorphanol 0.2 mg kg -1 combined with alfaxalone 2 mg kg -1 (group AB2) or 5 mg kg -1 (group AB5) IM. If sedation was inadequate, alfaxalone 2 mg kg -1 IM was administered and cats were excluded from further analysis. Temperament [1 (friendly) to 5 (aggressive)], response to injection, sedation score at 2, 6, 8, 15, 20, 30, 40, 50 and 60 minutes, overall sedation quality scored after data collection [1 (excellent) to 4 (inadequate)] and recovery quality were assessed. Heart rate (HR), respiratory rate (f R ) and arterial haemoglobin saturation (SpO 2 ) were recorded every 5 minutes. Groups were compared using t tests and Mann-Whitney U tests. Sedation was analysed using two-way anova, and additional alfaxalone using Fisher's exact test (p cats in AB2 and two in AB5 (p = 0.005). Recovery quality, HR, f R and SpO 2 were similar. Seven cats required oxygen supplementation. Complete recovery times were shorter in AB2 (81.8 ± 24.3 versus 126.6 ± 33.3 minutes; p = 0.009). Twitching was the most common adverse event. In combination with butorphanol, IM alfaxalone at 5 mg kg -1 provided better quality sedation than 2 mg kg -1 . Monitoring of SpO 2 is recommended. Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.

  19. Visual cortex reactivity in sedated children examined with perfusion MRI (FAIR)

    DEFF Research Database (Denmark)

    Born, A.P.; Rostrup, Egill; Miranda Gimenez-Ricco, Maria Jo

    2002-01-01

    Sleeping and sedated children can respond to visual stimulation with a decrease in blood oxygenation level dependent (BOLD) functional MRI signal response. The contribution of metabolic and hemodynamic parameters to this inverse signal response is incompletely understood. It has been hypothesized...... that it is caused by a relatively greater increase of oxygen consumption compared to rCBF (regional cerebral blood flow) increase. We studied the rCBF changes during visual stimulation in four sedated children, aged 4-71 months, and four alert adults, with an arterial water spin labeling technique (FAIR) and BOLD f.......99-2.93), respectively. Thus, in the children, an rCBF increase could not be detected by perfusion MRI, but indications of a FAIR signal decrease were found. An rCBF decrease in the primary visual cortex during stimulation has not been reported previously, but it is a possible explanation for the negative BOLD response...

  20. Palliative sedation: from the family perspective.

    Science.gov (United States)

    Vayne-Bossert, Petra; Zulian, Gilbert B

    2013-12-01

    Palliative sedation (PS) is a treatment option in case of refractory symptoms at the end of life. The emotional impact on nurses and doctors has been widely studied. We explore the experience of family members during a PS procedure. An anonymous questionnaire was sent to the closest family members (n = 17) of patients who died while receiving palliative sedation. The response rate was 59% (10 of 17). Nine relatives were sufficiently informed about PS. In all, 70% evaluated the chosen moment for initiation of PS as adequate. All the relatives noticed a significant improvement in the refractory symptom with a mean reduction in the estimated suffering of 6.25 points on a visual analog scale. Palliative sedation should be performed in the best possible way for the patient and his family in order to efficiently reduce a refractory symptom.

  1. Acoustic radiation from weakly wrinkled premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Lieuwen, Tim; Mohan, Sripathi; Rajaram, Rajesh; Preetham, [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0150 (United States)

    2006-01-01

    This paper describes a theoretical analysis of acoustic radiation from weakly wrinkled (i.e., u'/S{sub L}<1) premixed flames. Specifically, it determines the transfer function relating the spectrum of the acoustic pressure oscillations, P'({omega}), to that of the turbulent velocity fluctuations in the approach flow, U'({omega}). In the weakly wrinkled limit, this transfer function is local in frequency space; i.e., velocity fluctuations at a frequency {omega} distort the flame and generate sound at the same frequency. This transfer function primarily depends upon the flame Strouhal number St (based on mean flow velocity and flame length) and the correlation length, {lambda}, of the flow fluctuations. For cases where the ratio of the correlation length and duct radius {lambda}/a>>1, the acoustic pressure and turbulent velocity power spectra are related by P'({omega})-{omega}{sup 2}U'({omega}) and P'({omega})-U'({omega}) for St<<1 and St>>1, respectively. For cases where {lambda}/a<<1, the transfer functions take the form P'({omega})-{omega}{sup 2}({lambda}/a){sup 2}U'({omega}) and P'({omega})-{omega}{sup 2}({lambda}/a){sup 2}({psi}-{delta}ln({lambda}/a))U'({omega}) for St<<1 and St>>1, respectively, where (PS) and {delta} are constants. The latter result demonstrates that this transfer function does not exhibit a simple power law relationship in the high frequency region of the spectra. The simultaneous dependence of this pressure-velocity transfer function upon the Strouhal number and correlation length suggests a mechanism for the experimentally observed maximum in acoustic spectra and provides some insight into the controversy in the literature over how this peak should scale with the flame Strouhal number.

  2. Office-based deep sedation for pediatric ophthalmologic procedures using a sedation service model.

    Science.gov (United States)

    Lalwani, Kirk; Tomlinson, Matthew; Koh, Jeffrey; Wheeler, David

    2012-01-01

    Aims. (1) To assess the efficacy and safety of pediatric office-based sedation for ophthalmologic procedures using a pediatric sedation service model. (2) To assess the reduction in hospital charges of this model of care delivery compared to the operating room (OR) setting for similar procedures. Background. Sedation is used to facilitate pediatric procedures and to immobilize patients for imaging and examination. We believe that the pediatric sedation service model can be used to facilitate office-based deep sedation for brief ophthalmologic procedures and examinations. Methods. After IRB approval, all children who underwent office-based ophthalmologic procedures at our institution between January 1, 2000 and July 31, 2008 were identified using the sedation service database and the electronic health record. A comparison of hospital charges between similar procedures in the operating room was performed. Results. A total of 855 procedures were reviewed. Procedure completion rate was 100% (C.I. 99.62-100). There were no serious complications or unanticipated admissions. Our analysis showed a significant reduction in hospital charges (average of $1287 per patient) as a result of absent OR and recovery unit charges. Conclusions. Pediatric ophthalmologic minor procedures can be performed using a sedation service model with significant reductions in hospital charges.

  3. Office-Based Deep Sedation for Pediatric Ophthalmologic Procedures Using a Sedation Service Model

    Directory of Open Access Journals (Sweden)

    Kirk Lalwani

    2012-01-01

    Full Text Available Aims. (1 To assess the efficacy and safety of pediatric office-based sedation for ophthalmologic procedures using a pediatric sedation service model. (2 To assess the reduction in hospital charges of this model of care delivery compared to the operating room (OR setting for similar procedures. Background. Sedation is used to facilitate pediatric procedures and to immobilize patients for imaging and examination. We believe that the pediatric sedation service model can be used to facilitate office-based deep sedation for brief ophthalmologic procedures and examinations. Methods. After IRB approval, all children who underwent office-based ophthalmologic procedures at our institution between January 1, 2000 and July 31, 2008 were identified using the sedation service database and the electronic health record. A comparison of hospital charges between similar procedures in the operating room was performed. Results. A total of 855 procedures were reviewed. Procedure completion rate was 100% (C.I. 99.62–100. There were no serious complications or unanticipated admissions. Our analysis showed a significant reduction in hospital charges (average of $1287 per patient as a result of absent OR and recovery unit charges. Conclusions. Pediatric ophthalmologic minor procedures can be performed using a sedation service model with significant reductions in hospital charges.

  4. Experimental study of the structure of rich premixed 1,3-butadiene/CH4/O2/Ar flame.

    OpenAIRE

    Gueniche , Hadj-Ali; Glaude , Pierre-Alexandre; Fournet , René; Battin-Leclerc , Frédérique

    2006-01-01

    traduit de Fizika Goreniya I Vzryva, 2006, 42, 89-95.; The structure of a laminar rich premixed 1,3-C4H6/CH4/O2/Ar flame have been investigated. 1,3-Butadiene, methane, oxygen and argon mole fractions are 0.033; 0.2073; 0.3315, and 0.4280, respectively, for an equivalent ratio of 1.80. The flame has been stabilized on a burner at a pressure of 6.7 kPa (50 Torr). The concentration profiles of stable species were measured by gas chromatography after sampling with a quartz probe. Quantified spec...

  5. Experimental study of the structure of rich premixed 1,3-butadiene/CH4/O2/Ar flame

    OpenAIRE

    Gueniche, Hadj-Ali; Glaude, Pierre-Alexandre; Fournet, René; Battin-Leclerc, Frédérique

    2007-01-01

    The structure of a laminar rich premixed 1,3-C4H6/CH4/O2/Ar flame have been investigated. 1,3-Butadiene, methane, oxygen and argon mole fractions are 0.033; 0.2073; 0.3315, and 0.4280, respectively, for an equivalent ratio of 1.80. The flame has been stabilized on a burner at a pressure of 6.7 kPa (50 Torr). The concentration profiles of stable species were measured by gas chromatography after sampling with a quartz probe. Quantified species included carbon monoxide and dioxide, methane, oxyg...

  6. [Sedation in the terminal phase of life].

    Science.gov (United States)

    Verhagen, E H; Eliel, M R; de Graeff, A; Teunissen, S C

    1999-12-25

    In 2 patients, a woman aged 38 years and a man aged 48 years, in the terminal phase of life due to metastasized+ malignancy, palliative care failed. They suffered seriously from pain, delirium, restlessness, nausea, and fear. Deep sedation was given to induce almost continuous sleep without the intention of causing death. After one and five quiet days respectively the patients died. Deep sedation is an option when palliative care fails to diminish serious suffering. Midazolam, given by continuous subcutaneous infusion is the drug of choice.

  7. Three-dimensional simulations of cellular non-premixed jet flames

    Energy Technology Data Exchange (ETDEWEB)

    Valaer, A.L.; Frouzakis, C.E.; Boulouchos, K. [Aerothermochemistry and Combustion System Laboratory, Swiss Federal Institute of Technology, CH-8092 Zurich (Switzerland); Papas, P. [Division of Engineering, Colorado School of Mines, Golden, CO 80401 (United States); Tomboulides, A.G. [Department of Engineering and Management of Energy Resources, University of Western Macedonia, 50100 Kozani (Greece)

    2010-04-15

    The formation, dynamics and structure of cellular flames in circular non-premixed jets are examined with three-dimensional numerical simulations incorporating detailed descriptions of chemistry and transport. Similar to past experiments reported in the literature, CO{sub 2}-diluted hydrogen in diluted or pure oxygen co-flowing streams in the proximity of the extinction limit are considered. As in the experiments, several preferred cellular states are found to co-exist with the particular state realized depending on initial conditions as well as on the jet characteristics. The simulations provide additionally the temporal transitions to different stationary or rotating cellular flames, their detailed structure, and the dependence of the scaling of the realized number of cells with the vorticity thickness. (author)

  8. Auditory processing during deep propofol sedation and recovery from unconsciousness

    OpenAIRE

    Koelsch, Stefan; Heinke, Wolfgang; Sammler, Daniela; Olthoff, Derk

    2006-01-01

    Objective Using evoked potentials, this study investigated effects of deep propofol sedation, and effects of recovery from unconsciousness, on the processing of auditory information with stimuli suited to elicit a physical MMN, and a (music-syntactic) ERAN. Methods Levels of sedation were assessed using the Bispectral Index (BIS) and the Modified Observer's Assessment of Alertness and Sedation Scale (MOAAS). EEG-measurements were performed during wakefulness, deep propofol sedation (MOAAS 2–3...

  9. Færre indikationer for sedation ved respiratorbehandling

    DEFF Research Database (Denmark)

    Strøm, Thomas; Rian, Omar; Toft, Palle

    2012-01-01

    Critically ill patients undergoing mechanical ventilation have traditionally been deeply sedated. In the latest decade growing evidence supports less sedation as being beneficial for the patients. A daily interruption of sedation has been shown to reduce the length of mechanical ventilation and t...

  10. Neural correlates of successful semantic processing during propofol sedation

    NARCIS (Netherlands)

    Adapa, Ram M.; Davis, Matthew H.; Stamatakis, Emmanuel A.; Absalom, Anthony R.; Menon, David K.

    Sedation has a graded effect on brain responses to auditory stimuli: perceptual processing persists at sedation levels that attenuate more complex processing. We used fMRI in healthy volunteers sedated with propofol to assess changes in neural responses to spoken stimuli. Volunteers were scanned

  11. Moderate and deep nurse-administered propofol sedation is safe

    DEFF Research Database (Denmark)

    Jensen, Jeppe Thue; Møller, Ann; Hornslet, Pernille

    2015-01-01

    INTRODUCTION: Non-anaesthesiologist-administered propofol sedation (NAPS/NAAP) is increasingly used in many countries. Most regimens aim for light or moderate sedation. Little evidence on safety of deep NAPS sedation is available. The aim of this study was to explore the safety of intermittent deep...

  12. Pediatric Gastrointestinal Endoscopic Sedation: A 2010 Nationwide Survey in Taiwan

    Directory of Open Access Journals (Sweden)

    Po-Hon Chen

    2012-06-01

    Conclusion: A majority of pediatric EGD in Taiwan was performed under sedation and applied more often to younger children. Endoscopists were more satisfied during EGD when practicing sedation. This survey should help formulate updated practice guidelines and policies regarding endoscopic sedation.

  13. Study of possible reduction or withdrawal of vitamin premix during ...

    African Journals Online (AJOL)

    Jane

    2011-07-06

    Jul 6, 2011 ... The effect of dietary vitamin premix withdrawal or reduction between 29 and 35, 36 and 42, and 29 and. 42 days of age on broiler chicken performance and immunocompetence was evaluated. The diets were formulated based on wheat and barley, and the experiment was conducted in floor pens ...

  14. Study of possible reduction or withdrawal of vitamin premix during ...

    African Journals Online (AJOL)

    The effect of dietary vitamin premix withdrawal or reduction between 29 and 35, 36 and 42, and 29 and 42 days of age on broiler chicken performance and immunocompetence was evaluated. The diets were formulated based on wheat and barley, and the experiment was conducted in floor pens (experiment 1) and battery ...

  15. Fuel and combustion stratification study of Partially Premixed Combustion

    NARCIS (Netherlands)

    Izadi Najafabadi, M.; Dam, N.; Somers, B.; Johansson, B.

    2016-01-01

    Relatively high levels of stratification is one of the main advantages of Partially Premixed Combustion (PPC) over the Homogeneous Charge Compression Ignition (HCCI) concept. Fuel stratification smoothens heat release and improves controllability of this kind of combustion. However, the lack of a

  16. Effect of Different Routes of Vitamin/Mineral premix Administration ...

    African Journals Online (AJOL)

    An experiment was conducted to determine the best route of vitamin/mineral premix administration to broilers using a completely randomized design. The routes of administrations were through formulated diets, daily in drinking water, and daily mixing in feed ration. Histological examination of the liver did not reveal any ...

  17. Sedatives for opiate withdrawal in newborn infants.

    Science.gov (United States)

    Osborn, David A; Jeffery, Heather E; Cole, Michael J

    2010-10-06

    Neonatal abstinence syndrome (NAS) due to opiate withdrawal may result in disruption of the mother-infant relationship, sleep-wake abnormalities, feeding difficulties, weight loss and seizures. Treatments used to ameliorate symptoms and reduce morbidity include opiates, sedatives and non-pharmacological treatments. To assess the effectiveness and safety of using a sedative compared to a non-opiate control for NAS due to withdrawal from opiates, and to determine which type of sedative is most effective and safe. This update included searches of the Cochrane Central Register of Controlled Trials (Issue 1, 2010), MEDLINE 1966 to April 2010 and abstracts of conference proceedings. Trials enrolling infants with NAS born to mothers with an opiate dependence with > 80% follow-up and using random or quasi-random allocation to sedative or control. Control could include another sedative or non-pharmacological treatment. Each author assessed study quality and extracted data independently. Seven studies enrolling 385 patients were included. There were substantial methodological concerns for most studies including the use of quasi-random allocation methods and sizeable, largely unexplained differences in reported numbers allocated to each group.One study reported phenobarbitone compared to supportive care alone did not reduce treatment failure or time to regain birthweight, but resulted in a significant reduction in duration of supportive care (MD -162.1 min/day, 95% CI -249.2, -75.1). Comparing phenobarbitone to diazepam, meta-analysis of two studies found phenobarbitone resulted in a significant reduction in treatment failure (typical RR 0.39, 95% CI 0.24, 0.62). Comparing phenobarbitone with chlorpromazine, one study reported no significant difference in treatment failure.In infants treated with an opiate, one study reported addition of clonidine resulted in no significant difference in treatment failure, seizures or mortality. In infants treated with an opiate, one study

  18. Quantification of extinction mechanism in counterflow premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sang Kyu [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Cho, Eun Seong [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of); Chung, Suk Ho [Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2014-09-15

    The extinction mechanisms of stretched premixed flames have been investigated numerically for the fuels of CH{sub 4}, C{sub 3}H{sub 8}, H{sub 2}, CO and for the mixture fuels of CH{sub 4}+H{sub 2} and CO+H{sub 2} by adopting symmetric double premixed flames in a counterflow configuration. The local equilibrium temperature concept was used as a measure of energy loss or gain in order to quantify the extinction mechanism by preferential diffusion and/or incomplete reaction. The energy loss ratio from preferential diffusion arising from non-unity Lewis number and the loss ratio from incomplete reaction were calculated at various equivalence ratios near flame extinction. The results showed that the extinction of lean H{sub 2} , CH{sub 4}, CH{sub 4}+H{sub 2}, CO+H{sub 2}, and rich C{sub 3}H{sub 8} premixed flames was caused by incomplete reaction due to insufficient reaction time, indicating that the effective Lewis number was smaller than unity, while the effect of preferential diffusion resulted in energy gain. However, the extinction of rich H{sub 2}, CH{sub 4}, CH{sub 4}+H{sub 2}, CO+H{sub 2}, and lean C{sub 3}H{sub 8} premixed flames was affected by the combined effects of preferential diffusion and incomplete reaction indicating that the effective Lewis number was larger than unity. In CO premixed flames, incomplete reaction was dominant in both lean and rich cases due to the effective Lewis number close to unity. The effect of H{sub 2} mixing to CO is found to be quite significant as compared to CH{sub 4}+H{sub 2} cases, which can alter the flame behavior of CO flames to that of H{sub 2}.

  19. Quantification of extinction mechanism in counterflow premixed flames

    International Nuclear Information System (INIS)

    Choi, Sang Kyu; Cho, Eun Seong; Chung, Suk Ho

    2014-01-01

    The extinction mechanisms of stretched premixed flames have been investigated numerically for the fuels of CH 4 , C 3 H 8 , H 2 , CO and for the mixture fuels of CH 4 +H 2 and CO+H 2 by adopting symmetric double premixed flames in a counterflow configuration. The local equilibrium temperature concept was used as a measure of energy loss or gain in order to quantify the extinction mechanism by preferential diffusion and/or incomplete reaction. The energy loss ratio from preferential diffusion arising from non-unity Lewis number and the loss ratio from incomplete reaction were calculated at various equivalence ratios near flame extinction. The results showed that the extinction of lean H 2 , CH 4 , CH 4 +H 2 , CO+H 2 , and rich C 3 H 8 premixed flames was caused by incomplete reaction due to insufficient reaction time, indicating that the effective Lewis number was smaller than unity, while the effect of preferential diffusion resulted in energy gain. However, the extinction of rich H 2 , CH 4 , CH 4 +H 2 , CO+H 2 , and lean C 3 H 8 premixed flames was affected by the combined effects of preferential diffusion and incomplete reaction indicating that the effective Lewis number was larger than unity. In CO premixed flames, incomplete reaction was dominant in both lean and rich cases due to the effective Lewis number close to unity. The effect of H 2 mixing to CO is found to be quite significant as compared to CH 4 +H 2 cases, which can alter the flame behavior of CO flames to that of H 2 .

  20. Quantification of extinction mechanism in counterflow premixed flames

    KAUST Repository

    Choi, Sangkyu

    2014-09-01

    The extinction mechanisms of stretched premixed flames have been investigated numerically for the fuels of CH4, C3H8, H2, CO and for the mixture fuels of CH4+H2 and CO+H2 by adopting symmetric double premixed flames in a counterflow configuration. The local equilibrium temperature concept was used as a measure of energy loss or gain in order to quantify the extinction mechanism by preferential diffusion and/or incomplete reaction. The energy loss ratio from preferential diffusion arising from non-unity Lewis number and the loss ratio from incomplete reaction were calculated at various equivalence ratios near flame extinction. The results showed that the extinction of lean H2, CH4, CH4+H2, CO+H2, and rich C3H8 premixed flames was caused by incomplete reaction due to insufficient reaction time, indicating that the effective Lewis number was smaller than unity, while the effect of preferential diffusion resulted in energy gain. However, the extinction of rich H2, CH4, CH4+H2, CO+H2, and lean C3H8 premixed flames was affected by the combined effects of preferential diffusion and incomplete reaction indicating that the effective Lewis number was larger than unity. In CO premixed flames, incomplete reaction was dominant in both lean and rich cases due to the effective Lewis number close to unity. The effect of H2 mixing to CO is found to be quite significant as compared to CH4+H2 cases, which can alter the flame behavior of CO flames to that of H2.

  1. SEDATIVE AND ANALGESIC EFFECTS OF DETOMIDINE HYDROCHLORIDE IN GOATS

    OpenAIRE

    A. N. Tunio., A. B. Kalhoro and I.H. Kathio1

    2003-01-01

    The sedative and analgesic effects of three dose rates of detomidine (40, 50 and 60µg/kg body weight) were studied in six goats. Moderate to deep sedation occurred after administration of 40µg/kg of detomidine as compared to deep sedation produced by 50 and 60µg/kg of detomidine. The degree, onset and duration of sedation and onset and duration of maximum sedation were all dose dependent. Skin analgesia and recumbency were produced in all animals with higher doses (50 and 60µg/kg) and in thre...

  2. Effect of sedation with detomidine and butorphanol on pulmonary gas exchange in the horse.

    Science.gov (United States)

    Nyman, Görel; Marntell, Stina; Edner, Anna; Funkquist, Pia; Morgan, Karin; Hedenstierna, Göran

    2009-05-07

    Sedation with alpha2-agonists in the horse is reported to be accompanied by impairment of arterial oxygenation. The present study was undertaken to investigate pulmonary gas exchange using the Multiple Inert Gas Elimination Technique (MIGET), during sedation with the alpha2-agonist detomidine alone and in combination with the opioid butorphanol. Seven Standardbred trotter horses aged 3-7 years and weighing 380-520 kg, were studied. The protocol consisted of three consecutive measurements; in the unsedated horse, after intravenous administration of detomidine (0.02 mg/kg) and after subsequent butorphanol administration (0.025 mg/kg). Pulmonary function and haemodynamic effects were investigated. The distribution of ventilation-perfusion ratios (VA/Q) was estimated with MIGET. During detomidine sedation, arterial oxygen tension (PaO2) decreased (12.8 +/- 0.7 to 10.8 +/- 1.2 kPa) and arterial carbon dioxide tension (PaCO2) increased (5.9 +/- 0.3 to 6.1 +/- 0.2 kPa) compared to measurements in the unsedated horse. Mismatch between ventilation and perfusion in the lungs was evident, but no increase in intrapulmonary shunt could be detected. Respiratory rate and minute ventilation did not change. Heart rate and cardiac output decreased, while pulmonary and systemic blood pressure and vascular resistance increased. Addition of butorphanol resulted in a significant decrease in ventilation and increase in PaCO2. Alveolar-arterial oxygen content difference P(A-a)O2 remained impaired after butorphanol administration, the VA/Q distribution improved as the decreased ventilation and persistent low blood flow was well matched. Also after subsequent butorphanol no increase in intrapulmonary shunt was evident. The results of the present study suggest that both pulmonary and cardiovascular factors contribute to the impaired pulmonary gas exchange during detomidine and butorphanol sedation in the horse.

  3. Effect of sedation with detomidine and butorphanol on pulmonary gas exchange in the horse

    Directory of Open Access Journals (Sweden)

    Morgan Karin

    2009-05-01

    Full Text Available Abstract Background Sedation with α2-agonists in the horse is reported to be accompanied by impairment of arterial oxygenation. The present study was undertaken to investigate pulmonary gas exchange using the Multiple Inert Gas Elimination Technique (MIGET, during sedation with the α2-agonist detomidine alone and in combination with the opioid butorphanol. Methods Seven Standardbred trotter horses aged 3–7 years and weighing 380–520 kg, were studied. The protocol consisted of three consecutive measurements; in the unsedated horse, after intravenous administration of detomidine (0.02 mg/kg and after subsequent butorphanol administration (0.025 mg/kg. Pulmonary function and haemodynamic effects were investigated. The distribution of ventilation-perfusion ratios (VA/Q was estimated with MIGET. Results During detomidine sedation, arterial oxygen tension (PaO2 decreased (12.8 ± 0.7 to 10.8 ± 1.2 kPa and arterial carbon dioxide tension (PaCO2 increased (5.9 ± 0.3 to 6.1 ± 0.2 kPa compared to measurements in the unsedated horse. Mismatch between ventilation and perfusion in the lungs was evident, but no increase in intrapulmonary shunt could be detected. Respiratory rate and minute ventilation did not change. Heart rate and cardiac output decreased, while pulmonary and systemic blood pressure and vascular resistance increased. Addition of butorphanol resulted in a significant decrease in ventilation and increase in PaCO2. Alveolar-arterial oxygen content difference P(A-aO2 remained impaired after butorphanol administration, the VA/Q distribution improved as the decreased ventilation and persistent low blood flow was well matched. Also after subsequent butorphanol no increase in intrapulmonary shunt was evident. Conclusion The results of the present study suggest that both pulmonary and cardiovascular factors contribute to the impaired pulmonary gas exchange during detomidine and butorphanol sedation in the horse.

  4. A favorable course of palliative sedation: searching for indicators using caregivers' perspectives.

    Science.gov (United States)

    Brinkkemper, Tijn; Rietjens, Judith A C; Deliens, Luc; Ribbe, Miel W; Swart, Siebe J; Loer, Stephan A; Zuurmond, Wouter W A; Perez, Roberto S G M

    2015-03-01

    Comparing characteristics of a favorable sedation course during palliative sedation to a less favorable course based on the reports Dutch physicians and nurses. Cases identified as having a favorable sedation course less often concerned a male patient (P = .019 nurses' cases), reached the intended sedation depth significantly quicker (P sedation (P = .015 physicians' cases), and had a shorter total duration of sedation compared (P sedation course. A favorable course during palliative sedation seems more probable when health care professionals report on a (relatively) shorter time to reach the required depth of sedation and when a deeper level of sedation can be obtained. © The Author(s) 2013.

  5. Rectal Thiopental versus Intramuscular Ketamine in Pediatric Procedural Sedation and Analgesia; a Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Reza Azizkhani

    2015-01-01

    Full Text Available Introduction: Physicians frequently deal with procedures which require sedation of pediatric patients. Laceration repair is one of them. No study has been performed regarding the comparison between induction of sedation with sodium thiopental and ketamine in laceration repair. Therefore, the present study was aimed to comparison of induced sedation by rectal sodium thiopental and muscular injection of hydrochloride ketamine in pediatric patients need laceration repair. Methods: The presented study is a single-blinded clinical trial performed through 2013 to 2014 in Ayatollah Kashani and Alzahra Hospitals, Isfahan, Iran. Patients from 3 months to 14 years, needed sedation for laceration repair, were entered. Patients were sequentially evaluated and randomly categorized in two groups of hydrochloride ketamine with dose of 2-4 milligram per kilogram and sodium thiopental with dose of 25 milligram per kilogram. Demographic data and vital signs before drug administration and after induction of sedation, Ramsey score, time to onset of action, and sedation recovery time were evaluated. Chi-squared, Mann-Whitney, and Non-parametric analysis of covariance tests were used. P<0.05 was considered as a significant level. Results: In this study 60 pediatric patients were entered. 30 patients with mean age of 42.8±18.82 months were received sodium thiopental and the rest with mean age of 30.08±16.88 months given ketamine. Mann-Whitney test was showed that time to onset of action in sodium thiopental group (28.23±5.18 minutes was significantly higher than ketamine (7.77±4.13 minutes, (p<0.001. The sedation recovery time in ketamine group (29.83±7.70 was higher than sodium thiopental. Depth of sedation had no significant difference between two groups based on Ramsey score (p=0.87. No significant difference was seen between two groups in the respiratory rate (df=1, 58; F=0.002; P=0.96 and heart rate (df=1, 58; F=0.98; P=0.33. However, arterial oxygen

  6. CSP-based chemical kinetics mechanisms simplification strategy for non-premixed combustion: An application to hybrid rocket propulsion

    KAUST Repository

    Ciottoli, Pietro P.

    2017-08-14

    A set of simplified chemical kinetics mechanisms for hybrid rocket applications using gaseous oxygen (GOX) and hydroxyl-terminated polybutadiene (HTPB) is proposed. The starting point is a 561-species, 2538-reactions, detailed chemical kinetics mechanism for hydrocarbon combustion. This mechanism is used for predictions of the oxidation of butadiene, the primary HTPB pyrolysis product. A Computational Singular Perturbation (CSP) based simplification strategy for non-premixed combustion is proposed. The simplification algorithm is fed with the steady-solutions of classical flamelet equations, these being representative of the non-premixed nature of the combustion processes characterizing a hybrid rocket combustion chamber. The adopted flamelet steady-state solutions are obtained employing pure butadiene and gaseous oxygen as fuel and oxidizer boundary conditions, respectively, for a range of imposed values of strain rate and background pressure. Three simplified chemical mechanisms, each comprising less than 20 species, are obtained for three different pressure values, 3, 17, and 36 bar, selected in accordance with an experimental test campaign of lab-scale hybrid rocket static firings. Finally, a comprehensive strategy is shown to provide simplified mechanisms capable of reproducing the main flame features in the whole pressure range considered.

  7. Palliative sedation: not just normal medical practice. Ethical reflections on the Royal Dutch Medical Association's guideline on palliative sedation.

    Science.gov (United States)

    Janssens, Rien; van Delden, Johannes J M; Widdershoven, Guy A M

    2012-11-01

    The main premise of the Royal Dutch Medical Association's (RDMA) guideline on palliative sedation is that palliative sedation, contrary to euthanasia, is normal medical practice. Although we do not deny the ethical distinctions between euthanasia and palliative sedation, we will critically analyse the guideline's argumentation strategy with which euthanasia is demarcated from palliative sedation. First, we will analyse the guideline's main premise, which entails that palliative sedation is normal medical treatment. After this, we will critically discuss three crucial propositions of the guideline that are used to support this premise: (1) the patient's life expectancy should not exceed 2 weeks; (2) the aim of the physician should be to relieve suffering and (3) expert consultation is optional. We will conclude that, if inherent problematic aspects of palliative sedation are taken seriously, palliative sedation is less normal than it is now depicted in the guideline.

  8. Advanced paediatric conscious sedation: an alternative to dental general anaesthetic in the U.K.

    Science.gov (United States)

    Hand, Darren; Averley, Paul; Lyne, John; Girdler, Nick

    2011-01-01

    Child dental anxiety is widespread, and it is not always possible to treat children using traditional methods such as behavioural management, local anaesthesia and even relative analgesia. In such cases a dental general anaesthetic (DGA) is the only option available to facilitate dental treatment in anxious children. This study describes an advanced conscious sedation protocol which allows invasive treatment to be carried out in anxious children. It incorporates the use of titrated intravenous midazolam and fentanyl and inhalation agents, sevoflurane and nitrous oxide/oxygen, which is administered by a Consultant Anaesthetist. The aim is to produce an evidence- based study which can offer a sedation technique as a safe and effective alternative to a DGA. Retrospective audit. 267 clinical records were audited retrospectively from a specialist sedation-based clinic, for children aged 5-15 years old. The subjects all underwent invasive dental procedures with this technique between August and November 2008 as an alternative to a DGA. 262/267 (98%) of the subjects were treated safely and successfully and without the loss of verbal communication using this technique. This included many treatments requiring four quadrant dentistry, with both restorations and extractions as necessary being carried out in one visit. 5 subjects (2%) did not tolerate treatment and had to be referred for a DGA. No medical emergencies occurred. Based on the evidence for this group of patients, this advanced conscious sedation technique, offers a safe and effective alternative to DGA. This technique must be carried out in an appropriate environment by an appropriately trained and experienced team who are able to comply with the recommendations for "alternative" sedation techniques.

  9. Safety, cost, and clinical considerations for the use of premixed parenteral nutrition.

    Science.gov (United States)

    Hall, Jacob W

    2015-06-01

    Premixed parenteral nutrition (PN) can be used for PN therapy in place of traditional compounded or customized PN. Premixed PN may have a number of advantages over compounded PN such as decreased costs, decreased compounding time, reduced chance for error, and reduced incidence of bloodstream infections. However, premixed PN may not be appropriate for all patients and may have other additional costs associated with its use. This article discusses the data available with regard to the use of premixed PN, focusing on the potential advantages and disadvantages of using premixed PN, and also discusses the implementation of premixed PN in a large tertiary cancer center. © 2015 American Society for Parenteral and Enteral Nutrition.

  10. Large eddy simulation of premixed and non-premixed combustion in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Undapalli, Satish

    A new combustor referred to as Stagnation Point Reverse Flow (SPRF) combustor has been developed at Georgia Tech to meet the increasingly stringent emission regulations. The combustor incorporates a novel design to meet the conflicting requirements of low pollution and high stability in both premixed and non-premixed modes. The objective of this thesis work is to perform Large Eddy Simulations (LES) on this lab-scale combustor and elucidate the underlying physics that has resulted in its excellent performance. To achieve this, numerical simulations have been performed in both the premixed and non-premixed combustion modes, and velocity field, species field, entrainment characteristics, flame structure, emissions, and mixing characteristics have been analyzed. Simulations have been carried out first for a non-reactive case to resolve relevant fluid mechanics without heat release by the computational grid. The computed mean and RMS quantities in the non-reacting case compared well with the experimental data. Next, the simulations were extended for the premixed reactive case by employing different sub-grid scale combustion chemistry closures: Eddy Break Up (EBU), Artificially Thickened Flame (TF) and Linear Eddy Mixing (LEM) models. Results from the EBU and TF models exhibit reasonable agreement with the experimental velocity field. However, the computed thermal and species fields have noticeable discrepancies. Only LEM with LES (LEMLES), which is an advanced scalar approach, has been able to accurately predict both the velocity and species fields. Scalar mixing plays an important role in combustion, and this is solved directly at the sub-grid scales in LEM. As a result, LEM accurately predicts the scalar fields. Due to the two way coupling between the super-grid and sub-grid quantities, the velocity predictions also compare very well with the experiments. In other approaches, the sub-grid effects have been either modeled using conventional approaches (EBU) or need

  11. Increased precuneus connectivity during propofol sedation.

    Science.gov (United States)

    Liu, Xiaolin; Li, Shi-Jiang; Hudetz, Anthony G

    2014-02-21

    Using functional magnetic resonance imaging in human participants, we show that sedation by propofol to the point of lost overt responsiveness during the performance of an auditory verbal memory task unexpectedly increases functional connectivity of the precuneus with cortical regions, particularly the dorsal prefrontal and visual cortices. After recovery of consciousness, functional connectivity returns to a pattern similar to that observed during the wakeful baseline. In the context of a recent proposal that highlights the uncoupling of consciousness, connectedness, and responsiveness in general anesthesia, the increased precuneus functional connectivity under propofol sedation may reflect disconnected endogenous mentation or dreaming that continues at a reduced level of metabolic activity. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. Analgesics and sedatives in vascular interventionist radiologic

    International Nuclear Information System (INIS)

    Gregorio, M.A. de; Opta, J.M.; Pulido, J.M.; Encarnacion, C.E.; Arino, I., Fernandez, J.A.; Alfonso, E.R.

    1993-01-01

    Interventionist radiology routinely requires the use of different drugs (analgesics and sedatives) in the course of a procedure. Aside from their therapeutic action, these drugs can produce secondary or undesirable effects, making necessary an in-depth knowledge of them to assure their safe and efficient management. The aim of this work is to provide the vascular interventionist radiologist with additional information on the management of those drugs that contribute to minimizing patient discomfort and pain in interventionist procedures. Author

  13. [Comparison of two methods for conscious sedation in maxillofacial surgery with local anesthesia].

    Science.gov (United States)

    Zöller, J; Zöller, B; Hassfeld, S; Köhler, J

    1992-01-01

    A randomised, prospective study was conducted to compare the efficiency and safety of methods for intravenous conscious sedation in patients undergoing oral surgery under local analgesia. 150 systemically healthy patients (ASA Class I and II) participated. Three groups were formed: group 1 received 0.05 mg/kg midazolam; group 2 0.05 mg/kg midazolam, 1.5 mg/kg tramadol, 50 mg alizaprid; group 3 0.05 mg/kg midazolam, 0.2 mg/kg nalbuphine, 50 mg alizaprid. Blood pressure, heart rate and oxygen saturation were measured throughout the procedure. The results confirmed that the use of nalbuphine (group 3) allows a reduction in the mean dosage of midazolam required to produce satisfactory sedation and effected a more rapid recovery time compared to group 12 and 2. With the combination nalbuphine and alizaprid nausea and vomiting could be reduced for the most part compared to group 2.

  14. Dreaming and recall during sedation for colonoscopy.

    Science.gov (United States)

    Stait, M L; Leslie, K; Bailey, R

    2008-09-01

    Dreaming is reported by one in five patients who are interviewed on emergence from general anaesthesia, but the incidence, predictors and consequences of dreaming during procedural sedation are not known. In this prospective observational study, 200 patients presenting for elective colonoscopy under intravenous sedation were interviewed on emergence to determine the incidences of dreaming and recall. Sedation technique was left to the discretion of the anaesthetist. The incidence of dreaming was 25.5%. Patients reporting dreaming were younger than those who did not report dreaming. Doses of midazolam and fentanyl were similar between dreamers and non-dreamers, however propofol doses were higher in patients who reported dreams than those who did not. Patients reported short, simple dreams about everyday life--no dream suggested near-miss recall of the procedure. Frank recall of the procedure was reported by 4% of the patients, which was consistent with propofol doses commensurate with light general anaesthesia. The only significant predictor of recall was lower propofol dose. Satisfaction with care was generally high, however dreamers were more satisfied with their care than non-dreamers.

  15. Determination of appropriate models and parameters for premixing calculations

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ik-Kyu; Kim, Jong-Hwan; Min, Beong-Tae; Hong, Seong-Wan

    2008-03-15

    The purpose of the present work is to use experiments that have been performed at Forschungszentrum Karlsruhe during about the last ten years for determining the most appropriate models and parameters for premixing calculations. The results of a QUEOS experiment are used to fix the parameters concerning heat transfer. The QUEOS experiments are especially suited for this purpose as they have been performed with small hot solid spheres. Therefore the area of heat exchange is known. With the heat transfer parameters fixed in this way, a PREMIX experiment is recalculated. These experiments have been performed with molten alumina (Al{sub 2}O{sub 3}) as a simulant of corium. Its initial temperature is 2600 K. With these experiments the models and parameters for jet and drop break-up are tested.

  16. Determination of appropriate models and parameters for premixing calculations

    International Nuclear Information System (INIS)

    Park, Ik-Kyu; Kim, Jong-Hwan; Min, Beong-Tae; Hong, Seong-Wan

    2008-03-01

    The purpose of the present work is to use experiments that have been performed at Forschungszentrum Karlsruhe during about the last ten years for determining the most appropriate models and parameters for premixing calculations. The results of a QUEOS experiment are used to fix the parameters concerning heat transfer. The QUEOS experiments are especially suited for this purpose as they have been performed with small hot solid spheres. Therefore the area of heat exchange is known. With the heat transfer parameters fixed in this way, a PREMIX experiment is recalculated. These experiments have been performed with molten alumina (Al 2 O 3 ) as a simulant of corium. Its initial temperature is 2600 K. With these experiments the models and parameters for jet and drop break-up are tested

  17. Partially premixed prevalorized kerosene spray combustion in turbulent flow

    Energy Technology Data Exchange (ETDEWEB)

    Chrigui, M.; Ahmadi, W.; Sadiki, A.; Janicka, J. [Institute for Energy and Powerplant Technology, TU Darmstadt, Petersenstr. 30, 64287 Darmstadt (Germany); Moesl, K. [Lehrstuhl fuer Thermodynamik, TU Muenchen, Boltzmannstr. 15, D-85747 Garching (Germany)

    2010-04-15

    A detailed numerical simulation of kerosene spray combustion was carried out on a partially premixed, prevaporized, three-dimensional configuration. The focus was on the flame temperature profile dependency on the length of the pre-vaporization zone. The results were analyzed and compared to experimental data. A fundamental study was performed to observe the temperature variation and flame flashback. Changes were made to the droplet diameter, kerosene flammability limits, a combustion model parameter and the location of the combustion initialization. Investigations were performed for atmospheric pressure, inlet air temperature of 90 C and a global equivalence ratio of 0.7. The simulations were carried out using the Eulerian Lagrangian procedure under a fully two-way coupling. The Bray-Moss-Libby model was adjusted to account for the partially premixed combustion. (author)

  18. Effects of premixed flames on turbulence and turbulent scalar transport

    Energy Technology Data Exchange (ETDEWEB)

    Lipatnikov, A.N.; Chomiak, J. [Department of Applied Mechanics, Chalmers University of Technology, 412 75 Goeteborg (Sweden)

    2010-02-15

    Experimental data and results of direct numerical simulations are reviewed in order to show that premixed combustion can change the basic characteristics of a fluctuating velocity field (the so-called flame-generated turbulence) and the direction of scalar fluxes (the so-called countergradient or pressure-driven transport) in a turbulent flow. Various approaches to modeling these phenomena are discussed and the lack of a well-elaborated and widely validated predictive approach is emphasized. Relevant basic issues (the transition from gradient to countergradient scalar transport, the role played by flame-generated turbulence in the combustion rate, the characterization of turbulence in premixed flames, etc.) are critically considered and certain widely accepted concepts are disputed. Despite the substantial progress made in understanding the discussed effects over the past decades, these basic issues strongly need further research. (author)

  19. Experimental study of flame stability in biogas premix system

    International Nuclear Information System (INIS)

    Diaz G, Carlos A; Amell A Andres; Cardona Luis F

    2008-01-01

    Utilization of new renewable energy sources have had a special interest in last years looking for decrease the dependence of fossil fuels and the environmental impact generated for them. This work studies experimentally the flame stability of a simulated biogas with a volumetric composition of 60% methane and 40% carbon dioxide. The objective of this study is to obtain information about design and interchangeability of gases in premixed combustion systems that operate with different fuel gases. The critical velocity gradient was the stability criteria used. Utilization of this criteria and the experimental method followed, using a partial premixed burner, stability flame diagram of biogas studied had been obtained. Presence of carbon dioxide has a negative effect in flame stability, decreasing significantly the laminar flame speed and consequently, the stability range of biogas burners because of apparition of blow off.

  20. Safety and effectiveness of moderate sedation for radiologic non-vascular intervention

    International Nuclear Information System (INIS)

    Kim, Tae-Hoon

    2006-01-01

    The purpose of this study was to prospectively characterize the safety and effectiveness of moderate sedation/analgesia for performing radiologic non-vascular abdominal intervention. During a 3-month period, a total of 63 adult patients with a mean age of 64 years (range:27-82) underwent moderate sedation for 72 radiologic non-vascular interventional procedures. A combination of fentanyl citrate and midazolam hydrochloride, based on the patient's body weight, was intravenously administered until the patient was drowsy and tranquil. The adverse events associated with this moderate sedation were assessed. The visual analog scale format was used to measure the subjective feelings of the patient's pre-pro- cedural anxiety and intraprocedural pain. The mean total dose per kilogram of body weight of fentanyl used in PTBD was 1.148 μg. The mean total dose per kilogram of body weight of midazolam was 0.035 mg in PTBD, PTGBD, AD, PCN, DJS, GS and FRA, 0.039 mg in TDC, and 0.043 mg in BS. A temporary reduction of systolic blood pressure to less than 80 mmHg was observed during 5 procedures (6.9%), whereas a temporary elevation of systolic blood pressure above 150 mmHg was observed during 10 procedures (13.8%). A reduction of arterial oxygen saturation to less than 90% was observed during 14 procedures (19.4%). None of the patients required pharmacologic reversal agents or cardiopulmonary resuscitation. The mean anxiety score recorded before all procedures was 5.2 (distressing). The mean pain score during the procedure, which was recorded after all procedures, was 2.9 (mild). Moderate sedation allows performance of safe and effective radiologic non-vascular intervention, and it is also easy for an interventional radiologist to use. The patients should be continuously monitored to check their vital signs and arterial oxygen saturation during the procedures

  1. Safety and effectiveness of moderate sedation for radiologic non-vascular intervention

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae-Hoon [Dankook University Hospital, Chungju (Korea, Republic of)

    2006-06-15

    The purpose of this study was to prospectively characterize the safety and effectiveness of moderate sedation/analgesia for performing radiologic non-vascular abdominal intervention. During a 3-month period, a total of 63 adult patients with a mean age of 64 years (range:27-82) underwent moderate sedation for 72 radiologic non-vascular interventional procedures. A combination of fentanyl citrate and midazolam hydrochloride, based on the patient's body weight, was intravenously administered until the patient was drowsy and tranquil. The adverse events associated with this moderate sedation were assessed. The visual analog scale format was used to measure the subjective feelings of the patient's pre-pro- cedural anxiety and intraprocedural pain. The mean total dose per kilogram of body weight of fentanyl used in PTBD was 1.148 {mu}g. The mean total dose per kilogram of body weight of midazolam was 0.035 mg in PTBD, PTGBD, AD, PCN, DJS, GS and FRA, 0.039 mg in TDC, and 0.043 mg in BS. A temporary reduction of systolic blood pressure to less than 80 mmHg was observed during 5 procedures (6.9%), whereas a temporary elevation of systolic blood pressure above 150 mmHg was observed during 10 procedures (13.8%). A reduction of arterial oxygen saturation to less than 90% was observed during 14 procedures (19.4%). None of the patients required pharmacologic reversal agents or cardiopulmonary resuscitation. The mean anxiety score recorded before all procedures was 5.2 (distressing). The mean pain score during the procedure, which was recorded after all procedures, was 2.9 (mild). Moderate sedation allows performance of safe and effective radiologic non-vascular intervention, and it is also easy for an interventional radiologist to use. The patients should be continuously monitored to check their vital signs and arterial oxygen saturation during the procedures.

  2. Premixed burner experiments: Geometry, mixing, and flame structure issues

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, A.K.; Lewis, M.J.; Gupta, M. [Univ of Maryland, College Park, MD (United States)] [and others

    1995-10-01

    This research program is exploring techniques for improved fuel-air mixing, with the aim of achieving combustor operations up to stoichiometric conditions with minimal NO x and maximum efficiency. The experimental studies involve the use of a double-concentric natural gas burner that is operable in either premixed or non-premixed modes, and the system allows systematic variation of equivalence ratio, swirl strength shear length region and flow momentum in each annulus. Flame structures formed with various combinations of swirl strengths, flow throughput and equivalence ratios in premixed mode show the significant impact of swirl flow distribution on flame structure emanating from the mixedness. This impact on flame structure is expected to have a pronounced effect on the heat release rate and the emission of NO{sub x}. Thus, swirler design and configuration remains a key factor in the quest for completely optimized combustion. Parallel numerical studies of the flow and combustion phenomena were carried out, using the RSM and thek-{epsilon} turbulence models. These results have not only indicated the strengths and limitations of CFD in performance and pollutants emission predictions, but have provided guidelines on the size and strength of the recirculation produced and the spatio-temporal structure of the combustion flowfield. The first stage of parametric studies on geometry and operational parameters at Morgan State University have culminated in the completion of a one-dimensional flow code that is integrated with a solid, virtual model of the existing premixed burner. This coupling will provide the unique opportunity to study the impact of geometry on the flowfield and vice-versa, with particular emphasis on concurrent design optimization.

  3. Fuel and combustion stratification study of Partially Premixed Combustion

    OpenAIRE

    Izadi Najafabadi, M.; Dam, N.; Somers, B.; Johansson, B.

    2016-01-01

    Relatively high levels of stratification is one of the main advantages of Partially Premixed Combustion (PPC) over the Homogeneous Charge Compression Ignition (HCCI) concept. Fuel stratification smoothens heat release and improves controllability of this kind of combustion. However, the lack of a clear definition of “fuel and combustion stratifications” is obvious in literature. Hence, it is difficult to compare stratification levels of different PPC strategies or other combustion concepts. T...

  4. Variation in diurnal sedation in mechanically ventilated patients who are managed with a sedation protocol alone or a sedation protocol and daily interruption.

    Science.gov (United States)

    Mehta, Sangeeta; Meade, Maureen; Burry, Lisa; Mallick, Ranjeeta; Katsios, Christina; Fergusson, Dean; Dodek, Peter; Burns, Karen; Herridge, Margaret; Devlin, John W; Tanios, Maged; Fowler, Robert; Jacka, Michael; Skrobik, Yoanna; Olafson, Kendiss; Cook, Deborah

    2016-08-01

    Mechanically ventilated patients may receive more sedation during the night than during the day, potentially delaying extubation. We compared nighttime and daytime benzodiazepine and opioid administration in adult patients enrolled in a multicenter sedation trial comparing protocolized sedation alone or protocolized sedation combined with daily sedation interruption; and we evaluated whether nighttime and daytime doses were associated with liberation from mechanical ventilation. This is a secondary analysis of a randomized trial which was conducted in 16 North American medical-surgical ICUs. In all 423 patients, nurses applied a validated sedation scale hourly to titrate benzodiazepine and opioid infusions to achieve a light level of sedation. Using fentanyl equivalents and midazolam equivalents, we compared dosages administered during night (19:00 to 07:00) and day (07:00 to 19:00) shifts. Using multivariable logistic regression we evaluated the association between nighttime and daytime opioid and sedative doses, and spontaneous breathing trial (SBT) conduct, SBT success, and extubation. Nighttime benzodiazepine and opioid doses were significantly higher than daytime doses (mean difference midazolam equivalents 23.3 mg, 95 % CI 12.9, 33.8, p Patients were more often restrained during day shifts (76.3 % vs 73.7 %, p patient despite successful SBT. Patients received higher doses of opioids and benzodiazepines at night. Higher nighttime doses were associated with SBT failure and delayed extubation. ClinicalTrials.gov NCT00675363 . Registered 7 May 2008.

  5. 'Palliative sedation'? A retrospective cohort study on the use and labelling of continuously administered sedatives on a palliative care unit.

    Science.gov (United States)

    Schildmann, Eva; Pörnbacher, Sebastian; Kalies, Helen; Bausewein, Claudia

    2018-03-01

    Sedatives are frequently used towards the end of life. However, there is scarce information when their use is labelled as 'palliative sedation'. To assess the use and labelling of 'continuous administration of sedatives within the last 7 days of life', based on objective operational criteria, on a palliative care unit. Retrospective cohort study, using medical records. Explorative statistical analysis (SPSS 23). Patients who died on a palliative care unit from August 2014 to July 2015. Sedatives recorded were benzodiazepines, levomepromazine, haloperidol ⩾5 mg/day and propofol. Of the 192 patients, 149 (78%) patients received continuous sedatives within the last week of life. The prevalence of delirium/agitation was significantly higher in patients with continuous sedatives compared to those without continuous sedatives at admission to the unit (35% vs 16%, p = 0.02) and on the day before death (58% vs 40%, p = 0.04). The term '(palliative) sedation' was used in the records for 22 of 149 (15%) patients with continuous sedatives. These patients had significantly higher total daily midazolam doses 2 days before death (median (range), 15.0 (6.0-185.0) mg vs 11.5 (1.0-70.0) mg, p = 0.04) and on the day of death (median (range), 19.5 (7.5-240.0) mg vs 12.5 (2.0-65.0) mg, p = 0.01). The dose range was large in both groups. The prevalence of delirium/agitation was associated with the administration of continuous sedatives. There was no consistent pattern regarding labelling the use of continuous sedatives as '(palliative) sedation'. Multicentre mixed-methods research is needed for a better characterization of sedation practices in palliative care.

  6. Large Eddy Simulation of High-Speed, Premixed Ethylene Combustion

    Science.gov (United States)

    Ramesh, Kiran; Edwards, Jack R.; Chelliah, Harsha; Goyne, Christopher; McDaniel, James; Rockwell, Robert; Kirik, Justin; Cutler, Andrew; Danehy, Paul

    2015-01-01

    A large-eddy simulation / Reynolds-averaged Navier-Stokes (LES/RANS) methodology is used to simulate premixed ethylene-air combustion in a model scramjet designed for dual mode operation and equipped with a cavity for flameholding. A 22-species reduced mechanism for ethylene-air combustion is employed, and the calculations are performed on a mesh containing 93 million cells. Fuel plumes injected at the isolator entrance are processed by the isolator shock train, yielding a premixed fuel-air mixture at an equivalence ratio of 0.42 at the cavity entrance plane. A premixed flame is anchored within the cavity and propagates toward the opposite wall. Near complete combustion of ethylene is obtained. The combustor is highly dynamic, exhibiting a large-scale oscillation in global heat release and mass flow rate with a period of about 2.8 ms. Maximum heat release occurs when the flame front reaches its most downstream extent, as the flame surface area is larger. Minimum heat release is associated with flame propagation toward the cavity and occurs through a reduction in core flow velocity that is correlated with an upstream movement of the shock train. Reasonable agreement between simulation results and available wall pressure, particle image velocimetry, and OH-PLIF data is obtained, but it is not yet clear whether the system-level oscillations seen in the calculations are actually present in the experiment.

  7. ASSESSMENT OF FLOW AND TECHNOLOGICAL BEHAVIOR OF FRENCH BREAD PREMIXES

    Directory of Open Access Journals (Sweden)

    E. VALDUGA

    2008-08-01

    Full Text Available

    In this work formulations of French bread premixes were investigated. The premixes were based on blends of Argentinean and Brazilian wheat. The bread produced with the mixtures was compared to the bread obtained with standard flour, which did not contain any additives. The flour was characterized by physico-chemical and biochemical analysis (humidity, ashes, water absorption, color, gluten index, flour strength and a-amylase activity. The bread rolls were prepared using a standard formulation (without additives and two different formulations, using ascorbic acid, a-amylase, esterlac, soybean flour and diacetyl tartaric acid emulsifier. The physico-chemical analysis results indicate that the standard flour is better than the formulations. Nevertheless bread-making tests showed that the premixes formulations have better performance concerning the specific volume and the sensory characteristics. Statistical analysis confirmed that there is a significant difference in the specific volume and the sensory characteristics between the formulations, proving that the use of additives can enhance the quality of the French bread.

  8. Sedative effects of oral pregabalin premedication on intravenous sedation using propofol target-controlled infusion.

    Science.gov (United States)

    Karube, Noriko; Ito, Shinichi; Sako, Saori; Hirokawa, Jun; Yokoyama, Takeshi

    2017-08-01

    The sedative effects of pregabalin during perioperative period have not been sufficiently characterized. The aim of this study was to verify the sedative effects of premedication with pregabalin on intravenous sedation (IVS) using propofol and also to assess the influences of this agent on circulation, respiration, and postanesthetic complications. Ten healthy young volunteers underwent 1 h of IVS using propofol, three times per subject, on separate days (first time, no pregabalin; second time, pregabalin 100 mg; third time, pregabalin 200 mg). The target blood concentration (C T ) of propofol was increased in a stepwise fashion based on the bispectral index (BIS) value. Ramsay's sedation score (RSS) was determined at each propofol C T . Propofol C T was analyzed at each sedation level. Circulation and respiration during IVS and complications were also verified. Propofol C T was reduced at BIS values of 60 and 70 in both premedicated groups (100 mg: p = 0.043 and 0.041; 200 mg: p = 0.004 and 0.016, respectively) and at a BIS value of 80 in the pregabalin 200 mg group (p < 0.001). Propofol C T was decreased at RSS 4-6 in the pregabalin 100 mg group (RSS 4: p = 0.047; RSS 5: p = 0.007; RSS 6: p = 0.014), and at RSS 3-6 in the pregabalin 200 mg group (RSS 3-5: p < 0.001; RSS 6: p = 0.002). We conclude that oral premedication with pregabalin reduces the amount of propofol required to obtain an acceptable and adequate sedation level.

  9. Intention, procedure, outcome and personhood in palliative sedation and euthanasia.

    Science.gov (United States)

    Materstvedt, Lars Johan

    2012-03-01

    Palliative sedation at the end of life has become an important last-resort treatment strategy for managing refractory symptoms as well as a topic of controversy within palliative care. Furthermore, palliative sedation is prominent in the public debate about the possible legalisation of voluntary assisted dying (physician-assisted suicide and euthanasia). This article attempts to demonstrate that palliative sedation is fundamentally different from euthanasia when it comes to intention, procedure, outcome and the status of the person. Nonetheless, palliative sedation in its most radical form of terminal deep sedation parallels euthanasia in one respect: both end the experience of suffering. However, only the latter intentionally ends life and also has this as its goal. There is the danger that deep sedation could bring death forward in time due to particular side effects of the treatment. Still that would, if it happens, not be intended, and accordingly is defensible in view of the doctrine of double effect.

  10. Comparison of sedation strategies for critically ill patients

    DEFF Research Database (Denmark)

    Hutton, Brian; Burry, Lisa D.; Kanji, Salmaan

    2016-01-01

    Background: Sedatives and analgesics are administered to provide sedation and manage agitation and pain in most critically ill mechanically ventilated patients. Various sedation administration strategies including protocolized sedation and daily sedation interruption are used to mitigate drug...... their efficacy and safety for mechanically ventilated patients. Methods: We will search the following from 1980 to March 2016: Ovid MEDLINE, CINAHL, Embase, PsycINFO, and Web of Science. We will also search the Cochrane Library, gray literature, and the International Clinical Trials Registry Platform. We...... of interest include duration of mechanical ventilation, time to first extubation, ICU and hospital length of stay, re-intubation, tracheostomy, mortality, total sedative and opioid exposure, health-related quality of life, and adverse events. To inform our NMA, we will first conduct conventional pair...

  11. Techniques to administer oral, inhalational, and IV sedation in dentistry

    Directory of Open Access Journals (Sweden)

    Diana Krystyna Harbuz

    2016-02-01

    Full Text Available Background Sedation in dentistry is a controversial topic given the variety of opinions regarding its safe practice. Aims This article evaluates the various techniques used to administer sedation in dentistry and specific methods practiced to form a recommendation for clinicians. Methods An extensive literature search was performed using PubMed, Medline, Google Scholar, Google, and local library resources. Results Most of the literature revealed a consensus that light sedation on low-risk American Society of Anesthesiologists (ASA groups, that is ASA I, and possibly II, is the safest method for sedation in a dental outpatient setting. Conclusion Formal training is essential to achieve the safe practice of sedation in dentistry or medicine. The appropriate setting for sedation should be determined as there is an increased risk outside the hospital setting. Patients should be adequately assessed and medication titrated appropriately, based on individual requirements.

  12. Evaluation of nitrous oxide inhalation sedation during inferior alveolar block administration in children aged 7-10 years: A randomized control trial

    Directory of Open Access Journals (Sweden)

    Deepti Takkar

    2015-01-01

    Full Text Available Background: Nitrous oxide-oxygen (N 2 O-O 2 is being used in combination with many drugs and this possess risk for leading to deep sedation or reflexes being compromised. Aim: The purpose of our study was to use N 2 O-O 2 alone, to evaluate its effectiveness for pain control during inferior alveolar nerve block administration in children. Design: This was a single-centered, simple randomized, double-blinded, placebo-controlled parallel-group study involving 40 children in the age group of 7-10 years divided into 2 groups: N 2 O-O 2 sedation and oxygen. Pain perception for local anesthesia was assessed using face, legs, activity, cry, consolability scale. Children′s behavior was assessed using Frankl ratings, depth of sedation using Observer′s Assessment of Alertness/Sedation scale. The vital signs and oxygen saturation were recorded. Results: There was a significantly lower pain reaction to local anesthetic administration in the N 2 O-O 2 group (P < 0.01. Improvement in the behavior of the children belonging to N 2 O-O 2 group during and after the procedure as compared to the O 2 group (P < 0.01 was also observed. All the vital signs recorded were in the normal physiologic limits in both the groups. Conclusion: Pain experienced by children receiving N 2 O-O 2 sedation was significantly lower. N 2 O-O 2 inhalation sedation produces adequate sedation with vital signs within normal limits and treatments successfully completed.

  13. Balanced Propofol Sedation in Patients Undergoing EUS-FNA: A Pilot Study to Assess Feasibility and Safety

    Directory of Open Access Journals (Sweden)

    N. Pagano

    2011-01-01

    Full Text Available Introduction and aims. Balanced propofol sedation (BPS administered by gastroenterologists has gained popularity in endoscopic procedures. Few studies exist about the safety of this approach during endosonography with fine needle aspiration (EUS-FNA. We assessed the safety of BPS in EUS-FNA. Materials and methods. 112 consecutive patients, referred to our unit to perform EUS-FNA, from February 2008 to December 2009, were sedated with BPS. A second gastroenterologist administered the drugs and monitorized the patient. Results. All the 112 patients (62 males, mean age 58.35 completed the examination. The mean dose of midazolam and propofol was, respectively, of 2.1 mg (range 1–4 mg and 350 mg (range 180–400. All patients received oxygen with a mean flux of 4 liter/minute (range 2–6 liters/minute. The mean recovery time after procedure was 25 minutes (range 18–45 minutes. No major complications related to sedation were registered during all procedures. The oxygen saturation of all patients never reduced to less than 85%. Blood systolic pressure during and after the procedure never reduced to less than 100 mmHg. Conclusions. In our experience BPS administered by non-anaesthesiologists provided safe and successful sedation in patients undergoing EUS-FNA.

  14. The role of sedation tests in identifying sedative drug effects in healthy volunteers and their power to dissociate sedative-related impairments from memory dysfunctions.

    Science.gov (United States)

    Wezenberg, E; Sabbe, B G C; Hulstijn, W; Ruigt, G S F; Verkes, R J

    2007-08-01

    The study investigated whether four specified drugs would show similar patterns on tests considered to measure sedation. In addition, their drug-effect patterns on sedation and memory performance were compared to determine whether the sedative effects could be differentiated from the memory effects. Two double-blind, placebo-controlled, crossover studies, each with 16 healthy volunteers, were performed, one testing lorazepam (2.5 mg) and mirtazapine (15 mg) and the other olanzapine (10 mg) and haloperidol (2.5 mg). Subjective sedation was assessed by means of visual analogue scales (VAS) and objective sedation using a simple-reaction-time (SRT) task and a choice-reaction-time (CRT) task, code substitution (symbol digit substitution test (SDST)) and the peak velocity of saccadic eye movements (SEM). A verbal memory test (VMT) was administered to evaluate memory capacity. Apart from haloperidol, all drugs proved to impair performance on all five sedation indices. Contrary to the VAS, the objective measures yielded different response profiles. Two types of drug-effect patterns emerged: one for greater impairments in response speed (SRT, SEM) and one for greater impairments in information processing (CRT, SDST). Lorazepam and olanzapine impeded memory performance, whereas mirtazapine did not. With the use of standardized scores it proved possible to differentiate between the size of the effects of the drugs on the sedation and memory tests. To accurately assess the level and nature of sedation and to differentiate sedation from memory impairments different types of sedation measures are required. Besides studying the subjective effects, it is recommended to also test psychomotor responses and information processing speed.

  15. Intranasal dexmedetomidine for sedation for pediatric computed tomography imaging.

    Science.gov (United States)

    Mekitarian Filho, Eduardo; Robinson, Fay; de Carvalho, Werther Brunow; Gilio, Alfredo Elias; Mason, Keira P

    2015-05-01

    This prospective observational pilot study evaluated the aerosolized intranasal route for dexmedetomidine as a safe, effective, and efficient option for infant and pediatric sedation for computed tomography imaging. The mean time to sedation was 13.4 minutes, with excellent image quality, no failed sedations, or significant adverse events. Registered with ClinicalTrials.gov: NCT01900405. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Chloral hydrate in pediatric magnetic resonance imaging: evaluation of a 10-year sedation experience administered by radiologists

    International Nuclear Information System (INIS)

    Delgado, Jorge; Toro, Rodrigo; Rascovsky, Simon; Arango, Andres; Angel, Gabriel J.; Calvo, Victor; Delgado, Jorge A.

    2015-01-01

    Chloral hydrate is a sedative that has been used for magnetic resonance imaging (MRI). To evaluate the use, effectiveness and safety of chloral hydrate administered by radiologists for the sedation of children who require MRI procedures. We retrospectively reviewed the clinical charts for all patients ages 0 - 10 years old who underwent sedation with chloral hydrate for MRI from January 2000 to December 2010. Demographic factors, dose information, indication for MRI, therapeutic failures and adverse reactions to the drug were reviewed. One thousand, seven hundred and three children (946 males, 757 females) with a median age of 2.5 years (range: 4 days - 9.91 years) received chloral hydrate. Moderate to deep sedation was achieved in 1,618/1,703 (95%) of the patients, 35/1,703 (2.1%) of the patients failed to achieve moderate to deep sedation, and 47/1,703 (2.8%) of the patients woke up during MRI examination. Adverse reactions were present in 31/1,703 (1.8%) of the patients. Three severe adverse reactions occurred (0.18%). A single dose of chloral hydrate (40-60 mg/kg) was administered to 1,477/1,703 patients (86.7%). An additional dose of chloral hydrate (10-20 mg/kg), given 15 min after the first dose or when the patient woke up during the MRI examination, was required in 226/1,703 patients (13.3%). The likelihood of requiring an additional dose in children older than 2 years was 2.2 times the likelihood compared to children younger than 2 years (OR = 2.2 [95%CI: 1.6-3.0]). The use of a reduced dose (<50 mg/kg) was not associated with a higher therapeutic failure rate (OR = 1.04 [95%CI 0.57-1.89]). Chloral hydrate is an appropriate sedation option for pediatric patients in MRI services when strict patient selection criteria are met. The use of a reduced dose does not affect the effectiveness of sedation. The lack of data regarding the presence of transient oxygen desaturation, the time to induce sedation and the exact duration of sedation are limitations of this

  17. Chloral hydrate in pediatric magnetic resonance imaging: evaluation of a 10-year sedation experience administered by radiologists

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Jorge; Toro, Rodrigo; Rascovsky, Simon; Arango, Andres; Angel, Gabriel J.; Calvo, Victor; Delgado, Jorge A. [Fundacion Instituto de Alta Tecnologia Medica, Department of Radiology, Medellin (Colombia)

    2014-08-21

    Chloral hydrate is a sedative that has been used for magnetic resonance imaging (MRI). To evaluate the use, effectiveness and safety of chloral hydrate administered by radiologists for the sedation of children who require MRI procedures. We retrospectively reviewed the clinical charts for all patients ages 0 - 10 years old who underwent sedation with chloral hydrate for MRI from January 2000 to December 2010. Demographic factors, dose information, indication for MRI, therapeutic failures and adverse reactions to the drug were reviewed. One thousand, seven hundred and three children (946 males, 757 females) with a median age of 2.5 years (range: 4 days - 9.91 years) received chloral hydrate. Moderate to deep sedation was achieved in 1,618/1,703 (95%) of the patients, 35/1,703 (2.1%) of the patients failed to achieve moderate to deep sedation, and 47/1,703 (2.8%) of the patients woke up during MRI examination. Adverse reactions were present in 31/1,703 (1.8%) of the patients. Three severe adverse reactions occurred (0.18%). A single dose of chloral hydrate (40-60 mg/kg) was administered to 1,477/1,703 patients (86.7%). An additional dose of chloral hydrate (10-20 mg/kg), given 15 min after the first dose or when the patient woke up during the MRI examination, was required in 226/1,703 patients (13.3%). The likelihood of requiring an additional dose in children older than 2 years was 2.2 times the likelihood compared to children younger than 2 years (OR = 2.2 [95%CI: 1.6-3.0]). The use of a reduced dose (<50 mg/kg) was not associated with a higher therapeutic failure rate (OR = 1.04 [95%CI 0.57-1.89]). Chloral hydrate is an appropriate sedation option for pediatric patients in MRI services when strict patient selection criteria are met. The use of a reduced dose does not affect the effectiveness of sedation. The lack of data regarding the presence of transient oxygen desaturation, the time to induce sedation and the exact duration of sedation are limitations of this

  18. The proportionate value of proportionality in palliative sedation.

    Science.gov (United States)

    Berger, Jeffrey T

    2014-01-01

    Proportionality, as it pertains to palliative sedation, is the notion that sedation should be induced at the lowest degree effective for symptom control, so that the patient's consciousness may be preserved. The pursuit of proportionality in palliative sedation is a widely accepted imperative advocated in position statements and guidelines on this treatment. The priority assigned to the pursuit of proportionality, and the extent to which it is relevant for patients who qualify for palliative sedation, have been overstated. Copyright 2014 The Journal of Clinical Ethics. All rights reserved.

  19. Complications of three deep sedation methods for magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Solina Tith

    2012-01-01

    Conclusions: DS with a pentobarbital technique was associated with decreased odds for complications when compared to a propofol-based technique or a pentobarbital technique requiring supplemental sedation.

  20. "Sedation is tricky": A qualitative content analysis of nurses' perceptions of sedation administration in mechanically ventilated intensive care unit patients.

    Science.gov (United States)

    Hetland, Breanna; Guttormson, Jill; Tracy, Mary Fran; Chlan, Linda

    2018-03-20

    Critical care nurses are responsible for administering sedative medications to mechanically ventilated patients. With significant advancements in the understanding of the impact of sedative exposure on physiological and psychological outcomes of ventilated patients, updated practice guidelines for assessment and management of pain, agitation, and delirium in the intensive care unit were released in 2013. The primary aim of this qualitative study was to identify and describe themes derived from critical care nurses' comments regarding sedation administration practices with mechanically ventilated patients. This is a qualitative content analysis of secondary text data captured through a national electronic survey of members of the American Association of Critical-Care Nurses. A subsample (n = 67) of nurses responded to a single, open-ended item at the end of a survey that evaluated nurses' perceptions of current sedation administration practices. Multiple factors guided sedation administration practices, including individual patient needs, nurses' synthesis of clinical evidence, application of best practices, and various personal and professional practice perspectives. Our results also indicated nurses desire additional resources to improve their sedation administration practices including more training, better communication tools, and adequate staffing. Critical care nurses endorse recommendations to minimise sedation administration when possible, but a variety of factors, including personal perspectives, impact sedation administration in the intensive care unit and need to be considered. Critical care nurses continue to encounter numerous challenges when assessing and managing sedation of mechanically ventilated patients. Copyright © 2018 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.

  1. A Review of Agents for Palliative Sedation/Continuous Deep Sedation: Pharmacology and Practical Applications.

    Science.gov (United States)

    Bodnar, John

    2017-03-01

    Continuous deep sedation at the end of life is a specific form of palliative sedation requiring a care plan that essentially places and maintains the patient in an unresponsive state because their symptoms are refractory to any other interventions. Because this application is uncommon, many providers may lack practical experience in this specialized area and resources they can access are outdated, nonspecific, and/or not comprehensive. The purpose of this review is to provide an evidence- and experience-based reference that specifically addresses those medications and regimens and their practical applications for this very narrow, but vital, aspect of hospice care. Patient goals in a hospital and hospice environments are different, so the manner in which widely used sedatives are dosed and applied can differ greatly as well. Parameters applied in end-of-life care that are based on experience and a thorough understanding of the pharmacology of those medications will differ from those applied in an intensive care unit or other medical environments. By recognizing these different goals and applying well-founded regimens geared specifically for end-of-life sedation, we can address our patients' symptoms in a more timely and efficacious manner.

  2. Sedative medications outside the operating room and the pharmacology of sedatives

    DEFF Research Database (Denmark)

    Hansen, Tom G

    2015-01-01

    PURPOSE OF REVIEW: There is a growing medical demand for suitable sedatives and analgesics to support the ongoing progress in diagnostic procedures and imaging techniques. This review provides an update of the pharmacology of the most commonly used drugs used for these procedures and shortly...

  3. Recall of intensive care unit stay in patients managed with a sedation protocol or a sedation protocol with daily sedative interruption: a pilot study.

    Science.gov (United States)

    Ethier, Cheryl; Burry, Lisa; Martinez-Motta, Carlos; Tirgari, Sam; Jiang, Depeng; McDonald, Ellen; Granton, John; Cook, Deborah; Mehta, Sangeeta

    2011-04-01

    Analgesics and sedatives are integral for the relief of pain and anxiety in critically ill patients. However, these agents may contribute to amnesia for intensive care unit (ICU) events; which has been associated with development of posttraumatic stress disorder. Drug administration strategies that minimize sedative use have been associated with less amnesia. The objective of this pilot study was to evaluate recall of ICU stay in patients managed with 2 sedation strategies: a sedation protocol or a combination of sedation protocol and daily sedative/analgesic interruption. A questionnaire was administered on day 3 following ICU discharge to evaluate patients' recollections of pain, anxiety, fear, and sleep, as well as memories for specific ICU procedures. Participants were ICU survivors who had been enrolled in SLEAP - a randomized pilot trial comparing two sedation strategies, at 3 university-affiliated medical/surgical ICUs. Twenty-one patients who regained orientation within 72 hours of ICU discharge completed the questionnaire. More than 50% of patients recalled experiencing pain, anxiety, and fear to a moderate or extreme extent; and 57% reported inadequate sleep while in the ICU. Of the 21 patients, 48%, 33%, and 29% had no memories of endotracheal tube suctioning, being on a "breathing machine," and being bathed, respectively. A notable percentage of patients discharged from the ICU report moderate to extreme pain, anxiety, and fear, and inability to sleep during their ICU stay; and 29% to 48% have no recall of specific ICU events. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. A randomized controlled trial of daily sedation interruption in critically ill children

    NARCIS (Netherlands)

    Vet, N.J.; Wildt, S.N. de; Verlaat, C.W.; Knibbe, C.A.; Mooij, M.G.; Woensel, J.B. van; Rosmalen, J. van; Tibboel, D.; Hoog, M. de

    2016-01-01

    PURPOSE: To compare daily sedation interruption plus protocolized sedation (DSI + PS) to protocolized sedation only (PS) in critically ill children. METHODS: In this multicenter randomized controlled trial in three pediatric intensive care units in the Netherlands, mechanically ventilated critically

  5. A randomized controlled trial of daily sedation interruption in critically ill children

    NARCIS (Netherlands)

    Vet, Nienke J.; de Wildt, Saskia N.; Verlaat, Carin W. M.; Knibbe, Catherijne A. J.; Mooij, Miriam G.; van Woensel, Job B. M.; van Rosmalen, Joost; Tibboel, Dick; de Hoog, Matthijs

    2016-01-01

    To compare daily sedation interruption plus protocolized sedation (DSI + PS) to protocolized sedation only (PS) in critically ill children. In this multicenter randomized controlled trial in three pediatric intensive care units in the Netherlands, mechanically ventilated critically ill children with

  6. Moderate sedation for MRI in young children with autism

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Allison Kinder [Duke University Medical Center, Division of Pediatric Anesthesia, Durham (United States); Hazlett, Heather Cody; Garrett, Nancy T [University of North Carolina School of Medicine, Department of Psychiatry, Chapel Hill, NC (United States); Wilkerson, Christy [Duke University Medical Center, Department of Radiology, Durham, NC (United States); Piven, Joseph [University of North Carolina School of Medicine, Departments of Psychiatry and Pediatrics, Chapel Hill, NC (United States)

    2005-09-01

    Autism is a pervasive neurodevelopmental disorder. Because of the deficits associated with the condition, sedation of children with autism has been considered more challenging than sedation of other children. To test this hypothesis, we compared children with autism against clinical controls to determine differences in requirements for moderate sedation for MRI. Children ages 18-36 months with autism (group 1, n = 41) and children with no autistic behavior (group 2, n = 42) were sedated with a combination of pentobarbital and fentanyl per sedation service protocol. The sedation nurse was consistent for all patients, and all were sedated to achieve a Modified Ramsay Score of 4. Demographics and doses of sedatives were recorded and compared. There were no sedation failures in either group. Children in group 1 (autism) were significantly older than group 2 (32.02{+-}3.6 months vs 28.16{+-}6.7 months) and weighed significantly more (14.87{+-}2.1 kg vs 13.42{+-}2.2 kg). When compared on a per-kilogram basis, however, group 1 had a significantly lower fentanyl requirement than group 2 (1.25{+-}0.55 mcg/kg vs 1.57{+-}0.81 mcg/kg), but no significant difference was found in pentobarbital dosing between groups 1 and 2, respectively (4.92{+-}0.92 mg/kg vs 5.21{+-}1.6 mg/kg). Autistic children in this age range are not more difficult to sedate and do not require higher doses of sedative agents for noninvasive imaging studies. (orig.)

  7. Moderate sedation for MRI in young children with autism

    International Nuclear Information System (INIS)

    Ross, Allison Kinder; Hazlett, Heather Cody; Garrett, Nancy T.; Wilkerson, Christy; Piven, Joseph

    2005-01-01

    Autism is a pervasive neurodevelopmental disorder. Because of the deficits associated with the condition, sedation of children with autism has been considered more challenging than sedation of other children. To test this hypothesis, we compared children with autism against clinical controls to determine differences in requirements for moderate sedation for MRI. Children ages 18-36 months with autism (group 1, n = 41) and children with no autistic behavior (group 2, n = 42) were sedated with a combination of pentobarbital and fentanyl per sedation service protocol. The sedation nurse was consistent for all patients, and all were sedated to achieve a Modified Ramsay Score of 4. Demographics and doses of sedatives were recorded and compared. There were no sedation failures in either group. Children in group 1 (autism) were significantly older than group 2 (32.02±3.6 months vs 28.16±6.7 months) and weighed significantly more (14.87±2.1 kg vs 13.42±2.2 kg). When compared on a per-kilogram basis, however, group 1 had a significantly lower fentanyl requirement than group 2 (1.25±0.55 mcg/kg vs 1.57±0.81 mcg/kg), but no significant difference was found in pentobarbital dosing between groups 1 and 2, respectively (4.92±0.92 mg/kg vs 5.21±1.6 mg/kg). Autistic children in this age range are not more difficult to sedate and do not require higher doses of sedative agents for noninvasive imaging studies. (orig.)

  8. Experimental Investigation of Turbulence-Chemistry Interaction in High-Reynolds-Number Turbulent Partially Premixed Flames

    Science.gov (United States)

    2016-06-23

    AFRL-AFOSR-VA-TR-2016-0277 Experimental Investigation of Turbulence-Chemistry Interaction in High- Reynolds -Number Turbulent Partially Premixed...4. TITLE AND SUBTITLE [U] Experimental investigation of turbulence-chemistry interaction in high- Reynolds -number 5a. CONTRACT NUMBER turbulent...for public release Final Report: Experimental investigation of turbulence-chemistry interaction in high- Reynolds -number turbulent partially premixed

  9. 21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.

    Science.gov (United States)

    2010-04-01

    ... premixes, may continue to be used under prior sanctions in the commercial curing of meat and meat products... that apply to meat curing preparations for the home curing of meat and meat products, including poultry and wild game. To assure safe use of such ingredients the labeling of the premixes shall bear...

  10. A comparative experimental study on engine operating on premixed charge compression ignition and compression ignition mode

    Directory of Open Access Journals (Sweden)

    Bhiogade Girish E.

    2017-01-01

    Full Text Available New combustion concepts have been recently developed with the purpose to tackle the problem of high emissions level of traditional direct injection Diesel engines. A good example is the premixed charge compression ignition combustion. A strategy in which early injection is used causing a burning process in which the fuel burns in the premixed condition. In compression ignition engines, soot (particulate matter and NOx emissions are an extremely unsolved issue. Premixed charge compression ignition is one of the most promising solutions that combine the advantages of both spark ignition and compression ignition combustion modes. It gives thermal efficiency close to the compression ignition engines and resolves the associated issues of high NOx and particulate matter, simultaneously. Premixing of air and fuel preparation is the challenging part to achieve premixed charge compression ignition combustion. In the present experimental study a diesel vaporizer is used to achieve premixed charge compression ignition combustion. A vaporized diesel fuel was mixed with the air to form premixed charge and inducted into the cylinder during the intake stroke. Low diesel volatility remains the main obstacle in preparing premixed air-fuel mixture. Exhaust gas re-circulation can be used to control the rate of heat release. The objective of this study is to reduce exhaust emission levels with maintaining thermal efficiency close to compression ignition engine.

  11. Effect of air-excess on blends of RON70 partially premixed combustion

    NARCIS (Netherlands)

    Wang, S.; Bakker, P.C.; Somers, L.M.T.; de Goey, L.P.H.

    Partially Premixed Combustion (PPC) is a combustion concept that aims to provide combustion with low smoke and NOx emissions and a high thermal efficiency. Extending the ignition delay to enhance premixing, avoiding spray-driven combustion, and controlling temperature at an optimum level through use

  12. Subgrid scale modeling in large-Eddy simulation of turbulent combustion using premixed fdlamelet chemistry

    NARCIS (Netherlands)

    Vreman, A.W.; Oijen, van J.A.; Goey, de L.P.H.; Bastiaans, R.J.M.

    2009-01-01

    Large-eddy simulation (LES) of turbulent combustion with premixed flamelets is investigated in this paper. The approach solves the filtered Navier-Stokes equations supplemented with two transport equations, one for the mixture fraction and another for a progress variable. The LES premixed flamelet

  13. Dry low NOx combustion system with pre-mixed direct-injection secondary fuel nozzle

    Science.gov (United States)

    Zuo, Baifang; Johnson, Thomas; Ziminsky, Willy; Khan, Abdul

    2013-12-17

    A combustion system includes a first combustion chamber and a second combustion chamber. The second combustion chamber is positioned downstream of the first combustion chamber. The combustion system also includes a pre-mixed, direct-injection secondary fuel nozzle. The pre-mixed, direct-injection secondary fuel nozzle extends through the first combustion chamber into the second combustion chamber.

  14. Evaluation of adult outpatient magnetic resonance imaging sedation practices: are patients being sedated optimally?

    International Nuclear Information System (INIS)

    Middelkamp, J.E.; Forster, B.B; Keogh, C.; Lennox, P.; Mayson, K.

    2009-01-01

    To evaluate the use of anxiolytics in adult outpatient magnetic resonance imaging (MRI) centres and to determine whether utilisation is optimal based on the pharmacology of the drugs used, who prescribes these drugs, and how patients are managed after administration. Identical paper and Web-based surveys were used to anonymously collect data about radiologists' use of anxiolytic agents for adult outpatient MRI examinations. The survey questions were about the type of facility, percentage of studies that require sedation, the drug used and route of administration, who orders the drug, timing of administration, patient monitoring during and observation after the study, use of a dedicated nurse for monitoring, and use of standard sedation and discharge protocols. The χ2 analysis for statistical association among variables was used. Eighty-five of 263 surveys were returned (32% response rate). The radiologist ordered the medication (53%) in slightly more facilities than the referring physician (44%) or the nurse. Forty percent of patients received medication 15-30 minutes before MRI, which is too early for peak effect of oral or sublingual drugs. Lorazepam was most commonly used (64% first choice). Facilities with standard sedation protocols (56%) were more likely to use midazolam than those without standard sedation protocols (17% vs 10%), to have a nurse for monitoring (P = .032), to have standard discharge criteria (P = .001), and to provide written information regarding adverse effects (P = .002). Many outpatients in MRI centres may be scanned before the peak effect of anxiolytics prescribed. A standard sedation protocol in such centres is associated with a more appropriate drug choice, as well as optimized monitoring and postprocedure care. (author)

  15. Propofol Effect on Stress Response and Free Radicals in Patient during Surgery and Sedation Procedure

    Directory of Open Access Journals (Sweden)

    Theresia Monica Rahardjo

    2015-12-01

    Full Text Available BACKGROUND: Propofol is an intravenous anesthetic used worldwide as an anesthesia induction and maintenance agent. Propofol also used as sedation agent in Intensive Care Unit (ICU. Despite it’s usual anesthesia properties, propofol has an unique pharmacologic characteristic, especially as antioxidant and stress response reduction. These advantages suggested propofol has positive effects when used as an anesthesia agent in surgery or sedation in ICU in conditions when high stress and free radical level are released. CONTENT: Stress response and free radical can be elevated in various conditions including surgery or during care in ICU, especially critical ill patient. Cortisol is a major stress hormone that influences metabolism, cardiovascular and central nervous system, either in acute or chronic phase. Oxidative stress was marked by free radical elevation called Radical Oxygen Species (ROS. Combination of both elements (cortisol and ROS can worsen patient condition. Propofol with anti-stress and antioxidant properties could be used to reduce stress response and attenuate free radical level in order to improve patient condition. SUMMARY: The anti-stress and antioxidant properties of Propofol are interesting, because these benefits can be added as adjunctive therapy when propofol was used as an anesthetic agent in surgery and a sedation in ICU. KEYWORDS: propofol, stress response, antioxidant.

  16. Comparison of oral ketamine and oral midazolam as sedative agents in pediatric dentistry

    Directory of Open Access Journals (Sweden)

    Damle S

    2008-09-01

    Full Text Available The safe and effective treatment of uncooperative or combative preschool children with extensive dental needs is one of pediatric dentist′s ongoing challenges. The traditional methods of behavior management are no longer acceptable to parents as they are not ready to spare more time for dental treatment of their children. Keeping this in mind, the present study was designed and carried out to evaluate the sedative effects of oral ketamine and oral midazolam prior to general anesthesia. Twenty uncooperative children in the age-group of 2-6 years were selected after thorough medical examination and investigations. Informed consent was obtained from the parent. This was a randomized double-blind study. An anesthesiologist administered either 0.5 mg/kg midazolam or 5 mg/kg ketamine orally. The heart rate, respiratory rate, and oxygen saturation were recorded at regular intervals. The sedation and anxiolysis scores were also recorded. The parents were asked to answer a questionnaire at the follow-up session the next day on the surgical experience of the parent and the child and side effects experienced, if any. When the data was subjected to statistical analysis, it was observed that both drugs resulted in adequate sedation at the end of 30 min, with oral midazolam providing significantly better anxiolysis. The heart rate and respiratory rate were marginally higher with oral ketamine. The questionnaire revealed a better response with oral midazolam; side effects were more prominent with oral ketamine.

  17. Study on Combustion Oscillation of Premixed Flame with Pilot Fuel at Elevated Pressures

    Science.gov (United States)

    Ohtsuka, Masaya; Yoshida, Shohei; Hirata, Yoshitaka; Kobayashi, Nariyoshi

    Acoustically-coupled combustion oscillation is studied for premixed flame with pilot fuel to be used in gas turbine combustors. Premixed gas is passed through swirl vanes and burnt with the centrally injected pilot fuel. The dependencies of pressure, fuel to air ratio, premixed fuel rate, inlet velocity and air temperature on the combustion oscillation are investigated. Two kinds of oscillation modes of ˜100Hz and ˜350Hz are activated according to inlet velocities. Fluctuating pressures are amplified when the premixed fuel rate is over ˜80% at elevated pressures. The fluctuating pressure peak moves to a higher premixed fuel ratio region with increased pressure or fuel to air ratio for the Helmholz type mode. Combustion oscillation occurs when the pilot fuel velocity is changed proportionally with the flame length.

  18. [Psychomotor agitation, pharmaceutical sedation and psychiatric emergency in psychotic patients].

    Science.gov (United States)

    Passamar, M; Tellier, O; Vilamot, B

    2011-12-01

    Psychomotor agitation, very common among psychiatric emergencies, raises the question of pharmaceutical sedation, its indications, and its issues, notably with regard to the observance in postemergency. A new approach to sedation places it within its therapeutic aim and also takes into account the sometimes harmful impact on the course of the patient's care. A pretherapeutical, analysis both clinical and environmental is crucial. The time spent on the initial meeting and assessment is essential. The evolution of professional practices in mental health allows us to distinguish three kinds of sedation (vigilance, behaviour and psychical) that guide the choice and the mode of psychotropic drug use. The harmful effects of an ever-increasing use of sedation is debated. The use of atypical antipsychotics and injectable forms is argued. Early psychical sedation is preferable to the obsolete practice of vigilance sedation and to behavioural sedation with its limited indications. The use of excessive or prolonged sedation might have a detrimental effect on the care offered after psychiatric emergency treatment. Copyright © 2011. Published by Elsevier Masson SAS.

  19. Continuous Palliative Sedation for Cancer and Noncancer Patients

    NARCIS (Netherlands)

    Swart, S.J.; Rietjens, J.A.C.; van Zuylen, L.; Zuurmond, W.W.A.; Perez, R.S.G.M.; van der Maas, P.J.; van Delden, J.J.M.; van der Heide, A.

    2012-01-01

    Context: Palliative care is often focused on cancer patients. Palliative sedation at the end of life is an intervention to address severe suffering in the last stage of life. Objectives: To study the practice of continuous palliative sedation for both cancer and noncancer patients. Methods: In 2008,

  20. Atelectasis on pediatric chest CT: comparison of sedation techniques

    International Nuclear Information System (INIS)

    Sargent, M.A.; McEachern, A.M.; Jamieson, D.H.

    1999-01-01

    Background. A change in practice at our institution resulted in increased use of anesthesia for CT scan of the chest in children who required sedation. Objective. To determine whether there is a difference in the frequency or severity of pulmonary atelectasis on CT scan in children sedated by anesthesiologists compared with children sedated by radiologists using intravenous pentobarbital. Materials and methods. Retrospective blinded review of 60 CT scans of the chest performed in 41 children. Forty-one studies in children sedated by radiologists (median age 29 months) were compared with 19 studies in children sedated by anesthesiologists (median age 25 months). Results. Atelectasis sufficient to obscure pulmonary metastases was shown in 5 of 41 (12 %) radiology sedations and 13 of 19 (68 %) anesthesiology sedations (P < 0.01). Higher grades of atelectasis were recorded in children under anesthesia (P < 0.01). Conclusion. Atelectasis is more frequent and more severe in children undergoing general anesthesia compared with intravenous pentobarbital sedation. Consideration should be given to the use of forced inspiration in children anesthetized for CT scan of the chest. (orig.)

  1. Sedative properties of Mitracarpus villosus leaves in mice

    African Journals Online (AJOL)

    admin

    anxiolytics increase the head-dip counts. The reduction in the number of head dips shown by the extract is therefore an indication of the presence of psychoactive constituents that are sedative in nature. The sedative property of the plant was confirmed by its ability to potentiate the duration of diazepam induced sleep.

  2. Recording EEG In Young Children Without Sedation | Curuneaux ...

    African Journals Online (AJOL)

    Background Although it has been considered that sedation in children undergoing EEG tests is effective and safe and complications are infrequent, occasionally adverse sedation-related events are presented. Objective The aim of this work was to determine if it is possible to carry out EEG in children up to 4 years old ...

  3. Propofol dose and incidence of dreaming during sedation.

    Science.gov (United States)

    Eer, Audrey Singyi; Padmanabhan, Usha; Leslie, Kate

    2009-10-01

    Dreaming is commonly reported after propofol-based sedation. We measured the incidence of dreaming and bispectral index (BIS) values in colonoscopy patients sedated with combinations of propofol, midazolam and fentanyl. Two hundred patients presenting for elective outpatient colonoscopy were sedated with combinations of propofol, midazolam and fentanyl. BIS was monitored throughout the procedure. Patients were interviewed immediately after they emerged from sedation. The primary end point was a report of dreaming during sedation. Ninety-seven patients were administered propofol alone, 44 were administered propofol and fentanyl, 16 were administered propofol and midazolam and 43 were administered propofol, midazolam and fentanyl. Dreaming was reported by 19% of patients. Dreamers received higher doses of propofol and had lower BIS values during sedation. Age of 50 years or less, preoperative quality of recovery score of less than 14, higher home dream recall, propofol dose of more than 300 mg and time to Observers' Assessment of Alertness/Sedation score equalling 5 of 8 min or less were independent predictors of dreaming. Dreaming during sedation is associated with higher propofol dose and lower BIS values.

  4. Use of sedation to relieve refractory symptoms in dying patients ...

    African Journals Online (AJOL)

    Indications. Agitated delirium was the most common reason (45%) for using sedation, followed by intractable vomiting due to inoperable malignant intestinal obstruction in 25% of patients. Three patients with persistent convulsions or myoclonic jerking and 2 patients with severe refractory dyspnoea required some sedation.

  5. Experience with Conscious sedation for Oocyte Retrieval in Nigeria

    African Journals Online (AJOL)

    elearning

    The aim of this study was to assess clients' pain experience, acceptance of conscious sedation and correlates of pain during oocyte retrieval ... Conscious sedation and analgesia are one of several methods used to relieve pain during oocyte retrieval in. IVF procedures. .... relieves anxiety and reduces the patient's memory.

  6. [Sedation and analgesia practices among Spanish neonatal intensive care units].

    Science.gov (United States)

    Avila-Alvarez, A; Carbajal, R; Courtois, E; Pertega-Diaz, S; Muñiz-Garcia, J; Anand, K J S

    2015-08-01

    Pain management and sedation is a priority in neonatal intensive care units. A study was designed with the aim of determining current clinical practice as regards sedation and analgesia in neonatal intensive care units in Spain, as well as to identify factors associated with the use of sedative and analgesic drugs. A multicenter, observational, longitudinal and prospective study. Thirty neonatal units participated and included 468 neonates. Of these, 198 (42,3%) received sedatives or analgesics. A total of 19 different drugs were used during the study period, and the most used was fentanyl. Only fentanyl, midazolam, morphine and paracetamol were used in at least 20% of the neonates who received sedatives and/or analgesics. In infusions, 14 different drug prescriptions were used, with the most frequent being fentanyl and the combination of fentanyl and midazolam. The variables associated with receiving sedation and/or analgesia were, to have required invasive ventilation (P3 (P=.023; OR=2.26), the existence of pain evaluation guides in the unit (Pneonates admitted to intensive care units receive sedatives or analgesics. There is significant variation between Spanish neonatal units as regards sedation and analgesia prescribing. Our results provide evidence on the "state of the art", and could serve as the basis of preparing clinical practice guidelines at a national level. Copyright © 2015 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

  7. Sedative and cardiorespiratory effects of detomidine constant rate infusion in sheep.

    Science.gov (United States)

    de Moura, Rauane Sousa; Bittar, Isabela Plazza; da Silva, Luiz Henrique; Villela, Ana Carolina Vasquez; Dos Santos Júnior, Marcelo Borges; Borges, Naida Cristina; Franco, Leandro Guimarães

    2018-02-01

    The use of sheep in experiments is widespread and is increasing worldwide, and so is the need to develop species-specific anaesthetic techniques to ensure animal safety. Previous studies have mentioned several protocols involving the administration of alpha-2 adrenergic agonists in sheep; however, assessment of the efficacy and safety of these infusion techniques is still relatively new. Thus, the aim of the present study is to assess the effectiveness of detomidine constant rate infusion (CRI) in sheep by measuring the cardiovascular and respiratory parameters, blood gas variables and sedation scores. Eight adult female Santa Inês sheep received 20 µg/kg of detomidine hydrochloride intravenously as a bolus loading dose, followed by an infusion rate of 60 µg/kg/h. The heart rates and respiratory rates changed continuously during the CRI period. No arrhythmias were observed. The reduction in arterial partial pressure of oxygen (PaO 2 ) was not significant, but one animal showed signs of hypoxaemia (minimum PaO 2 of 66.9 mmHg). The arterial partial pressure of carbon dioxide (PaCO 2 ) increased, but the animals did not become hypercapnic. The bicarbonate (HCO 3- ), pH and base excess (BE) tended towards metabolic alkalosis. The cardiac output (CO), stroke volume (SV), cardiac index (CI) and ejection fraction (EF%) showed no significant changes. The fractional shortening (FS%) decreased slightly, starting at T 45min . Sedation scores varied between 3 (0/10) after sedation and during recovery and 7 (0/10) during CRI. We concluded that administering detomidine at an infusion rate of 60 µg/kg/h in Santa Inês sheep is a simple technique that produces satisfactory sedation for minimally invasive procedures.

  8. Comfort and patient-centred care without excessive sedation

    DEFF Research Database (Denmark)

    Vincent, Jean-Louis; Shehabi, Yahya; Walsh, Timothy S

    2016-01-01

    We propose an integrated and adaptable approach to improve patient care and clinical outcomes through analgesia and light sedation, initiated early during an episode of critical illness and as a priority of care. This strategy, which may be regarded as an evolution of the Pain, Agitation...... and Delirium guidelines, is conveyed in the mnemonic eCASH-early Comfort using Analgesia, minimal Sedatives and maximal Humane care. eCASH aims to establish optimal patient comfort with minimal sedation as the default presumption for intensive care unit (ICU) patients in the absence of recognised medical...... requirements for deeper sedation. Effective pain relief is the first priority for implementation of eCASH: we advocate flexible multimodal analgesia designed to minimise use of opioids. Sedation is secondary to pain relief and where possible should be based on agents that can be titrated to a prespecified...

  9. SEDATIVE AND ANALGESIC EFFECTS OF DETOMIDINE HYDROCHLORIDE IN GOATS

    Directory of Open Access Journals (Sweden)

    A. N. Tunio., A. B. Kalhoro and I.H. Kathio1

    2003-07-01

    Full Text Available The sedative and analgesic effects of three dose rates of detomidine (40, 50 and 60µg/kg body weight were studied in six goats. Moderate to deep sedation occurred after administration of 40µg/kg of detomidine as compared to deep sedation produced by 50 and 60µg/kg of detomidine. The degree, onset and duration of sedation and onset and duration of maximum sedation were all dose dependent. Skin analgesia and recumbency were produced in all animals with higher doses (50 and 60µg/kg and in three animals with lower dose (40µg/kg. Duration of recumbency was 22.66 ± 1.45, 35.16 ± 1.68 and 55.66 ± 1.64 minutes after administration of 40, 50 and 60µg/kg of detomidine, respectively.

  10. The rate of adverse events during IV conscious sedation.

    Science.gov (United States)

    Schwamburger, Nathan T; Hancock, Raymond H; Chong, Chol H; Hartup, Grant R; Vandewalle, Kraig S

    2012-01-01

    Conscious sedation has become an integral part of dentistry; it is often used to reduce anxiety or fear in some patients during oral surgery, periodontal surgery, implant placement, and general dentistry procedures. The purpose of this study was to evaluate the frequency of adverse events during IV conscious sedation provided by credentialed general dentists and periodontists in the United States Air Force (USAF). Sedation clinical records (Air Force Form 1417) from calendar year 2009 were requested from all USAF bases. A total of 1,468 records were reviewed and 19 adverse events were noted in 17 patients. IV complication (infiltration) was the most common adverse event. The overall adverse event rate was 1.3 per 100 patients treated. The results of this study show that moderate sedation provided by general dentists and periodontists in the USAF has a low incidence of adverse events, and conscious sedation remains a viable option for providers for the reduction of anxiety in select patients.

  11. Response mechanisms of attached premixed flames subjected to harmonic forcing

    Science.gov (United States)

    Shreekrishna

    The persistent thrust for a cleaner, greener environment has prompted air pollution regulations to be enforced with increased stringency by environmental protection bodies all over the world. This has prompted gas turbine manufacturers to move from nonpremixed combustion to lean, premixed combustion. These lean premixed combustors operate quite fuel-lean compared to the stochiometric, in order to minimize CO and NOx productions, and are very susceptible to oscillations in any of the upstream flow variables. These oscillations cause the heat release rate of the flame to oscillate, which can engage one or more acoustic modes of the combustor or gas turbine components, and under certain conditions, lead to limit cycle oscillations. This phenomenon, called thermoacoustic instabilities, is characterized by very high pressure oscillations and increased heat fluxes at system walls, and can cause significant problems in the routine operability of these combustors, not to mention the occasional hardware damages that could occur, all of which cumulatively cost several millions of dollars. In a bid towards understanding this flow-flame interaction, this research works studies the heat release response of premixed flames to oscillations in reactant equivalence ratio, reactant velocity and pressure, under conditions where the flame preheat zone is convectively compact to these disturbances, using the G-equation. The heat release response is quantified by means of the flame transfer function and together with combustor acoustics, forms a critical component of the analytical models that can predict combustor dynamics. To this end, low excitation amplitude (linear) and high excitation amplitude (nonlinear) responses of the flame are studied in this work. The linear heat release response of lean, premixed flames are seen to be dominated by responses to velocity and equivalence ratio fluctuations at low frequencies, and to pressure fluctuations at high frequencies which are in the

  12. Study on biogas premixed charge diesel dual fuelled engine

    International Nuclear Information System (INIS)

    Duc, Phan Minh; Wattanavichien, Kanit

    2007-01-01

    This paper presents an experimental investigation of a small IDI biogas premixed charge diesel dual fuelled CI engine used in agricultural applications. Engine performance, diesel fuel substitution, energy consumption and long term use have been concerned. The attained results show that biogas-diesel dual fuelling of this engine revealed almost no deterioration in engine performance but lower energy conversion efficiency which was offset by the reduced fuel cost of biogas over diesel. The long term use of this engine with biogas-diesel dual fuelling is feasible with some considerations

  13. Flashback mechanisms in lean premixed gas turbine combustion

    CERN Document Server

    Benim, Ali Cemal

    2014-01-01

    Blending fuels with hydrogen offers the potential to reduce NOx and CO2 emissions in gas turbines, but doing so introduces potential new problems such as flashback.  Flashback can lead to thermal overload and destruction of hardware in the turbine engine, with potentially expensive consequences. The little research on flashback that is available is fragmented. Flashback Mechanisms in Lean Premixed Gas Turbine Combustion by Ali Cemal Benim will address not only the overall issue of the flashback phenomenon, but also the issue of fragmented and incomplete research.Presents a coherent review of f

  14. Premixer assembly for mixing air and fuel for combustion

    Science.gov (United States)

    York, William David; Johnson, Thomas Edward; Keener, Christopher Paul

    2016-12-13

    A premixer assembly for mixing air and fuel for combustion includes a plurality of tubes disposed at a head end of a combustor assembly. Also included is a tube of the plurality of tubes, the tube including an inlet end and an outlet end. Further included is at least one non-circular portion of the tube extending along a length of the tube, the at least one non-circular portion having a non-circular cross-section, and the tube having a substantially constant cross-sectional area along its length

  15. Auditory processing during deep propofol sedation and recovery from unconsciousness.

    Science.gov (United States)

    Koelsch, Stefan; Heinke, Wolfgang; Sammler, Daniela; Olthoff, Derk

    2006-08-01

    Using evoked potentials, this study investigated effects of deep propofol sedation, and effects of recovery from unconsciousness, on the processing of auditory information with stimuli suited to elicit a physical MMN, and a (music-syntactic) ERAN. Levels of sedation were assessed using the Bispectral Index (BIS) and the Modified Observer's Assessment of Alertness and Sedation Scale (MOAAS). EEG-measurements were performed during wakefulness, deep propofol sedation (MOAAS 2-3, mean BIS=68), and a recovery period. Between deep sedation and recovery period, the infusion rate of propofol was increased to achieve unconsciousness (MOAAS 0-1, mean BIS=35); EEG measurements of recovery period were performed after subjects regained consciousness. During deep sedation, the physical MMN was markedly reduced, but still significant. No ERAN was observed in this level. A clear P3a was elicited during deep sedation by those deviants, which were task-relevant during the awake state. As soon as subjects regained consciousness during the recovery period, a normal MMN was elicited. By contrast, the P3a was absent in the recovery period, and the P3b was markedly reduced. Results indicate that the auditory sensory memory (as indexed by the physical MMN) is still active, although strongly reduced, during deep sedation (MOAAS 2-3). The presence of the P3a indicates that attention-related processes are still operating during this level. Processes of syntactic analysis appear to be abolished during deep sedation. After propofol-induced anesthesia, the auditory sensory memory appears to operate normal as soon as subjects regain consciousness, whereas the attention-related processes indexed by P3a and P3b are markedly impaired. Results inform about effects of sedative drugs on auditory and attention-related mechanisms. The findings are important because these mechanisms are prerequisites for auditory awareness, auditory learning and memory, as well as language perception during anesthesia.

  16. A Detailed Chemical Kinetic Reaction Mechanism for Oxidation of Four Small Alkyl Esters in Laminar Premixed Flames

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C K; Pitz, W J; Westmoreland, P R; Dryer, F L; Chaos, M; Osswald, P; Kohse-Hoinghaus, K; Cool, T A; Wang, J; Yang, B; Hansen, N; Kasper, T

    2008-02-08

    A detailed chemical kinetic reaction mechanism has been developed for a group of four small alkyl ester fuels, consisting of methyl formate, methyl acetate, ethyl formate and ethyl acetate. This mechanism is validated by comparisons between computed results and recently measured intermediate species mole fractions in fuel-rich, low pressure, premixed laminar flames. The model development employs a principle of similarity of functional groups in constraining the H atom abstraction and unimolecular decomposition reactions in each of these fuels. As a result, the reaction mechanism and formalism for mechanism development are suitable for extension to larger oxygenated hydrocarbon fuels, together with an improved kinetic understanding of the structure and chemical kinetics of alkyl ester fuels that can be extended to biodiesel fuels. Variations in concentrations of intermediate species levels in these flames are traced to differences in the molecular structure of the fuel molecules.

  17. Conscious sedation for patients undergoing enteroclysis: Comparing the safety and patient-reported effectiveness of two protocols

    International Nuclear Information System (INIS)

    Maglinte, Dean D.T.; Applegate, Kimberly E.; Rajesh, Arumugam; Jennings, S. Gregory; Ford, Jason M.; Savabi, Mojgan Sarah; Lappas, John C.

    2009-01-01

    Objective: To compare the safety and patient-reported effectiveness of two regimens for conscious sedation during enteroclysis. Materials and methods: We surveyed two groups of outpatients and retrospectively reviewed procedure records for conscious sedation and complications. Patients were divided into Group One (received sedative/amnesic diazepam), and Group Two, (received amnesic/sedative, midazolam and analgesic fentanyl). Results: All enteroclyses were successfully completed; there were no hospital admissions due to complications. In Group One (n = 106), mean dose of diazepam was 12.7 mg. 25% had oxygen desaturation (n = 25), and post-procedure vomiting without aspiration (n = 1). 56% of outpatients completed phone surveys, and 68% recalled procedural discomfort. In Group Two (n = 45), mean doses were 3.9 mg midazolam and 108 mcg fentanyl. 31% had desaturation (n = 13), and post-procedure vomiting without aspiration (n = 1). 87% had only a vague recall of the procedure or of any discomfort. Conclusion: A combination of amnesic and fentanyl prevented the recall of discomfort of nasoenteric intubation and infusion in most patients who had enteroclysis compared to diazepam. Most of the patients would undergo the procedure again, if needed.

  18. Conscious sedation for patients undergoing enteroclysis: Comparing the safety and patient-reported effectiveness of two protocols

    Energy Technology Data Exchange (ETDEWEB)

    Maglinte, Dean D.T. [Department of Radiology, Indiana University Medical Center, 550 N, University Boulevard, University Hospital Room 0279, Indianapolis, IN 46202-5253 (United States)], E-mail: dmaglint@iupui.edu; Applegate, Kimberly E.; Rajesh, Arumugam; Jennings, S. Gregory; Ford, Jason M. [Department of Radiology, Indiana University Medical Center, 550 N, University Boulevard, University Hospital Room 0279, Indianapolis, IN 46202-5253 (United States); Savabi, Mojgan Sarah [Division of Gastroenterology, Department of Medicine, Indiana University School of Medicine, 550 N, University Boulevard, Indianapolis, IN 46202-5253 (United States); Lappas, John C. [Department of Radiology, Indiana University Medical Center, 550 N, University Boulevard, University Hospital Room 0279, Indianapolis, IN 46202-5253 (United States)

    2009-06-15

    Objective: To compare the safety and patient-reported effectiveness of two regimens for conscious sedation during enteroclysis. Materials and methods: We surveyed two groups of outpatients and retrospectively reviewed procedure records for conscious sedation and complications. Patients were divided into Group One (received sedative/amnesic diazepam), and Group Two, (received amnesic/sedative, midazolam and analgesic fentanyl). Results: All enteroclyses were successfully completed; there were no hospital admissions due to complications. In Group One (n = 106), mean dose of diazepam was 12.7 mg. 25% had oxygen desaturation (n = 25), and post-procedure vomiting without aspiration (n = 1). 56% of outpatients completed phone surveys, and 68% recalled procedural discomfort. In Group Two (n = 45), mean doses were 3.9 mg midazolam and 108 mcg fentanyl. 31% had desaturation (n = 13), and post-procedure vomiting without aspiration (n = 1). 87% had only a vague recall of the procedure or of any discomfort. Conclusion: A combination of amnesic and fentanyl prevented the recall of discomfort of nasoenteric intubation and infusion in most patients who had enteroclysis compared to diazepam. Most of the patients would undergo the procedure again, if needed.

  19. Gasoline – ignition improver – oxygenate blends as fuels for advanced compression ignition combustion

    NARCIS (Netherlands)

    Zhou, L.; Boot, M.D.; Goey, de L.P.H.

    2013-01-01

    Mixing is inhibited both by the relatively low volatility of conventional diesel fuel and the short premixing time due to high fuel reactivity (i.e. cetane number (CN)). Consequently, in this research two promising oxygenates which can be produced from 2 nd generation biomass -ethanol from cellulose

  20. Effect of energetic electrons on combustion of premixed burner flame

    Science.gov (United States)

    Sasaki, Koichi

    2011-10-01

    In many studies of plasma-assisted combustion, authors superpose discharges onto flames to control combustion reactions. This work is motivated by more fundamental point of view. The standpoint of this work is that flames themselves are already plasmas. We irradiated microwave power onto premixed burner flame with the intention of heating electrons in it. The microwave power was limited below the threshold for a discharge. We obtained the enhancement of burning velocity by the irradiation of the microwave power, which was understood by the shortening of the flame length. At the same time, we observed the increases in the optical emission intensities of OH and CH radicals. Despite the increases in the optical emission intensities, the optical emission spectra of OH and CH were not affected by the microwave irradiation, indicating that the enhancement of the burning velocity was not attributed to the increase in the gas temperature. On the other hand, we observed significant increase in the optical emission intensity of the second positive system of molecular nitrogen, which is a clear evidence for electron heating in the premixed burner flame. Therefore, it is considered that the enhancement of the burning velocity is obtained by nonequilibrium combustion chemistry which is driven by energetic electrons. By irradiating pulsed microwave power, we examined the time constants for the increases and decreases in the optical emission intensities of N2, OH, CH, and continuum radiation.

  1. Direct Numerical Simulations of Statistically Stationary Turbulent Premixed Flames

    KAUST Repository

    Im, Hong G.

    2016-07-15

    Direct numerical simulations (DNS) of turbulent combustion have evolved tremendously in the past decades, thanks to the rapid advances in high performance computing technology. Today’s DNS is capable of incorporating detailed reaction mechanisms and transport properties of hydrocarbon fuels, with physical parameter ranges approaching laboratory scale flames, thereby allowing direct comparison and cross-validation against laser diagnostic measurements. While these developments have led to significantly improved understanding of fundamental turbulent flame characteristics, there are increasing demands to explore combustion regimes at higher levels of turbulent Reynolds (Re) and Karlovitz (Ka) numbers, with a practical interest in new combustion engines driving towards higher efficiencies and lower emissions. The article attempts to provide a brief overview of the state-of-the-art DNS of turbulent premixed flames at high Re/Ka conditions, with an emphasis on homogeneous and isotropic turbulent flow configurations. Some important qualitative findings from numerical studies are summarized, new analytical approaches to investigate intensely turbulent premixed flame dynamics are discussed, and topics for future research are suggested. © 2016 Taylor & Francis.

  2. Streamline segment statistics of premixed flames with nonunity Lewis numbers

    Science.gov (United States)

    Chakraborty, Nilanjan; Wang, Lipo; Klein, Markus

    2014-03-01

    The interaction of flame and surrounding fluid motion is of central importance in the fundamental understanding of turbulent combustion. It is demonstrated here that this interaction can be represented using streamline segment analysis, which was previously applied in nonreactive turbulence. The present work focuses on the effects of the global Lewis number (Le) on streamline segment statistics in premixed flames in the thin-reaction-zones regime. A direct numerical simulation database of freely propagating thin-reaction-zones regime flames with Le ranging from 0.34 to 1.2 is used to demonstrate that Le has significant influences on the characteristic features of the streamline segment, such as the curve length, the difference in the velocity magnitude at two extremal points, and their correlations with the local flame curvature. The strengthenings of the dilatation rate, flame normal acceleration, and flame-generated turbulence with decreasing Le are principally responsible for these observed effects. An expression for the probability density function (pdf) of the streamline segment length, originally developed for nonreacting turbulent flows, captures the qualitative behavior for turbulent premixed flames in the thin-reaction-zones regime for a wide range of Le values. The joint pdfs between the streamline length and the difference in the velocity magnitude at two extremal points for both unweighted and density-weighted velocity vectors are analyzed and compared. Detailed explanations are provided for the observed differences in the topological behaviors of the streamline segment in response to the global Le.

  3. Comprehensive Validation of Skeletal Mechanism for Turbulent Premixed Methane–Air Flame Simulations

    KAUST Repository

    Luca, Stefano

    2017-08-01

    A new skeletal mechanism, consisting of 16 species and 72 reactions, has been developed for lean methane–air premixed combustion from the GRI-Mech 3.0. The skeletal mechanism is validated for elevated unburnt temperatures (800 K) and pressures up to 4 atm, thereby addressing realistic gas turbine conditions. The skeletal mechanism is obtained by applying the directed relation graph method and performing sensitivity analysis on the detailed mechanism. The mechanism has been validated for flame speed and flame structure in a wide range of conditions and configurations. A good agreement between the skeletal mechanism and GRI-3.0 was obtained. The configurations considered include one-dimension laminar premixed flames, laminar non-premixed counterflow burners, and two- and three-dimensional unsteady configurations with variations of temperature, pressure, and composition. The skeletal mechanism allows for the inclusion of accurate finite rate chemistry in large-scale direct numerical simulations of lean turbulent premixed flames. In a large-scale direct numerical simulation, the use of the skeletal mechanism reduces the memory requirements by more than a factor of 3 and accelerates the simulation by a factor of 7 compared with the detailed mechanism. The skeletal mechanism is suitable for unsteady three-dimensional simulations of methane turbulent premixed, non-premixed, and globally lean partially premixed flames and is available as supplementary material.

  4. Soot reduction under DC electric fields in counterflow non-premixed laminar ethylene flames

    KAUST Repository

    Park, Daegeun

    2014-04-23

    The effects of DC electric fields on non-premixed ethylene flames in a counterflow burner were studied experimentally with a focus on the reduction of soot particles. The experiment was conducted by connecting a high voltage terminal and a ground terminal to a lower (fuel) and upper (oxidizer) nozzle, respectively. We applied direct current (DC) potentials in a range of -5 kV < Vdc < 5 kV. Uniform electric fields were then generated in the gap between the two nozzles. The experimental conditions were selected to cover both soot formation (SF) and soot formation oxidation (SFO) flames. The flames subjected to the negative electric fields moved toward the fuel nozzle because of an ionic wind due to the Lorentz force acting on the positive ions in the flames. In addition, the yellow luminosity significantly decreased, indicating changes in the sooting characteristics. To analyze the sooting characteristics under the electric fields, planar laser induced incandescence (PLII) and fluorescence (PLIF) techniques were used to visualize the soot, polycyclic aromatic hydrocarbons (PAHs), and OH radicals. The sooting limits in terms of the fuel and oxygen mole fractions were measured. No substantial soot formation due to the effects of the DC electric fields for the tested range of voltages and reactant mole fractions could be identified. The detailed flame behaviors and sooting characteristics under the DC electric fields are discussed. Copyright © Taylor & Francis Group, LLC.

  5. Investigation on Effect of Air Velocity in Turbulent Non-Premixed Flames

    Directory of Open Access Journals (Sweden)

    Namazian Zafar

    2016-09-01

    Full Text Available In this study, the turbulent non-premixed methane-air flame is simulated to determine the effect of air velocity on the length of flame, temperature distribution and mole fraction of species. The computational fluid dynamics (CFD technique is used to perform this simulation. To solve the turbulence flow, k-ε model is used. In contrast to the previous works, in this study, in each one of simulations the properties of materials are taken variable and then the results are compared. The results show that at a certain flow rate of fuel, by increasing the air velocity, similar to when the properties are constant, the width of the flame becomes thinner and the maximum temperature is higher; the penetration of oxygen into the fuel as well as fuel consumption is also increased. It is noteworthy that most of the pollutants produced are NOx, which are strongly temperature dependent. The amount of these pollutants rises when the temperature is increased. As a solution, decreasing the air velocity can decrease the amount of these pollutants. Finally, comparing the result of this study and the other work, which considers constant properties, shows that the variable properties assumption leads to obtaining more exact solution but the trends of both results are similar.

  6. The near-field region behaviour of hydrogen-air turbulent non-premixed flame

    Energy Technology Data Exchange (ETDEWEB)

    Tabet, F. [EDF R and D, EIFER (European Institute for Energy Research), Karlsruhe (Germany); Sarh, B. [Centre National de la Recherche Scientifique (CNRS), Institut de Combustion, Aerothermique, Reactivite et Environnement (ICARE), Orleans (France); Universite d' Orleans, Institut Universitaire de Technologie d' Orleans (France); Birouk, M. [University of Manitoba, Department of Mechanical and Manufacturing Engineering, Winnipeg, MB (Canada); Goekalp, I. [Centre National de la Recherche Scientifique (CNRS), Institut de Combustion, Aerothermique, Reactivite et Environnement (ICARE), Orleans (France)

    2012-02-15

    A computational study of mixing process and air entrainment in hydrogen turbulent non-premixed flame characterized by strong gradients of velocity and density at the inlet section is presented. Different approaches for turbulence-combustion interactions are evaluated in the framework of RSM (Reynolds Stress Model) turbulence model and the computational results are compared to experimental data. The combustion models investigated are SLFM (Steady Laminar Flamelet Model) and EDC (Eddy Dissipation Concept). Mixing is described by oxygen atom mixture fraction and air entrainment is characterized by gas mass flow rate. Computational results are compared to measurements in physical space at two locations (the first one represent the near-field region and the second one the far-field region). At the first station, the results showed an overestimation of mixing and air entrainment and an inaccurate consumption of O{sub 2} and H{sub 2}. In addition, the predictions are found to be sensitive to combustion modelling. At the second station, the description of mixing and air entrainment is improved and the predictions are in reasonably agreement with experimental data. Less dependency to combustion modelling is noticed in this location. Further analysis of the near-field region based on the turbulence time scales revealed that turbulence is not well developed in this region of the flame. (orig.)

  7. Sedation during bronchoscopy: data from a nationwide sedation and monitoring survey.

    Science.gov (United States)

    Gaisl, Thomas; Bratton, Daniel J; Heuss, Ludwig T; Kohler, Malcolm; Schlatzer, Christian; Zalunardo, Marco P; Frey, Martin; Franzen, Daniel

    2016-08-05

    There is limited knowledge on practice patterns in procedural sedation and analgesia (PSA), the use of propofol, and monitoring during flexible bronchoscopy (FB). The purpose of this study was to assess the current practice patterns of FBs and to focus on the use of propofol, the education of the proceduralist, and the involvement of anaesthesiologists during FB. An anonymous questionnaire was sent to 299 pulmonologists. Only respondents who were active physicians in adult respiratory medicine performing FB were subsequently analysed. The response rate was 78 % and 27,149 FB in the previous 12 months were analysed. The overall sedation-related morbidity rate was 0.02 % and mortality was 7/100'000 FB. Sedation was used in 95 % of bronchoscopies. The main drugs used for PSA were propofol (77 %) and midazolam (46 %). In 84 % of PSAs propofol was used without the attendance of an anaesthesiologist. The use of propofol was associated with high volume bronchoscopists (p vital parameters has become standard practice, pulmonologists reported a very low rate of systematic basic education and training in the field of PSA (50 %). In Switzerland, PSA during FB is mostly performed with propofol without the attendance of an anaesthesiologist and the use of this drug is expected to increase in the future. While monitoring standards are very high there is need for policies to improve education, systematic training, and support for pulmonologists for PSA during FB.

  8. Palliative Sedation: An Analysis of International Guidelines and Position Statements.

    Science.gov (United States)

    Gurschick, Lauren; Mayer, Deborah K; Hanson, Laura C

    2015-09-01

    To describe the suggested clinical practice of palliative sedation as it is presented in the literature and discuss available guidelines for its use. CINAHL, PubMed, and Web of Science were searched for publications since 1997 for recommended guidelines and position statements on palliative sedation as well as data on its provision. Keywords included palliative sedation, terminal sedation, guidelines, United States, and end of life. Inclusion criteria were palliative sedation policies, frameworks, guidelines, or discussion of its practice, general or oncology patient population, performance of the intervention in an inpatient unit, for humans, and in English. Exclusion criteria were palliative sedation in children, acute illness, procedural, or burns, and predominantly ethical discussions. Guidelines were published by American College of Physicians-American Society of Internal Medicine (2000), Hospice and Palliative Nurses Association (2003), American Academy of Hospice and Palliative Medicine (2006), American Medical Association (2008), Royal Dutch Medical Association (2009), European Association for Palliative Care (2009), National Hospice and Palliative Care Organization (2010), and National Comprehensive Cancer Network (2012). Variances throughout guidelines include definitions of the practice, indications for its use, continuation of life-prolonging therapies, medications used, and timing/prognosis. The development and implementation of institutional-based guidelines with clear stance on the discussed variances is necessary for consistency in practice. Data on provision of palliative sedation after implementation of guidelines needs to be collected and disseminated for a better understanding of the current practice in the United States. © The Author(s) 2014.

  9. Suboptimal palliative sedation in primary care: an exploration.

    Science.gov (United States)

    Pype, Peter; Teuwen, Inge; Mertens, Fien; Sercu, Marij; De Sutter, An

    2018-02-01

    Palliative sedation is a therapeutic option to control refractory symptoms in terminal palliative patients. This study aims at describing the occurrence and characteristics of suboptimal palliative sedations in primary care and at exploring the way general practitioners (GPs) experience suboptimal palliative sedation in their practice. We conducted a mixed methods study with a quantitative prospective survey in primary care and qualitative semi-structured interviews with GPs. The research team defined suboptimal palliative sedation as a time interval until deep sleep >1.5 h and/ or >2 awakenings after the start of the unconsciousness. Descriptive statistics were calculated on the quantitative data. Thematic analysis was used to analyse interview transcripts. We registered 63 palliative sedations in 1181 home deaths, 27 forms were completed. Eleven palliative sedations were suboptimal: eight due to the long time span until deep sleep; three due the number of unintended awakenings. GPs' interview analysis revealed two major themes: the shifting perception of failure and the burden of responsibility. Suboptimal palliative sedation occurs frequently in primary palliative care. Efficient communication towards family members is needed to prevent them from having unrealistic expectations and to prevent putting pressure on the GP to hasten the procedure. Sharing the burden of decision-making during the procedure with other health care professionals might diminish the heavy responsibility as perceived by GPs.

  10. Palliative sedation in end-of-life care.

    Science.gov (United States)

    Maltoni, Marco; Scarpi, Emanuela; Nanni, Oriana

    2013-07-01

    The aim of this review was to present and comment on recent data published on palliative sedation in palliative and end-of-life care. Palliative sedation is a medical procedure used to deal with the refractory symptoms occurring in the advanced stages of cancer. It has clinical, nursing, relational and ethical implications, making it a highly sensitive issue. Over the last 12 months, a number of authors have published interesting new findings on different areas of palliative sedation, that is prevalence, indications, monitoring, duration and choice of drugs. In particular, a clear definition of palliative sedation and of its more pronounced form, deep continuous sedation (DCS), has emerged. It has been confirmed that, when performed in the correct way and with the right aims, palliative sedation does not have a detrimental impact on survival. Recent findings confirm that palliative sedation is an integral part of a medical palliative care approach and is needed in certain clinical situations. It is a legitimate clinical practice from any ethical point of view. While oncologists should have a basic knowledge of the procedure, its in depth study is a core competency for palliative care physicians.

  11. Patient satisfaction with procedural sedation in the emergency department.

    Science.gov (United States)

    Johnson, Olivia G; Taylor, David McD; Lee, Marina; Ding, Juen-Li; Ashok, Aadith; Johnson, Damian; Peck, Daniel; Knott, Jonathan; Weinberg, Laurence

    2017-06-01

    The aim of this study was to determine patient satisfaction with procedural sedation as a function of nature of the procedure and depth of sedation. We undertook a prospective observational study of adult patients who received procedural sedation in two EDs (20 month period). The level of sedation was determined by an investigator, using the Observers Assessment of Anaesthesia/Sedation Scale (1 = awake to 6 = no response to noxious stimuli). Patient satisfaction was measured with the Iowa Satisfaction with Anaesthesia Scale after full recovery. This was self-administered, comprised 11 items (e.g. 'I felt pain') and has a score range of -3 (poor satisfaction) to +3 (very satisfied). A total of 163 patients were enrolled (51.2% men, mean age 50.7 years). The median (interquartile range) satisfaction score was 2.7 (0.7). Patient satisfaction was lower among patients who had orthopaedic procedures (median 2.6 vs 2.8, P patient satisfaction is high. Greater satisfaction is associated with deeper sedation, sedation with propofol and non-orthopaedic procedures. © 2017 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  12. The interpersonal work of dental conscious sedation: A qualitative analysis.

    Science.gov (United States)

    Woolley, Stephen M; Chadwick, Barbara; Pugsley, Lesley

    2017-08-01

    Whilst there is a considerable body of literature examining the pharmacology of conscious sedation, the social tasks required to successfully provide conscious sedation have not been reported. This paper discusses data regarding the interpersonal work integral to effective conscious sedation provision, from a larger qualitative study exploring how patients and clinicians engage with secondary care conscious sedation provided within the UK. Semi-structured interviews were conducted with 13 conscious sedation providers and nine patients within UK-based secondary care sedation settings. Digital audio-recordings were transcribed verbatim and subsequently analysed using a constant comparative method within NVivo Data Analysis Software. Four main themes of interpersonal work were reported by participants: displaying care, containing emotions, demonstrating competence and maximizing the effect. This study shows that performing conscious sedation requires more than technical delivery, and involves the projection of attributes in a literal "performance." The importance of managing outward emotional appearance reflects previous dental research. The need to manage outward appearance, and the emotional impact this has, is of relevance to all clinicians. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Chloral hydrate sedation in radiology: retrospective audit of reduced dose

    Energy Technology Data Exchange (ETDEWEB)

    Bracken, Jennifer [Children' s University Hospital, Radiology Department, Dublin (Ireland); Royal Children' s Hospital, Department of Medical Imaging, Parkville, Victoria (Australia); Heaslip, Ingrid; Ryan, Stephanie [Children' s University Hospital, Radiology Department, Dublin (Ireland)

    2012-03-15

    Chloral hydrate (CH) is safe and effective for sedation of suitable children. The purpose of this study was to assess whether adequate sedation is achieved with reduced CH doses. We retrospectively recorded outpatient CH sedations over 1 year. We defined standard doses of CH as 50 mg/kg (infants) and 75 mg/kg (children >1 year). A reduced dose was defined as at least 20% lower than the standard dose. In total, 653 children received CH sedation (age, 1 month-3 years 10 months), 42% were given a reduced initial dose. Augmentation dose was required in 10.9% of all children, and in a higher proportion of children >1 year (15.7%) compared to infants (5.7%; P < 0.001). Sedation was successful in 96.7%, and more frequently successful in infants (98.3%) than children >1 year (95.3%; P = 0.03). A reduced initial dose had no negative effect on outcome (P = 0.19) or time to sedation. No significant complications were seen. We advocate sedation with reduced CH doses (40 mg/kg for infants; 60 mg/kg for children >1 year of age) for outpatient imaging procedures when the child is judged to be quiet or sleepy on arrival. (orig.)

  14. [Recommendations for analgesia and sedation in neonatal intensive care].

    Science.gov (United States)

    Rawicz, Marcin

    2008-01-01

    The purpose of the study was to present recommendations, relevant to the management of neonates and infants aged 0-1 years, treated in intensive care settings. They include general principles and recommendations for pain and sedation assessment, sedation and pain management and advice on the use of pharmacological strategies. The bolus (on demand) administration of sedative agents should be avoided because of increased risk of cardiovascular depression and/or neurological complications. Midazolam administration time should be limited to 72 hours because of tachyphylaxis, and the possibility of development of a withdrawal syndrome and neurological complications (grade A, LOE 1b). The level of sedation and pain should be regularly assessed and documented, using presented scales; the COMFORT scale is preferred. Opioids, given in continuous infusion, are the drugs of choice for neonatal sedation. To avoid withdrawal syndrome, the total doses and time of administration of sedative agents should be limited. Methadone is a drug of choice in the treatment of a withdrawal (Grade B, LOE 2). Intravenous ketamine is recommended, when short-term sedation/anaesthesia is required (Grade C, LOE 3) for painful and/or stressful intensive care procedures. (Grade C, LOE 2). Muscle relaxants should be used for endotracheal intubation and in the situations when mechanical ventilation is not possible due to maximal respiratory effort of the patient.

  15. Effect of Dimethyl Ether Mixing on Soot Size Distribution in Premixed Ethylene Flame

    KAUST Repository

    Li, Zepeng

    2016-04-21

    As a byproduct of incomplete combustion, soot attracts increasing attentions as extensive researches exploring serious health and environmental effects from soot particles. Soot emission reduction requires a comprehensive understanding of the mechanism for polycyclic aromatic hydrocarbons and of soot formation and aging processes. Therefore, advanced experimental techniques and numerical simulations have been conducted to investigate this procedure. In order to investigate the effects of dimethyl ether (DME) mixing on soot particle size distribution functions (PSDFs), DME was mixed in premixed ethylene/oxygen/argon at flames at the equivalence ratio of 2.0 with a range of mixing ratio from 0% to 30% of the total carbon fed. Two series of atmospheric pressure flames were tested in which cold gas velocity was varied to obtain different flame temperatures. The evolution of PSDFs along the centerline of the flame was determined by burner stabilized stagnation probe and scanning mobility particle sizer (SMPS) techniques, yielding the PSDFs for various separation distances above the burner surface. Meanwhile, the flame temperature profiles were carefully measured by a thermocouple and the comparison to that of simulated laminar premixed burner-stabilized stagnation flame was satisfactory. Additionally, to understand the chemical role of DME mixing in soot properties, characterization measurements were conducted on soot samples using thermo-gravimetric analysis (TGA) and elemental analysis (EA). Results of the evolution of PSDFs and soot volume fraction showed that adding DME into ethylene flame could reduce soot yield significantly. The addition of DME led to the decrease of both the soot nucleation rate and the particle mass growth rate. To explain the possible mechanism for the observation, numerical simulations were performed. Although DME addition resulted in the slight increase of methyl radicals from pyrolysis, the decrease in acetylene and propargyl radicals

  16. Thermal stability of vitamins A and E in rations and vitamin premixes for shrimp

    OpenAIRE

    Prado, João Paulo de Sousa; Cavalheiro, José Marcelino Oliveira; Silva, Fernanda Vanessa Gomes da; Queiroga Neto, Vicente; Bora, Pushkar Singh; Cavalheiro, Thiago Brandão

    2011-01-01

    O trabalho teve como objetivo avaliar a estabilidade térmica das vitaminas A e E em diferentes rações e premixes vitamínicos utilizados na carcinicultura. Foram utilizadas no experimento três rações comerciais peletilizadas e desintegradas em diferentes diâmetros e dois premixes vitamínicos. As amostras de cada dieta e de premixes foram acondicionadas em recipientes plásticos e armazenadas nas seguintes condições: ambiente refrigerado (6°C±2°C), ambiente climatizado (20°C&p...

  17. Experiences of Family Members of Dying Patients Receiving Palliative Sedation.

    Science.gov (United States)

    Tursunov, Olga; Cherny, Nathan I; Ganz, Freda DeKeyser

    2016-11-01

    To describe the experience of family members of patients receiving palliative sedation at the initiation of treatment and after the patient has died and to compare these experiences over time.
. Descriptive comparative study.
. Oncology ward at Shaare Zedek Medical Center in Jerusalem, Israel.
. A convenience sample of 34 family members of dying patients receiving palliative sedation. 
. A modified version of a questionnaire describing experiences of family members with palliative sedation was administered during palliative sedation and one to four months after the patient died. Descriptive statistics were used to describe the results of the questionnaire, and appropriate statistical analyses were conducted for comparisons over time.
. Experiences of family members and time.
. Most relatives were satisfied with the sedation and staff support. Palliative sedation was experienced as an ethical way to relieve suffering. However, one-third felt that it shortened the patient's life. An explanation of the treatment was given less than half of the time and was usually given on the same day treatment was started. This explanation was given by physicians and nurses. Many felt that they were not ready for changes in the patient's condition and wanted increased opportunities to discuss the treatment with oncology care providers. No statistically significant differences in experiences were found over time. 
. Relatives' experiences of palliative sedation were generally positive and stable over time. Important experiences included timing of the initiation of sedation, timing and quality of explanations, and communication.
. Nurses should attempt to initiate discussions of the possible role of sedation in the event of refractory symptoms and follow through with continued discussions. The management of refractory symptoms at the end of life, the role of sedation, and communication skills associated with decision making related to palliative sedation should be a

  18. Considerations of physicians about the depth of palliative sedation at the end of life

    Science.gov (United States)

    Swart, Siebe J.; van der Heide, Agnes; van Zuylen, Lia; Perez, Roberto S.G.M.; Zuurmond, Wouter W.A.; van der Maas, Paul J.; van Delden, Johannes J.M.; Rietjens, Judith A.C.

    2012-01-01

    Background: Although guidelines advise titration of palliative sedation at the end of life, in practice the depth of sedation can range from mild to deep. We investigated physicians’ considerations about the depth of continuous sedation. Methods: We performed a qualitative study in which 54 physicians underwent semistructured interviewing about the last patient for whom they had been responsible for providing continuous palliative sedation. We also asked about their practices and general attitudes toward sedation. Results: We found two approaches toward the depth of continuous sedation: starting with mild sedation and only increasing the depth if necessary, and deep sedation right from the start. Physicians described similar determinants for both approaches, including titration of sedatives to the relief of refractory symptoms, patient preferences, wishes of relatives, expert advice and esthetic consequences of the sedation. However, physicians who preferred starting with mild sedation emphasized being guided by the patient’s condition and response, and physicians who preferred starting with deep sedation emphasized ensuring that relief of suffering would be maintained. Physicians who preferred each approach also expressed different perspectives about whether patient communication was important and whether waking up after sedation is started was problematic. Interpretation: Physicians who choose either mild or deep sedation appear to be guided by the same objective of delivering sedation in proportion to the relief of refractory symptoms, as well as other needs of patients and their families. This suggests that proportionality should be seen as a multidimensional notion that can result in different approaches toward the depth of sedation. PMID:22331961

  19. Nurse administered propofol sedation for pulmonary endoscopies requires a specific protocol

    DEFF Research Database (Denmark)

    Jensen, Jeppe Thue; Banning, Anne-Marie; Clementsen, Paul

    2012-01-01

    This study provides an evaluation and risk analysis of propofol sedation for endoscopic pulmonary procedures according to our unit's "gastroenterologic nurse-administered propofol sedation (NAPS) guideline".......This study provides an evaluation and risk analysis of propofol sedation for endoscopic pulmonary procedures according to our unit's "gastroenterologic nurse-administered propofol sedation (NAPS) guideline"....

  20. Excitable dynamics in high-Lewis number premixed gas combustion at normal and microgravity

    Science.gov (United States)

    Pearlman, Howard

    1995-01-01

    Freely-propagating, premixed gas flames in high-Lewis (Le) number, quiescent mixtures are studied experimentally in tubes of various diameter at normal (lg) and microgravity (mu g). A premixture of lean butane and oxygen diluted with helium, argon, neon, nitrogen or a mixture of multiple diluents is examined such that the thermal diffusivity of the mixture (and to a lesser extent, the mass diffusivity of the rate-limiting component) is systematically varied. In effect, different diluents allow variation of the Le without changing the chemistry. The flames are recorded with high speed cinematography and their stability is visually assessed. Different modes of propagation were observed depending on the diameter of the tubes (different conductive heat loss), the composition of the mixture and the g-level. At 1g, four modes of propagation were observed in small and intermediate diameter tubes (large conductive heat loss): (1) steadily propagating flames, (2) radial and longitudinal pulsating flames, (3) 'wavering' flames, and (4) rotating spiral flames. As the diameter of the tube increases, the radial modes become more pronounced while the longitudinal modes systematically disappear. Also, multiple, simultaneous, spatially-separated 'pacemaker' sites are observed in intermediate and large diameter tubes. Each site starts as a small region of high luminosity and develops into a flamelet which assumes the form of one of the fore mentioned modes. These flamelets eventually interact, annihilate each other in their regions of intersection and merge at their newly created free-ends. For very large tubes, radially-propagating wave-trains (believed to be 'trigger waves') are observed. These are analogous to the radial pulsations observed in the smaller diameter tubes. At mu g, three modes of propagation have been observed: (1) steadily propagating flames, (2) radial and longitudinal pulsating flames, and (3) multi-armed, rotating flames. Since the pulsating mode exists at mu

  1. Effect of hydrogen on hydrogen-methane turbulent non-premixed flame under MILD condition

    Energy Technology Data Exchange (ETDEWEB)

    Mardani, Amir; Tabejamaat, Sadegh [Department of Aerospace engineering, Amirkabir university of technology (Tehran polytechnic), Hafez Ave., PO. Box: 15875-4413, Tehran (Iran)

    2010-10-15

    Energy crises and the preservation of the global environment are placed man in a dilemma. To deal with these problems, finding new sources of fuel and developing efficient and environmentally friendly energy utilization technologies are essential. Hydrogen containing fuels and combustion under condition of the moderate or intense low-oxygen dilution (MILD) are good choices to replace the traditional ones. In this numerical study, the turbulent non-premixed CH{sub 4}+H{sub 2} jet flame issuing into a hot and diluted co-flow air is considered to emulate the combustion of hydrogen containing fuels under MILD conditions. This flame is related to the experimental condition of Dally et al. [Proc. Combust. Inst. 29 (2002) 1147-1154]. In general, the modelling is carried out using the EDC model, to describe turbulence-chemistry interaction, and the DRM-22 reduced mechanism and the GRI2.11 full mechanism to represent the chemical reactions of H{sub 2}/methane jet flame. The effect of hydrogen content of fuel on flame structure for two co-flow oxygen levels is studied by considering three fuel mixtures, 5%H{sub 2}+95%CH{sub 4}, 10%H{sub 2}+90%CH{sub 4} and 20% H{sub 2}+80%CH{sub 4}(by mass). In this study, distribution of species concentrations, mixture fraction, strain rate, flame entrainment, turbulent kinetic energy decay and temperature are investigated. Results show that the hydrogen addition to methane leads to improve mixing, increase in turbulent kinetic energy decay along the flame axis, increase in flame entrainment, higher reaction intensities and increase in mixture ignitability and rate of heat release. (author)

  2. Sedation of Pediatric Patients in Magnetic Resonance Imaging

    National Research Council Canada - National Science Library

    Ricks, Alesia

    2000-01-01

    .... The purpose of this study was to explore the combination sedative of ketamine, midazolam, and atropine administered intramuscularly and determine if it is safe and effective for pediatric patients...

  3. Dissociations in the expression of the sedative effects of triazolam.

    Science.gov (United States)

    Weingartner, H J; Sirocco, K; Rawlings, R; Joyce, E; Hommer, D

    1995-05-01

    Fifteen normal volunteers were administered 0.250, 0.375, and 0.500 mg of triazolam and placebo in a double-blind repeated measures cross-over design. Subjects demonstrated dose-dependent impairments in free recall, a test of explicit memory requiring awareness and reflection, and sedation as assessed by objective behavioral measures (the digit symbol substitution task) and subjective visual analogue scales. The sedative drug response did not account for the impairment in free recall. Differences in performance of the two tests of sedation indicated that the effect of this drug on reflective processes accounts for impairment in episodic memory and the inability to track the sedative effects of this drug at the higher doses tested in this study.

  4. Sedative and Anticonvulsant Activities of the Ethanol Root Extract of ...

    African Journals Online (AJOL)

    Purpose: To investigate the sedative, hypnotic and anticonvulsant activities of the ethanol extract of the roots of the Flemingia chappar (ERFC) on the central nervous system (CNS) of mice. Methods: The ..... Higher extract doses (400 and.

  5. Characteristics of premixed flames stabilized in an axisymmetric curved-wall jet burner with tip modification

    KAUST Repository

    Kim, Daejoong; Gil, Y. S.; Chung, TaeWon; Chung, Suk-Ho

    2009-01-01

    The stabilization characteristics of premixed flames in an axisymmetric curved-wall jet burner have been experimentally investigated. This burner utilized the Coanda effect on top of a burner tip. The initially spherical burner tip was modified to a

  6. Tip opening of premixed bunsen flames: Extinction with negative stretch and local Karlovitz number

    KAUST Repository

    Vu, Tranmanh; Cha, Min; Lee, Byeongjun; Chung, Suk-Ho

    2015-01-01

    The characteristics of tip openings in premixed bunsen flames have been studied experimentally by measuring OH radicals from laser-induced fluorescence and tip curvatures from chemiluminescent images. Results showed that the tip opening occurred

  7. Impact of flame-wall interaction on premixed flame dynamics and transfer function characteristics

    KAUST Repository

    Kedia, K.S.; Altay, H.M.; Ghoniem, A.F.

    2011-01-01

    In this paper, we numerically investigate the response of a perforated-plate stabilized laminar methane-air premixed flame to imposed inlet velocity perturbations. A flame model using detailed chemical kinetics mechanism is applied and heat exchange

  8. Dynamics and Suppression Effectiveness of Monodisperse Water Droplets in Non-Premixed Counterflow Flames

    National Research Council Canada - National Science Library

    Zegers, E. J; Williams, B. A; Sheinson, R. S; Fleming, J. W

    2000-01-01

    ...-premixed propane/air counterflow flames are reported. Droplets were generated piezoelectrically, and the size and velocity distributions and the number density were determined by phase-Doppler particle anemometry...

  9. Investigation of Scalar Filtered Density Function in Turbulent Partially Premixed Flames

    National Research Council Canada - National Science Library

    Tong, Chenning

    2006-01-01

    ... using measurement data obtained in turbulent partially premixed methane/air (Sandia) flames. For SGS scalar variance small compared to its mean, the FMDF is not far from Gaussian and the SGS scalar is well mixed...

  10. Combustion stratification study of partially premixed combustion using Fourier transform analysis of OH* chemiluminescence images

    KAUST Repository

    Izadi Najafabadi, Mohammad; Somers, Bart; Johansson, Bengt; Dam, Nico

    2017-01-01

    A relatively high level of stratification (qualitatively: lack of homogeneity) is one of the main advantages of partially premixed combustion over the homogeneous charge compression ignition concept. Stratification can smooth the heat release rate

  11. Effect of AC electric fields on the stabilization of premixed bunsen flames

    KAUST Repository

    Kim, Minkuk; Chung, Suk-Ho; Kim, Hwanho

    2011-01-01

    The stabilization characteristics of laminar premixed bunsen flames have been investigated experimentally for stoichiometric methane-air mixture by applying AC voltage to the nozzle with the single-electrode configuration. The detachment velocity

  12. Analysis of Hydrogen/Air Turbulent Premixed Flames at Different Karlovitz Numbers Using Computational Singular Perturbation

    KAUST Repository

    Manias, Dimitrios; Tingas, Alexandros-Efstathios; Hernandez Perez, Francisco E.; Im, Hong G.; Galassi, Riccardo Malpica; Ciottoli, Pietro Paolo; Valorani, Mauro

    2018-01-01

    The dynamics and structure of two turbulent H2/air premixed flames, representative of the corrugated flamelet (Case 1) and thin reaction zone (Case 2) regimes, are analyzed and compared, using the computational singular perturbation (CSP) tools

  13. Flow structures in a lean-premixed swirl-stabilized combustor with microjet air injection

    KAUST Repository

    LaBry, Zachary A.; Shanbhogue, Santosh J.; Speth, Raymond L.; Ghoniem, Ahmed F.

    2011-01-01

    The major challenge facing the development of low-emission combustors is combustion instability. By lowering flame temperatures, lean-premixed combustion has the potential to nearly eliminate emissions of thermally generated nitric oxides

  14. An Investigation of a Hybrid Mixing Model for PDF Simulations of Turbulent Premixed Flames

    Science.gov (United States)

    Zhou, Hua; Li, Shan; Wang, Hu; Ren, Zhuyin

    2015-11-01

    Predictive simulations of turbulent premixed flames over a wide range of Damköhler numbers in the framework of Probability Density Function (PDF) method still remain challenging due to the deficiency in current micro-mixing models. In this work, a hybrid micro-mixing model, valid in both the flamelet regime and broken reaction zone regime, is proposed. A priori testing of this model is first performed by examining the conditional scalar dissipation rate and conditional scalar diffusion in a 3-D direct numerical simulation dataset of a temporally evolving turbulent slot jet flame of lean premixed H2-air in the thin reaction zone regime. Then, this new model is applied to PDF simulations of the Piloted Premixed Jet Burner (PPJB) flames, which are a set of highly shear turbulent premixed flames and feature strong turbulence-chemistry interaction at high Reynolds and Karlovitz numbers. Supported by NSFC 51476087 and NSFC 91441202.

  15. Investigation of non-premixed flame combustion characters in GO2/GH2 shear coaxial injectors using non-intrusive optical diagnostics

    Science.gov (United States)

    Dai, Jian; Yu, NanJia; Cai, GuoBiao

    2015-12-01

    Single-element combustor experiments are conducted for three shear coaxial geometry configuration injectors by using gaseous oxygen and gaseous hydrogen (GO2/GH2) as propellants. During the combustion process, several spatially and timeresolved non-intrusive optical techniques, such as OH planar laser induced fluorescence (PLIF), high speed imaging, and infrared imaging, are simultaneously employed to observe the OH radical concentration distribution, flame fluctuations, and temperature fields. The results demonstrate that the turbulent flow phenomenon of non-premixed flame exhibits a remarkable periodicity, and the mixing ratio becomes a crucial factor to influence the combustion flame length. The high speed and infrared images have a consistent temperature field trend. As for the OH-PLIF images, an intuitionistic local flame structure is revealed by single-shot instantaneous images. Furthermore, the means and standard deviations of OH radical intensity are acquired to provide statistical information regarding the flame, which may be helpful for validation of numerical simulations in future. Parameters of structure configurations, such as impinging angle and oxygen post thickness, play an important role in the reaction zone distribution. Based on a successful flame contour extraction method assembled with non-linear anisotropic diffusive filtering and variational level-set, it is possible to implement a fractal analysis to describe the fractal characteristics of the non-premixed flame contour. As a result, the flame front cannot be regarded as a fractal object. However, this turbulent process presents a self-similarity characteristic.

  16. Premixed Flames Under Microgravity and Normal Gravity Conditions

    Science.gov (United States)

    Krikunova, Anastasia I.; Son, Eduard E.

    2018-03-01

    Premixed conical CH4-air flames were studied experimentally and numerically under normal straight, reversed gravity conditions and microgravity. Low-gravity experiments were performed in Drop tower. Classical Bunsen-type burner was used to find out features of gravity influence on the combustion processes. Mixture equivalence ratio was varied from 0.8 to 1.3. Wide range of flow velocity allows to study both laminar and weakly turbulized flames. High-speed flame chemoluminescence video-recording was used as diagnostic. The investigations were performed at atmospheric pressure. As results normalized flame height, laminar flame speed were measured, also features of flame instabilities were shown. Low- and high-frequency flame-instabilities (oscillations) have a various nature as velocity fluctuations, preferential diffusion instability, hydrodynamic and Rayleigh-Taylor ones etc., that was explored and demonstrated.

  17. Direct numerical simulations of turbulent lean premixed combustion

    International Nuclear Information System (INIS)

    Sankaran, Ramanan; Hawkes, Evatt R; Chen, Jacqueline H; Lu Tianfeng; Law, Chung K

    2006-01-01

    In recent years, due to the advent of high-performance computers and advanced numerical algorithms, direct numerical simulation (DNS) of combustion has emerged as a valuable computational research tool, in concert with experimentation. The role of DNS in delivering new Scientific insight into turbulent combustion is illustrated using results from a recent 3D turbulent premixed flame simulation. To understand the influence of turbulence on the flame structure, a 3D fully-resolved DNS of a spatially-developing lean methane-air turbulent Bunsen flame was performed in the thin reaction zones regime. A reduced chemical model for methane-air chemistry consisting of 13 resolved species, 4 quasi-steady state species and 73 elementary reactions was developed specifically for the current simulation. The data is analyzed to study possible influences of turbulence on the flame thickness. The results show that the average flame thickness increases, in qualitative agreement with several experimental results

  18. Dynamics of premixed hydrogen/air flames in mesoscale channels

    Energy Technology Data Exchange (ETDEWEB)

    Pizza, Gianmarco [Paul Scherrer Institute, Combustion Research, CH-5232, Villigen PSI (Switzerland); Aerothermochemistry and Combustion Systems Laboratory, Swiss Federal Institute of Technology, CH-8092, Zurich (Switzerland); Frouzakis, Christos E.; Boulouchos, Konstantinos [Aerothermochemistry and Combustion Systems Laboratory, Swiss Federal Institute of Technology, CH-8092, Zurich (Switzerland); Mantzaras, John [Paul Scherrer Institute, Combustion Research, CH-5232, Villigen PSI (Switzerland); Tomboulides, Ananias G. [Department of Engineering and Management of Energy Resources, University of Western Macedonia, 50100 Kozani (Greece)

    2008-10-15

    Direct numerical simulation with detailed chemistry and transport is used to study the stabilization and dynamics of lean ({phi}=0.5) premixed hydrogen/air atmospheric pressure flames in mesoscale planar channels. Channel heights of h=2, 4, and 7 mm, and inflow velocities in the range 0.3{<=}U{sub IN}{<=}1100cm/ s are investigated. Six different burning modes are identified: mild combustion, ignition/extinction, closed steady symmetric flames, open steady symmetric flames, oscillating and, finally, asymmetric flames. Chaotic behavior of cellular flame structures is observed for certain values of U{sub IN}. Stability maps delineating the regions of the different flame types are finally constructed. (author)

  19. Internal combustion engine using premixed combustion of stratified charges

    Science.gov (United States)

    Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

    2003-12-30

    During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

  20. Non-sedation versus sedation with a daily wake-up trial in critically ill patients receiving mechanical ventilation (NONSEDA Trial)

    DEFF Research Database (Denmark)

    Toft, Palle; Olsen, Hanne Tanghus; Jørgensen, Helene Korvenius

    2014-01-01

    comparing sedation with no sedation, a priori powered to have all-cause mortality as primary outcome.The objective is to assess the benefits and harms of non-sedation versus sedation with a daily wake-up trial in critically ill patients. METHODS: The non-sedation (NONSEDA) trial is an investigator......-sedation supplemented with pain management during mechanical ventilation.Control intervention is sedation with a daily wake-up trial.The primary outcome will be all cause mortality at 90 days after randomization. Secondary outcomes will be: days until death throughout the total observation period; coma- and delirium...... in mortality with a type I error risk of 5% and a type II error risk of 20% (power at 80%). DISCUSSION: The trial investigates potential benefits of non-sedation. This might have large impact on the future treatment of mechanically ventilated critically ill patients.Trial register: ClinicalTrials.gov NCT...

  1. Early structure of LPG partially premixed conically stabilized flames

    KAUST Repository

    Elbaz, Ayman M.

    2013-01-01

    This paper presents experimental investigation of LPG partially premixed turbulent flames stabilized within a conical nozzle burner under constant degree of partial premixing. The stability limits and mean flame structure are presented based on the mean gas temperature and the concentration of CO, O 2, NO, and HC at the flame early region of reaction. The investigation covered the influence of the nozzle cone angle, the jet exit velocity and the jet equivalence ratio. The stability results show that the flames with cone are more stable than those without cone. For conical stabilized flames, the stability results exhibit three different sensitivity regions between the jet velocity and equivalence ratio. The inflame measurements prove that the flame stability could be attributed to the triple flame structure at the flame leading edge. The data show that the triple flame structure is influenced by cone angle, the jet velocity and the equivalence ratio. The flame is believed to be controlled by the recirculation flow inside the cone. Increasing the cone angle induced higher air entrainment to the reaction zone as depicted by a higher O 2 concentration within the flame leading edge. Increasing the jet velocity to a certain limit enhances the intensity of combustion at the flame leading edge, while excessive increase in jet velocity reduces this intensity. At a fixed jet velocity the higher the equivalence ratio, the higher the amount of fuel diffused and engulfed to the reaction zone, the more delay of the combustion completion and the higher the emission concentrations of the flame. © 2012 Elsevier Inc.

  2. Chloral hydrate sedation in radiology: retrospective audit of reduced dose

    International Nuclear Information System (INIS)

    Bracken, Jennifer; Heaslip, Ingrid; Ryan, Stephanie

    2012-01-01

    Chloral hydrate (CH) is safe and effective for sedation of suitable children. The purpose of this study was to assess whether adequate sedation is achieved with reduced CH doses. We retrospectively recorded outpatient CH sedations over 1 year. We defined standard doses of CH as 50 mg/kg (infants) and 75 mg/kg (children >1 year). A reduced dose was defined as at least 20% lower than the standard dose. In total, 653 children received CH sedation (age, 1 month-3 years 10 months), 42% were given a reduced initial dose. Augmentation dose was required in 10.9% of all children, and in a higher proportion of children >1 year (15.7%) compared to infants (5.7%; P 1 year (95.3%; P = 0.03). A reduced initial dose had no negative effect on outcome (P = 0.19) or time to sedation. No significant complications were seen. We advocate sedation with reduced CH doses (40 mg/kg for infants; 60 mg/kg for children >1 year of age) for outpatient imaging procedures when the child is judged to be quiet or sleepy on arrival. (orig.)

  3. Performing bone marrow biopsies with or without sedation: a comparison.

    Science.gov (United States)

    Giannoutsos, I; Grech, H; Maboreke, T; Morgenstern, G

    2004-06-01

    Although intravenous sedation (ISED) in addition to a local anaesthetic (LA) is commonly used in the performance of a bone marrow aspirate and trephine (BMAT), it is not clear under what circumstances and in which way sedation may be most beneficial. In this study, information was gathered using a questionnaire, from 112 patients shortly after undergoing BMAT; the duration of the procedures and the length of the biopsy cores were measured and any complications noted. Most patients (68%) chose to receive LA only, and almost all (74/76) were happy with their decision. Patients who received sedation gave lower pain scores than patients receiving LA only (1 vs. 3) and were found to have lower levels of apprehension at the thought of having a repeat procedure. Patients having a repeat BMAT showed a slightly increased preference for having sedation compared with patients who were undergoing it for the first time. There is some concern that guidelines regarding the use of ISED for procedures other than BMAT are not always adhered to, and current practice may be best revealed by a large-scale audit of sedation practice for the performance of BMAT. Patients should be given the choice of having ISED if the appropriate resources are available, but in most cases the additional small risk of receiving sedation can be avoided.

  4. Fospropofol Disodium for Sedation in Elderly Patients Undergoing Flexible Bronchoscopy.

    Science.gov (United States)

    Silvestri, Gerard A; Vincent, Brad D; Wahidi, Momen M

    2011-01-01

    BACKGROUND: Fospropofol disodium is a water-soluble prodrug of propofol. A subset analysis was undertaken of elderly patients (≥65 y) undergoing flexible bronchoscopy, who were part of a larger multicenter, randomized, double-blind study. METHODS: Patients received fentanyl citrate (50 mcg) followed by fospropofol at initial (4.88mg/kg) and supplemental (1.63mg/kg) doses. The primary end point was sedation success (3 consecutive Modified Observer's Assessment of Alertness/Sedation scores of ≤4 and procedure completion without alternative sedative or assisted ventilation). Treatment success, time to fully alert, patient and physician satisfaction, and safety/tolerability were also evaluated. RESULTS: In the elderly patients subset (n=61), sedation success was 92%, the mean time to fully alert was 8.0±10.9 min, and memory retention was 72% during recovery, and these were comparable with the younger patients subgroup (age, Sedation-related adverse events occurred in 23% of the elderly and 18% of the younger patients (age, sedation, rapid time to fully alert, and high satisfaction in this elderly subset undergoing flexible bronchoscopy, which was comparable with outcomes in younger patients.

  5. Intensifying existing premix therapy (BIAsp 30) with BIAsp 50 and BIAsp 70

    DEFF Research Database (Denmark)

    Brito, Miguel; Ligthelm, Robert Jan; Boemi, Massimo

    2011-01-01

    In 2009, consensus guidelines were published on intensification of insulin therapy using the premix analog biphasic insulin aspart (BIAsp) 30 in the treatment of type 2 diabetes, based on the recommendations of an international, independent expert panel. The guidelines included recommendations an...... assist physicians in introducing mid-/high-ratio premixes to optimize the insulin therapy of patients with type 2 diabetes who are failing to achieve glycemic targets on a BIAsp 30 BID or TID regimen....

  6. Performance and emissions of a dual-fuel pilot diesel ignition engine operating on various premixed fuels

    International Nuclear Information System (INIS)

    Yousefi, Amin; Birouk, Madjid; Lawler, Benjamin; Gharehghani, Ayatallah

    2015-01-01

    and the higher content of oxygen with increased methanol, soot and CO emissions are significantly reduced for richer premixed methanol mixtures. According to these findings, a dual-fuel engine operating on methanol and diesel performs better at rich conditions, whereas the performance of hydrogen and diesel is superior to that of natural gas/diesel and methanol/diesel mixtures at lean conditions.

  7. Direct Numerical Simulations of NOx formation in spatially developing turbulent premixed Bunsen flames with mixture inhomogeneity

    KAUST Repository

    Luca, Stefano

    2017-01-05

    Direct Numerical Simulation of three-dimensional spatially developing turbulent methane/air flames are performed. Four flames are simulated; they differ for the level of premixing of the fuel inlet: one has a fully premixed inlet, the other three have a partially premixed inlet that mimic a common injection strategy in stationary gas turbines. The jet consist of a methane/air mixture with global equivalence ratio ɸ = 0.7 and temperature of 800 K. The simulations are performed at 4 atm. The inlet velocity field and the fuel/air fields were extracted from a fully developed turbulent channel simulation. Chemistry is treated with a new skeletal chemical mechanism consisting of 33 species developed specifically for the DNS. The data are analyzed to study possible influences of partial premixing on the flame structure and the combustion efficiency. The results show that increasing the level of partial premixing, the fluctuations of heat release rate increase, due to the richer and leaner pockets of mixture in the flame, while the conditional mean decreases. Increasing the level of partial premixing, the peak of NO and the range of NO values for a given temperature increase. An analysis of NO production is performed categorizing the different initiation steps in the Ndecomposition through four pathways: thermal, prompt, NNH and NO. Different behaviour with respect to laminar flames is found for the NNH pathway suggesting that turbulence influences this pathway of formation of NO.

  8. Use of Piggyback Electrolytes for Patients Receiving Individually Prescribed vs Premixed Parenteral Nutrition.

    Science.gov (United States)

    Busch, Rebecca A; Curtis, Caitlin S; Leverson, Glen E; Kudsk, Kenneth A

    2015-07-01

    Parenteral nutrition (PN) is available as individualized prescriptions frequently prepared with an automated compounding device or as commercially prepared premixed solutions. Our institution exclusively used individualized PN until an amino acid shortage forced a temporary switch to premixed solutions. In general, premixed solutions contain lower electrolyte levels than individualized formulations prescribed for patients with normal organ function. We aimed to quantify supplemental intravenous piggyback (IVPB) electrolyte use in adult patients receiving individualized and premixed PN and to quantify any effect on difference in the cost of therapy. We compared use of supplemental IVPB electrolytes administered to patients receiving PN during consecutive periods prior to and during the amino acid shortage. Electrolyte IVPBs tabulated were potassium chloride, 10 and 20 mEq; magnesium sulfate, 2 g and 4 g; potassium phosphate, 7.5 and 15 mmol; and sodium phosphate, 7.5 and 15 mmol IVPB. There was no statistical difference in the number of PN formulations administered per day during each period (14.7 ± 3.9 vs 14.0 ± 2.6, individualized vs premixed, respectively). Total IVPB electrolytes prescribed per day increased significantly from the individualized PN period to the premixed PN period (7.03 ± 3.8 vs 13.8 ± 6.8; P Parenteral and Enteral Nutrition.

  9. Subcutaneous dissociative conscious sedation (sDCS an alternative method for airway regional blocks: a new approach

    Directory of Open Access Journals (Sweden)

    Javid Mihan J

    2011-10-01

    Full Text Available Abstract Background Predicted difficult airway is a definite indication for awake intubation and spontaneous ventilation. Airway regional blocks which are commonly used to facilitate awake intubation are sometimes impossible or forbidden. On the other hand deep sedation could be life threatening in the case of compromised airway. The aim of this study is evaluating "Subcutaneous Dissociative Conscious Sedation" (sDCS as an alternative method to airway regional blocks for awake intubation. Methods In this prospective, non-randomized study, 30 patients with predicted difficult airway (laryngeal tumors, who were scheduled for direct laryngoscopic biopsy (DLB, underwent "Subcutaneous Dissociative Conscious Sedation" (sDCS exerted by intravenous fentanyl 3-4ug/kg and subcutaneous ketamine 0.6-0.7 mg/kg. The tongue and pharynx were anesthetized with lidocaine spray (4%. 10 minutes after a subcutaneous injection of ketamine direct laryngoscopy was performed. Extra doses of fentanyl 50-100 ug were administered if the patient wasn't cooperative enough for laryngoscopy. Patients were evaluated for hemodynamic stability (heart rate and blood pressure, oxygen saturation (Spo2, patient cooperation (obedient to open the mouth for laryngoscopy and the number of tries for laryngoscopy, patient comfort (remaining moveless, hallucination, nystagmus and salivation (need for aspiration before laryngoscopy. Results Direct laryngoscopy was performed successfully in all patients. One patient needed extra fentanyl and then laryngoscopy was performed successfully on the second try. All patients were cooperative enough during laryngoscopy. Hemodynamic changes more than 20% occurred in just one patient. Oxygen desaturation (spo2 Conclusions Subcutaneous Dissociative Conscious Sedation (sDCS as a new approach to airway is an acceptable and safe method for awake intubation and it can be suggested as a noninvasive substitute of low complication rate for regional airway

  10. Effects of premixed diethyl ether (DEE) on combustion and exhaust emissions in a HCCI-DI diesel engine

    International Nuclear Information System (INIS)

    Cinar, Can; Can, Ozer; Sahin, Fatih; Yucesu, H. Serdar

    2010-01-01

    In this study, the effects of premixed ratio of diethyl ether (DEE) on the combustion and exhaust emissions of a single-cylinder, HCCI-DI engine were investigated. The experiments were performed at the engine speed of 2200 rpm and 19 N m operating conditions. The amount of the premixed DEE was controlled by a programmable electronic control unit (ECU) and the DEE injection was conducted into the intake air charge using low pressure injector. The premixed fuel ratio (PFR) of DEE was changed from 0% to 40% and results were compared to neat diesel operation. The percentages of premixed fuel were calculated from the energy ratio of premixed DEE fuel to total energy rate of the fuels. The experimental results show that single stage ignition was found with the addition of premixed DEE fuel. Increasing and phasing in-cylinder pressure and heat release were observed in the premixed stage of the combustion. Lower diffusion combustion was also occurred. Cycle-to cycle variations were very small with diesel fuel and 10% DEE premixed fuel ratio. Audible knocking occurred with 40% DEE premixed fuel ratio. NO x -soot trade-off characteristics were changed and improvements were found simultaneously. NO x and soot emissions decreased up to 19.4% and 76.1%, respectively, while exhaust gas temperature decreased by 23.8%. On the other hand, CO and HC emissions increased.

  11. Palliative sedation and moral distress: A qualitative study of nurses.

    Science.gov (United States)

    Lokker, M E; Swart, S J; Rietjens, J A C; van Zuylen, L; Perez, R S G M; van der Heide, A

    2018-04-01

    Clinical nursing practice may involve moral distress, which has been reported to occur frequently when nurses care for dying patients. Palliative sedation is a practice that is used to alleviate unbearable and refractory suffering in the last phase of life and has been linked to distress in nurses. The aim of this study was to explore nurses' reports on the practice of palliative sedation focusing on their experiences with pressure, dilemmas and morally distressing situations. In-depth interviews with 36 nurses working in hospital, nursing home or primary care. Several nurses described situations in which they felt that administration of palliative sedation was in the patient's best interest, but where they were constrained from taking action. Nurses also reported on situations where they experienced pressure to be actively involved in the provision of palliative sedation, while they felt this was not in the patient's best interest. The latter situation related to (1) starting palliative sedation when the nurse felt not all options to relieve suffering had been explored yet; (2) family requesting an increase of the sedation level where the nurse felt that this may involve unjustified hastening of death; (3) a decision by the physician to start palliative sedation where the patient had previously expressed an explicit wish for euthanasia. Nurses experienced moral distress in situations where they were not able to act in what they believed is the patient's best interest. Situations involving moral distress require nurses to be well informed and able to adequately communicate with suffering patients, distressed family and physicians. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. 'Targeting' sedation: the lived experience of the intensive care nurse.

    Science.gov (United States)

    Everingham, Kirsty; Fawcett, Tonks; Walsh, Tim

    2014-03-01

    To discuss the findings from a phenomenological study that provides insights into the intensive care nurses' 'world' following changes in the sedation management of patients in an intensive care unit. Intensive care sedation practices have undergone significant changes. Patients, where possible, are now managed on lighter levels of sedation, often achieved through the performance of sedation holds (SHs). The performance of SHs is normally carried out by the bedside nurse but compliance is reported to be poor. There has been little exploration of the nurses' experiences of these changes and the implications of SHs and subsequent wakefulness on their delivery of care. Following ethical approval, 16 intensive care nurses, experienced and inexperienced, from within a general intensive care unit. A Heideggerian phenomenological approach was used. Data collection consisted of interviews guided by an aide memoir and a framework adapted from Van Manen informed the analysis. The findings reveal new insights into the world of the intensive care nurse in the light of the changes to sedation management. They demonstrate that there have been unforeseen outcomes from well-intentioned initiatives to improve the quality of patients' care. There were implications from the changes introduced for the nurses care delivery. The main themes that emerged were 'working priorities' and 'unintended consequences', in turn revealing embedded tensions between evidence-based targets and holistic care. Intensive care nurses find that the current approach to the changes in sedation management can threaten their professional obligation and personal desire to provide holistic care. The 'targeted' approach by healthcare organisations is perceived to militate against the patient-centred care they want to deliver. Sedation management is complex and needs further consideration particularly the potential constraints 'target-led' care has on nursing practice. © 2013 Blackwell Publishing Ltd.

  13. Continuous palliative sedation for cancer and noncancer patients.

    Science.gov (United States)

    Swart, Siebe J; Rietjens, Judith A C; van Zuylen, Lia; Zuurmond, Wouter W A; Perez, Roberto S G M; van der Maas, Paul J; van Delden, Johannes J M; van der Heide, Agnes

    2012-02-01

    Palliative care is often focused on cancer patients. Palliative sedation at the end of life is an intervention to address severe suffering in the last stage of life. To study the practice of continuous palliative sedation for both cancer and noncancer patients. In 2008, a structured questionnaire was sent to 1580 physicians regarding their last patient receiving continuous sedation until death. A total of 606 physicians (38%) filled out the questionnaire, of whom 370 (61%) reported on their last case of continuous sedation (cancer patients: n=282 [76%] and noncancer patients: n=88 [24%]). More often, noncancer patients were older, female, and not fully competent. Dyspnea (odds ratio [OR]=2.13; 95% confidence interval [CI]: 1.22, 3.72) and psychological exhaustion (OR=2.64; 95% CI: 1.26, 5.55) were more often a decisive indication for continuous sedation for these patients. A palliative care team was consulted less often for noncancer patients (OR=0.45; 95% CI: 0.21, 0.96). Also, preceding sedation, euthanasia was discussed less often with noncancer patients (OR=0.42; 95% CI: 0.24, 0.73), whereas their relatives more often initiated discussion about euthanasia than relatives of cancer patients (OR=3.75; 95% CI: 1.26, 11.20). The practice of continuous palliative sedation in patients dying of cancer differs from patients dying of other diseases. These differences seem to be related to the less predictable course of noncancer diseases, which may reduce physicians' awareness of the imminence of death. Increased attention to noncancer diseases in palliative care practice and research is, therefore, crucial as is more attention to the potential benefits of palliative care consultation. Copyright © 2012 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

  14. [Analgesia and sedation in neonatal-pediatric intensive care].

    Science.gov (United States)

    Schlünder, C; Houben, F; Hartwig, S; Theisohn, M; Roth, B

    1991-01-01

    In pediatric intensive care, analgesia and sedation has become increasingly important for newborns as well as prematures in recent years. However, its importance is frequently not well recognized and sedation is confounded with analgesia. In our intensive-care unit (ICU), fentanyl and midazolam have proved to be useful. In newborn and premature infants, fentanyl alone has been sufficient because of its analgesic and sedative action. In a study on 20 newborns and prematures suffering from severe respiratory problems as compared with a historical group that did not receive fentanyl, we could show that in subjects receiving fentanyl, considerably less treatment with sedatives and other analgesics was necessary. Cardiopulmonary tolerance was satisfactory. The highest bilirubin values were reached about 1 day earlier and were slightly higher than those measured in the control group, but oral nutrition could be initiated sooner. In small infants, additional midazolam was given after cardiac surgery. During the first 72 h, we found a correlation between serum levels of midazolam and the depth of sedation; however, after 72 h of medication, the dose had to be raised because of an increase in metabolic clearance. During the concomitant administration of midazolam and fentanyl, significantly less midazolam was needed to achieve appropriate analog-sedation. Prior to the administration of analgesics and sedatives, care should be taken to ensure that circulatory conditions are stable and that there is no hypovolemia, and the drugs must be given slowly during several minutes. Especially in a pediatric ICU, light and noise should be diminished and contact between the parents and the child should be encouraged, even when the child is undergoing mechanical ventilation.

  15. Efficacy of Ketamine in Pediatric Sedation Dentistry: A Systematic Review.

    Science.gov (United States)

    Oh, Samuel; Kingsley, Karl

    2018-05-01

    Ketamine has been used as a safe and effective sedative to treat adults and children exhibiting high levels of anxiety or fear during dental treatment. Pediatric dentistry often involves patients with high levels of anxiety and fear and possibly few positive dental experiences. Patient management can involve behavioral approaches, as well as the use of sedation or general anesthesia with a variety of agents, including midazolam, diazepam, hydroxyzine, meperidine, and ketamine. The aim of this study was to investigate the clinical efficacy of ketamine use in pediatric sedation dentistry through systematic review and analysis. A systematic review of publications between 1990 and 2015 was conducted using PubMed and MEDLINE databases maintained by the US National Library of Medicine and the National Institutes of Health. The keywords used were (ketamine) AND (dental OR dentistry) AND (sedation). The abstract and title of all potential publications were then screened for clinical trials and to remove non-English articles, non-human or animal trials, and other non-dental or non-relevant studies. A total of 1,657 citations were initially identified, reviewed, and screened, eventually resulting in inclusion of 25 clinical trials in this systematic review. Nineteen studies evaluated ketamine effects in pediatric dental sedation using oral (non-invasive) administration, three involved subcutaneous or intramuscular injection, and three were completed intravenously. Evidence analysis of these trials revealed the majority (n = 22/25) provided strong, positive evidence for the use of ketamine (alone or in combination) to reduce dental anxiety and behavioral non-compliance with the remainder suggesting equivocal results. Additional endpoints evaluated in some studies involved dosage, as well as time to achieve sedation effect. The use of ketamine (alone or in combination) can provide safe, effective, and timely sedation in pediatric patients regardless of the route of

  16. High-Flow Nasal Oxygen in Patient With Obstructive Sleep Apnea Undergoing Awake Craniotomy: A Case Report.

    Science.gov (United States)

    Wong, Jaclyn W M; Kong, Amy H S; Lam, Sau Yee; Woo, Peter Y M

    2017-12-15

    Patients with obstructive sleep apnea are frequently considered unsuitable candidates for awake craniotomy due to anticipated problems with oxygenation, ventilation, and a potentially difficult airway. At present, only a handful of such accounts exist in the literature. Our report describes the novel use of high-flow nasal oxygen therapy for a patient with moderate obstructive sleep apnea who underwent an awake craniotomy under deep sedation. The intraoperative application of high-flow nasal oxygen therapy achieved satisfactory oxygenation, maintained the partial carbon dioxide pressure within a reasonable range even during periods of deep sedation, permitted responsive patient monitoring during mapping, and provided excellent patient and surgeon satisfaction.

  17. Experimental study of adiabatic cellular premixed flames of methane (ethane, propane) + oxygen + carbon dioxide mixtures

    NARCIS (Netherlands)

    Konnov, A.A.; Dyakov, I.V.

    2007-01-01

    Experimental studies of adiabatic cellular flames of CH4 + O2 + CO2, C2H6 + O2 + CO2, and C3H8 + O2 + CO2 are presented. Visual and photographic observations of the flames were performed to quantify their cellular structure. Non-stretched flames of methane and propane were stabilized at atmospheric

  18. When there are no good choices: illuminating the borderland between proportionate palliative sedation and palliative sedation to unconsciousness.

    Science.gov (United States)

    Reid, Thomas T; Demme, Richard A; Quill, Timothy E

    2011-01-01

    Despite state-of-the-art palliative care, some patients will require proportionate palliative sedation as a last-resort option to relieve intolerable suffering at the end of life. In this practice, progressively increasing amounts of sedation are provided until the target suffering is sufficiently relieved. Uncertainty and debate arise when this practice approaches palliative sedation to unconsciousness (PSU), especially when unconsciousness is specifically intended or when the target symptoms are more existential than physical. We constructed a case series designed to highlight some of the common approaches and challenges associated with PSU and the more aggressive end of the spectrum of proportionate palliative sedation as retrospectively identified by palliative care consultants over the past 5 years from a busy inpatient palliative care service at a tertiary medical center in Rochester (NY, USA). Ten cases were identified as challenging by the palliative care attendings, of which four were selected for presentation for illustrative purposes because they touched on central issues including loss of capacity, the role of existential suffering, the complexity of clinical intention, the role of an institutional policy and use of anesthetics as sedative agents. Two other cases were selected focusing on responses to two special situations: a request for PSU that was rejected; and anticipatory planning for total sedation in the future. Although relatively rare, PSU and more aggressive end-of-the-spectrum proportionate palliative sedation represent responses to some of the most challenging cases faced by palliative care clinicians. These complex cases clearly require open communication and collaboration among caregivers, patients and family. Knowing how to identify these circumstances, and how to approach these interventions of last resort are critical skills for practitioners who take care of patients at the end of life.

  19. A combined single-multiphase flow formulation of the premixing phase using the level set method

    International Nuclear Information System (INIS)

    Leskovar, M.; Marn, J.

    1999-01-01

    The premixing phase of a steam explosion covers the interaction of the melt jet or droplets with the water prior to any steam explosion occurring. To get a better insight of the hydrodynamic processes during the premixing phase beside hot premixing experiments, where the water evaporation is significant, also cold isothermal premixing experiments are performed. The specialty of isothermal premixing experiments is that three phases are involved: the water, the air and the spheres phase, but only the spheres phase mixes with the other two phases whereas the water and air phases do not mix and remain separated by a free surface. Our idea therefore was to treat the isothermal premixing process with a combined single-multiphase flow model. In this combined model the water and air phase are treated as a single phase with discontinuous phase properties at the water air interface, whereas the spheres are treated as usually with a multiphase flow model, where the spheres represent the dispersed phase and the common water-air phase represents the continuous phase. The common water-air phase was described with the front capturing method based on the level set formulation. In the level set formulation, the boundary of two-fluid interfaces is modeled as the zero set of a smooth signed normal distance function defined on the entire physical domain. The boundary is then updated by solving a nonlinear equation of the Hamilton-Jacobi type on the whole domain. With this single-multiphase flow model the Queos isothermal premixing Q08 has been simulated. A numerical analysis using different treatments of the water-air interface (level set, high-resolution and upwind) has been performed for the incompressible and compressible case and the results were compared to experimental measurements.(author)

  20. Impact of Vitiation on a Swirl-Stabilized and Premixed Methane Flame

    Directory of Open Access Journals (Sweden)

    Mao Li

    2017-10-01

    Full Text Available Vitiation refers to the condition where the oxygen concentration in the air is reduced due to the mix of dilution gas. The vitiation effects on a premixed methane flame were investigated on a swirl-stabilized gas turbine model combustor under atmospheric pressure. The main purpose is to analyze the combustion stability and CO emission performance in vitiated air and compare the results with the flame without vitiation. The N2, CO2, and H2O (steam were used as the dilution gas. Measurements were conducted in a combustor inlet temperature of 384 K and 484 K. The equivalence ratio was varied from stoichiometric conditions to the LBO (Lean Blowout limits where the flame was physically blown out from the combustor. The chemical kinetics calculation was performed with Chemkin software to analyze the vitiation effects on the flame reaction zone. Based on the calculation results, the changes in the temperature gradient, CO concentration, and active radicals across the flame reaction zone were identified. The time-averaged CH chemiluminescence images were recorded and the results indicated the features of the flame shape and location. The CH signal intensity provided the information about the heat-release zone in the combustor. The combustion LBO limits were measured and the vitiation of CO2 and H2O were found to have a stronger impact to elevate the LBO limits than N2. Near the LBO limits, the instability of the flame reaction was revealed by the high-speed chemiluminescence imaging and the results were analyzed by FFT (Fast Fourier Transfer. CO emission was measured with a water-cooled probe which is located at the exit of the combustor. The combustion vitiation has been found to have the compression effect on the operation range for low CO emission. However, this compression effect could be compensated by improving the combustor inlet temperature.

  1. A Conscious Sedation Protocol for Videolaryngostroboscopy in Pediatric Patients

    Directory of Open Access Journals (Sweden)

    Samantha Anne

    2010-01-01

    Full Text Available Objective. To determine best sedation protocol for videolaryngostroboscopy in children unable to tolerate non-sedated evaluation. Materials and Methods. Consecutive case series of 10 children with voice disturbances, unable to tolerate nonsedated videolaryngostroboscopy at an academic tertiary care children’s hospital. Flexible fiberoptic videolaryngostroboscopy was performed and interpreted by pediatric otolaryngologist and speech and language pathologist. Sedation was administered with newly described protocol that allowed functional portion of evaluation. Main Outcome Measures: ability to follow commands and tolerate flexible fiberoptic videolaryngostroboscopy. Secondary Outcome Measures: total phonation time, complications, need for subsequent videolaryngostroboscopic attempts, clinical outcomes, and follow-up. Results. 10 children underwent procedure under conscious sedation. 9/10 children were able to perform simple tasks and maintain adequate phonation time to complete stroboscopic exam. 1/10 patients failed to complete exam because of crying during entire exam. Mean exam time was 2 minutes 52 seconds (SD 86 seconds, phonation time is 1 minute 44 seconds (SD 60 seconds, and number of tasks completed was 10.5 (SD 8.6. Conclusions. Conscious sedation for videolaryngostroboscopy can be safely and effectively performed in children unable to comply with nonsedated examination. Such studies provide valuable diagnostic information to make a diagnosis and to devise a treatment plan.

  2. Treatment outcomes of using inhalation sedation for comprehensive dental care.

    Science.gov (United States)

    Madouh, M; BaniHani, A; Tahmassebi, J F

    2018-02-01

    To assess the outcomes of dental treatment under inhalation sedation within a UK specialist hospital setting. This was a retrospective cohort study of the case notes of patients under 17 years of age who received dental treatment using inhalation sedation at a UK specialist setting during the period 2006-2011. Treatment outcomes were categorised into five groups: (1) treatment completed as planned, (2) modified treatment completed, (3) treatment abandoned in sedation unit and patient referred for treatment under general analgesia (GA), (4) treatment abandoned in sedation unit and patient referred for treatment under local analgesia (LA), (5) child failed to return to complete treatment. In total, the case notes of 453 patients were evaluated. The mean age of the patients was 10.3 ± 2.9 years. Treatment was completed successfully in 63.6% of the cases, 15.9% were referred for treatment under GA, 11.2% failed to return to complete the treatment, 7.1% received modified treatment completed, and only 2.2% were referred for treatment under LA. Treatment outcomes were significantly associated with patient`s age (p = 0.002). The treatment outcome "treatment abandoned and child referred to be treated under GA" had significantly lower mean patient ages than the other outcomes. The majority of children referred for inhalation sedation, completed their course of treatment. A significantly higher proportion of those in the younger age group required GA to complete their treatment.

  3. Survey on sedation in paediatric dentistry: a global perspective.

    Science.gov (United States)

    Wilson, Stephen; Alcaino, Eduardo A

    2011-09-01

    Paediatric dentists receive training in sedation during their advanced education training, but evidence suggests that this training varies widely. The purpose of this study was to survey members of the International Association of Paediatric Dentistry (IAPD) and the European Academy of Paediatric Dentistry (EAPD) on their opinion on pharmacological and other behavioural management techniques and their training related to provision of oral health care of paediatric patients in the dental setting. A request was made for access to the IAPD and EAPD membership email addresses. The responses were recorded anonymously and data uploaded into spss (version 9) and analysed using descriptive analysis and chi-square with and without tabulation processes. A total of 311 respondents of 1973 targeted individuals answered the survey. The response rate was 16%. The majority of the respondents came from the continent of Europe, Asia, and the Americas. The most frequent type of sedation was general anaesthesia (52% of the respondents), followed by nitrous oxide (46%) and then oral sedation (44%). At least 91% of the respondents indicated that they were interested in the development of continuing education on the topic of sedation. Paediatric dentists around the world use relatively few behaviour management techniques, including pharmacological management. There is a definite interest in continuing education in the area of sedation. The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

  4. Numerical Investigation of Soot Formation in Non-premixed Flames

    KAUST Repository

    Abdelgadir, Ahmed Gamaleldin

    2017-05-01

    Soot is a carbon particulate formed as a result of the combustion of fossil fuels. Due to the health hazard posed by the carbon particulate, government agencies have applied strict regulations to control soot emissions from road vehicles, airplanes, and industrial plants. Thus, understanding soot formation and evolution is critical. Practical combustion devices operate at high pressure and in the turbulent regime. Elevated pressures and turbulence on soot formation significantly and fundamental understanding of these complex interactions is still poor. In this study, the effects of pressure and turbulence on soot formation and growth are investigated numerically. As the first step, the evolution of the particle size distribution function (PSDF) and soot particles morphology are investigated in turbulent non-premixed flames. A Direct Simulation Monte Carlo (DSMC) code is developed and used. The stochastic reactor describes the evolution of soot in fluid parcels following Lagrangian trajectories in a turbulent flow field. The trajectories are sampled from a Direct Numerical Simulation (DNS) of an n-heptane turbulent non-premixed flame. Although individual trajectories display strong bimodality as in laminar flames, the ensemble-average PSDF possesses only one mode and a broad tail, which implies significant polydispersity induced by turbulence. Secondly, the effect of the flow and mixing fields on soot formation at atmospheric and elevated pressures is investigated in coflow laminar diffusion flames. The experimental observation and the numerical prediction of the spatial distribution are in good agreement. Based on the common scaling methodology of the flames (keeping the Reynolds number constant), the scalar dissipation rate decreases as pressure increases, promoting the formation of PAH species and soot. The decrease of the scalar dissipation rate significantly contributes to soot formation occurring closer to the nozzle and outward on the flames wings as pressure

  5. Impact of office-based intravenous deep sedation providers upon traditional sedation practices employed in pediatric dentistry.

    Science.gov (United States)

    Tarver, Michael; Guelmann, Marcio; Primosch, Robert

    2012-01-01

    This survey intended to determine how the implementation of office-based IV deep sedation by a third party provider (OIVSED) impacted the traditional sedation practices employed in pediatric dentistry private practice settings. A digital survey was e-mailed to 924 members of the American Academy of Pediatric Dentistry practicing in California, Florida, and New York, chosen because these states had large samples of practicing pediatric dentists in geographically disparate locations. 151 pediatric dentists using OIVSED responded to the survey. Improved efficiency, safety and quality of care provided, and increased parental acceptance were reported advantages of this service. Although less costly than hospital-based general anesthesia, the average fee for this service was a deterrent to some parents considering this option. Sixty-four percent of respondents continued to provide traditional sedation modalities, mostly oral sedation, in their offices, as parenteral routes taught in their training programs were less often selected. OIVSED users reported both a reduction in the use of traditional sedation modalities in their offices and use of hospital-based GA services in exchange for perceived improvements in efficiency, safety and quality of care delivered. Patient costs, in the absence of available health insurance coverage, inhibited accessing this service by some parents.

  6. Sedation and patient monitoring in vascular and interventional radiology

    Energy Technology Data Exchange (ETDEWEB)

    McDermott, V G.M.; Chapman, M E; Gillespie, I [Royal Infirmary, Edinburgh (United Kingdom)

    1993-08-01

    A postal survey of British and Irish interventional radiologists was carried out in 1991 to assess current practice with respect to sedation and monitoring of patients during angiography and interventional procedures. The response rate was 65%, 49% of patients are fasted prior to angiography and 68% prior to interventional procedures. Radiologists participate in obtaining consent in 60% of cases. Patients are often (50%) sedated for angiography and usually (62-94% depending on the procedure) sedated for interventional procedures. Nurses are present for most procedures, but are given the task of monitoring the patient's vital signs in only 49% of cases. Anaesthetists are present for less than 10% of interventional procedures. The findings indicate a wide variation in practice and a need to standardize practice at a uniform high level. (author).

  7. The gas chimney formation during the steam explosion premixing phase

    International Nuclear Information System (INIS)

    Leskovar, M.

    2001-01-01

    The crucial part in isothermal premixing experiment simulation is the correct prediction of the gas chimney, which forms when the spheres penetrate into water. The first simulation results with the developed original combined multiphase model showed that the gas chimney starts to close at the wrong place at the top of the chimney and not in the middle, like it was observed in the experiments. To find the physical explanation for this identified weakness of our numerical model a comprehensive parametric analysis (mesh size, initial water-air surface thickness, water density, momentum coupling starting position) has been performed. It was established that the reason for the unphysical gas chimney closing at the top could be the gradual air-water density transition in the experiment model, since there is due to the finite differences description always a transition layer with intermediate phases density over the pure water phase. It was shown that this difference between our numerical model and the experiment can be somewhat compensated if the spheres interfacial drag coefficient at the upmost mesh plane of the unphysical air-water transition layer is artificially risen. On this way a more correct gas chimney formation can be obtained.(author)

  8. Experiments for the premixing phase (QUEOS); Experimente zur Vorvermischungsphase (QUEOS)

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, L.; Huber, R.; Haessler, M.; Kirstahler, M.; Kuhn, D.; Rehme, K.; Schumacher, G.; Schwall, M.; Wachter, E.; Woerner, G.

    1995-08-01

    Experiments are performed with solid spheres at high temperatures to establish a data base for the premixing phase of a steam explosion, which will be used for code improvement and validation. The hot spheres (T{<=}2600 K) are being dropped into saturated water at 1 bar pressure. The objective of the experiments is to obtain data on the cooling rate of the spheres, their distribution in the water, the amount of generated steam and its distribution with respect to the spheres. The spheres have a diameter of 4.2 mm, 4.8 mm and 10 mm, respectively, depending on the material used. Molybdenum coated with Rhenium to inhibit oxidation and ZrO{sub 2} are used. The experimental parameters are the mass flow of the spheres, their density and their temperature. The QUEOS test facility has been set up and tested. A series of first tests has been performed with cold spheres and spheres at 1000 C. The main results are the distribution of the spheres during the fall through the water and their distribution at the bottom of the water vessel. A large air bubble is being entrained into the water in both the cold and hot tests. (orig./HP)

  9. Turbulent premixed flames on fractal-grid-generated turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Soulopoulos, N; Kerl, J; Sponfeldner, T; Beyrau, F; Hardalupas, Y; Taylor, A M K P [Mechanical Engineering Department, Imperial College London, London SW7 2AZ (United Kingdom); Vassilicos, J C, E-mail: ns6@ic.ac.uk [Department of Aeronautics, Imperial College London, London SW7 2AZ (United Kingdom)

    2013-12-15

    A space-filling, low blockage fractal grid is used as a novel turbulence generator in a premixed turbulent flame stabilized by a rod. The study compares the flame behaviour with a fractal grid to the behaviour when a standard square mesh grid with the same effective mesh size and solidity as the fractal grid is used. The isothermal gas flow turbulence characteristics, including mean flow velocity and rms of velocity fluctuations and Taylor length, were evaluated from hot-wire measurements. The behaviour of the flames was assessed with direct chemiluminescence emission from the flame and high-speed OH-laser-induced fluorescence. The characteristics of the two flames are considered in terms of turbulent flame thickness, local flame curvature and turbulent flame speed. It is found that, for the same flow rate and stoichiometry and at the same distance downstream of the location of the grid, fractal-grid-generated turbulence leads to a more turbulent flame with enhanced burning rate and increased flame surface area. (paper)

  10. Tangential stretching rate (TSR) analysis of non premixed reactive flows

    KAUST Repository

    Valorani, Mauro

    2016-10-16

    We discuss how the Tangential stretching rate (TSR) analysis, originally developed and tested for spatially homogeneous systems (batch reactors), is extended to spatially non homogeneous systems. To illustrate the effectiveness of the TSR diagnostics, we study the ignition transient in a non premixed, reaction–diffusion model in the mixture fraction space, whose dependent variables are temperature and mixture composition. The reactive mixture considered is syngas/air. A detailed H2/CO mechanism with 12 species and 33 chemical reactions is employed. We will discuss two cases, one involving only kinetics as a model of front propagation purely driven by spontaneous ignition, the other as a model of deflagration wave involving kinetics/diffusion coupling. We explore different aspects of the system dynamics such as the relative role of diffusion and kinetics, the evolution of kinetic eigenvalues, and of the tangential stretching rates computed by accounting for the combined action of diffusion and kinetics as well for kinetics only. We propose criteria based on the TSR concept which allow to identify the most ignitable conditions and to discriminate between spontaneous ignition and deflagration front.

  11. Determination and Scaling of Thermo Acoustic Characteristics of Premixed Flames

    Directory of Open Access Journals (Sweden)

    P. R. Alemela

    2010-06-01

    Full Text Available The paper investigates the determination and the scaling of thermo acoustical characteristics of lean premixed flames as used in gas turbine combustion systems. In the first part, alternative methods to characterize experimentally the flame dynamics are outlined and are compared on the example of a scaled model of an industrial gas turbine burner. Transfer matrix results from the most general direct method are contrasted with data obtained from the hybrid method, which is based on Rankine-Hugoniot relations and the experimental flame transfer function obtained from OH*-chemiluminescence measurements. Also the new network model based regression method is assessed, which is based on a n – τ – σ dynamic flame model. The results indicate very good consistency between the three techniques, providing a global check of the methods/tools used for analyzing the thermo acoustic mechanisms of flames. In the second part, scaling rules are developed that allow to calculate the dynamic flame characteristics at different operation points. Towards this a geometric flame length model is formulated. Together with the other operational data of the flame it provides the dynamic flame model parameters at these points. The comparison between the measured and modeled flame lengths as well as the n – τ – σ parameters shows an excellent agreement.

  12. Characteristics of sound radiation from turbulent premixed flames

    Science.gov (United States)

    Rajaram, Rajesh

    Turbulent combustion processes are inherently unsteady and, thus, a source of acoustic radiation, which occurs due to the unsteady expansion of reacting gases. While prior studies have extensively characterized the total sound power radiated by turbulent flames, their spectral characteristics are not well understood. The objective of this research work is to measure the flow and acoustic properties of an open turbulent premixed jet flame and explain the spectral trends of combustion noise. The flame dynamics were characterized using high speed chemiluminescence images of the flame. A model based on the solution of the wave equation with unsteady heat release as the source was developed and was used to relate the measured chemiluminescence fluctuations to its acoustic emission. Acoustic measurements were performed in an anechoic environment for several burner diameters, flow velocities, turbulence intensities, fuels, and equivalence ratios. The acoustic emissions are shown to be characterized by four parameters: peak frequency (Fpeak), low frequency slope (beta), high frequency slope (alpha) and Overall Sound Pressure Level (OASPL). The peak frequency (Fpeak) is characterized by a Strouhal number based on the mean velocity and a flame length. The transfer function between the acoustic spectrum and the spectrum of heat release fluctuations has an f2 dependence at low frequencies, while it converged to a constant value at high frequencies. Furthermore, the OASPL was found to be characterized by (Fpeak mfH)2, which resembles the source term in the wave equation.

  13. Hydrogen-hydrocarbon turbulent non-premixed flame structure

    Energy Technology Data Exchange (ETDEWEB)

    Tabet, F. [ANSYS-Benelux, 4 Avenue Pasteur, B-1300 Wavre (Belgium); Sarh, B.; Goekalp, I. [Institut de Combustion, Aerothermique, Reactivite et Environnement (ICARE), Centre National de la Recherche Scientifique (CNRS), 1 C avenue de la recherche scientifique, Orleans 45071 Cedex 2 (France)

    2009-06-15

    In this study, the structure of turbulent non-premixed CH{sub 4}-H{sub 2}/air flames is analyzed with a special emphasis on mixing and air entrainment. The amount of H{sub 2} in the fuel mixture varies under constant volumetric fuel flow. Mixing is described by mixture fraction and its variance while air entrainment is characterized by the ratio of gas mass flow to fuel mass flow at the inlet section. The flow field and the chemistry are coupled by the flamelet assumption. Mixture fraction and its variance are transported by the computational fluid dynamics (CFD) code. The slow chemistry aspect of NO{sub x} is handled by solving an additional transport equation with a source term derived from flamelet library. The results obtained show an improvement of mixing with hydrogen addition leading to a strong consumption of CH{sub 4} and a high air entrainment into the centerline region. As a global effect of this, the composite fuels burn faster and thereby reduce the residence time which ultimately shortens the flame length and thickness. On the other hand, hydrogen is found to increase NO{sub x} level. (author)

  14. Premixed flame chemistry of a gasoline primary reference fuel surrogate

    KAUST Repository

    Selim, Hatem

    2017-03-10

    Investigating the combustion chemistry of gasoline surrogate fuels promises to improve detailed reaction mechanisms used for simulating their combustion. In this work, the combustion chemistry of one of the simplest, but most frequently used gasoline surrogates – primary reference fuel 84 (PRF 84, 84 vol% iso-octane and 16 vol% n-heptane), has been examined in a stoichiometric premixed laminar flame. Time-of-flight mass spectrometry coupled with a vacuum ultraviolet (VUV) synchrotron light source for species photoionization was used. Reactants, major end-products, stable intermediates, free radicals, and isomeric species were detected and quantified. Numerical simulations were conducted using a detailed chemical kinetic model with the most recently available high temperature sub-mechanisms for iso-octane and heptane, built on the top of an updated pentane isomers model and AramcoMech 2.0 (C0C4) base chemistry. A detailed interpretation of the major differences between the mechanistic pathways of both fuel components is given. A comparison between the experimental and numerical results is depicted and rate of production and sensitivity analyses are shown for the species with considerable disagreement between the experimental and numerical findings.

  15. Thermodynamics of premixed combustion in a heat recirculating micro combustor

    International Nuclear Information System (INIS)

    Rana, Uttam; Chakraborty, Suman; Som, S.K.

    2014-01-01

    A thermodynamic model has been developed to evaluate exergy transfer and its destruction in the process of premixed combustion in a heat recirculating micro combustor. Exergy destruction caused by process irreversibilities is characterized by entropy generation in the process. The entropy transport equation along with the solution of temperature and species concentration fields in the wake of flame sheet assumptions have been used to determine the different components of entropy generation. The role of thermal conductivity and thickness of combustor wall, and Peclet number on transfer and destruction rate of exergy is depicted in the process of flame stabilization via heat recirculation. The entropy generations due to gas phase heat conduction and chemical reaction are identified as the major sources of exergy destruction. The total irreversibility in pre-flame region is confined only within a small distance upstream of the flame. It has been observed that the local volumetric entropy generation is higher near the axis than that near the combustor wall. The second law efficiency is almost invariant with heat loss from the combustor, Peclet number, and thermal conductivity and thickness of combustor wall. - Highlights: • Irreversibility in the combustor is mainly due to conduction and chemical reaction. • Entropy generation near the axis is higher compared to that near the wall. • Heat recirculation and process irreversibility decrease with heat loss. • The second law efficiency is almost independent of Peclet number. • Second law efficiency is almost independent of wall thermal conductivity

  16. Premixed Combustion of Coconut Oil on Perforated Burner

    Directory of Open Access Journals (Sweden)

    I.K.G. Wirawan

    2013-10-01

    Full Text Available Coconut oil premixed combustion behavior has been studied experimentally on perforated burner with equivalence ratio (φ varied from very lean until very rich. The results showed that burning of glycerol needs large number of air so that the laminar burning velocity (SL is the highest at very lean mixture and the flame is in the form of individual Bunsen flame on each of the perforated plate hole. As φ is increased the  SL decreases and the secondary Bunsen flame with open tip occurs from φ =0.54 at the downstream of perforated flame. The perforated flame disappears at φ = 0.66 while the secondary Bunsen flame still exist with SL increases following that of hexadecane flame trend and then extinct when the equivalence ratio reaches one or more. Surrounding ambient air intervention makes SL decreases, shifts lower flammability limit into richer mixture, and performs triple and cellular flames. The glycerol diffusion flame radiation burned fatty acids that perform cellular islands on perforated hole.  Without glycerol, laminar flame velocity becomes higher and more stable as perforated flame at higher φ. At rich mixture the Bunsen flame becomes unstable and performs petal cellular around the cone flame front. Keywords: cellular flame; glycerol; perforated flame;secondary Bunsen flame with open tip; triple flame

  17. Transport of inertial particles in a turbulent premixed jet flame

    International Nuclear Information System (INIS)

    Battista, F; Picano, F; Casciola, C M; Troiani, G

    2011-01-01

    The heat release, occurring in reacting flows, induces a sudden fluid acceleration which particles follow with a certain lag, due to their finite inertia. Actually, the coupling between particle inertia and the flame front expansion strongly biases the spatial distribution of the particles, by inducing the formation of localized clouds with different dimensions downstream the thin flame front. A possible indicator of this preferential localization is the so-called Clustering Index, quantifying the departure of the actual particle distribution from the Poissonian, which would correspond to a purely random spatial arrangement. Most of the clustering is found in the flame brush region, which is spanned by the fluctuating instantaneous flame front. The effect is significant also for very light particles. In this case a simple model based on the Bray-Moss-Libby formalism is able to account for most of the deviation from the Poissonian. When the particle inertia increases, the effect is found to increases and persist well within the region of burned gases. The effect is maximum when the particle relaxation time is of the order of the flame front time scale. The evidence of this peculiar source of clustering is here provided by data from a direct numerical simulation of a turbulent premixed jet flame and confirmed by experimental data.

  18. Measurements of turbulent premixed flame dynamics using cinema stereoscopic PIV

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, Adam M.; Driscoll, James F. [University of Michigan, Department of Aerospace Engineering, Ann Arbor, MI (United States); Ceccio, Steven L. [University of Michigan, Department of Mechanical Engineering, Ann Arbor, MI (United States)

    2008-06-15

    A new experimental method is described that provides high-speed movies of turbulent premixed flame wrinkling dynamics and the associated vorticity fields. This method employs cinema stereoscopic particle image velocimetry and has been applied to a turbulent slot Bunsen flame. Three-component velocity fields were measured with high temporal and spatial resolutions of 0.9 ms and 140{mu}m, respectively. The flame-front location was determined using a new multi-step method based on particle image gradients, which is described. Comparisons are made between flame fronts found with this method and simultaneous CH-PLIF images. These show that the flame contour determined corresponds well to the true location of maximum gas density gradient. Time histories of typical eddy-flame interactions are reported and several important phenomena identified. Outwardly rotating eddy pairs wrinkle the flame and are attenuated at they pass through the flamelet. Significant flame-generated vorticity is produced downstream of the wrinkled tip. Similar wrinkles are caused by larger groups of outwardly rotating eddies. Inwardly rotating pairs cause significant convex wrinkles that grow as the flame propagates. These wrinkles encounter other eddies that alter their behavior. The effects of the hydrodynamic and diffusive instabilities are observed and found to be significant contributors to the formation and propagation of wrinkles. (orig.)

  19. Jet flow and premixed jet flame control by plasma swirler

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gang, E-mail: ligang@iet.cn [Key laboratory of light duty gas turbine, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Jiang, Xi [School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Zhao, Yujun [School of Mechanism, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Liu, Cunxi [Key laboratory of light duty gas turbine, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Chen, Qi [School of Mechanism, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Xu, Gang; Liu, Fuqiang [Key laboratory of light duty gas turbine, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China)

    2017-04-04

    A swirler based on dielectric barrier discharge plasma actuators is designed and its effectiveness in both jet flow and premixed jet flame control is demonstrated. In contrast to traditional spanwise-oriented actuators, plasma actuators are placed along the axial direction of the injector to induce a circumferential velocity to the main flow and create a swirl flow without any insertion or moving part. In the DBD plasma swirl injector, the discharge does not ignite the mixture nor does it induce flashback. Flame visualization is obtained by cameras while velocity profiles are obtained by Laser Doppler Anemometry measurements. The results obtained indicate the effectiveness of the new design. - Highlights: • The discharge does not ignite the mixture nor does it induce flashback. • The prominent advantage of this novel plasma swirler is its swirl number adjustable without any mechanical movement. • The frequency of the plasma swirler is adjustable. • The plasma swirler can be used as an oscillator to the reactants. • The plasma swirler can be used alone or combine with other traditional swirlers.

  20. Blowoff dynamics of bluff body stabilized turbulent premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, Swetaprovo; Kostka, Stanislav; Renfro, Michael W.; Cetegen, Baki M. [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, U-3139, Storrs, CT 06269 (United States)

    2010-04-15

    This article concerns the flame dynamics of a bluff body stabilized turbulent premixed flame as it approaches lean blowoff. Time resolved chemiluminescence imaging along with simultaneous particle image velocimetry and OH planar laser-induced fluorescence were utilized in an axisymmetric bluff body stabilized, propane-air flame to determine the sequence of events leading to blowoff and provide a quantitative analysis of the experimental results. It was found that as lean blowoff is approached by reduction of equivalence ratio, flame speed decreases and the flame shape progressively changes from a conical to a columnar shape. For a stably burning conical flame away from blowoff, the flame front envelopes the shear layer vortices. Near blowoff, the columnar flame front and shear layer vortices overlap to induce high local stretch rates that exceed the extinction stretch rates instantaneously and in the mean, resulting in local flame extinction along the shear layers. Following shear layer extinction, fresh reactants can pass through the shear layers to react within the recirculation zone with all other parts of the flame extinguished. This flame kernel within the recirculation zone may survive for a few milliseconds and can reignite the shear layers such that the entire flame is reestablished for a short period. This extinction and reignition event can happen several times before final blowoff which occurs when the flame kernel fails to reignite the shear layers and ultimately leads to total flame extinguishment. (author)

  1. On flame kernel formation and propagation in premixed gases

    Energy Technology Data Exchange (ETDEWEB)

    Eisazadeh-Far, Kian; Metghalchi, Hameed [Northeastern University, Mechanical and Industrial Engineering Department, Boston, MA 02115 (United States); Parsinejad, Farzan [Chevron Oronite Company LLC, Richmond, CA 94801 (United States); Keck, James C. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2010-12-15

    Flame kernel formation and propagation in premixed gases have been studied experimentally and theoretically. The experiments have been carried out at constant pressure and temperature in a constant volume vessel located in a high speed shadowgraph system. The formation and propagation of the hot plasma kernel has been simulated for inert gas mixtures using a thermodynamic model. The effects of various parameters including the discharge energy, radiation losses, initial temperature and initial volume of the plasma have been studied in detail. The experiments have been extended to flame kernel formation and propagation of methane/air mixtures. The effect of energy terms including spark energy, chemical energy and energy losses on flame kernel formation and propagation have been investigated. The inputs for this model are the initial conditions of the mixture and experimental data for flame radii. It is concluded that these are the most important parameters effecting plasma kernel growth. The results of laminar burning speeds have been compared with previously published results and are in good agreement. (author)

  2. Influence of Turbulent Scalar Mixing Physics on Premixed Flame Propagation

    Directory of Open Access Journals (Sweden)

    H. Kolla

    2011-01-01

    Full Text Available The influence of reactive scalar mixing physics on turbulent premixed flame propagation is studied, within the framework of turbulent flame speed modelling, by comparing predictive ability of two algebraic flame speed models: one that includes all relevant physics and the other ignoring dilatation effects on reactive scalar mixing. This study is an extension of a previous work analysing and validating the former model. The latter is obtained by neglecting modelling terms that include dilatation effects: a direct effect because of density change across the flame front and an indirect effect due to dilatation on turbulence-scalar interaction. An analysis of the limiting behaviour shows that neglecting the indirect effect alters the flame speed scaling considerably when / is small and the scaling remains unaffected when / is large. This is evident from comparisons of the two models with experimental data which show that the quantitative difference between the two models is as high as 66% at /=0.3 but only 4% at /=52.4. Furthermore, neglecting the direct effect results in a poor prediction of turbulent flame speed for all values of /, and both effects are important for practically relevant values of this velocity ratio.

  3. Strained flamelets for turbulent premixed flames II: Laboratory flame results

    Energy Technology Data Exchange (ETDEWEB)

    Kolla, H.; Swaminathan, N. [Department of Engineering, Cambridge University, Cambridge CB2 1PZ (United Kingdom)

    2010-07-15

    The predictive ability of strained flamelets model for turbulent premixed flames is assessed using Reynolds Averaged Navier Stokes (RANS) calculations of laboratory flames covering a wide range of conditions. Reactant-to-product (RtP) opposed flow laminar flames parametrised using the scalar dissipation rate of reaction progress variable are used as strained flamelets. Two turbulent flames: a rod stabilised V-flame studied by Robin et al. [Combust. Flame 153 (2008) 288-315] and a set of pilot stabilised Bunsen flames studied by Chen et al. [Combust. Flame 107 (1996) 223-244] are calculated using a single set of model parameters. The V-flame corresponds to the corrugated flamelets regime. The strained flamelet model and an unstrained flamelet model yield similar predictions which are in good agreement with experimental measurements for this flame. On the other hand, for the Bunsen flames which are in the thin reaction zones regime, the unstrained flamelet model predicts a smaller flame brush compared to experiment. The predictions of the strained flamelets model allowing for fluid-dynamics stretch induced attenuation of the chemical reaction are in good agreement with the experimental data. This model predictions of major and minor species are also in good agreement with experimental data. The results demonstrate that the strained flamelets model using the scalar dissipation rate can be used across the combustion regimes. (author)

  4. Direct numerical simulation of bluff-body-stabilized premixed flames

    KAUST Repository

    Arias, Paul G.

    2014-01-10

    To enable high fidelity simulation of combustion phenomena in realistic devices, an embedded boundary method is implemented into direct numerical simulations (DNS) of reacting flows. One of the additional numerical issues associated with reacting flows is the stable treatment of the embedded boundaries in the presence of multicomponent species and reactions. The implemented method is validated in two test con gurations: a pre-mixed hydrogen/air flame stabilized in a backward-facing step configuration, and reactive flows around a square prism. The former is of interest in practical gas turbine combustor applications in which the thermo-acoustic instabilities are a strong concern, and the latter serves as a good model problem to capture the vortex shedding behind a bluff body. In addition, a reacting flow behind the square prism serves as a model for the study of flame stabilization in a micro-channel combustor. The present study utilizes fluid-cell reconstruction methods in order to capture important flame-to-solid wall interactions that are important in confined multicomponent reacting flows. Results show that the DNS with embedded boundaries can be extended to more complex geometries without loss of accuracy and the high fidelity simulation data can be used to develop and validate turbulence and combustion models for the design of practical combustion devices.

  5. Premixed combustion under electric field in a constant volume chamber

    KAUST Repository

    Cha, Min Suk

    2012-12-01

    The effects of electric fields on outwardly propagating premixed flames in a constant volume chamber were experimentally investigated. An electric plug, subjected to high electrical voltages, was used to generate electric fields inside the chamber. To minimize directional ionic wind effects, alternating current with frequency of 1 kHz was employed. Lean and rich fuel/air mixtures for both methane and propane were tested to investigate various preferential diffusion conditions. As a result, electrically induced instability showing cracked structure on the flame surface could be observed. This cracked structure enhanced flame propagation speed for the initial period of combustion and led to reduction in flame initiation and overall combustion duration times. However, by analyzing pressure data, it was found that overall burning rates are not much affected from the electric field for the pressurized combustion period. The reduction of overall combustion time is less sensitive to equivalence ratio for methane/air mixtures, whereas the results demonstrate pronounced effects on a lean mixture for propane. The improvement of combustion characteristics in lean mixtures will be beneficial to the design of lean burn engines. Two hypothetical mechanisms to explain the electrically induced instability were proposed: 1) ionic wind initiated hydrodynamic instability and 2) thermodiffusive instability through the modification of transport property such as mass diffusivity. © 2012 IEEE.

  6. A test device for premixed gas turbine combustion oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Richards, G.A.; Gemmen, R.S.; Yip, M.J.

    1996-03-01

    This report discusses design and operation of a single-nozzle test combustor for studying lean, premixed combustion oscillations from gas turbine fuel nozzles. It was used to study oscillations from a prototype fuel nozzle that produced oscillations during testing in a commercial engine. Similar, but not identical, oscillations were recorded in the test device. Basic requirements of the device design were that the flame geometry be maintained and acoustic losses be minimized; this was achieved by using a Helmholtz resonator as the combustor geometry. Surprisingly, the combustor oscillated strongly at several frequencies, without modification of the resonator. Brief survey of operating conditions suggests that it may be helpful to characterize oscillating behavior in terms of reference velocity and inlet air temperature with the rig backpressure playing a smaller role. The preliminary results do not guarantee that the single-nozzle test device will reproduce arbitrary oscillations that occur on a complete engine test. Nozzle/nozzle interactions may complicate the response, and oscillations controlled by acoustic velocities transverse to the nozzle axis may not be reproduced in a test device that relies on a bulk Helmholtz mode. Nevertheless, some oscillations can be reproduced, and the single-nozzle test device allows both active and passive control strategies to be tested relatively inexpensively.

  7. Premixed combustion under electric field in a constant volume chamber

    KAUST Repository

    Cha, Min; Lee, Yonggyu

    2012-01-01

    The effects of electric fields on outwardly propagating premixed flames in a constant volume chamber were experimentally investigated. An electric plug, subjected to high electrical voltages, was used to generate electric fields inside the chamber. To minimize directional ionic wind effects, alternating current with frequency of 1 kHz was employed. Lean and rich fuel/air mixtures for both methane and propane were tested to investigate various preferential diffusion conditions. As a result, electrically induced instability showing cracked structure on the flame surface could be observed. This cracked structure enhanced flame propagation speed for the initial period of combustion and led to reduction in flame initiation and overall combustion duration times. However, by analyzing pressure data, it was found that overall burning rates are not much affected from the electric field for the pressurized combustion period. The reduction of overall combustion time is less sensitive to equivalence ratio for methane/air mixtures, whereas the results demonstrate pronounced effects on a lean mixture for propane. The improvement of combustion characteristics in lean mixtures will be beneficial to the design of lean burn engines. Two hypothetical mechanisms to explain the electrically induced instability were proposed: 1) ionic wind initiated hydrodynamic instability and 2) thermodiffusive instability through the modification of transport property such as mass diffusivity. © 2012 IEEE.

  8. Palliative sedation at home for terminally ill children with cancer.

    Science.gov (United States)

    Korzeniewska-Eksterowicz, Aleksandra; Przysło, Łukasz; Fendler, Wojciech; Stolarska, Małgorzata; Młynarski, Wojciech

    2014-11-01

    The presence of symptoms that are difficult to control always requires adjustment of treatment, and palliative sedation (PS) should be considered. We analyzed our experience in conducting PS at home for terminally ill children with cancer during a seven-year period. We performed a retrospective analysis of medical records of children with cancer treated at home between the years 2005 and 2011. We analyzed the data of 42 cancer patients (18% of all patients); in 21 cases, PS was initiated (solid tumors n = 11, brain tumors [5], bone tumors [4], leukemia [1]). Sedation was introduced because of pain (n = 13), dyspnea (9), anxiety (5), or two of those symptoms (6). The main drug used for sedation was midazolam; all patients received morphine. There were no significant differences in the dose of morphine or midazolam depending on the patient's sex; age was correlated with an increase of midazolam dose (R = 0.68; P = 0.005). Duration of sedation (R = 0.61; P = 0.003) and its later initiation (R = 0.43; P = 0.05) were correlated with an increase of the morphine dose. All patients received adjuvant treatment; in patients who required a morphine dose increase, metoclopramide was used more often (P = 0.0002). Patients did not experience any adverse reactions. Later introduction of sedation was associated with a marginally higher number of intervention visits and a significantly higher number of planned visits (R = 0.53; P = 0.013). Sedation may be safely used at home. It requires close monitoring and full cooperation between the family and hospice team. Because of the limited data on home PS in pediatric populations, further studies are needed. Copyright © 2014 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  9. The use of dexmedetomidine in intensive care sedation

    Directory of Open Access Journals (Sweden)

    Massimo Antonelli

    2013-05-01

    Full Text Available The goals and recommendations for ICU (Intensive Care Unit patients’ sedation and analgesia should be to have adequately sedated patients who are calm and arousal, so that they can guarantee a proper evaluation and an adequate control of pain. This way, it is also possible to perform their neurological evaluation, preserving intellectual faculties and helping them in actively participating to their care. Dexmedetomidine is a selective alpha-2 receptor agonist, member of theraputical cathegory: “other hypnotics and sedatives” (ATC: N05CM18. Dexmedetomidine is recommended for the sedation of adult ICU patients who need a sedation level not deeper than arousal in response to verbal stimulation (corresponding to Richmond Agitation-Sedation Scale 0 to -3. After the EMA approval, some European government authorities have elaborated HTA on dexmedetomidine, based on clinical evidence derived from Prodex and Midex trials. Dexmedetomidine resulted to be as effective as propofol and midazolam in maintaining the target depth of sedation in ICU patients. The mean duration of mechanical ventilation with dexmedetomidine was numerically shorter than with propofol and significantly shorter than with midazolam. The resulting favourable economic profile of dexmedetomidine supported the clinical use in ICU. Dexmedetomidine seems to provide clinical benefits due to the reduction of mechanical ventilation and ventilator weaning duration. Within the present review, an economic analysis of costs associated to the use of dexmedetomidine was therefore performed also in the Italian care setting. Thus, four different analyses were carried out based on the quantification of the total number of days in ICU, the time spent on mechanical ventilation, the weighted average number of days with mechanical ventilation or not and TISS points (Therapeutic Intervention Scoring System. Despite the incremental cost for drug therapy associated with dexmedetomidine, a reduction of

  10. Swozzle based burner tube premixer including inlet air conditioner for low emissions combustion

    Science.gov (United States)

    Tuthill, Richard Sterling; Bechtel, II, William Theodore; Benoit, Jeffrey Arthur; Black, Stephen Hugh; Bland, Robert James; DeLeonardo, Guy Wayne; Meyer, Stefan Martin; Taura, Joseph Charles; Battaglioli, John Luigi

    2002-01-01

    A burner for use in a combustion system of a heavy-duty industrial gas turbine includes a fuel/air premixer having an air inlet, a fuel inlet, and an annular mixing passage. The fuel/air premixer mixes fuel and air into a uniform mixture for injection into a combustor reaction zone. The burner also includes an inlet flow conditioner disposed at the air inlet of the fuel/air premixer for controlling a radial and circumferential distribution of incoming air. The pattern of perforations in the inlet flow conditioner is designed such that a uniform air flow distribution is produced at the swirler inlet annulus in both the radial and circumference directions. The premixer includes a swozzle assembly having a series of preferably air foil shaped turning vanes that impart swirl to the airflow entering via the inlet flow conditioner. Each air foil contains internal fuel flow passages that introduce natural gas fuel into the air stream via fuel metering holes that pass through the walls of the air foil shaped turning vanes. By injecting fuel in this manner, an aerodynamically clean flow field is maintained throughout the premixer. By injecting fuel via two separate passages, the fuel/air mixture strength distribution can be controlled in the radial direction to obtain optimum radial concentration profiles for control of emissions, lean blow outs, and combustion driven dynamic pressure activity as machine and combustor load are varied.

  11. Response of partially premixed flames to acoustic velocity and equivalence ratio perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.T.; Lee, J.G.; Quay, B.D.; Santavicca, D.A. [Center for Advanced Power Generation, Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA (United States)

    2010-09-15

    This article describes an experimental investigation of the forced response of a swirl-stabilized partially premixed flame when it is subjected to acoustic velocity and equivalence ratio fluctuations. The flame's response is analyzed using phase-resolved CH{sup *} chemiluminescence images and flame transfer function (FTF) measurements, and compared with the response of a perfectly premixed flame under acoustic perturbations. The nonlinear response of the partially premixed flame is manifested by a partial extinction of the reaction zone, leading to rapid reduction of flame surface area. This nonlinearity, however, is observed only when the phase difference between the acoustic velocity and the equivalence ratio at the combustor inlet is close to zero. The condition, {delta}{phi}{sub {phi}}'-V'{approx}0 , indicates that reactant mixtures with high equivalence ratio impinge on the flame front with high velocity, inducing large fluctuations of the rate of heat release. It is found that the phase difference between the acoustic velocity and equivalence ratio nonuniformities is a key parameter governing the linear/nonlinear response of a partially premixed flame, and it is a function of modulation frequency, inlet velocity, fuel injection location, and fuel injector impedance. The results presented in this article will provide insight into the response of a partially premixed flame, which has not been well explored to date. (author)

  12. Buoyant Unstable Behavior of Initially Spherical Lean Hydrogen-Air Premixed Flames

    Directory of Open Access Journals (Sweden)

    Zuo-Yu Sun

    2014-07-01

    Full Text Available Buoyant unstable behavior in initially spherical lean hydrogen-air premixed flames within a center-ignited combustion vessel have been studied experimentally under a wide range of pressures (including reduced, normal, and elevated pressures. The experimental observations show that the flame front of lean hydrogen-air premixed flames will not give rise to the phenomenon of cellular instability when the equivalence ratio has been reduced to a certain value, which is totally different from the traditional understanding of the instability characteristics of lean hydrogen premixed flames. Accompanied by the smoothened flame front, the propagation mode of lean hydrogen premixed flames transitions from initially spherical outwardly towards upwardly when the flames expand to certain sizes. To quantitatively investigate such buoyant instability behaviors, two parameters, “float rate (ψ” and “critical flame radius (Rcr”, have been proposed in the present article. The quantitative results demonstrate that the influences of initial pressure (Pint on buoyant unstable behaviors are different. Based on the effects of variation of density difference and stretch rate on the flame front, the mechanism of such buoyant unstable behaviors has been explained by the competition between the stretch force and the results of gravity and buoyancy, and lean hydrogen premixed flames will display buoyant unstable behavior when the stretch effects on the flame front are weaker than the effects of gravity and buoyancy.

  13. Comparison Between Premixed and Compounded Parenteral Nutrition Solutions in Hospitalized Patients Requiring Parenteral Nutrition.

    Science.gov (United States)

    Beattie, Colleen; Allard, Johane; Raman, Maitreyi

    2016-04-01

    Parenteral nutrition (PN) may be provided through compounded or premixed solutions. To determine the proportion of stable custom-compounded PN prescriptions that would fit within a 20% deviance of an existing premixed PN solution. A retrospective study design was used. Inpatients who received PN in non-critical care units in the preceding year were screened for eligibility. Results are reported descriptively as means (95% confidence intervals) and proportions. We reviewed 97 PN prescriptions that met inclusion criteria. Stable hospital PN prescriptions compared with the reference premixed prescription provided 1838 (1777-1898) vs 1843 (1781-1905) kcal/d, P = .43; dextrose, 266 (254-277) vs 225 (216-234) g/d, P magnesium, 5.4 (4.8-5.4) vs 7.6 (7.4-7.9) mmol/L. Calories and protein were remarkably similar, but dextrose, lipid, and electrolytes differed between hospital PN and the reference premixed prescription. We believe that there may be a role for premixed solutions in quaternary centers in stable non-critically ill patients. © 2016 American Society for Parenteral and Enteral Nutrition.

  14. Consultation with specialist palliative care services in palliative sedation: considerations of Dutch physicians

    NARCIS (Netherlands)

    Koper, I.; Heide, A.; Janssens, M.J.P.A.; Swart, S.; Perez, R.S.G.M.; Rietjens, J.A.C.

    2014-01-01

    Purpose: Palliative sedation is considered a normal medical practice by the Royal Dutch Medical Association. Therefore, consultation of an expert is not considered mandatory. The European Association of Palliative Care (EAPC) framework for palliative sedation, however, is more stringent: it

  15. Sedation in children undergoing magnetic resonance imaging comparative study between dexmedetomidine and ketamine

    Directory of Open Access Journals (Sweden)

    Abeer M. Eldeek

    2016-07-01

    Conclusion: Dexmedetomidine provided adequate sedation in most of the children without hemodynamic or respiratory embarrassment, in comparison with ketamine which provided adequate sedation but with delayed discharge time and more side effects.

  16. Continuous Deep Sedation Until Death in Nursing Home Residents with Dementia: A Case Series

    NARCIS (Netherlands)

    Anquinet, L.; Rietjens, J.A.C.; Vandervoort, A.; van der Steen, J.T.; van der Stichele, R.; Deliens, L.; Block, L.

    2013-01-01

    Objectives To describe the characteristics of continuous deep sedation until death and the prior decision-making process of nursing home residents dying with dementia and to evaluate this practice according to features reflecting sedation guideline recommendations. Design Epidemiological

  17. Patient safety during procedural sedation using capnography monitoring : A systematic review and meta-analysis

    NARCIS (Netherlands)

    Saunders, Rhodri; Struys, Michel M. R. F.; Pollock, Richard F.; Mestek, Michael; Lightdale, Jenifer R.

    2017-01-01

    Objective: To evaluate the effect of capnography monitoring on sedation-related adverse events during procedural sedation and analgesia (PSA) administered for ambulatory surgery relative to visual assessment and pulse oximetry alone. Design and setting: Systematic literature review and random

  18. LES of a laboratory-scale turbulent premixed bunsen flame using FSD, PCM-FPI and thickened flame models

    NARCIS (Netherlands)

    Hernandez Perez, F.E.; Yuen, F.T.C.; Groth, C.P.T.; Gülder, O.L.

    2011-01-01

    Large-eddy simulations (LES) of a turbulent premixed Bunsen flame were carried out with three subfilter-scale (SFS) modelling approaches for turbulent premixed combustion. One approach is based on the artificially thickened flame and power-law flame wrinkling models, the second approach is based on

  19. The use of observational scales to monitor symptom control and depth of sedation in patients requiring palliative sedation: a systematic review.

    Science.gov (United States)

    Brinkkemper, Tijn; van Norel, Arjanne M; Szadek, Karolina M; Loer, Stephan A; Zuurmond, Wouter W A; Perez, Roberto S G M

    2013-01-01

    Palliative sedation is the intentional lowering of consciousness of a patient in the last phase of life to relieve suffering from refractory symptoms such as pain, delirium and dyspnoea. In this systematic review, we evaluated the use of monitoring scales to assess the degree of control of refractory symptoms and/or the depth of the sedation. A database search of PubMed and Embase was performed up to January 2010 using the search terms 'palliative sedation' OR 'terminal sedation'. Retro- and prospective studies as well as reviews and guidelines containing information about monitoring of palliative sedation, written in the English, German or Dutch language were included. The search yielded 264 articles of which 30 were considered relevant. Most studies focused on monitoring refractory symptoms (pain, fatigue or delirium) or the level of awareness to control the level of sedation. Four prospective and one retrospective study used scales validated in other settings: the Numeric Pain Rating Scale, the Visual Analogue Scale, the Memorial Delirium Assessment Scale, the Communication Capacity Scale and Agitation Distress Scale. Only the Community Capacity Scale was partially validated for use in a palliative sedation setting. One guideline described the use of a scale validated in another setting. A minority of studies reported the use of observational scales to monitor the effect of palliative sedation. Future studies should be focused on establishing proper instruments, most adequate frequency and timing of assessment, and interdisciplinary evaluation of sedation depth and symptom control for palliative sedation.

  20. Flemish Palliative-Care Nurses’ Attitudes to Palliative Sedation: Results of a Quantitative Study

    OpenAIRE

    Gielen, Joris; Van den Branden, Stef; van Iersel, Trudie; Broeckaert, Bert

    2012-01-01

    Palliative sedation is an option of last resort to control refractory suffering. In order to better understand palliative-care nurses’ attitudes to palliative sedation, an anonymous questionnaire was sent to all nurses (589) employed in palliative care in Flanders (Belgium). In all, 70.5% of the nurses (n=415) responded. A large majority did not agree that euthanasia is preferable to palliative sedation, were against non-voluntary euthanasia in the case of a deeply and continuously sedated pa...

  1. Evident cognitive impairments in seemingly recovered patients after midazolam-based light sedation during diagnostic endoscopy

    OpenAIRE

    Yen-Hsuan Hsu; Feng-Sheng Lin; Chi-Cheng Yang; Chih-Peng Lin; Mau-Sun Hua; Wei-Zen Sun

    2015-01-01

    Midazolam is a widely used sedative agent during colonoscopy, with cognitive toxicity. However, the potential cognitive hazard of midazolam-based light sedation has not been sufficiently examined. We aimed to examine the cognitive safety and vulnerability profile under midazolam light sedation, with a particular focus on individual variations. Methods: We conducted a prospective case-controlled study in an academic hospital. In total, 30 patients undergoing sedative colonoscopy as part of ...

  2. Experimental and kinetic modeling investigation of rich premixed toluene flames doped with n-butanol.

    Science.gov (United States)

    Li, Yuyang; Yuan, Wenhao; Li, Tianyu; Li, Wei; Yang, Jiuzhong; Qi, Fei

    2018-04-25

    n-Butanol is a promising renewable biofuel and has a lot of advantages as a gasoline additive compared with ethanol. Though the combustion of pure n-butanol has been extensively investigated, the chemical structures of large hydrocarbons doped with n-butanol, especially for aromatic fuels, are still insufficiently understood. In this work, rich premixed toluene/n-butanol/oxygen/argon flames were investigated at 30 Torr with synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). The blending ratio of n-butanol was varied from 0 to 50%, while the equivalence ratio was maintained at a quite rich value (1.75) for the purpose of studying the influence of n-butanol on the aromatic growth process. Flame species including radicals, reactive molecules, isomers and polycyclic aromatic hydrocarbons (PAHs) were identified and their mole fraction profiles were measured. A kinetic model of toluene/n-butanol combustion was developed from our recently reported toluene and n-butanol models. It is observed that the production of most toluene decomposition products and larger aromatics was suppressed as the blending ratio of n-butanol increases. Meanwhile, the addition of n-butanol generally enhanced the formation of most observed C2-C4 hydrocarbons and C1-C4 oxygenated species. The rate of production (ROP) analysis and experimental observations both indicate that the interaction between toluene and n-butanol in their decomposition processes mainly occurs at the formation of small intermediates, e.g. acetylene and methyl. In particular, the interaction between toluene and n-butanol in methyl formation influences the formation of large monocyclic aromatics such as ethylbenzene, styrene and phenylacetylene, making their maximum mole fractions decay slowly upon increasing the blending ratio of n-butanol compared with toluene and benzyl. The increase of the blending ratio of n-butanol reduces the formation of key PAH precursors such as benzyl, fulvenallenyl

  3. Palliative sedation for terminally ill cancer patients in a tertiary cancer center in Shanghai, China.

    Science.gov (United States)

    Gu, Xiaoli; Cheng, Wenwu; Chen, Menglei; Liu, Minghui; Zhang, Zhe

    2015-01-01

    There are a number of studies dedicated to characteristics of sedation, but these studies are mostly bound to western country practices. The aim of this study is to describe the characteristics of patients who suffered from cancer and who had been sedated until their death in Shanghai, China. Retrospective medical data of 244 terminally ill cancer patients including 82 sedated patients were collected. Data collected included demographic characteristics, disease-related characteristics and details of the sedation. In sedated cases, patients and/or caregivers gave the consent to start palliative sedation due to unmanageable symptoms. On average, sedation was performed 24.65(±1.78)hours before death. Agitated delirium and dyspnea were the most frequent indications for palliative sedation. There was no significant difference in survival time from admission till death between sedated and non-sedated patients (p > 0.05). Palliative sedation is effective for reducing terminally ill cancer patients' suffering without hastening death. Prospective research is needed to determine the optimal conditions for Chinese patients including indications, decision making process, informed consent, cultural and ethical issues, type of sedation and drugs.

  4. At-home palliative sedation for end-of-life cancer patients.

    Science.gov (United States)

    Alonso-Babarro, Alberto; Varela-Cerdeira, Maria; Torres-Vigil, Isabel; Rodríguez-Barrientos, Ricardo; Bruera, Eduardo

    2010-07-01

    Using a decision-making and treatment checklist developed to facilitate the at-home palliative sedation process, we assessed the incidence and efficacy of palliative sedation for end-of-life cancer patients with intractable symptoms who died at home. We retrospectively reviewed the medical records of 370 patients who were followed by a palliative home care team. Twenty-nine of 245 patients (12%) who died at home had received palliative sedation. The mean age of the patients who received palliative sedation was 58 +/- 17 years, and the mean age of the patients who did not receive palliative sedation was 69 +/- 15 years (p = 0.002). No other differences were detected between patients who did or did not receive palliative sedation. The most common indications for palliative sedation were delirium (62%) and dyspnea (14%). Twenty-seven patients (93%) received midazolam for palliative sedation (final mean dose of 74 mg), and two (7%) received levomepromazine (final mean dose of 125 mg). The mean time between palliative sedation initiation and time of death was 2.6 days. In 13 of the cases (45%), the palliative sedation decision was made with the patient and his or her family members, and in another 13 patients (45%), the palliative sedation decision was made only with the patient's family members. We concluded that palliative sedation may be used safely and efficaciously to treat dying cancer patients with refractory symptoms at home.

  5. Increase in palliative sedation and reasons in cancer patients in Dutch general practice 2005–2014.

    NARCIS (Netherlands)

    Donker, G.A.; Dijk, C.E. van

    2015-01-01

    Background: Little is known about the quantity and reasons for use of palliative sedation in cancer patients in general practice and the reason to apply palliative sedation when a request for euthanasia was pending. Aim: To gain more insight into the reasons for palliative sedation at the end of

  6. Palliative sedation at home in the Netherlands: a nationwide survey among nurses.

    Science.gov (United States)

    Brinkkemper, Tijn; Klinkenberg, Marianne; Deliens, Luc; Eliel, Miriam; Rietjens, Judith A C; Zuurmond, Wouter W A; Perez, Roberto S G M

    2011-08-01

    This paper is a report of a nationwide study conducted to assess experiences of nurses involved in palliative sedation at home after introduction of a physicians' guideline for palliative sedation. Most studies investigating the practice of palliative sedation focus on physicians' practices and attitudes. However, little is known about experiences and attitudes of nurses. A web-based structured questionnaire was offered to 387 nurses providing medical technical care in 2007, assessing their experiences concerning decision-making, treatment policy and communication, focussing on the last patient receiving palliative sedation. The questionnaire was filled out by 201 nurses (response rate 52%). The majority of respondents agreed with the indication for palliative sedation. However, 21% reported to have refused carrying out a palliative sedation in the preceding year. The general practitioner was not present at the start of palliative sedation in a third of the cases, but was available when needed. The sedation was considered insufficiently effective by 42% of the respondents. According to a third of the respondents, the level of sedation was not related to the required level of symptom relief nor were changes in dosage based on the severity of symptoms. Although the guideline for palliative sedation appears to be followed adequately in the majority of cases with respect to indication for palliative sedation and reportage. The survey findings revealed shortcomings in medication policy, communication, medical control over the start and continued monitoring of palliative sedation. © 2011 The Authors. Journal of Advanced Nursing © 2011 Blackwell Publishing Ltd.

  7. A randomized controlled trial of daily sedation interruption in critically ill children

    NARCIS (Netherlands)

    N.J. Vet (Nienke); S.N. de Wildt (Saskia); C.W.M. Verlaat (Carin); C.A.J. Knibbe (Catherijne); M.G. Mooij (Miriam); J.B. van Woensel (Job); J.M. van Rosmalen (Joost); D. Tibboel (Dick); M. de Hoog (Matthijs)

    2016-01-01

    textabstractPurpose: To compare daily sedation interruption plus protocolized sedation (DSI + PS) to protocolized sedation only (PS) in critically ill children. Methods: In this multicenter randomized controlled trial in three pediatric intensive care units in the Netherlands, mechanically

  8. A Favorable Course of Palliative Sedation: Searching for Indicators Using Caregivers' Perspectives

    NARCIS (Netherlands)

    Brinkkemper, T.; Rietjens, J.A.C.; Deliens, L.; Ribbe, M.W.; Swart, S.J.; Loer, S.A.; Zuurmond, W.W.A.; Perez, R.S.G.M.

    2015-01-01

    Objective:Comparing characteristics of a favorable sedation course during palliative sedation to a less favorable course based on the reports Dutch physicians and nurses.Results:Cases identified as having a favorable sedation course less often concerned a male patient (P = .019 nurses' cases),

  9. Palliative sedation at home in the Netherlands: a nationwide survey among nurses

    NARCIS (Netherlands)

    Brinkkemper, T.; Klinkenberg, M.; Deliens, L.; Eliel, M.; Rietjens, J.A.C.; Zuurmond, W.W.A.; Perez, R.S.G.M.

    2011-01-01

    Aim. This paper is a report of a nationwide study conducted to assess experiences of nurses involved in palliative sedation at home after introduction of a physicians' guideline for palliative sedation. Background. Most studies investigating the practice of palliative sedation focus on physicians'

  10. Feasibility of measuring memory response to increasing dexmedetomidine sedation in children

    OpenAIRE

    Mason, K. P.; Kelhoffer, E. R.; Prescilla, R.; Mehta, M.; Root, J. C.; Young, V. J.; Robinson, F.; Veselis, R. A.

    2017-01-01

    Background. The memory effect of dexmedetomidine has not been prospectively evaluated in children. We evaluated the feasibility of measuring memory and sedation responses in children during dexmedetomidine sedation for non-painful radiological imaging studies. Secondarily, we quantified changes in memory in relation to the onset of sedation.

  11. Sedation practice in Nordic and non-Nordic ICUs: a European survey.

    Science.gov (United States)

    Egerod, Ingrid; Albarran, John W; Ring, Mette; Blackwood, Bronagh

    2013-07-01

    A trend towards lighter sedation has been evident in many intensive care units (ICUs). The aims of the survey were to describe sedation practice in European ICUs and to compare sedation practice in Nordic and non-Nordic countries. A cross-sectional survey of ICU nurses attending the fourth European federation of Critical Care Nursing associations (EfCCNa) in Denmark, 2011. Data included use of protocols; sedation, pain and delirium assessment tools; collaborative decision-making; sedation and analgesic medications; and educational preparation related to sedation. Response rate was 42% (n = 291) from 22 countries where 53% (n = 148) used sedation protocols. Nordic nurses reported greater use of sedation (91% versus 67%, p Nordic nurses. Decision-making on sedation was more inter-professionally collaborative in Nordic ICUs (83% versus 61%, p Nordic nurses reported greater consistency in maintaining circadian rhythm (66% versus 49%, p Nordic context might be more germane to the goal of lighter sedation and better pain management. Our study raises awareness of current sedation practice, paving the way towards optimized ICU sedation management. © 2013 The Authors. Nursing in Critical Care © 2013 British Association of Critical Care Nurses.

  12. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    Science.gov (United States)

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  13. Large eddy simulation of turbulent premixed combustion flows over backward facing step

    Energy Technology Data Exchange (ETDEWEB)

    Park, Nam Seob [Yuhan University, Bucheon (Korea, Republic of); Ko, Sang Cheol [Jeju National University, Jeju (Korea, Republic of)

    2011-03-15

    Large eddy simulation (LES) of turbulent premixed combustion flows over backward facing step has been performed using a dynamic sub-grid G-equation flamelet model. A flamelet model for the premixed flame is combined with a dynamic sub-grid combustion model for the filtered propagation of flame speed. The objective of this study is to investigate the validity of the dynamic sub-grid G-equation model in a complex turbulent premixed combustion flow. For the purpose of validating the LES combustion model, the LES of isothermal and reacting shear layer formed at a backward facing step is carried out. The calculated results are compared with the experimental results, and a good agreement is obtained.

  14. Large eddy simulation of turbulent premixed combustion flows over backward facing step

    International Nuclear Information System (INIS)

    Park, Nam Seob; Ko, Sang Cheol

    2011-01-01

    Large eddy simulation (LES) of turbulent premixed combustion flows over backward facing step has been performed using a dynamic sub-grid G-equation flamelet model. A flamelet model for the premixed flame is combined with a dynamic sub-grid combustion model for the filtered propagation of flame speed. The objective of this study is to investigate the validity of the dynamic sub-grid G-equation model in a complex turbulent premixed combustion flow. For the purpose of validating the LES combustion model, the LES of isothermal and reacting shear layer formed at a backward facing step is carried out. The calculated results are compared with the experimental results, and a good agreement is obtained

  15. An Investigation of a Hybrid Mixing Timescale Model for PDF Simulations of Turbulent Premixed Flames

    Science.gov (United States)

    Zhou, Hua; Kuron, Mike; Ren, Zhuyin; Lu, Tianfeng; Chen, Jacqueline H.

    2016-11-01

    Transported probability density function (TPDF) method features the generality for all combustion regimes, which is attractive for turbulent combustion simulations. However, the modeling of micromixing due to molecular diffusion is still considered to be a primary challenge for TPDF method, especially in turbulent premixed flames. Recently, a hybrid mixing rate model for TPDF simulations of turbulent premixed flames has been proposed, which recovers the correct mixing rates in the limits of flamelet regime and broken reaction zone regime while at the same time aims to properly account for the transition in between. In this work, this model is employed in TPDF simulations of turbulent premixed methane-air slot burner flames. The model performance is assessed by comparing the results from both direct numerical simulation (DNS) and conventional constant mechanical-to-scalar mixing rate model. This work is Granted by NSFC 51476087 and 91441202.

  16. Outcomes following implementation of a pediatric procedural sedation guide for referral to general anesthesia for magnetic resonance imaging studies.

    Science.gov (United States)

    Grunwell, Jocelyn R; Marupudi, Neelima K; Gupta, Rohan V; Travers, Curtis D; McCracken, Courtney E; Williamson, Julie L; Stockwell, Jana A; Fortenberry, James D; Couloures, Kevin; Cravero, Joseph; Kamat, Pradip P

    2016-06-01

    Guidelines for referral of children to general anesthesia (GA) to complete MRI studies are lacking. We devised a pediatric procedural sedation guide to determine whether a pediatric procedural sedation guide would decrease serious adverse events and decrease failed sedations requiring rescheduling with GA. We constructed a consensus-based sedation guide by combining a retrospective review of reasons for referral of children to GA (n = 221) with published risk factors associated with the inability to complete the MRI study with sedation. An interrupted time series analysis of 11 530 local sedation records from the Pediatric Sedation Research Consortium between July 2008 and March 2013, adjusted for case-mix differences in the pre- and postsedation guide cohorts, evaluated whether a sedation guide resulted in decreased severe adverse events (SAE) and failed sedation rates. A significant increase in referrals to GA following implementation of a sedation guide occurred (P pediatric procedural sedation services. © 2016 John Wiley & Sons Ltd.

  17. Oxygen toxicity

    Directory of Open Access Journals (Sweden)

    C. A. van der Westhuizen

    1990-07-01

    Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

  18. The Effect of Acepromazine Alone or in Combination with Methadone, Morphine, or Tramadol on Sedation and Selected Cardiopulmonary Variables in Sheep

    Directory of Open Access Journals (Sweden)

    Lilian Toshiko Nishimura

    2017-01-01

    Full Text Available The sedative and selected cardiopulmonary effects of acepromazine alone or in combination with methadone, morphine, or tramadol were compared in sheep. Six ewes were randomly assigned to treatments: A (0.05 mg/kg acepromazine, AM (A plus 0.5 mg/kg methadone, AMO (A plus 0.5 mg/kg morphine, and AT (A plus 5 mg/kg tramadol. Parameters were assessed before sedative drug administration (baseline and every 15 minutes thereafter, for two hours. Treatments A and AM were associated with increases in sedation score for 60 minutes and treatments AMO and AT for 30 minutes; however, there were no significant differences between treatments. There was a decrease in mean arterial pressure compared to baseline values in treatment A at 15, 45, 60, and 90 minutes, in treatment AM at 15 minutes, and in treatment AT from 45 to 120 minutes. Arterial blood carbon dioxide pressure increased at all time points in all treatments. Arterial oxygen pressure decreased in treatment AMO at 15, 30, and 120 minutes and in treatment AT at 15–45, 105, and 120 minutes, compared to baseline. Acepromazine alone causes a level of sedation similar to that observed when it is coadministered with opioids methadone, morphine, and tramadol. These combinations did not cause clinical cardiopulmonary changes.

  19. An Experimental Investigation of Premixed Combustion in Extreme Turbulence

    Science.gov (United States)

    Wabel, Timothy Michael

    This work has explored various aspects of high Reynolds number combustion that have received much previous speculation. A new high-Reynolds number premixed Bunsen burner, called Hi-Pilot, was designed to produce turbulence intensities in the extreme range of turbulence. The burner was modified several times in order to prevent boundary layer separation in the nozzle, and a large co-flow was designed that was capable of maintaining reactions over the entire flame surface. Velocity and turbulence characteristics were measured using a combination of Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV). Flame structure was studied using a combination of formaldehyde (CH2O), hydroxyl (OH), and the CH radical. Planar Laser Induced Fluorescence (PLIF). The spatial Overlap of formaldehyde and OH PLIF qualitatively measures the reaction rate between formaldehyde molecules and OH radicals, and is a measure of the reaction layers of the flame. CH PLIF provides an alternative measure of the reaction zone, and was measured to compare with the Overlap PLIF results. Reaction layers are the full-width at half-maximum of the Overlap or CH PLIF signal, and extinction events were defined as regions where the PLIF signal drops below this threshold. Preheat structures were measured using formaldehyde PLIF, and are defined as beginning at 35% of the local maximum PLIF signal, and continue up to the leading edge of the reaction layer. Previous predictions of regime diagram boundaries were tested at the largest values of turbulent Reynolds number to date. The Overlap and CH PLIF diagnostics allowed extensive testing of the predicted broken reaction zones boundary of Peters. Measurements indicated that all run conditions are in the Broadened Preheat - Thin Reaction layers regime, but several conditions are expected to display a broken reaction zone structure. Therefore the work shows that Peters's predicted boundary is not correct, and therefore a Karlovitz number of 100 is

  20. Tabulated Combustion Model Development For Non-Premixed Flames

    Science.gov (United States)

    Kundu, Prithwish

    Turbulent non-premixed flames play a very important role in the field of engineering ranging from power generation to propulsion. The coupling of fluid mechanics and complicated combustion chemistry of fuels pose a challenge for the numerical modeling of these type of problems. Combustion modeling in Computational Fluid Dynamics (CFD) is one of the most important tools used for predictive modeling of complex systems and to understand the basic fundamentals of combustion. Traditional combustion models solve a transport equation of each species with a source term. In order to resolve the complex chemistry accurately it is important to include a large number of species. However, the computational cost is generally proportional to the cube of number of species. The presence of a large number of species in a flame makes the use of CFD computationally expensive and beyond reach for some applications or inaccurate when solved with simplified chemistry. For highly turbulent flows, it also becomes important to incorporate the effects of turbulence chemistry interaction (TCI). The aim of this work is to develop high fidelity combustion models based on the flamelet concept and to significantly advance the existing capabilities. A thorough investigation of existing models (Finite-rate chemistry and Representative Interactive Flamelet (RIF)) and comparative study of combustion models was done initially on a constant volume combustion chamber with diesel fuel injection. The CFD modeling was validated with experimental results and was also successfully applied to a single cylinder diesel engine. The effect of number of flamelets on the RIF model and flamelet initialization strategies were studied. The RIF model with multiple flamelets is computationally expensive and a model was proposed on the frame work of RIF. The new model was based on tabulated chemistry and incorporated TCI effects. A multidimensional tabulated chemistry database generation code was developed based on the 1

  1. Effect of xylazine sedation on some clinico-physiological and ...

    African Journals Online (AJOL)

    Xylazine is classified pharmacologically as an effective sedative, analgesic, muscle relaxant, immobilizing and hypnotic agent in domestic animals (Torre and Erausquine, 1988; Ewing, 1990; Adams, 2001). Xylazine is also known to significantly ameliorate the effects induced by stress stimuli (Ali et al., 2006). It does not ...

  2. A national guideline for palliative sedation in the Netherlands

    NARCIS (Netherlands)

    Verkerk, Marian; van Wijlick, Eric; Legemaate, Johan; de Graeff, Alexander

    2007-01-01

    The first national guideline on palliative sedation in The Netherlands has been adopted by the General Board of the Royal Dutch Medical Association. By law, the physician is obliged to take this guideline into consideration. In this paper, we present the main principles of the guideline. Palliative

  3. Palliative sedation largely in accordance with Dutch national guideline

    NARCIS (Netherlands)

    Swart, S. J.; Rietjens, J. A.; Brinkkemper, T.; Zuylen, L. van; Burg-Verhage, W. A. van; Zuurmond, W. W.; Ribbe, M. W.; Blanker, M. H.; Perez, R. S.; Heide, A. van der

    2011-01-01

    OBJECTIVE: To evaluate the practice of continuous palliative sedation after the introduction of a national guideline. DESIGN: Investigation by questionnaire. METHOD: In 2008, 1580 physicians were asked to fill out a questionnaire regarding the last patient for whom they had prescribed continuous

  4. Safety and efficacy of procedural sedation and analgesia (PSA ...

    African Journals Online (AJOL)

    Safety and efficacy of procedural sedation and analgesia (PSA) conducted by medical officers in a level 1 hospital in Cape Town. ... Respiratory complications were treated with simple airway manoeuvres; no patient required intubation or experienced respiratory problems after waking up. There was no significant difference ...

  5. Continuous Palliative Sedation: Not Only a Response to Physical Suffering

    NARCIS (Netherlands)

    Swart, S.J.; Heide, A.; van Zuylen, L.; Perez, R.S.G.M.; Zuurmond, W.W.A.; van der Maas, P.J.; van Delden, J.J.M.; Rietjens, J.A.C.

    2014-01-01

    Background: Palliative sedation is a medical intervention aimed at relieving symptoms that can no longer be controlled by conventional treatment. Ample knowledge is available regarding the nature of such symptoms, but there is no in-depth information regarding how health care workers decide about

  6. Changes in resting neural connectivity during propofol sedation.

    Directory of Open Access Journals (Sweden)

    Emmanuel A Stamatakis

    2010-12-01

    Full Text Available The default mode network consists of a set of functionally connected brain regions (posterior cingulate, medial prefrontal cortex and bilateral parietal cortex maximally active in functional imaging studies under "no task" conditions. It has been argued that the posterior cingulate is important in consciousness/awareness, but previous investigations of resting interactions between the posterior cingulate cortex and other brain regions during sedation and anesthesia have produced inconsistent results.We examined the connectivity of the posterior cingulate at different levels of consciousness. "No task" fMRI (BOLD data were collected from healthy volunteers while awake and at low and moderate levels of sedation, induced by the anesthetic agent propofol. Our data show that connectivity of the posterior cingulate changes during sedation to include areas that are not traditionally considered to be part of the default mode network, such as the motor/somatosensory cortices, the anterior thalamic nuclei, and the reticular activating system.This neuroanatomical signature resembles that of non-REM sleep, and may be evidence for a system that reduces its discriminable states and switches into more stereotypic patterns of firing under sedation.

  7. Anticonvulsant and sedative effect of Fufang Changniu pills and ...

    African Journals Online (AJOL)

    Results: Gallic acid, liquiritin, cinnamyl alcohol, cinnamic acid and glycyrrhizic acid were detected in. FCP decoction. FCP (50, 100 and 200 mg/kg) showed significant anticonvulsant and sedative effects on epileptic mice induced by MES (p < 0.05) and PTZ (p < 0.05). Moreover, pentobarbital sodium-induced sleeping time ...

  8. The impact of sedation on pulse pressure variation

    Czech Academy of Sciences Publication Activity Database

    Zvoníček, V.; Jurák, Pavel; Halámek, Josef; Kružliak, P.; Vondra, Vlastimil; Leinveber, P.; Cundrle, I.; Pavlík, M.; Suk, P.; Šrámek, V.

    2015-01-01

    Roč. 28, č. 4 (2015), s. 203-207 ISSN 1036-7314 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : pulse pressure variation * sedation * heart lung interactions * mechanical ventilation * brain death * oesophageal pressure Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.479, year: 2015

  9. Who is referred for sedation for dentistry and why?

    Science.gov (United States)

    Boyle, C A; Newton, T; Milgrom, P

    2009-03-28

    To assess referrals to sedation, examining dental anxiety and background of patients, and compare these characteristics to those referred to a restorative dentistry clinic. Descriptive, cross sectional survey. Subjects were 100 consecutive new patients in sedation and special care and 50 new patients in restorative dentistry at Guy's and St Thomas NHS Foundation Trust. A questionnaire included demographics, self-reported oral health and dental attendance, and dental fear. Information from the patients records was taken: ASA classification, previous sedation or general anaesthesia, alcohol and tobacco use, and medications. The best predictors of referral were dental anxiety level and an irregular attendance. The most important fears were seeing, hearing and feeling the vibrations of the dental drill, and the perception of an accelerated heart rate. Other factors such as general, mental and dental health and alcohol use were related to referral but less important. Referral is consistent with the goal of the sedation clinic to see anxious patients. Referring general practitioners are able to identify these patients.

  10. Reflexology: its effects on physiological anxiety signs and sedation needs.

    Science.gov (United States)

    Akin Korhan, Esra; Khorshid, Leyla; Uyar, Mehmet

    2014-01-01

    To investigate whether reflexology has an effect on the physiological signs of anxiety and level of sedation in patients receiving mechanically ventilated support, a single blinded, randomized controlled design with repeated measures was used in the intensive care unit of a university hospital in Turkey. Patients (n = 60) aged between 18 and 70 years and were hospitalized in the intensive care unit and receiving mechanically ventilated support. Participants were randomized to a control group or an intervention group. The latter received 30 minutes of reflexology therapy on their feet, hands, and ears for 5 days. Subjects had vital signs taken immediately before the intervention and at the 10th, 20th, and 30th minutes of the intervention. In the collection of the data, "American Association of Critical-Care Nurses Sedation Assessment Scale" was used. The reflexology therapy group had a significantly lower heart rate, systolic blood pressure, diastolic blood pressure, and respiratory rate than the control group. A statistically significant difference was found between the averages of the scores that the patients included in the experimental and control groups received from the agitation, anxiety, sleep, and patient-ventilator synchrony subscales of the American Association of Critical-Care Nurses Sedation Assessment Scale. Reflexology can serve as an effective method of decreasing the physiological signs of anxiety and the required level of sedation in patients receiving mechanically ventilated support. Nurses who have appropriate training and certification may include reflexology in routine care to reduce the physiological signs of anxiety of patients receiving mechanical ventilation.

  11. Terminal sedation and euthanasia: A comparison of clinical practices

    NARCIS (Netherlands)

    J.A.C. Rietjens (Judith); J.J.M. van Delden (Hans); A. van der Heide (Agnes); A.M. Vrakking (Astrid); B.D. Onwuteaka-Philipsen (Bregje); P.J. van der Maas (Paul); G. van der Wal (Gerrit)

    2006-01-01

    textabstractBackground: An important issue in the debate about terminal sedation is the extent to which it differs from euthanasia. We studied clinical differences and similarities between both practices in the Netherlands. Methods: Personal interviews were held with a nationwide stratified sample

  12. Pharmacological therapy for analgesia and sedation in the newborn.

    Science.gov (United States)

    Anand, K J S; Hall, R W

    2006-11-01

    Rapid advances have been made in the use of pharmacological analgesia and sedation for newborns requiring neonatal intensive care. Practical considerations for the use of systemic analgesics (opioids, non-steroidal anti-inflammatory agents, other drugs), local and topical anaesthetics, and sedative or anaesthetic agents (benzodiazepines, barbiturates, other drugs) are summarised using an evidence-based medicine approach, while avoiding mention of the underlying basic physiology or pharmacology. These developments have inspired more humane approaches to neonatal intensive care. Despite these advances, little is known about the clinical effectiveness, immediate toxicity, effects on special patient populations, or long-term effects after neonatal exposure to analgesics or sedatives. The desired or adverse effects of drug combinations, interactions with non-pharmacological interventions or use for specific conditions also remain unknown. Despite the huge gaps in our knowledge, preliminary evidence for the use of neonatal analgesia and sedation is available, but must be combined with a clear definition of clinical goals, continuous physiological monitoring, evaluation of side effects or tolerance, and consideration of long-term clinical outcomes.

  13. Experimental study on flame propagation characteristics of Hydrogen premixed gas in gas pipeline

    Science.gov (United States)

    Ma, Danzhu; Li, Zhuang; Jia, Fengrui; Li, Zhou

    2018-06-01

    Hydrogen is the cleanest high-energy gas fuel, and also is the main industrial material. However, hydrogen is more explosive and more powerful than conventional gas fuels, which restricts its application. In particular, the expansion of premixed combustion under a strong constraint is more complicated, the reaction spreads faster. The flame propagation characteristics of premixed hydrogen/air were investigated by experiment. The mechanism of reaction acceleration is discussed, and then the speed of the flame propagation and the reaction pressure were tested and analysed.

  14. Lean premixed flames for low NO{sub x} combustors

    Energy Technology Data Exchange (ETDEWEB)

    Sojka, P.; Tseng, L.; Bryjak, J. [Purdue Univ., West Lafayette, IN (United States)] [and others

    1995-10-01

    Gas turbines are being used throughout the world to generate electricity. Due to increasing fuel costs and environmental concerns, gas turbines must meet stringent performance requirements, demonstrating high thermal efficiencies and low pollutant emissions. In order for U.S. manufactured gas turbines to stay competitive, their NO{sub x} levels must be below 10 ppm and their thermal efficiencies should approach 60%. Current technology is being stretched to achieve these goals. The twin goals of high efficiency and low NO{sub x} emissions require extending the operating range of current gas turbines. Higher efficiency requires operation at higher pressures and temperatures. Lower NO{sub x} emissions requires lower flame temperatures. Lower flame temperatures can be achieved through partially to fully pre-mixed combustion. However, increased performance and lower emissions result in a set of competing goals. In order to achieve a successful compromise between high efficiency and low NO{sub x} emissions, advanced design tools must be developed. One key design tool is a computationally efficient, high pressure, turbulent flow, combustion model capable of predicting pollutant formation in an actual gas turbine. Its development is the goal of this program. Achieving this goal requires completion of three tasks. The first task is to develop a reduced chemical kinetics model describing N{sub O}x formation in natural gas-air systems. The second task is to develop a computationally efficient model that describes turbulence-chemistry interactions. The third task is to incorporate the reduced chemical kinetics and turbulence-chemistry interaction models into a commercially available flow solver and compare its predictions with experimental data obtained under carefully controlled conditions so that the accuracy of model predictions can be evaluated.

  15. The risk of shorter fasting time for pediatric deep sedation.

    Science.gov (United States)

    Clark, Mathew; Birisci, Esma; Anderson, Jordan E; Anliker, Christina M; Bryant, Micheal A; Downs, Craig; Dalabih, Abdallah

    2016-01-01

    Current guidelines adopted by the American Academy of Pediatrics calls for prolonged fasting times before performing pediatric procedural sedation and analgesia (PSA). PSA is increasingly provided to children outside of the operating theater by sedation trained pediatric providers and does not require airway manipulation. We investigated the safety of a shorter fasting time compared to a longer and guideline compliant fasting time. We tried to identify the association between fasting time and sedation-related complications. This is a prospective observational study that included children 2 months to 18 years of age and had an American Society of Anesthesiologists physical status classification of I or II, who underwent deep sedation for elective procedures, performed by pediatric critical care providers. Procedures included radiologic imaging studies, electroencephalograms, auditory brainstem response, echocardiograms, Botox injections, and other minor surgical procedures. Subjects were divided into two groups depending on the length of their fasting time (4-6 h and >6 h). Complication rates were calculated and compared between the three groups. In the studied group of 2487 subjects, 1007 (40.5%) had fasting time of 4-6 h and the remaining 1480 (59.5%) subjects had fasted for >6 h. There were no statistically significant differences in any of the studied complications between the two groups. This study found no difference in complication rate in regard to the fasting time among our subjects cohort, which included only healthy children receiving elective procedures performed by sedation trained pediatric critical care providers. This suggests that using shorter fasting time may be safe for procedures performed outside of the operating theater that does not involve high-risk patients or airway manipulation.

  16. Current UK dental sedation practice and the 'National Institute for Health and Care Excellence' (NICE) guideline 112: sedation in children and young people.

    Science.gov (United States)

    Coulthard, P; Craig, D; Holden, C; Robb, N D; Sury, M; Chopra, S; Holroyd, I

    2015-04-24

    Describe current dental sedation practice for under 19-year-olds in the UK and compare it with the recommendations of NICE guidance 112. Members of the Society for the Advancement of Anaesthesia in Dentistry and members of the Dental Sedation Teachers Group were invited to participate in an online survey. Two hundred and sixty-six dentists and doctors completed the survey. Eighty-two percent were operator and sedationist (operator-sedationist). Ninety-five percent provided written information and 94% obtained written consent. Eighty-four percent kept a written or electronic sedation record. Eighty-six percent complied with life support training expectations. Eighty-six percent had immediate access to resuscitation equipment. Sixty-seven percent of sedationists reported that treatment could not be completed under sedation for sedation was unsuccessful, 61% said they would schedule general anaesthesia and 54.5% would schedule advanced sedation care. Forty-nine percent believed that a dentist was an appropriate person to provide advanced sedation for 12-18 years. Only 24% thought a dentist should provide advanced sedation for childrensedation was thought to be primary care by 33% and secondary care by 68%. We found good agreement between the current practice of sedation and the recommendations of the NICE guidance 112.

  17. [Deep continuous palliative sedation in the Opinion adopted by the Italian National Bioethics Committee (Deep palliative sedation)].

    Science.gov (United States)

    Cembrani, Fabio

    2016-01-01

    The Author examines the recent opinion delivered by the Italian National Committee for Bioethics on deep palliative sedation. In particular, it examines its strengths and ample shade that show its ideology, once again, in contrast with the right of every human being to die with dignity.

  18. Recall of ICU Stay in Patients Managed With a Sedation Protocol or a Sedation Protocol With Daily Interruption.

    Science.gov (United States)

    Burry, Lisa; Cook, Deborah; Herridge, Margaret; Devlin, John W; Fergusson, Dean; Meade, Maureen; Steinberg, Marilyn; Skrobik, Yoanna; Olafson, Kendiss; Burns, Karen; Dodek, Peter; Granton, John; Ferguson, Niall; Jacka, Michael; Tanios, Maged; Fowler, Robert; Reynolds, Steven; Keenan, Sean; Mallick, Ranjeeta; Mehta, Sangeeta

    2015-10-01

    To 1) describe factual, emotional, and delusional memories of ICU stay for patients enrolled in the SLEAP (Daily sedation interruption in mechanically ventilated critically ill patients cared for with a sedation protocol) trial; 2) compare characteristics of patients with and without ICU recall, and patients with and without delusional memories; and 3) determine factors associated with delusional memories 28 days after ICU discharge. Prospective cohort. Sixteen North American medical and surgical ICUs. Critically ill, mechanically ventilated adults randomized in the SLEAP trial. Post-ICU interviews on days 3, 28, and 90 using the validated ICU Memory Tool. Overall, 289 of 297 ICU survivors (97%) (146 protocolized sedation and 143 protocolized sedation plus daily interruption patients) were interviewed at least once. Because there were no differences in recall status or types of memories between the two sedation groups, we present the findings for all patients rather than by study group. On days 3, 28, and 90, 28%, 26%, and 36% of patients, respectively, reported no recall of being in the ICU (overall perception, self-reported) (p = 0.75). Mean daily doses of benzodiazepines and opioids were lower in patients with no ICU recall than those with recall (p patients reporting no recall of ICU stay on day 3, 97% and 90% reported at least one factual and one emotional memory from ICU, respectively. Emotional memories declined with time after ICU discharge, particularly panic and confusion. Delusional memories 28 days after discharge were common (70%) yet unrelated to delirium (p = 0.84), recall status (p = 0.15), total dose of benzodiazepine (p = 0.78), or opioid (p = 0.21). Delusional memories were less likely with longer duration of mechanical ventilation (odds ratio, 0.955; 95% CI, 0.91-1.00; p = 0.04). Recall of ICU stay and types of memories reported were not influenced by the trial sedation strategy. Lack of ICU recall and delusional memories were common after ICU

  19. Monitoring sedation status over time in ICU patients: reliability and validity of the Richmond Agitation-Sedation Scale (RASS).

    Science.gov (United States)

    Ely, E Wesley; Truman, Brenda; Shintani, Ayumi; Thomason, Jason W W; Wheeler, Arthur P; Gordon, Sharon; Francis, Joseph; Speroff, Theodore; Gautam, Shiva; Margolin, Richard; Sessler, Curtis N; Dittus, Robert S; Bernard, Gordon R

    2003-06-11

    Goal-directed delivery of sedative and analgesic medications is recommended as standard care in intensive care units (ICUs) because of the impact these medications have on ventilator weaning and ICU length of stay, but few of the available sedation scales have been appropriately tested for reliability and validity. To test the reliability and validity of the Richmond Agitation-Sedation Scale (RASS). Prospective cohort study. Adult medical and coronary ICUs of a university-based medical center. Thirty-eight medical ICU patients enrolled for reliability testing (46% receiving mechanical ventilation) from July 21, 1999, to September 7, 1999, and an independent cohort of 275 patients receiving mechanical ventilation were enrolled for validity testing from February 1, 2000, to May 3, 2001. Interrater reliability of the RASS, Glasgow Coma Scale (GCS), and Ramsay Scale (RS); validity of the RASS correlated with reference standard ratings, assessments of content of consciousness, GCS scores, doses of sedatives and analgesics, and bispectral electroencephalography. In 290-paired observations by nurses, results of both the RASS and RS demonstrated excellent interrater reliability (weighted kappa, 0.91 and 0.94, respectively), which were both superior to the GCS (weighted kappa, 0.64; P<.001 for both comparisons). Criterion validity was tested in 411-paired observations in the first 96 patients of the validation cohort, in whom the RASS showed significant differences between levels of consciousness (P<.001 for all) and correctly identified fluctuations within patients over time (P<.001). In addition, 5 methods were used to test the construct validity of the RASS, including correlation with an attention screening examination (r = 0.78, P<.001), GCS scores (r = 0.91, P<.001), quantity of different psychoactive medication dosages 8 hours prior to assessment (eg, lorazepam: r = - 0.31, P<.001), successful extubation (P =.07), and bispectral electroencephalography (r = 0.63, P

  20. Risk and safety of pediatric sedation/anesthesia for procedures outside the operating room.

    Science.gov (United States)

    Cravero, Joseph P

    2009-08-01

    Sedation and anesthesia outside the operating room represents a rapidly growing field of practice that involves a number of different specialty providers including anesthesiology. The literature surrounding this work is found in a variety of journals - many outside anesthesiology. This review is intended to inform readers about the current status of risk and safety involving sedation/anesthesia for tests and minor procedures utilizing a wide range of sources. Two large database studies have helped to define the frequency and nature of adverse events in pediatric sedation/anesthesia practice from a multispecialty perspective. A number of papers describing respiratory and hemodynamic aspects of dexmedetomidine sedation have also been published. Finally, a number of studies relating to training sedation providers, reporting of sedation adverse events, sedation for vulnerable populations, and (in particular) ketamine sedation adverse respiratory events have also come to light. The latest publications continue to document a relatively low risk to pediatric sedation yet also warn us about the potential adverse events in this field. The results help to define competencies required to deliver pediatric sedation and make this practice even safer. Particularly interesting are new jargon and methodologies for defining adverse events and the use of new methods for training sedation providers.

  1. Continuous palliative sedation until death: practice after introduction of the Dutch national guideline.

    Science.gov (United States)

    Swart, Siebe J; van der Heide, Agnes; Brinkkemper, Tijn; van Zuylen, Lia; Perez, Roberto; Rietjens, Judith

    2012-09-01

    In 2005, a national palliative guideline was launched in The Netherlands. The authors describe the practice of continuous palliative sedation until death (CPS) after the introduction of this guideline. In 2008, a random sample of physicians (n=1580) were asked to fill out a questionnaire regarding the last patient in whom they had provided CPS until death. The response was 38%. In all, 82% of the respondents were aware of the existence of the national guideline. Dyspnoea, pain and physical exhaustion were most often mentioned as decisive indications for continuous sedation. The decision to use sedation was discussed with all competent patients, but in 18% this merely involved informing the patient. Life expectancy at the start of continuous sedation was estimated to be less than 2 weeks in 97% of the cases. In 14%, the physicians had felt pressure to start the sedation, predominantly from patients and relatives. Physicians were present at the start of the sedation in 81% of the cases. Midazolam was used to induce the sedation in 92%. Overall, 41% of the physicians estimated that continuous sedation had hastened death to some extent. Most physicians thought that patients' complaints were adequately relieved by continuous sedation, that relatives were satisfied and that a good quality of dying was achieved. Continuous palliative sedation practice in The Netherlands largely reflects the recommendations from the national guideline. Issues needing further attention are the pressure felt by physicians to start continuous sedation and the potential life-shortening effect as mentioned by the physicians.

  2. Flemish palliative-care nurses' attitudes to palliative sedation: a quantitative study.

    Science.gov (United States)

    Gielen, Joris; Van den Branden, Stef; Van Iersel, Trudie; Broeckaert, Bert

    2012-09-01

    Palliative sedation is an option of last resort to control refractory suffering. In order to better understand palliative-care nurses' attitudes to palliative sedation, an anonymous questionnaire was sent to all nurses (589) employed in palliative care in Flanders (Belgium). In all, 70.5% of the nurses (n = 415) responded. A large majority did not agree that euthanasia is preferable to palliative sedation, were against non-voluntary euthanasia in the case of a deeply and continuously sedated patient and considered it generally better not to administer artificial floods or fluids to such a patient. Two clusters were found: 58.5% belonged to the cluster of advocates of deep and continuous sedation and 41.5% belonged to the cluster of nurses restricting the application of deep and continuous sedation. These differences notwithstanding, overall the attitudes of the nurses are in accordance with the practice and policy of palliative sedation in Flemish palliative-care units.

  3. The flow field structure of highly stabilized partially premixed flames in a concentric flow conical nozzle burner with coflow

    KAUST Repository

    Elbaz, Ayman M.

    2015-08-29

    The stability limits, the stabilization mechanism, and the flow field structure of highly stabilized partially premixed methane flames in a concentric flow conical nozzle burner with air co-flow have been investigated and presented in this work. The stability map of partial premixed flames illustrates that the flames are stable between two extinction limits. A low extinction limit when partial premixed flames approach non-premixed flame conditions, and a high extinction limit, with the partial premixed flames approach fully premixed flame conditions. These two limits showed that the most stable flame conditions are achieved at a certain degree of partial premixed. The stability is improved by adding air co-flow. As the air co-flow velocity increases the most stable flames are those that approach fully premixed. The turbulent flow field of three flames at 0, 5, 10 m/s co-flow velocity are investigated using Stereo Particle Image Velocimetry (SPIV) in order to explore the improvement of the flame stability due to the use of air co-flow. The three flames are all at a jet equivalence ratio (Φj) of 2, fixed level of partial premixing and jet Reynolds number (Rej) of 10,000. The use of co-flow results in the formation of two vortices at the cone exit. These vortices act like stabilization anchors for the flames to the nozzle tip. With these vortices in the flow field, the reaction zone shifts toward the reduced turbulence intensity at the nozzle rim of the cone. Interesting information about the structure of the flow field with and without co-flow are identified and reported in this work.

  4. Direct Numerical Simulations of NOx formation in spatially developing turbulent premixed Bunsen flames with mixture inhomogeneity

    KAUST Repository

    Luca, Stefano; Attili, Antonio; Bisetti, Fabrizio

    2017-01-01

    have a partially premixed inlet that mimic a common injection strategy in stationary gas turbines. The jet consist of a methane/air mixture with global equivalence ratio ɸ = 0.7 and temperature of 800 K. The simulations are performed at 4 atm. The inlet

  5. Dynamics of flow–soot interaction in wrinkled non-premixed ethylene–air flames

    KAUST Repository

    Arias, Paul G.; Lecoustre, Vivien R.; Roy, Somesh; Luo, Zhaoyu; Haworth, Daniel C.; Lu, Tianfeng; Trouvé , Arnaud; Im, Hong G.

    2015-01-01

    A two-dimensional simulation of a non-premixed ethylene–air flame was conducted by employing a detailed gas-phase reaction mechanism considering polycyclic aromatic hydrocarbons, an aerosol-dynamics-based soot model using a method of moments

  6. Applying Lean Techniques to Reduce Intravenous Waste Through Premixed Solutions and Increasing Production Frequency.

    Science.gov (United States)

    Lin, Alex C; Penm, Jonathan; Ivey, Marianne F; Deng, Yihong; Commins, Monica

    This study aims to use lean techniques and evaluate the impact of increasing the use of premixed IV solutions and increased IV production frequency on IV waste. Study was conducted at a tertiary hospital pharmacy department in three phases. Phase I included evaluation of IV waste when IV production occurred three times a day and eight premixed IV products were used. Phase II increased the number of premixed IV products to 16. Phase III then increased IV production to five times a day. During Phase I, an estimate of 2,673 IV doses were wasted monthly, accounting for 6.14% of overall IV doses. This accounted for 688 L that cost $60,135. During Phase II, the average monthly IV wastage reduced significantly to 1,069 doses (2.84%), accounting for 447 L and $34,003. During Phase III, the average monthly IV wastage was further decreased to 675 doses (1.69%), accounting for 78 L and $3,431. Hence, a potential annual saving of $449,208 could result from these changes. IV waste was reduced through the increased use of premixed solutions and increasing IV production frequency.

  7. Modeling of confined and unconfined laminar premixed flames on slit and tube burners

    NARCIS (Netherlands)

    Mallens, R.M.M.; Lange, de H.C.; Ven, van de C.J.H.; Goey, de L.P.H.

    1995-01-01

    A model is presented for laminar premixed Bunsen flames on slit and cylindrical burners burning in a surrounding atmosphere. A comparison between modeling and experimental results shows that the model can reproduce the experimental results within 10% accuracy. The influence of a surrounding

  8. Emission noise spectrum in a premixed H2-O2-N2 flame

    NARCIS (Netherlands)

    Alkemade, C.T.J.; Hooymayers, H.P.; Lijnse, P.L.; Vierbergen, T.J.M.J.

    Experimental noise spectra in the frequency range of 15–105 Hz are reported for the thermal emission of the first resonance doublet of Na and K in a premixed H2-O2-N2 flame, and for the flame background emission. Under certain conditions, low-frequency peaks arise in the noise spectrum below 100 Hz,

  9. Direct numerical simulations of premixed turbulent flames with flamelet-generated manifolds

    NARCIS (Netherlands)

    Oijen, van J.A.; Bastiaans, R.J.M.; Goey, de L.P.H.

    2005-01-01

    Direct numerical simulation is a very powerful tool to evaluate the validity of new models and theories for turbulent combustion. In this paper, direct numerical simulations of spherically expanding premixed turbulent flames in the thin reaction zone regime and in the broken reaction zone regime are

  10. Comprehensive Validation of Skeletal Mechanism for Turbulent Premixed Methane–Air Flame Simulations

    KAUST Repository

    Luca, Stefano; Al-Khateeb, Ashraf N.; Attili, Antonio; Bisetti, Fabrizio

    2017-01-01

    A new skeletal mechanism, consisting of 16 species and 72 reactions, has been developed for lean methane–air premixed combustion from the GRI-Mech 3.0. The skeletal mechanism is validated for elevated unburnt temperatures (800 K) and pressures up

  11. DNS of non-premixed combustion in a compressible mixing layer

    NARCIS (Netherlands)

    Bastiaans, R.J.M.; Somers, L.M.T.; Lange, de H.C.; Geurts, B.J.

    2001-01-01

    The non-premixed reaction of fuel with air in a mixing layer is studied using DNS. The situation is a model for the mixing-controlled combustion in a Diesel engine. We show that the combustion region can be comparably passive with respect to relatively large scale aerodynamic instabilities. However

  12. A numerical study of a premixed flame on a slit burner

    NARCIS (Netherlands)

    Somers, L.M.T.; Goey, de L.P.H.

    1995-01-01

    A numerical study of a premixed methane/air flame on a 4 mm slit burner is presented. A local grid refinement technique is used to deal with large gradients and curvature of all variables encountered in the flame, keeping the number of grid points within reasonable bounds. The method used here leads

  13. Experimental study on the potential of higher octane number fuels for low load partially premixed combustion

    NARCIS (Netherlands)

    Wang, S.; van der Waart, K.; Somers, B.; de Goey, P.

    2017-01-01

    The optimal fuel for partially premixed combustion (PPC) is considered to be a gasoline boiling range fuel with an octane number around 70. Higher octane number fuels are considered problematic with low load and idle conditions. In previous studies mostly the intake air temperature did not exceed 30

  14. Transient combustion modeling of an oscillating lean premixed methane/air flam

    NARCIS (Netherlands)

    Withag, J.A.M.; Kok, Jacobus B.W.; Syed, Khawar

    2009-01-01

    The main objective of the present study is to demonstrate accurate low frequency transient turbulent combustion modeling. For accurate flame dynamics some improvements were made to the standard TFC combustion model for lean premixed combustion. With use of a 1D laminar flamelet code, predictions

  15. Subfilter Scale Modelling for Large Eddy Simulation of Lean Hydrogen-Enriched Turbulent Premixed Combustion

    NARCIS (Netherlands)

    Hernandez Perez, F.E.

    2011-01-01

    Hydrogen (H2) enrichment of hydrocarbon fuels in lean premixed systems is desirable since it can lead to a progressive reduction in greenhouse-gas emissions, while paving the way towards pure hydrogen combustion. In recent decades, large-eddy simulation (LES) has emerged as a promising tool to

  16. Compression ignition of light naphtha and its multicomponent surrogate under partially premixed conditions

    NARCIS (Netherlands)

    Vallinayagam, R.; Vedharaj, S.; An, Y.; Dawood, A.; Izadi Najafabadi, M.; Somers, B.; Chang, J.; Sarathy, M.; Johansson, B.

    2017-01-01

    Light naphtha is the light distillate from crude oil and can be used in compression ignition (CI) engines; its low boiling point and octane rating (RON = 64.5) enable adequate premixing. This study investigates the combustion characteristics of light naphtha (LN) and its multicomponent surrogate

  17. Saturation mechanism of the heat release response of a premixed swirl flame using LES

    NARCIS (Netherlands)

    Krediet, H.J.; Beck, C. H.; Krebs, W.; Kok, J. B.W.

    2013-01-01

    The nonlinear heat release response of a premixed swirl flame to velocity perturbations is investigated using Large Eddy Simulation. The nonlinear heat release response is required for the prediction of thermoacoustic limit cycle pressure amplitudes and is represented here by the Flame Describing

  18. Acute toxicity study of Vilocym Premix (herbal growth promoter for Livestockin Wistar Albino Rat

    Directory of Open Access Journals (Sweden)

    A.H. Ahmad

    2009-06-01

    Full Text Available An experimental study with the objective of safety evaluation of Vilocym Premix, herbal growth promoter for Livestock (supplied by Ayurvet Ltd., Baddi, India, was done as per standard guidelines of OECD-423 for acute toxicity testing. Vilocym Premix is a scientifically developed combination of herbs that contains herbal ingredients namely Azadirachta indica, Curcuma longa & many more alongwith natural zeolites. The study was done in 3 males and 3 female Wistar Albino rats, which were administered an initial dose of 50 mg/kg body weight followed by dose rates of 300, 500 & 5000 mg/kg body weight of test compound. The animals were observed for signs of convulsions, tremors, circling, depression, excitement and mortality. Body weight was recorded at 0,7th and 14th day and plasma total protein, albumin; AST and ALT were measured after 3rd day of experiment. No abnormal sign of symptoms were observed in any of the animal fed with Vilocym Premix at the dose rate of 50, 300, 500 & 5000 mg/kg. No mortality was observed indicating safety of herbal premix. [Vet. World 2009; 2(3.000: 100-102

  19. Numerical and experimental investigation of NO{sub x} formation in lean premixed combustion of methane

    Energy Technology Data Exchange (ETDEWEB)

    Bengtsson, K; Benz, P; Marti, T; Schaeren, R; Schlegel, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    A high pressure jet-stirred reactor has been built and employed to investigate NO{sub x} formation in lean premixed combustion of methane/air. Experimental results are compared with numerical predictions using the model of a perfectly stirred reactor and elementary reaction mechanisms. Four reaction mechanisms are considered with respect to NO{sub x} formation. (author) 3 figs., 6 refs.

  20. Optimization of operating conditions in the early direct injection premixed charge compression ignition regime

    NARCIS (Netherlands)

    Boot, M.D.; Luijten, C.C.M.; Rijk, E.P.; Albrecht, B.A.; Baert, R.S.G.

    2009-01-01

    Early Direct Injection Premixed Charge Compression Ignition (EDI PCCI) is a widely researched combustion concept, which promises soot and CO2 emission levels of a spark-ignition (SI) and compression-ignition (CI) engine, respectively. Application of this concept to a conventional CI engine using a

  1. The application of Flamelet Generated Manifolds in partailly-premixed flames

    NARCIS (Netherlands)

    Ramaekers, W.J.S.; Albrecht, B.A.; Oijen, van J.A.; Goey, de L.P.H.; Eggels, R.L.G.M.

    2005-01-01

    To reduce harmful emissions numerical models are developed to simulate combustion processes in engineering applications. In this paper a model for partially-premixed combustion used in Reynolds Averaged Navier-Stokes Simulations (RANS) is presented. A flamelet approach combined with a Probability

  2. Oxygen Therapy

    Science.gov (United States)

    ... their breathing to dangerously low levels. Will I need oxygen when I sleep? Usually if you use supplemental oxygen during the ... your health care provider tells you you only need to use oxygen for exercise or sleep. Even if you feel “fine” off of your ...

  3. Properties of Ni-Mo steel prepared from premixed and prealloyed powder in sintered, forged and annealed state

    International Nuclear Information System (INIS)

    Salak, A.; Hrubjak, M.

    Investigated were 2Ni-0.5Mo steel specimens made of premixed powder on the base of Hametag iron and of ATST-A prealloyed powder with graphite additives of 0.3% and 0.8%. In the sintered and forged state, specimens prepared from premixed powder exhibit better strength properties compared with those made of prealloyed ATST-A powder. After annealing, the carbon content has a different bearing on both systems. With premixed powder steel of 0.6% carbon content the tensile strength amounts to 1,800 MPa whilst that of prealloyed steel specimens with 0.2% carbon content is about 1,240 MPa. (author)

  4. Success rate of IR midazolam sedation in combination with C-CLAD in pediatric dental patients—a prospective observational study

    Directory of Open Access Journals (Sweden)

    Malka Ashkenazi

    2014-03-01

    Full Text Available Objective. To evaluate the success rate of intra-rectal (IR midazolam in combination with nitrous oxide/oxygen (N2O sedation in young uncooperative dental patients when the local anesthesia is delivered by a computerized controlled local anesthetic delivery (C-CLAD.Study Design. This observational study consisted of 219 uncooperative children (age: 4.3 ± 1.69 y who received IR midazolam (0.4 mg/kg and N2O to complete their dental treatment. Measured variables included: child’s pain disruptive behavior during delivery of anesthesia by C-CLAD (CHEOP Scale, child behavior during treatment (Houpt scale, dental procedure performed, and side effects that appeared during treatment.Results. There was a high level of cooperation (mean score: 6.69 ± 2.1 during administration of local anesthesia. Good-to-excellent behavior was shown by 87% of the children during treatment. Planned treatment was completed by 184 (92% patients. No statistically significant changes were noticed in the oxygen saturation levels before and after treatment. Children with side effects included 3 (1.3% with nistagmus, 5 (2.3% with diplopia, and 18 (8.2% with hiccups. Three consecutive sedations decreased the overall behavior score by 5.7% compared to the first appointment (p < .05.Conclusions. IR midazolam-N2O sedation in combination with C-CLAD is very effective for delivery of dental treatment to young uncooperative children.

  5. Development of Criteria for Flameholding Tendencies within Premixer Passages for High Hydrogen Content Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Elliot Sullivan- [Univ. of California, Irvine, CA (United States); McDonell, Vincent G. [Univ. of California, Irvine, CA (United States)

    2014-12-01

    Due to increasingly stringent air quality requirements stationary power gas turbines have moved to lean-premixed operation, which reduces pollutant emissions but can result in flashback. Flashback can cause serious damage to the premixer hardware. Curtailing flashback can be difficult with hydrocarbon fuels and becomes even more challenging when hydrogen is used as the fuel. The two main approaches for coping with flashback are either to design a combustor that is resistant to flashback, or to design a premixer that will not anchor a flame if flashback occurs. Even with a well-designed combustor flashback can occur under certain circumstances, thus it is necessary to determine how to avoid flameholding within the premixer passageways of a gas turbine. To this end, an experiment was designed that would determine the flameholding propensities at elevated pressures and temperatures of three different classes of geometric features commonly found in gas turbine premixers, with both natural gas and hydrogen fuel. Experiments to find the equivalence ratio at blow off were conducted within an optically accessible test apparatus with four flameholders: 0.25 and 0.50 inch diameter cylinders, a reverse facing step with a height of 0.25 inches, and a symmetric airfoil with a thickness of 0.25 inches and a chord length of one inch. Tests were carried out at temperatures between 300 K and 750 K, at pressures up to 9 atmospheres. Typical bulk velocities were between 40 and 100 m/s. The effect of airfoil’s angle of rotation was also investigated. Blow off for hydrogen flames was found to occur at much lower adiabatic flame temperatures than natural gas flames. Additionally it was observed that at high pressures and high turbulence intensities, reactant velocity does not have a noticeable effect on the point of blow off due in large part to corresponding increases in turbulent flame speed. Finally a semi empirical correlation was developed that predicts flame extinction for both

  6. Sedation for pediatric neuroradiological examinations. Retrospective study of 160 cases

    International Nuclear Information System (INIS)

    Shose, Yoshiteru; Oi, Shizuo

    1995-01-01

    A retrospective study of 160 pediatric neuroradiological examinations was conducted to determine the efficacy and safety of two sedation regimens (figs. 1, 2). For CT purposes, 150 patients (fig. 3) were orally given monosodium trichlorethyl phosphate syrup (100 mg/kg, with repeat 50 mg/kg if necessary), and for cerebral angiography, 15 patients (fig. 4) were intramuscularly administered a modified D.P.T. cocktail (pentazocine, chlorpromadine, promethazine). Failure rate in the oral syrup group was 6%, and in the D.P.T. group 6.7%. Diagnostic-quality images were obtained in 99.3% and 100%, respectively, of the two groups. There were neither mortality nor significant complications (table 3). It was concluded that each method had proved acceptably safe and effective, and that measures can be taken to further decrease complications and sedation failures. (author)

  7. Analgesia and sedation practices for incarcerated inguinal hernias in children.

    Science.gov (United States)

    Al-Ansari, Khalid; Sulowski, Christopher; Ratnapalan, Savithiri

    2008-10-01

    In this study, the use of medications for analgesia and/or sedation for incarcerated inguinal hernia reductions in the emergency department was analyzed. A retrospective chart review was conducted for all patients presenting to a pediatric emergency department with incarcerated inguinal hernia from 2002 to 2005. A total of 99 children presented with incarcerated hernias during the study period. The median age was 11 months. Forty-four percent of children received medication for the procedure, of them 75% received parenteral and 25% oral or intranasal medications. Forty-five percent of children who received medication went through at least 1 hernia reduction attempt initially without medications. More than half the children with incarcerated inguinal hernias did not receive any medication for pain and/or sedation prior to hernia reduction. Guidelines for medication use for children with incarcerated inguinal hernias need to be developed.

  8. Clonidine for sedation and analgesia for neonates receiving mechanical ventilation.

    Science.gov (United States)

    Romantsik, Olga; Calevo, Maria Grazia; Norman, Elisabeth; Bruschettini, Matteo

    2017-05-10

    Although routine administration of pharmacologic sedation or analgesia during mechanical ventilation in preterm neonates is not recommended, its use in clinical practice remains common. Alpha-2 agonists, mainly clonidine and dexmedetomidine, are used as adjunctive (or alternative) sedative agents alongside opioids and benzodiazepines. Clonidine has not been systematically assessed for use in neonatal sedation during ventilation. To assess whether clonidine administered to term and preterm newborn infants receiving mechanical ventilation reduces morbidity and mortality rates. To compare the intervention versus placebo, no treatment, and dexmedetomidine; and to assess the safety of clonidine infusion for potential harms.To perform subgroup analyses according to gestational age; birth weight; administration method (infusion or bolus therapy); dose, duration, and route of clonidine administration; and pharmacologic sedation as a co-intervention. We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 12) in the Cochrane Library, MEDLINE via PubMed (1966 to January 10, 2017), Embase (1980 to January 10, 2017), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to January 10, 2017). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials. We searched for randomized controlled trials, quasi-randomized controlled trials, and cluster trials comparing clonidine versus placebo, no treatment, or dexmedetomidine administered to term and preterm newborns receiving mechanical ventilation via an endotracheal tube. For the included trial, two review authors independently extracted data (e.g. number of participants, birth weight, gestational age, all-cause death during initial hospitalization, duration of respiratory support, sedation

  9. Oxidative and biochemical responses in Brycon amazonicus anesthetized and sedated with Myrcia sylvatica (G. Mey.) DC. and Curcuma longa L. essential oils.

    Science.gov (United States)

    Saccol, Etiane M H; Londero, Érika P; Bressan, Caroline A; Salbego, Joseânia; Gressler, Luciane T; Silva, Lenise V F; Mourão, Rosa H V; Oliveira, Ricardo B; Llesuy, Susana F; Baldisserotto, Bernardo; Pavanato, Maria A

    2017-05-01

    To investigate the effects of rapid anesthesia and long-term sedation with the essential oils (EOs) of Myrcia sylvatica (EOMS) and Curcuma longa (EOCL) on biochemical and oxidative parameters in matrinxã. Prospective, randomized, laboratory experiment. A total of 72 matrinxã (Brycon amazonicus) adults weighing 404.8 ± 27.9 g were divided into eight groups of nine fish. Biochemical and oxidative effects were investigated in plasma and tissues of matrinxã subjected to rapid anesthesia (5 minutes) or long-term sedation (360 minutes, simulating the practice of transport) with EOMS (200 μL L -1 and 10 μL L -1 , respectively) and EOCL (500 μL L -1 and 40 μL L -1 , respectively). Transport simulation without sedation or anesthesia increased lipid peroxidation levels in the gills and kidney of fish in the control group. Anesthesia and sedation with EOs decreased cortisol concentrations and increased lactate concentrations compared with controls. Lipid peroxidation was lower in the brain, gills, liver and kidney of sedated and anesthetized fish, than in the control group. Anesthesia with EOs increased the activity of superoxide dismutase and glutathione-S-transferase in the brain, and catalase in the liver and gills, compared with controls. Long-term sedation with EOs increased superoxide dismutase, glutathione peroxidase and glutathione reductase activities in the brain, catalase in the liver, glutathione peroxidase and glutathione reductase in the gills and superoxide dismutase in the kidney. In general, nonprotein thiols content and total reactive antioxidant potential of tissues were higher after anesthesia and sedation with EOs compared with the control group. The concentrations of EOMS and EOCL used were effective at preventing a stress response and excess of reactive oxygen species formation. For these reasons, these substances may be recommended for use in the transportation of fish to improve survival and animal welfare. Copyright © 2017

  10. Oxygen Therapy

    Directory of Open Access Journals (Sweden)

    Bonnie Solmes

    2000-01-01

    Full Text Available LTOT is prescribed for people with chronic lung disease in whom there is a decrease in the ability of the lungs to supply enough oxygen to the body. The heart is obliged to pump faster to meet the body's oxygen requirements. This may place undue stress on the heart, resulting in palpitations, dizziness and fatigue. A low oxygen level in arterial blood is also harmful to the heart, the brain and the pulmonary blood vessels. Oxygen therapy is used to break this cycle. A person with low blood oxygen will often be able to accomplish more with less fatigue with the help of supplemental oxygen therapy. Shortness of breath is a mechanical problem resulting from the effects of chronic obstructive pulmonary disease. Oxygen therapy may or may not reduce shortness of breath, but it will help the lungs and heart to function with less stress.

  11. Non-sedation versus sedation with a daily wake-up trial in critically ill patients recieving mechanical ventilation - effects on long-term cognitive function

    DEFF Research Database (Denmark)

    Nedergaard, Helene Korvenius; Jensen, Hanne Irene; Stylsvig, Mette

    2016-01-01

    trauma, status epilepticus, patients treated with therapeutic hypothermia and patients with severe hypoxia). The experimental intervention will be non-sedation supplemented with pain management during mechanical ventilation. The control intervention will be sedation with a daily wake-up attempt...

  12. Residual sleepiness after N2O sedation: a randomized control trial [ISRCTN88442975

    Directory of Open Access Journals (Sweden)

    Lichtor J Lance

    2004-05-01

    Full Text Available Abstract Background Nitrous oxide (N2O provides sedation for procedures that result in constant low-intensity pain. How long do individuals remain sleepy after receiving N2O? We hypothesized that drug effects would be apparent for an hour or more. Methods This was a randomized, double blind controlled study. On three separate occasions, volunteers (N = 12 received 100% oxygen or 20% or 40% N2O for 30 min. Dependent measures included the multiple sleep latency test (MSLT, a Drug Effects/Liking questionnaire, visual analogue scales, and five psychomotor tests. Repeated measures analysis of variance was performed with drug and time as factors. Results During inhalation, drug effects were apparent based on the questionnaire, visual analogue scales, and psychomotor tests. Three hours after inhaling 100% oxygen or 20% N2O, subjects were sleepier than if they breathed 40% N2O. No other drug effects were apparent 1 hour after inhalation ceased. Patients did not demonstrate increased sleepiness after N2O inhalation. Conclusion We found no evidence for increased sleepiness greater than 1 hour after N2O inhalation. Our study suggests that long-term effects of N2O are not significant.

  13. Consultation with specialist palliative care services in palliative sedation: considerations of Dutch physicians.

    Science.gov (United States)

    Koper, Ian; van der Heide, Agnes; Janssens, Rien; Swart, Siebe; Perez, Roberto; Rietjens, Judith

    2014-01-01

    Palliative sedation is considered a normal medical practice by the Royal Dutch Medical Association. Therefore, consultation of an expert is not considered mandatory. The European Association of Palliative Care (EAPC) framework for palliative sedation, however, is more stringent: it considers the use of palliative sedation without consulting an expert as injudicious and insists on input from a multi-professional palliative care team. This study investigates the considerations of Dutch physicians concerning consultation about palliative sedation with specialist palliative care services. Fifty-four physicians were interviewed on their most recent case of palliative sedation. Reasons to consult were a lack of expertise and the view that consultation was generally supportive. Reasons not to consult were sufficient expertise, the view that palliative sedation is a normal medical procedure, time pressure, fear of disagreement with the service and regarding consultation as having little added value. Arguments in favour of mandatory consultation were that many physicians lack expertise and that palliative sedation is an exceptional intervention. Arguments against mandatory consultation were practical obstacles that may preclude fulfilling such an obligation (i.e. lack of time), palliative sedation being a standard medical procedure, corroding a physician's responsibility and deterring physicians from applying palliative sedation. Consultation about palliative sedation with specialist palliative care services is regarded as supportive and helpful when physicians lack expertise. However, Dutch physicians have both practical and theoretical objections against mandatory consultation. Based on the findings in this study, there seems to be little support among Dutch physicians for the EAPC recommendations on obligatory consultation.

  14. Opinions of the Dutch public on palliative sedation: a mixed-methods approach.

    Science.gov (United States)

    van der Kallen, Hilde T H; Raijmakers, Natasja J H; Rietjens, Judith A C; van der Male, Alex A; Bueving, Herman J; van Delden, Johannes J M; van der Heide, Agnes

    2013-10-01

    Palliative sedation is defined as deliberately lowering a patient's consciousness, to relieve intolerable suffering from refractory symptoms at the end of life. Palliative sedation is considered a last resort intervention in end-of-life care that should not be confused with euthanasia. To inform healthcare professionals about attitudes of the general public regarding palliative sedation. design and setting: A cross-sectional survey among members of the Dutch general public followed by qualitative interviews. One thousand nine hundred and sixty members of the general public completed the questionnaire, which included a vignette describing palliative sedation (response rate 78%); 16 participants were interviewed. In total, 22% of the responders indicated knowing the term 'palliative sedation'. Qualitative data showed a variety of interpretations of the term. Eighty-one per cent of the responders agreed with the provision of sedatives as described in a vignette of a patient with untreatable pain and a life expectancy of sedatives to alleviate his suffering. This percentage was somewhat lower for a patient with a life expectancy of sedatives with the aim of ending the patient's life (79%, P = 0.54). Most of the general public accept the use of palliative sedation at the end of life, regardless of a potential life-shortening effect. However, confusion exists about what palliative sedation represents. This should be taken into account by healthcare professionals when communicating with patients and their relatives on end-of-life care options.

  15. Assessment of patients' awareness and factors influencing patients' demands for sedation in endodontics.

    Science.gov (United States)

    Huh, Yoo Kyeom; Montagnese, Thomas A; Harding, Jarrod; Aminoshariae, Anita; Mickel, Andre

    2015-02-01

    Endodontic therapy is perceived by many as a procedure to be feared. Many studies have reported that fear and anxiety are major deterrents to seeking dental care in general, but only a few deal with the use of sedation in endodontic therapies. The purpose of this study was to assess patients' awareness of and factors influencing the potential demand for sedation in endodontics. We hypothesized that there is an association between demographic factors and the demand for sedation in endodontics. A survey consisting of 24 questions was given to patients 18 years and older who presented to the graduate endodontic clinic. Results were collected and statistically analyzed. Thirty-six percent of patients reported that their perception of sedation was being put to sleep, and 27% perceived it as related to or reducing pain. Concerns associated with endodontic therapy were the fear of pain (35%), fear of needles (16%), difficulty getting numb (10%), and anxiety (7%). The 2 major demographic factors that influenced the demand for sedation were cost and the level of anxiety (P endodontic therapy if the option of sedation was available. The demand for sedation in endodontics is high. Patients' understanding of sedation varies. More patients would consider having endodontic procedures if sedation was available. The provision of sedation by endodontists could result in more patients accepting endodontic therapies. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Paediatric conscious sedation: views and experience of specialists in paediatric dentistry.

    Science.gov (United States)

    Woolley, S M; Hingston, E J; Shah, J; Chadwick, B L

    2009-09-26

    The objectives were three-fold: to investigate the level of conscious sedation training received prior to and during specialist training in paediatric dentistry; to establish the use of conscious sedation during and following specialisation; and to determine the attitudes of specialists in paediatric dentistry to conscious sedation. A self-administered postal questionnaire was sent to all specialists in paediatric dentistry registered with the General Dental Council in January 2008. Non-responders were contacted again after a four-week period. A response rate of 60% was achieved. Of the 122 respondents, 67 (55%) had received sedation training as an undergraduate; 89 (75%) had been trained during specialisation. All respondents performed dental treatment under sedation as a trainee and the majority used nitrous oxide inhalation sedation (NOIS). Over 90% of respondents felt that NOIS should be available to all children, both in appropriate primary care settings and in hospitals. One hundred and twenty-one (99%) respondents thought that all trainees in paediatric dentistry should have sedation training. The most popular form of sedation amongst specialists in paediatric dentistry was NOIS. However, some of the respondents felt that children should have access to other forms of sedation in both the primary care and hospital settings. Additional research on other forms of sedation is required to evaluate their effectiveness and safety.

  17. People with insomnia: experiences with sedative hypnotics and risk perception

    OpenAIRE

    Cheung, Janet M. Y.; Bartlett, Delwyn J.; Armour, Carol L.; Ellis, Jason G.; Saini, Bandana

    2015-01-01

    Background - Sedative hypnotics form an important part of managing insomnia and are recommended for short-term use. It is standard practice for clinicians to inform the patient to use medications only ‘when required’, but the use of these medications is often chronic. Little is known about the impact of standard labelling/instructions on promoting appropriate medication use for managing insomnia.\\ud \\ud Objective - To explore patient medication-taking beliefs, experiences and behavioural prac...

  18. Standing sedation in captive zebra (Equus grevyi and Equus burchellii).

    Science.gov (United States)

    Hoyer, Mark; de Jong, Sara; Verstappen, Frank; Wolters, Marno

    2012-03-01

    Nine Grevy's zebras (Equus grevyi) and three Burchell's zebras (Equus burchellii) were immobilized in a standing position a total of 70 times for minor, nonpainful procedures over a 9-yr period. Standing sedation was successfully obtained with a combination of detomidine and butorphanol on 47 occasions (67.1%). Detomidine i.m. (median 0.10 mg/kg; range: 0.07-0.21) was administered by dart, followed 10 min later by butorphanol i.m. (median 0.13 mg/kg; range 0.04-0.24). The dosages were varied depending on the initial demeanor of the animal. On 23 occasions (32.9%), small amounts of etorphine (median 2.5 microg/kg; range 1.1-12.3 microg/kg) plus acepromazine (median 10 microg/kg; range 4.4-50 microg/kg) (as in Large Animal-Immobilon) had to be administered i.m. to gain sufficient sedation. In these latter cases, the animals were either excited or known for their aggressive character. The zebras were sufficiently immobilized for the length of most procedures (<45 min) without supplementation. At the end of the procedure, the animals were given atipamezole (2 mg per 1 mg detomidine used) and naltrexone (0.1 mg/kg) to reverse the sedative effects, irrespective of whether etorphine was used or not. Standing sedation, using the combination of the alpha-2 agonist detomidine and the partial agonist-antagonist opioid butorphanol (in some cases supplemented with etorphine + acepromazine), proved to be a very efficacious and safe method to be used in zebras under zoo conditions for short-lasting, nonpainful procedures.

  19. Use of opioids and sedatives at End-of-Life

    Directory of Open Access Journals (Sweden)

    Shin Wei Sim

    2014-01-01

    Full Text Available Despite their proven efficacy and safety, opioid and sedative use for palliation in patients afflicted with cancer in Singapore have been shown to be a fraction of that in other countries. This paper explores the various psychosocial and system-related factors that appear to propagate this conservative approach to care in what is largely a western-influenced care practice. A search for publications relating to sedative and opioid usage in Asia was performed on PubMed, Google, Google Scholar, World Health Organization, and Singapore′s government agency websites using search terms such as "opioids," "sedatives," "palliation," "end-of-life-care," "pain management," "palliative care," "cancer pain," "Asia," "Singapore," and "morphine." Findings were classified into three broad groups - system-related, physician-related, and patient-related factors. A cautious medico-legal climate, shortage of physicians trained in palliative care, and lack of instruments for symptom assessment of patients at the end of life contribute to system-related barriers. Physician-related barriers include delayed access to palliative care due to late referrals, knowledge deficits in non-palliative medicine physicians, and sub-optimal care provided by palliative physicians. Patients′ under-reporting of symptoms and fear of addiction, tolerance, and side effects of opioids and sedatives may lead to conservative opioid use in palliative care as well. System-related, physician-related, and patient-related factors play crucial roles in steering the management of palliative patients. Addressing and increasing the awareness of these factors may help ensure patients receive adequate relief and control of distressing symptoms.

  20. Disruption of cortical integration during midazolam-induced light sedation.

    Science.gov (United States)

    Liang, Peipeng; Zhang, Han; Xu, Yachao; Jia, Wenbin; Zang, Yufeng; Li, Kuncheng

    2015-11-01

    This work examines the effect of midazolam-induced light sedation on intrinsic functional connectivity of human brain, using a randomized, double-blind, placebo-controlled, cross-over, within-subject design. Fourteen healthy young subjects were enrolled and midazolam (0.03 mg/kg of the participant's body mass, to a maximum of 2.5 mg) or saline were administrated with an interval of one week. Resting-state fMRI was conducted before and after administration for each subject. We focus on two types of networks: sensory related lower-level functional networks and higher-order functions related ones. Independent component analysis (ICA) was used to identify these resting-state functional networks. We hypothesize that the sensory (visual, auditory, and sensorimotor) related networks will be intact under midazolam-induced light sedation while the higher-order (default mode, executive control, salience networks, etc.) networks will be functionally disconnected. It was found that the functional integrity of the lower-level networks was maintained, while that of the higher-level networks was significantly disrupted by light sedation. The within-network connectivity of the two types of networks was differently affected in terms of direction and extent. These findings provide direct evidence that higher-order cognitive functions including memory, attention, executive function, and language were impaired prior to lower-level sensory responses during sedation. Our result also lends support to the information integration model of consciousness. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  1. Predicting children's behaviour during dental treatment under oral sedation.

    Science.gov (United States)

    Lourenço-Matharu, L; Papineni McIntosh, A; Lo, J W

    2016-06-01

    The primary aim of this study was to assess whether parents' own anxiety and their perception of their child's dental fear and child's general fear can predict preoperatively their child's behaviour during dental treatment under oral sedation. The secondary aim was to assess whether the child's age, gender and ASA classification grade are associated with a child's behaviour under oral sedation. Cross-sectional prospective study. The Corah's Dental Anxiety Scale (DAS), Children's Fear Survey Schedule Dental-Subscale (CFSS-DS) and Children's Fear Survey Schedule Short-Form (CFSS-SF) questionnaires were completed by parents of children undergoing dental treatment with oral midazolam. Behaviour was rated by a single clinician using the overall behaviour section of the Houpt-Scale and scores dichotomised into acceptable or unacceptable behaviour. Data were analysed using χ (2), t test and logistic regression analysis. In total 404 children (215 girls, 53 %) were included, with the mean age of 4.57 years, SD = 1.9. Behaviour was scored as acceptable in 336 (83 %) and unacceptable in 68 (17 %) children. The level of a child's dental fear, as perceived by their parent, was significantly associated with the behaviour outcome (p = 0.001). Logistic regression analysis revealed that if the parentally perceived child's dental fear (CFSS-DS) rating was high, the odds of the child exhibiting unacceptable behaviour under oral sedation was two times greater than if their parents scored them a low dental fear rating (OR 2.27, 95 % CI 1.33-3.88, p = 0.003). CFSS-DS may be used preoperatively to help predict behaviour outcome when children are treated under oral sedation and facilitate treatment planning.

  2. Sedation with detomidine and acepromazine influences the endoscopic evaluation of laryngeal function in horses.

    Science.gov (United States)

    Lindegaard, C; Husted, L; Ullum, H; Fjeldborg, J

    2007-11-01

    Endoscopy of the upper airways of horses is used as a diagnostic tool and at purchase examinations. On some occasions it is necessary to use sedation during the procedure and it is often speculated that the result of the examination might be influenced due to the muscle-relaxing properties of the most commonly used sedatives. To evaluate the effect of detomidine (0.01 mg/kg bwt) and acepromazine (0.05 mg/kg bwt) on the appearance of symmetry of rima glottidis, ability to abduct maximally the arytenoid cartilages and the effect on recurrent laryngeal neuropathy (RLN) grade. Forty-two apparently normal horses underwent endoscopic examination of the upper airways on 3 different occasions, under the influence of 3 different treatments: no sedation (control), sedation with detomidine and sedation with acepromazine. All examinations were performed with a minimum of one week apart. The study was performed as an observer-blind cross-over study. Sedation with detomidine had a significant effect on the RLN grading (OR = 2.91) and ability maximally to abduct the left arytenoid cartilages (OR = 2.91). Sedation with acepromazine resulted in OR = 2.43 for the RLN grading and OR = 2.22 for the ability to abduct maximally. The ability to abduct maximally the right arytenoid cartilage was not altered. Sedating apparently healthy horses with detomidine or acepromazine significantly impairs these horses' ability to abduct fully the left but not the right arytenoid cartilage. This resulted in different diagnosis with respect to RLN when comparing sedation to no sedation. Since the ability to abduct the right arytenoid cartilage fully is not altered by sedation, it is speculated that horses changing from normal to abnormal laryngeal function when sedated, might be horses in an early stage of the disease. To confirm or reject these speculations, further studies are needed. Until then sedation during endoscopy should be used with care.

  3. Moral differences in deep continuous palliative sedation and euthanasia.

    Science.gov (United States)

    Juth, Niklas; Lindblad, Anna; Lynöe, Niels; Sjöstrand, Manne; Helgesson, Gert

    2013-06-01

    In palliative care there is much debate about which end of life treatment strategies are legitimate and which are not. Some writers argue that there is an important moral dividing-line between palliative sedation and euthanasia, making the first acceptable and the latter not. We have questioned this. In a recent article, Lars Johan Materstvedt has argued that we are wrong on two accounts: first, that we fail to account properly for the moral difference between continuous deep palliative sedation at the end of life and euthanasia, and, second, that we fail to account properly for the difference between permanent loss of consciousness and death. Regarding the first objection, we argue that Materstvedt misses the point: we agree that there is a difference in terms of intentions between continuous deep palliative sedation and euthanasia, but we question whether this conceptual difference makes up for a moral difference. Materstvedt fails to show that it does. Regarding the second objection, we argue that if nothing else is at stake than the value of the patient's life, permanent unconsciousness and death are morally indifferent.

  4. Framework for continuous palliative sedation therapy in Canada.

    Science.gov (United States)

    Dean, Mervyn M; Cellarius, Victor; Henry, Blair; Oneschuk, Doreen; Librach Canadian Society Of Palliative Care Physicians Taskforce, S Lawrence

    2012-08-01

    Canada does not have a standardized ethical and practice framework for continuous palliative sedation therapy (CPST). Although a number of institutional and regional guidelines exist, Canadian practice varies. Given the lack of international and national consensus on CPST, the Canadian Society for Palliative Care Physicians (CSPCP) formed a special task force to develop a consensus-based framework for CPST. Through a preliminary review of sedation practices nationally and internationally, it was determined that although considerable consensus was emerging on this topic, there remained both areas of contention and a lack of credible scientific evidence to support a definitive clinical practice guideline. This led to the creation of a framework to help guide policy, practice, and research. This framework was developed through the following steps: 1) literature review; 2) identification of issues; 3) preparation of a draft framework; 4) expert consultation and revision; 5) presentation at conferences and further revision; and 6) further revision and national consensus building. A thorough literature review, including gray literature, of sedation therapy at the end of life was conducted from which an initial framework was drafted. This document was reviewed by 30 multidisciplinary experts in Canada and internationally, revised several times, and then submitted to CSPCP members for review. Consensus was high on most parts of the framework. The framework for CPST will provide a basis for the development of safe, effective, and ethical use of CPST for patients in palliative care and at the end of life.

  5. Sedative and muscle relaxant activities of diterpenoids from Phlomidoschema parviflorum

    Directory of Open Access Journals (Sweden)

    Abdur Rauf

    Full Text Available Abstract Phlomidoschema parviflorum (Benth. Vved. (Basionym: Stachys parviflora Benth. Lamiaceae, have significance medicinal importance as it is used in number of health disorders including diarrhea, fever, sore mouth and throat, internal bleeding, weaknesses of the liver and heart genital tumors, sclerosis of the spleen, inflammatory tumors and cancerous ulcers. The present contribution deals with the sedative and muscle relaxant like effects of diterpenoids trivially named stachysrosane and stachysrosane, isolated from the ethyl acetate soluble fraction of P. parviflorum. Both compounds (at 5, 10 and 15 mg/kg, i.p were assessed for their in vivo sedative and muscle relaxant activity in open field and inclined plane test, respectively. The geometries of both compounds were optimized with density functional theory. The molecular docking of both compounds were performed with receptor gamma aminobutyric acid. Both compounds showed marked activity in a dose dependent manner. The docking studies showed that both compounds interact strongly with important residues in receptor gamma aminobutyric acid. The reported data demonstrate that both compounds exhibited significant sedative and muscle relaxant-like effects in animal models, which opens a door for novel therapeutic applications.

  6. Dexmedetomidine versus Remifentanil for Sedation during Awake Fiberoptic Intubation

    Directory of Open Access Journals (Sweden)

    Davide Cattano

    2012-01-01

    Full Text Available This study compared remifentanil and dexmedetomidine as awake fiberoptic intubation (AFOI anesthetics. Thirty-four adult ASA I-III patients were enrolled in a double-blinded randomized pilot study to receive remifentanil (REM or dexmedetomidine (DEX for sedation during AFOI (nasal and oral. Thirty patients completed the study and received 2 mg midazolam IV and topical anesthesia. The REM group received a loading dose of 0.75 mcg/kg followed by an infusion of 0.075 mcg/kg/min. The DEX group received a loading dose of 0.4 mcg/kg followed by an infusion of 0.7 mcg/kg/hr. Time to sedation, number of intubation attempts, Ramsay sedation scale (RSS score, bispectral index (BIS, and memory recall were recorded. All thirty patients were successfully intubated by AFOI (22 oral intubations/8 nasal. First attempt success rate with AFOI was higher in the REM group than the DEX group, 72% and 38% (P=0.02, respectively. The DEX group took longer to attain RSS of ≥3 and to achieve BIS <80, as compared to the REM group. Postloading dose verbal recall was poorer in the DEX group. Dexmedetomidine seems a useful adjunct for patients undergoing AFOI but is dependent on dosage and time. Further studies in the use of dexmedetomidine for AFOI are warranted.

  7. Mechanisms of stabilization and blowoff of a premixed flame downstream of a heat-conducting perforated plate

    KAUST Repository

    Kedia, Kushal S.; Ghoniem, Ahmed F.

    2012-01-01

    The objective of this work is to investigate the flame stabilization mechanism and the conditions leading to the blowoff of a laminar premixed flame anchored downstream of a heat-conducting perforated-plate/multi-hole burner, with overall nearly

  8. The flow field structure of highly stabilized partially premixed flames in a concentric flow conical nozzle burner with coflow

    KAUST Repository

    Elbaz, Ayman M.; Zayed, M.F.; Samy, M.; Roberts, William L.; Mansour, Mohy S.

    2015-01-01

    The stability limits, the stabilization mechanism, and the flow field structure of highly stabilized partially premixed methane flames in a concentric flow conical nozzle burner with air co-flow have been investigated and presented in this work

  9. Endoscopy and sedation: an inseparable binomial for the gastroenterologist.

    Science.gov (United States)

    Crespo, Javier; Terán, Álvaro

    2018-04-01

    The development of endoscopy and its increasing demand among the population have led to a growing need for propofol-based sedation techniques. Benefit is indisputable for both patients and endoscopists, but some aspects require considering the "who" and "how" of sedation as related to safety and health care costs. Propofol is first-choice in endoscopy for the European Society of Gastrointestinal Endoscopy because of its fast onset of action and short half-life, and many reports exist on its safety when used by gastroenterologists rather than anesthesiologists. In this issue of REED several originals support the efficiency and safety of propofol even for complex, high-risk, or protracted procedures such as endoscopic retrograde cholangiopancreatography (ERCP) and enteroscopy. Propofol may be safely and effectively administered by a team with specific skills acquired through education and using a specific procedure. However, difficulties arise in real-world clinical practice that preclude such training, which in Spain should be included in the MIR (médico interno residente) specialization program curriculum. The Comisión Nacional de Digestivo (Spanish National Commission on Digestive Diseases), sensitive to this training gap, has included in their latest version of the MIR program (under assessment) four additional competences, with number 145 (training in deep sedation) being most relevant here. In addition, the Spanish Society of Gastrointestinal Endoscopy (SEED) has invested significant efforts in sedation training, with over 50 courses on sedation for endoscopists and nurses. Continuing education and training in this field (for instance, refresher courses on advanced cardiopulmonary resuscitation) should be a goal for all endoscopy units. Because of the diversity found among hospitals, with single or multiple endoscopy rooms, efforts should be made to persuade those in charge of gastroenterology and anesthesiology departments to establish the necessary care

  10. Palliative sedation in Germany: factors and treatment practices associated with different sedation rate estimates in palliative and hospice care services.

    Science.gov (United States)

    Stiel, Stephanie; Nurnus, Mareike; Ostgathe, Christoph; Klein, Carsten

    2018-03-13

    Clinical practice of Palliative Sedation (PS) varies between institutions worldwide and sometimes includes problematic practices. Little available research points at different definitions and frameworks which may contribute to uncertainty of healthcare professionals in the application of PS. This analysis investigates what demographic factors and characteristics of treatment practices differ between institutions with high versus low sedation rates estimates in Palliative and Hospice Care in Germany. Data sets from 221 organisations from a prior online survey were separated into two sub-groups divided by their estimated sedation rate A) lower/equal to 16% (n = 187; 90.8%) and B) higher than 16% (n = 19; 9.2%) for secondary analysis. Demographic factors and characteristics of PS treatment practices between the two groups were compared using T-Tests and Chi 2 / Fisher Exact Tests and considered significant (*) at two-sided p palliative and hospice care representatives show divergence, which may be influenced one by another. A comprehensive framework considering conceptual, clinical, ethical, and legal aspects of different definitions of PS could help to better distinguish between different types and nuances of PS.

  11. Experimental and Numerical Study of Jet Controlled Compression Ignition on Combustion Phasing Control in Diesel Premixed Compression Ignition Systems

    OpenAIRE

    Qiang Zhang; Wuqiang Long; Jiangping Tian; Yicong Wang; Xiangyu Meng

    2014-01-01

    In order to directly control the premixed combustion phasing, a Jet Controlled Compression Ignition (JCCI) for diesel premixed compression ignition systems is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine without EGR at 3000 rpm. Numerical models were validated by load sweep experiments at fixed spark timing. Detailed combustion characteristics were analyzed based on the BMEP of 2.18 bar. The simulation results showed that the high temperature j...

  12. The Attitudes of Indian Palliative-care Nurses and Physicians to Pain Control and Palliative Sedation.

    Science.gov (United States)

    Gielen, Joris; Gupta, Harmala; Rajvanshi, Ambika; Bhatnagar, Sushma; Mishra, Seema; Chaturvedi, Arvind K; den Branden, Stef Van; Broeckaert, Bert

    2011-01-01

    We wanted to assess Indian palliative-care nurses and physicians' attitudes toward pain control and palliative sedation. From May to September 2008, we interviewed 14 physicians and 13 nurses working in different palliative-care programs in New Delhi, using a semi-structured questionnaire, and following grounded-theory methodology (Glaser and Strauss). The interviewees did not consider administration of painkillers in large doses an ethical problem, provided the pain killers are properly titrated. Mild palliative sedation was considered acceptable. The interviewees disagreed whether palliative sedation can also be deep and continuous. Arguments mentioned against deep continuous palliative sedation were the conviction that it may cause unacceptable side effects, and impedes basic daily activities and social contacts. A few interviewees said that palliative sedation may hasten death. Due to fears and doubts regarding deep continuous palliative sedation, it may sometimes be too easily discarded as a treatment option for refractory symptoms.

  13. Comparison between intravenous and intramuscular administration of ketamine in children sedation referred to emergency department

    Directory of Open Access Journals (Sweden)

    Behnaz Boroumand Rezazadeh

    2014-12-01

    Full Text Available Ketamine, among wide variety of sedative drugs, has shown beneficial effects when using during the procedural sedation, specifically in pediatrics. Various parameters should be considered in order to perform a safe and effective procedural sedation including optimum dosage of the sedative, administration methods of sedation, and need for applying any adjuvant drug. In this study, we aimed to review the studies, which have compared the efficacy of the different ways of the injection of ketamine such as intravenous or intramuscular ketamine application. Based on data obtained from the related articles, efficacy and safety of these two methods of ketamine usage in the pediatric procedural sedation were widely similar, but the intravenously administration of the ketamine can be proposed as the preferable mode.

  14. The Attitudes of Indian Palliative-care Nurses and Physicians to Pain Control and Palliative Sedation

    Science.gov (United States)

    Gielen, Joris; Gupta, Harmala; Rajvanshi, Ambika; Bhatnagar, Sushma; Mishra, Seema; Chaturvedi, Arvind K; den Branden, Stef Van; Broeckaert, Bert

    2011-01-01

    Aim: We wanted to assess Indian palliative-care nurses and physicians’ attitudes toward pain control and palliative sedation. Materials and Methods: From May to September 2008, we interviewed 14 physicians and 13 nurses working in different palliative-care programs in New Delhi, using a semi-structured questionnaire, and following grounded-theory methodology (Glaser and Strauss). Results: The interviewees did not consider administration of painkillers in large doses an ethical problem, provided the pain killers are properly titrated. Mild palliative sedation was considered acceptable. The interviewees disagreed whether palliative sedation can also be deep and continuous. Arguments mentioned against deep continuous palliative sedation were the conviction that it may cause unacceptable side effects, and impedes basic daily activities and social contacts. A few interviewees said that palliative sedation may hasten death. Conclusion: Due to fears and doubts regarding deep continuous palliative sedation, it may sometimes be too easily discarded as a treatment option for refractory symptoms. PMID:21633619

  15. Sedation in palliative care – a critical analysis of 7 years experience

    Science.gov (United States)

    Muller-Busch, H Christof; Andres, Inge; Jehser, Thomas

    2003-01-01

    Background The administration of sedatives in terminally ill patients becomes an increasingly feasible medical option in end-of-life care. However, sedation for intractable distress has raised considerable medical and ethical concerns. In our study we provide a critical analysis of seven years experience with the application of sedation in the final phase of life in our palliative care unit. Methods Medical records of 548 patients, who died in the Palliative Care Unit of GK Havelhoehe between 1995–2002, were retrospectively analysed with regard to sedation in the last 48 hrs of life. The parameters of investigation included indication, choice and kind of sedation, prevalence of intolerable symptoms, patients' requests for sedation, state of consciousness and communication abilities during sedation. Critical evaluation included a comparison of the period between 1995–1999 and 2000–2002. Results 14.6% (n = 80) of the patients in palliative care had sedation given by the intravenous route in the last 48 hrs of their life according to internal guidelines. The annual frequency to apply sedation increased continuously from 7% in 1995 to 19% in 2002. Main indications shifted from refractory control of physical symptoms (dyspnoea, gastrointestinal, pain, bleeding and agitated delirium) to more psychological distress (panic-stricken fear, severe depression, refractory insomnia and other forms of affective decompensation). Patients' and relatives' requests for sedation in the final phase were significantly more frequent during the period 2000–2002. Conclusion Sedation in the terminal or final phase of life plays an increasing role in the management of intractable physical and psychological distress. Ethical concerns are raised by patients' requests and needs on the one hand, and the physicians' self-understanding on the other hand. Hence, ethically acceptable criteria and guidelines for the decision making are needed with special regard to the nature of refractory

  16. Sedation in palliative care – a critical analysis of 7 years experience

    Directory of Open Access Journals (Sweden)

    Andres Inge

    2003-05-01

    Full Text Available Abstract Background The administration of sedatives in terminally ill patients becomes an increasingly feasible medical option in end-of-life care. However, sedation for intractable distress has raised considerable medical and ethical concerns. In our study we provide a critical analysis of seven years experience with the application of sedation in the final phase of life in our palliative care unit. Methods Medical records of 548 patients, who died in the Palliative Care Unit of GK Havelhoehe between 1995–2002, were retrospectively analysed with regard to sedation in the last 48 hrs of life. The parameters of investigation included indication, choice and kind of sedation, prevalence of intolerable symptoms, patients' requests for sedation, state of consciousness and communication abilities during sedation. Critical evaluation included a comparison of the period between 1995–1999 and 2000–2002. Results 14.6% (n = 80 of the patients in palliative care had sedation given by the intravenous route in the last 48 hrs of their life according to internal guidelines. The annual frequency to apply sedation increased continuously from 7% in 1995 to 19% in 2002. Main indications shifted from refractory control of physical symptoms (dyspnoea, gastrointestinal, pain, bleeding and agitated delirium to more psychological distress (panic-stricken fear, severe depression, refractory insomnia and other forms of affective decompensation. Patients' and relatives' requests for sedation in the final phase were significantly more frequent during the period 2000–2002. Conclusion Sedation in the terminal or final phase of life plays an increasing role in the management of intractable physical and psychological distress. Ethical concerns are raised by patients' requests and needs on the one hand, and the physicians' self-understanding on the other hand. Hence, ethically acceptable criteria and guidelines for the decision making are needed with special regard to

  17. Increase in palliative sedation and reasons in cancer patients in Dutch general practice 2005–2014.

    OpenAIRE

    Donker, G.A.; Dijk, C.E. van

    2015-01-01

    Background: Little is known about the quantity and reasons for use of palliative sedation in cancer patients in general practice and the reason to apply palliative sedation when a request for euthanasia was pending. Aim: To gain more insight into the reasons for palliative sedation at the end of life, also when a request for euthanasia was pending in cancer patients in Dutch general practice. Design and setting: Dynamic cohort study using registrations and questionnaire data of Dutch GPs. Met...

  18. Palliative sedation in end-of-life care and survival: a systematic review.

    Science.gov (United States)

    Maltoni, Marco; Scarpi, Emanuela; Rosati, Marta; Derni, Stefania; Fabbri, Laura; Martini, Francesca; Amadori, Dino; Nanni, Oriana

    2012-04-20

    Palliative sedation is a clinical procedure aimed at relieving refractory symptoms in patients with advanced cancer. It has been suggested that sedative drugs may shorten life, but few studies exist comparing the survival of sedated and nonsedated patients. We present a systematic review of literature on the clinical practice of palliative sedation to assess the effect, if any, on survival. A systematic review of literature published between January 1980 and December 2010 was performed using MEDLINE and EMBASE databases. Search terms included palliative sedation, terminal sedation, refractory symptoms, cancer, neoplasm, palliative care, terminally ill, end-of-life care, and survival. A manual search of the bibliographies of electronically identified articles was also performed. Eleven published articles were identified describing 1,807 consecutive patients in 10 retrospective or prospective nonrandomized studies, 621 (34.4%) of whom were sedated. One case-control study was excluded from prevalence analysis. The most frequent reason for sedation was delirium in the terminal stages of illness (median, 57.1%; range, 13.8% to 91.3%). Benzodiazepines were the most common drug category prescribed. Comparing survival of sedated and nonsedated patients, the sedation approach was not shown to be associated with worse survival. Even if there is no direct evidence from randomized clinical trials, palliative sedation, when appropriately indicated and correctly used to relieve unbearable suffering, does not seem to have any detrimental effect on survival of patients with terminal cancer. In this setting, palliative sedation is a medical intervention that must be considered as part of a continuum of palliative care.

  19. Current role of non-anesthesiologist administered propofol sedation in advanced interventional endoscopy

    DEFF Research Database (Denmark)

    Burtea, Daniela Elena; Dimitriu, Anca; Maloş, Anca Elena

    2015-01-01

    the patients and medical personnel. Current guidelines support the use of propofol sedation, which has the same rate of adverse effects as traditional sedation with benzodiazepines and/or opioids, but decreases the procedural and recovery time. Non-anesthesiologist administered propofol sedation has become......, improved satisfaction for patients and doctors, as well as decreased recovery and discharge time. Despite the advantages of non-anesthesiologist administered propofol, there is still a continuous debate related to the successful generalization of the procedures....

  20. Minimal and moderate oral sedation in the adult special needs patient.

    Science.gov (United States)

    Coke, John M; Edwards, Michael D

    2009-04-01

    Oral minimal/moderate sedation can be an effective tool to aid in the dental management of adult special needs patients. Specific sedative drugs must be chosen by the dentist that can be used safely and effectively on these patients. This article focuses on a select number of these drugs, specific medical and pharmacologic challenges presented by adult special needs patients, and techniques to safely administer oral minimal and moderate sedation.

  1. Sedative-hypnotic drug use among community-dwelling elderly in Taiwan.

    Science.gov (United States)

    Tseng, Han-Yun; Yu, Shu-Han; Lee, Chun-Yi; Huang, Wen-Hao; Huang, Seng-Loong; Wu, Chi-Shin; Chiu, Yen-Feng; Hsiung, Chao A

    2018-03-21

    Sedative-hypnotic medication use has been related to severe adverse events and risks. This study investigated the prevalence of and characteristics associated with the use of sedatives and hypnotics among community-dwelling elderly persons aged 65 years and over in Taiwan. A representative sample of community-dwelling adults was recruited. Clinical and sociodemographic data were collected for assessing physical, mental, and cognitive functioning and disorders. Sedatives and hypnotics use was determined via both self-reporting and prescription records. Logistic regression modeling was used to evaluate associations between sedative-hypnotic use and demographic and health status. Among the 3,978 participants aged 65 years and over, the rate of sedative-hypnotic use was 19.7% (n = 785). 4.5% (n = 35) of users reported sedative-hypnotic use without a doctor's prescription. Several sociodemographic characteristics were positively associated with sedative and hypnotic use, including older age, female gender, higher education level, married status, unemployment, and current alcohol consumption. Comorbid chronic and cardiovascular diseases, mental illness, depression, pain, and sleep problems also increased the likelihood of sedative-hypnotic use. This study is one of the largest pioneer studies to date to survey sedatives-hypnotics use among community-dwelling elderly. One in five community-dwelling older adults reported sedative-hypnotic drugs use in Taiwan, and about 5% of sedative and/or hypnotics usage was without a doctor's prescription. Findings could be helpful for drug-use safety interventions to identify target geriatric patients who are in general at higher risk of downstream harm associated with sedative-hypnotic use in geriatric patients.

  2. Prospective Observational Evaluation of Sedation and Pain Management Guideline Adherence Across New Jersey Intensive Care Units.

    Science.gov (United States)

    Brophy, Alison; Cardinale, Maria; Andrews, Liza B; Kaplan, Justin B; Adams, Christopher; Opsha, Yekaterina; Brandt, Kimberly A; Dixit, Deepali; Nerenberg, Steven F; Saleh, Julie A

    2018-01-01

    The practice guidelines for the management of pain, agitation, and delirium (PAD) from the Society of Critical Care Medicine shifted from primarily focusing on the treatment of anxiety in 2002 to the treatment of pain in 2013. This prospective, observational, multicenter study aimed to assess the degree of practice adherence to the PAD guidelines for ventilated patients in New Jersey intensive care units (ICUs). Pharmacist investigators at 8 centers designated 4 days at least 10 days apart to evaluate all patients on mechanical ventilation. The primary outcomes included adherence to 4 guideline recommendations: treatment of pain before sedation, use of nonnarcotic analgesic medications, use of nonbenzodiazepine sedative medications, and use of goal-directed sedation. Of 138 patients evaluated, 50% had a primary medical diagnosis (as opposed to surgical, cardiac, or neurological diagnosis), and the median Sequential Organ Failure Assessment (SOFA) score was 7. Pain was treated prior to administration of sedatives in 55.4% of subjects, with fentanyl being the primary analgesic used. In addition, 19% received no analgesia, and 11.5% received nonopioid analgesia. Sedative agents were administered to 87 subjects (48 nonbenzodiazepine and 39 benzodiazepine). Of those receiving benzodiazepines, 22 received intermittent bolus regimens and 16 received continuous infusions, of which 5 were for another indication besides sedation. Validated scales measuring the degree of sedation were completed at least once in 56 (81.6%) patients receiving sedatives. Current sedation practices suggest that integration of evidence-based PAD guidelines across New Jersey adult ICUs is inconsistent despite pharmacist involvement.

  3. Palliative sedation: a focus group study on the experiences of relatives.

    Science.gov (United States)

    Bruinsma, Sophie; Rietjens, Judith; van der Heide, Agnes

    2013-04-01

    Most studies that have investigated the practice of palliative sedation have focused on physicians' practices and attitudes. The aim of this study was to explore relatives' experiences with palliative sedation and to gain more insight in positive and negative elements in their evaluation of palliative sedation. Focus groups and individual interviews. Various care settings in the Netherlands. A total of 14 relatives of patients who received palliative sedation until death participated. Most relatives evaluated the provision of palliative sedation of their dying family member positively. Positive experiences were related to: the beneficial impact of palliative sedation on the patient's suffering, the opportunity that was offered to prepare for the patient's death, their involvement in the decision-making and care for the patient, and the pleasant care environment. However, the majority of the relatives were unsatisfied with one or more aspects of how information was being provided for. Some relatives were frustrated about the fact that nurses were not authorized to make decisions about the care for the patient and about the absence of physicians during weekends. None of the relatives mentioned the loss of the ability to communicate with the patient during the sedation and the possibility of "hastening death" as disadvantages of palliative sedation. Relatives tend to evaluate the provision of palliative sedation to their severely suffering family member positively because it contributes to a peaceful dying process. However, relatives indicated discontent with how information was being provided and with the communication in general.

  4. Level of consciousness in dying patients. The role of palliative sedation: a longitudinal prospective study.

    Science.gov (United States)

    Claessens, Patricia; Menten, Johan; Schotsmans, Paul; Broeckaert, Bert

    2012-05-01

    Patients suffering from a terminal illness often are confronted with severe symptoms during the last phase of their lives. Palliative sedation, although one of the options of last resort, remains a much debated and controversial issue and is often referred to as a form of slow euthanasia or euthanasia in disguise. A prospective longitudinal and descriptive design was used. Each patient admitted in one of the 8 participating units was included if they met the inclusion criteria and gave written informed consent. 266 patients were included. The incidence of palliative sedation was 7;5%. For the group of sedated patients results show that 90% entered the palliative care unit being fully conscious. Two patients were comatose upon arrival. 90% of the patients remained fully conscious up to the day palliative sedation was started. When looking at the effect of palliative sedation on the level of consciousness the analysis strongly suggest that the palliative sedation - as expected- has an impact on the GCS score. Irrespective of the dichotomization of the score the probability of having a lower GCS increases substantially once sedation is initiated. Additionally, results show that once palliative sedation is administered, the level of consciousness gradually goes down up until the day of death. Palliative sedation is nor slow euthanasia nor an ambivalent practice. It is an intentional medical treatment which is administered in a proportional way when refractory suffering occurs. It occurs in extraordinary situations and at the very end of the dying process.

  5. Muslim physicians and palliative care: attitudes towards the use of palliative sedation.

    Science.gov (United States)

    Muishout, George; van Laarhoven, Hanneke W M; Wiegers, Gerard; Popp-Baier, Ulrike

    2018-05-08

    Muslim norms concerning palliative sedation can differ from secular and non-Muslim perceptions. Muslim physicians working in a Western environment are expected to administer palliative sedation when medically indicated. Therefore, they can experience tension between religious and medical norms. To gain insight into the professional experiences of Muslim physicians with palliative sedation in terms of religious and professional norms. Interpretative phenomenological study using semi-structured interviews to take a closer look at the experiences of Muslim physicians with palliative sedation. Data were recorded, transcribed and analysed by means of interpretative phenomenological analysis (IPA). Ten Muslim physicians, working in the Netherlands, with professional experience of palliative sedation. Two main themes were identified: professional self-concept and attitudes towards death and dying. Participants emphasized their professional responsibility when making treatment decisions, even when these contravened the prevalent views of Islamic scholars. Almost all of them expressed the moral obligation to fight their patients' pain in the final stage of life. Absence of acceleration of death was considered a prerequisite for using palliative sedation by most participants. Although the application of palliative sedation caused friction with their personal religious conceptions on a good death, participants followed a comfort-oriented care approach corresponding to professional medical standards. All of them adopted efficient strategies for handling of palliative sedation morally and professionally. The results of this research can contribute to and provide a basis for the emergence of new, applied Islamic ethics regarding palliative sedation.

  6. Relieving existential suffering through palliative sedation: discussion of an uneasy practice.

    Science.gov (United States)

    Bruce, Anne; Boston, Patricia

    2011-12-01

    This article presents a discussion of the use of palliative sedation in response to intractable (not responsive to treatment) existential suffering. Patients suffering from a terminal illness are often faced with severe symptoms at the end of life. Although palliative sedation is sometimes used when no other options are effective in relieving unbearable pain or suffering, its use in response to intractable existential suffering in terminal illness remains controversial. A literature search was conducted for published articles addressing the use of palliative sedation between 1996 and 2009 using established databases. Palliative sedation remains an uneasy practice. The debates have centred on ethical issues surrounding decisions to use sedation and on separating the intent of palliative sedation (relief of intolerable symptoms) from the intent of euthanasia (hastening death). There is lack of consensus in defining existential suffering. Consequently, there is limited understanding of how decisions are being made when using palliative sedation to treat intractable existential suffering. Given the confusion and uncertainty about ethical and clinical justifications for palliative sedation in treating existential suffering, we argue that a better understanding of the controversies and decision-making process is needed. Greater understanding is required to prevent palliative sedation from becoming a substitute for intensive treatment of this kind of suffering. © 2011 Blackwell Publishing Ltd.

  7. Walking the line. Palliative sedation for existential distress: still a controversial issue?

    Science.gov (United States)

    Schur, Sophie; Radbruch, Lukas; Masel, Eva K; Weixler, Dietmar; Watzke, Herbert H

    2015-12-01

    Adequate symptom relief is a central aspect of medical care of all patients especially in those with an incurable disease. However, as an illness progresses and the end of life approaches, physical or psychoexistential symptoms may remain uncontrollable requiring palliative sedation. Although palliative sedation has become an increasingly implemented practice in the care of terminally ill patients, sedation in the management of refractory psychological symptoms and existential distress is still a controversial issue and much debated. This case report presents a patient who received palliative sedation for the treatment of existential distress and discusses considerations that may arise from such a therapeutic approach.

  8. Stressful experiences in relation to depth of sedation in mechanically ventilated patients.

    Science.gov (United States)

    Samuelson, Karin A M; Lundberg, Dag; Fridlund, Bengt

    2007-01-01

    In mechanically ventilated patients, sedatives and analgesics are commonly used to ensure comfort, but there is no documented knowledge about the impact of depth of sedation on patients' perception of discomfort. The aim of this study was, therefore, to investigate the relationship between stressful experiences and intensive care sedation, including the depth of sedation. During 18 months, 313 intubated mechanically ventilated adults admitted to two general intensive care units (ICU) for more than 24 h were included. Patients (n = 250) were interviewed on the general ward 5 days after ICU discharge using the ICU Stressful Experiences Questionnaire. Patient data including sedation scores as measured by the Motor Activity Assessment Scale (MAAS) were collected from hospital records after the interview. Of the 206 patients with memories of the intensive care, 82% remembered at least one experience as quite a bit or extremely bothersome. Multivariate analyses showed that higher proportion of MAAS score 3 (indicating more periods of wakefulness), longer ICU stay and being admitted emergent were factors associated with remembering stressful experiences of the ICU as more bothersome. The findings indicate that the depth of sedation has an impact on patients' perception of stressful experiences and that light sedation compared with heavy seems to increase the risk of perceiving experiences in the ICU as more bothersome. In reducing discomfort, depth of sedation and patient comfort should be assessed regularly, non-pharmacological interventions taken into account and the use of sedatives and analgesics adapted to the individual requirements of the patient.

  9. Review of palliative sedation and its distinction from euthanasia and lethal injection.

    Science.gov (United States)

    Hahn, Michael P

    2012-01-01

    Palliative sedation evolved from within the practice of palliative medicine and has become adopted by other areas of medicine, such as within intensive care practice. Clinician's usually come across this practice for dying patients who are foregoing or having life support terminated. A number of intolerable and intractable symptom burdens can occur during the end of life period that may require the use of palliative sedation. Furthermore, when patients receive palliative sedation, the continued use of hydration and nutrition becomes an issue of consideration and there are contentious bioethical issues involved in using or withholding these life-sustaining provisions. A general understanding of biomedical ethics helps prevent abuse in the practice of palliative sedation. Various sedative drugs can be employed in the provision of palliative sedation that can produce any desired effect, from light sedation to complete unconsciousness. Although there are some similarities in the pharmacotherapy of palliative sedation, euthanasia, physician-assisted suicide, and lethal injection, there is a difference in how the drugs are administered with each practice. There are some published guidelines about how palliative sedation should be practiced, but currently there is not any universally accepted standard of practice.

  10. [Survey of pediatric sedation in Japan--results of questionnaire to universities of dentistry].

    Science.gov (United States)

    Takeuchi, Lisa; Kuratani, Norifumi; Hoshijima, Hiroshi; Kikuchi, Hirosato

    2010-12-01

    Despite widespread use of sedation for stress management during dental treatment in adults, its prevalence of use for pediatric in patients Japan has not been clarified. We investigated here, the present situation of pediatric sedation by the questionnaire sent to the dental anesthesia departments of university hospitals in Japan. Postal survey was conducted of the dental anesthesia departments of university hospitals (29 institutions) throughout the country. Information was requested on hospital policy of indication and technique of pediatric sedation for dental treatment. The causes for avoiding pediatric sedation were also investigated. The response rate was 86.2% (25/29 institutions). Of these respondents, 16 institutions (64%, 16/25 institutions) employ sedation for pediatric dental treatment stress management. The cases performed were around 1-5 cases every month. However, the criteria for employment of pediatric sedation during dental treatment varied among institutes. They preferred to provide general endotracheal anesthesia for pediatric dental procedures, and tended to avoid sedation without airway security for children. The present survey suggests that pediatric sedation for stress management during dental treatment are employed in more than half of the dental university hospitals. However, there was little consensus regarding pediatric sedation during dental treatment among dental anesthesiologists in Japan.

  11. Comparison of oral Midazolam-Ketamine and Midazolam-Promethazine as sedative agents in pediatric dentistry

    Directory of Open Access Journals (Sweden)

    Mojtaba Vahid Golpayegani

    2012-01-01

    Conclusion: Under the current circumstances, Ketamine/Midazolam combination provided sufficient sedative effect in lower doses. However, Midazolam/Promethazine combination did not produce similar results.

  12. Sedative load and salivary secretion and xerostomia in community-dwelling older people.

    Science.gov (United States)

    Tiisanoja, Antti; Syrjälä, Anna-Maija; Komulainen, Kaija; Hartikainen, Sirpa; Taipale, Heidi; Knuuttila, Matti; Ylöstalo, Pekka

    2016-06-01

    The aim was to investigate how sedative load and the total number of drugs used are related to hyposalivation and xerostomia among 75-year-old or older dentate, non-smoking, community-dwelling people. The study population consisted of 152 older people from the Oral Health GeMS study. The data were collected by interviews and clinical examinations during 2004-2005. Sedative load, which measures the cumulative effect of taking multiple drugs with sedative properties, was calculated using the Sedative Load Model. The results showed that participants with a sedative load of either 1-2 or ≥3 had an increased likelihood of having low stimulated salivary flow (xerostomia (OR: 2.5, CI: 0.5-12) compared with participants without a sedative load. The results showed that the association between the total number of drugs and hyposalivation was weaker than the association between sedative load and hyposalivation. Sedative load is strongly related to hyposalivation and to a lesser extent with xerostomia. The adverse effects of drugs on saliva secretion are specifically related to drugs with sedative properties. © 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

  13. Effects of midazolam and morphine on cerebral oxygenation and hemodynamics in ventilated premature infants.

    NARCIS (Netherlands)

    Velden, A.A.E.M. van der; Hopman, J.C.W.; Klaessens, J.H.G.M.; Feuth, A.B.; Sengers, R.C.A.; Liem, K.D.

    2006-01-01

    BACKGROUND: Midazolam sedation and morphine analgesia are commonly used in ventilated premature infants. OBJECTIVES: To evaluate the effects of midazolam versus morphine infusion on cerebral oxygenation and hemodynamics in ventilated premature infants. METHODS: 11 patients (GA 26.6-33.0 weeks, BW

  14. Staff education, regular sedation and analgesia quality feedback, and a sedation monitoring technology for improving sedation and analgesia quality for critically ill, mechanically ventilated patients: a cluster randomised trial.

    Science.gov (United States)

    Walsh, Timothy S; Kydonaki, Kalliopi; Antonelli, Jean; Stephen, Jacqueline; Lee, Robert J; Everingham, Kirsty; Hanley, Janet; Phillips, Emma C; Uutela, Kimmo; Peltola, Petra; Cole, Stephen; Quasim, Tara; Ruddy, James; McDougall, Marcia; Davidson, Alan; Rutherford, John; Richards, Jonathan; Weir, Christopher J

    2016-10-01

    Optimal sedation of patients in intensive care units (ICUs) requires the avoidance of pain, agitation, and unnecessary deep sedation, but these outcomes are challenging to achieve. Excessive sedation can prolong ICU stay, whereas light sedation can increase pain and frightening memories, which are commonly recalled by ICU survivors. We aimed to assess the effectiveness of three interventions to improve sedation and analgesia quality: an online education programme; regular feedback of sedation-analgesia quality data; and use of a novel sedation-monitoring technology (the Responsiveness Index [RI]). We did a cluster randomised trial in eight ICUs, which were randomly allocated to receive education alone (two ICUs), education plus sedation-analgesia quality feedback (two ICUs), education plus RI monitoring technology (two ICUs), or all three interventions (two ICUs). Randomisation was done with computer-generated random permuted blocks, stratified according to recruitment start date. A 45 week baseline period was followed by a 45 week intervention period, separated by an 8 week implementation period in which the interventions were introduced. ICU and research staff were not masked to study group assignment during the intervention period. All mechanically ventilated patients were potentially eligible. We assessed patients' sedation-analgesia quality for each 12 h period of nursing care, and sedation-related adverse events daily. Our primary outcome was the proportion of care periods with optimal sedation-analgesia, defined as being free from excessive sedation, agitation, poor limb relaxation, and poor ventilator synchronisation. Analysis used multilevel generalised linear mixed modelling to explore intervention effects in a single model taking clustering and patient-level factors into account. A concurrent mixed-methods process evaluation was undertaken to help understand the trial findings. The trial is registered with ClinicalTrials.gov, number NCT01634451. Between

  15. Apneic oxygenation for elimination of respiratory motion artefact in an intubated patient undergoing helical chest computed tomography angiography.

    Directory of Open Access Journals (Sweden)

    Ioannis Pneumatikos

    2008-10-01

    Full Text Available Respiratory motion artifact in intubated and mechanically ventilated patients often reduces the quality of helical computed tomography pulmonary angiography (CTPA. Apneic oxygenation is a well established intra-operative technique that allows adequate oxygenation for short periods (up to 10 min in sedated and paralyzed patients. We describe the use of the apneic oxygenation for elimination of respiratory motion artefact in an intubated patient undergoing helical chest computed tomography angiography.

  16. Kecepatan Pembakaran Premixed Campuran Minyak Jarak - Liquefied Petroleum Gas (LPG pada Circular Tube Burner

    Directory of Open Access Journals (Sweden)

    Defmit B.N. Riwu

    2016-10-01

    Full Text Available This study was conducted to determine the characteristics of premixed combustion of a mixture of castor oil - LPG on a circular tube burner. Percentage of LPG fuel in a mixture of jatropha curcas oil - LPG varied as much as 10%, 20%, 30%, and 40% of the mass flow jatropha curcas oil vapor. Considering the flame of fire there are two angles formed which describe burning velocity. Also there are formed two cones of fire where the bright blue inside cone is a premixed flame, while the outer blue white cone is flame a diffusion flame. An increase in the percentage of LPG makes the value of top and bottom angle increase. So that the burning velocity on the upper angle decrease whilst on bottom angle increase.

  17. Management of Type 2 diabetes in Ramadan: Low-ratio premix insulin working group practical advice

    Science.gov (United States)

    Hassanein, Mohamed; Belhadj, Mohamed; Abdallah, Khalifa; Bhattacharya, Arpan D.; Singh, Awadhesh K.; Tayeb, Khaled; Al-Arouj, Monira; Elghweiry, Awad; Iraqi, Hinde; Nazeer, Mohamed; Jamoussi, Henda; Mnif, Mouna; Al-Madani, Abdulrazzaq; Al-Ali, Hossam; Ligthelm, Robert

    2014-01-01

    The challenge of insulin use during Ramadan could be minimized, if people with diabetes are metabolically stable and are provided with structured education for at least 2–3 months pre-Ramadan. Although, American diabetes association (ADA) recommendations 2010 and South Asian Consensus Guideline 2012 deal with management of diabetes in Ramadan and changes in insulin dosage, no specific guidance on widely prescribed low-ratio premix insulin is currently available. Hence, the working group for insulin therapy in Ramadan, after collective analysis, evaluation, and opinion from clinical practice, have formulated a practical advice to empower physicians with pre-Ramadan preparation, dose adjustment, and treatment algorithm for self-titration of low-ratio premix insulin. PMID:25364673

  18. Management of Type 2 diabetes in Ramadan: Low-ratio premix insulin working group practical advice

    Directory of Open Access Journals (Sweden)

    Mohamed Hassanein

    2014-01-01

    Full Text Available The challenge of insulin use during Ramadan could be minimized, if people with diabetes are metabolically stable and are provided with structured education for at least 2-3 months pre-Ramadan. Although, American diabetes association (ADA recommendations 2010 and South Asian Consensus Guideline 2012 deal with management of diabetes in Ramadan and changes in insulin dosage, no specific guidance on widely prescribed low-ratio premix insulin is currently available. Hence, the working group for insulin therapy in Ramadan, after collective analysis, evaluation, and opinion from clinical practice, have formulated a practical advice to empower physicians with pre-Ramadan preparation, dose adjustment, and treatment algorithm for self-titration of low-ratio premix insulin.

  19. Analysis of Hydrogen/Air Turbulent Premixed Flames at Different Karlovitz Numbers Using Computational Singular Perturbation

    KAUST Repository

    Manias, Dimitrios

    2018-01-08

    The dynamics and structure of two turbulent H2/air premixed flames, representative of the corrugated flamelet (Case 1) and thin reaction zone (Case 2) regimes, are analyzed and compared, using the computational singular perturbation (CSP) tools, by incorporating the tangential stretch rate (TSR) approach. First, the analysis is applied to a laminar premixed H2/air flame for reference. Then, a two-dimensional (2D) slice of Case 1 is studied at three time steps, followed by the comparison between two representative 2D slices of Case 1 and Case 2, respectively. Last, statistical analysis is performed on the full three-dimensional domain for the two cases. The dominant reaction and transport processes are identified for each case and the overall role of kinetics/transport is determined.

  20. Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), Colom 11, E-08222, Terrassa, Barcelona (Spain); de Goey, L.P.H. [Eindhoven University of Technology, Department of Mechanical Engineering, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2008-04-15

    The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)