Mechanical ventilation with lower tidal volumes and positive end-expiratory pressure prevents pulmonary inflammation in patients without preexisting lung injury.

Science.gov (United States)

Wolthuis, Esther K; Choi, Goda; Dessing, Mark C; Bresser, Paul; Lutter, Rene; Dzoljic, Misa; van der Poll, Tom; Vroom, Margreeth B; Hollmann, Markus; Schultz, Marcus J

2008-01-01

Mechanical ventilation with high tidal volumes aggravates lung injury in patients with acute lung injury or acute respiratory distress syndrome. The authors sought to determine the effects of short-term mechanical ventilation on local inflammatory responses in patients without preexisting lung injury. Patients scheduled to undergo an elective surgical procedure (lasting > or = 5 h) were randomly assigned to mechanical ventilation with either higher tidal volumes of 12 ml/kg ideal body weight and no positive end-expiratory pressure (PEEP) or lower tidal volumes of 6 ml/kg and 10 cm H2O PEEP. After induction of anesthesia and 5 h thereafter, bronchoalveolar lavage fluid and/or blood was investigated for polymorphonuclear cell influx, changes in levels of inflammatory markers, and nucleosomes. Mechanical ventilation with lower tidal volumes and PEEP (n = 21) attenuated the increase of pulmonary levels of interleukin (IL)-8, myeloperoxidase, and elastase as seen with higher tidal volumes and no PEEP (n = 19). Only for myeloperoxidase, a difference was found between the two ventilation strategies after 5 h of mechanical ventilation (P volumes and PEEP may limit pulmonary inflammation in mechanically ventilated patients without preexisting lung injury. The specific contribution of both lower tidal volumes and PEEP on the protective effects of the lung should be further investigated.

Hemodynamic differences between continual positive and two types of negative pressure ventilation.

Science.gov (United States)

Lockhat, D; Langleben, D; Zidulka, A

1992-09-01

In seven anesthetized dogs, ventilated with matching lung volumes, tidal volumes, and respiratory rates, we compared the effects on cardiac output (CO), arterial venous oxygen saturation difference (SaO2 - SVO2), and femoral and inferior vena cava pressure (1) intermittent positive pressure ventilation with positive end-expiratory pressure (CPPV); (2) iron-lung ventilation with negative end-expiratory pressure (ILV-NEEP); (3) grid and wrap ventilation with NEEP applied to the thorax and upper abdomen (G&W-NEEP). The values of CO and SaO2 - SVO2 with ILV-NEEP were similar to those with CPPV. However, with G&W-NEEP as compared with ILV-NEEP, mean CO was greater (2.9 versus 2.6 L/min, p = 0.02) and mean (SaO2 - SVO2) was lower (26.6% versus 28.3%, p = NS). Mean PFEM-IVC was higher with G&W-NEEP than with the other types of ventilation. We conclude that (1) ILV-NEEP is hemodynamically equivalent to CPPV and (2) G&W-NEEP has less adverse hemodynamic consequences. has less adverse hemodynamic consequences.

FCT (functional computed tomography) evaluation of the lung volumes at different PEEP (positive-end expiratory pressure) ventilation pattern, in mechanical ventilated patients

International Nuclear Information System (INIS)

Papi, M.G.; Di Segni, R.; Mazzetti, G.; Staffa, F.; Conforto, F.; Calimici, R.; Salvi, A.; Matteucci, G.

2007-01-01

Purpose To evaluate with FCT (functional computed tomography) total lung volume and fractional lung volumes at different PEEP (positive end expiratory pressure) values in acute mechanically ventilated patients. Methods Nine ICU (intensive care unity) patients (1 lung pneumonia, 2 polytrauma, 2 sepsis, 3 brain surgery, 1 pulmonary embolism); mean age 48 ± 15 years, 6 male, 3 female; GE 16 MDCT scan was performed with acquisition from apex to diaphragma in seven seca at different PEEP values. Raw CT data were analysed by an advantage workstation to obtain volume density masks and histograms of both lungs and each lung and these density ranges were applied: - 1000 - 950 hyper-ventilated lung, -900 - 650 well aerated lung, -950 - 500 all aerated lung, -500 + 200 lung tissue. Total and fractional lung volumes, Hounsfield unit (HU) were calculated and compared at different PEEP values (0, 5, 10, 15 cm H 2 O). In four patients lung volumes were compared between the more and the less involved lung at increased PEEP. Statistic analysis: comparison means-medians tests. Results Data calculated at five PEEP showed unexpected decrease of total lung volume and increase of lung density (HU); proportionally no significant improvement of oxigenation. (orig.)

FCT (functional computed tomography) evaluation of the lung volumes at different PEEP (positive-end expiratory pressure) ventilation pattern, in mechanical ventilated patients

Energy Technology Data Exchange (ETDEWEB)

Papi, M.G.; Di Segni, R.; Mazzetti, G.; Staffa, F. [Dept. of Radiology, S. Giovanni HS, Rome (Italy); Conforto, F.; Calimici, R.; Salvi, A. [Dept. of Anesthesiology, S. Giovanni HS, Rome (Italy); Matteucci, G. [Dept. of Pneumology, S. Giovanni HS, Rome (Italy)

2007-06-15

Purpose To evaluate with FCT (functional computed tomography) total lung volume and fractional lung volumes at different PEEP (positive end expiratory pressure) values in acute mechanically ventilated patients. Methods Nine ICU (intensive care unity) patients (1 lung pneumonia, 2 polytrauma, 2 sepsis, 3 brain surgery, 1 pulmonary embolism); mean age 48 {+-} 15 years, 6 male, 3 female; GE 16 MDCT scan was performed with acquisition from apex to diaphragma in seven seca at different PEEP values. Raw CT data were analysed by an advantage workstation to obtain volume density masks and histograms of both lungs and each lung and these density ranges were applied: - 1000 - 950 = hyper-ventilated lung, -900 - 650 well aerated lung, -950 - 500 all aerated lung, -500 + 200 lung tissue. Total and fractional lung volumes, Hounsfield unit (HU) were calculated and compared at different PEEP values (0, 5, 10, 15 cm H{sub 2}O). In four patients lung volumes were compared between the more and the less involved lung at increased PEEP. Statistic analysis: comparison means-medians tests. Results Data calculated at five PEEP showed unexpected decrease of total lung volume and increase of lung density (HU); proportionally no significant improvement of oxigenation. (orig.)

Combined Effects of Ventilation Mode and Positive End-Expiratory Pressure on Mechanics, Gas Exchange and the Epithelium in Mice with Acute Lung Injury

Science.gov (United States)

Thammanomai, Apiradee; Hamakawa, Hiroshi; Bartolák-Suki, Erzsébet; Suki, Béla

2013-01-01

The accepted protocol to ventilate patients with acute lung injury is to use low tidal volume (VT) in combination with recruitment maneuvers or positive end-expiratory pressure (PEEP). However, an important aspect of mechanical ventilation has not been considered: the combined effects of PEEP and ventilation modes on the integrity of the epithelium. Additionally, it is implicitly assumed that the best PEEP-VT combination also protects the epithelium. We aimed to investigate the effects of ventilation mode and PEEP on respiratory mechanics, peak airway pressures and gas exchange as well as on lung surfactant and epithelial cell integrity in mice with acute lung injury. HCl-injured mice were ventilated at PEEPs of 3 and 6 cmH2O with conventional ventilation (CV), CV with intermittent large breaths (CVLB) to promote recruitment, and a new mode, variable ventilation, optimized for mice (VVN). Mechanics and gas exchange were measured during ventilation and surfactant protein (SP)-B, proSP-B and E-cadherin levels were determined from lavage and lung homogenate. PEEP had a significant effect on mechanics, gas exchange and the epithelium. The higher PEEP reduced lung collapse and improved mechanics and gas exchange but it also down regulated surfactant release and production and increased epithelial cell injury. While CVLB was better than CV, VVN outperformed CVLB in recruitment, reduced epithelial injury and, via a dynamic mechanotransduction, it also triggered increased release and production of surfactant. For long-term outcome, selection of optimal PEEP and ventilation mode may be based on balancing lung physiology with epithelial injury. PMID:23326543

Simulation of late inspiratory rise in airway pressure during pressure support ventilation.

Science.gov (United States)

Yu, Chun-Hsiang; Su, Po-Lan; Lin, Wei-Chieh; Lin, Sheng-Hsiang; Chen, Chang-Wen

2015-02-01

Late inspiratory rise in airway pressure (LIRAP, Paw/ΔT) caused by inspiratory muscle relaxation or expiratory muscle contraction is frequently seen during pressure support ventilation (PSV), although the modulating factors are unknown. We investigated the effects of respiratory mechanics (normal, obstructive, restrictive, or mixed), inspiratory effort (-2, -8, or -15 cm H2O), flow cycle criteria (5-40% peak inspiratory flow), and duration of inspiratory muscle relaxation (0.18-0.3 s) on LIRAP during PSV using a lung simulator and 4 types of ventilators. LIRAP occurred with all lung models when inspiratory effort was medium to high and duration of inspiratory muscle relaxation was short. The normal lung model was associated with the fastest LIRAP, whereas the obstructive lung model was associated with the slowest. Unless lung mechanics were normal or mixed, LIRAP was unlikely to occur when inspiratory effort was low. Different ventilators were also associated with differences in LIRAP speed. Except for within the restrictive lung model, changes in flow cycle level did not abolish LIRAP if inspiratory effort was medium to high. Increased duration of inspiratory relaxation also led to the elimination of LIRAP. Simulation of expiratory muscle contraction revealed that LIRAP occurred only when expiratory muscle contraction occurred sometime after the beginning of inspiration. Our simulation study reveals that both respiratory resistance and compliance may affect LIRAP. Except for under restrictive lung conditions, LIRAP is unlikely to be abolished by simply lowering flow cycle criteria when inspiratory effort is strong and relaxation time is rapid. LIRAP may be caused by expiratory muscle contraction when it occurs during inspiration. Copyright © 2015 by Daedalus Enterprises.

Pulmonary lesion induced by low and high positive end-expiratory pressure levels during protective ventilation in experimental acute lung injury.

Science.gov (United States)

Pássaro, Caroline P; Silva, Pedro L; Rzezinski, Andréia F; Abrantes, Simone; Santiago, Viviane R; Nardelli, Liliane; Santos, Raquel S; Barbosa, Carolina M L; Morales, Marcelo M; Zin, Walter A; Amato, Marcelo B P; Capelozzi, Vera L; Pelosi, Paolo; Rocco, Patricia R M

2009-03-01

To investigate the effects of low and high levels of positive end-expiratory pressure (PEEP), without recruitment maneuvers, during lung protective ventilation in an experimental model of acute lung injury (ALI). Prospective, randomized, and controlled experimental study. University research laboratory. Wistar rats were randomly assigned to control (C) [saline (0.1 mL), intraperitoneally] and ALI [paraquat (15 mg/kg), intraperitoneally] groups. After 24 hours, each group was further randomized into four groups (six rats each) at different PEEP levels = 1.5, 3, 4.5, or 6 cm H2O and ventilated with a constant tidal volume (6 mL/kg) and open thorax. Lung mechanics [static elastance (Est, L) and viscoelastic pressure (DeltaP2, L)] and arterial blood gases were measured before (Pre) and at the end of 1-hour mechanical ventilation (Post). Pulmonary histology (light and electron microscopy) and type III procollagen (PCIII) messenger RNA (mRNA) expression were measured after 1 hour of mechanical ventilation. In ALI group, low and high PEEP levels induced a greater percentage of increase in Est, L (44% and 50%) and DeltaP2, L (56% and 36%) in Post values related to Pre. Low PEEP yielded alveolar collapse whereas high PEEP caused overdistension and atelectasis, with both levels worsening oxygenation and increasing PCIII mRNA expression. In the present nonrecruited ALI model, protective mechanical ventilation with lower and higher PEEP levels than required for better oxygenation increased Est, L and DeltaP2, L, the amount of atelectasis, and PCIII mRNA expression. PEEP selection titrated for a minimum elastance and maximum oxygenation may prevent lung injury while deviation from these settings may be harmful.

Performance characteristics of seven bilevel mechanical ventilators in pressure-support mode with different cycling criteria: a comparative bench study.

Science.gov (United States)

Chen, Yuqing; Cheng, Kewen; Zhou, Xin

2015-01-26

Pressure support ventilation from a bilevel device is a standard technique for non-invasive home ventilation. A bench study was designed to compare the performance and patient-ventilator synchronization of 7 bilevel ventilators, in the presence of system leaks. Ventilators were connected to a Hans Rudolph Series 1101 lung simulator (compliance, 50 mL/cmH2O; expiratory resistance, 20 cmH2O/L/s; respiratory rate, 15 breaths/min; inspiratory time, 1.0 s). All ventilators were set at 15 cmH2O pressure support and 5 cmH2O positive end-expiratory pressure. Tests were conducted at 2 system leaks (12-15 and 25-28 L/min). The performance characteristics and patient-ventilator asynchrony were assessed, including flow, airway pressure, time, and workload. The Breas Vivo30 could not synchronize with the simulator (frequent auto-triggering) at a leak of 25-28 L/min, but provided stable assisted ventilation when the leak was 12-15 L/min. Missed efforts and back-up ventilation occurred for the Weinmann VENTImotion and Airox Smartair Plus, requiring adjustment of trigger effort. All ventilators had a short trigger delay time (ventilators, possibly due to software algorithm differences. Adjusting the cycling criteria settings can alter the shape of the inspiratory phase and peak expiratory flow, and improve patient-ventilator synchrony.

Utilization of the lower inflection point of the pressure-volume curve results in protective conventional ventilation comparable to high frequency oscillatory ventilation in an animal model of acute respiratory distress syndrome

Directory of Open Access Journals (Sweden)

Felipe S. Rossi

2008-01-01

Full Text Available INTRODUCTION: Studies comparing high frequency oscillatory and conventional ventilation in acute respiratory distress syndrome have used low values of positive end-expiratory pressure and identified a need for better recruitment and pulmonary stability with high frequency. OBJECTIVE: To compare conventional and high frequency ventilation using the lower inflection point of the pressure-volume curve as the determinant of positive end-expiratory pressure to obtain similar levels of recruitment and alveolar stability. METHODS: After lung lavage of adult rabbits and lower inflection point determination, two groups were randomized: conventional (positive end-expiratory pressure = lower inflection point; tidal volume=6 ml/kg and high frequency ventilation (mean airway pressures= lower inflection point +4 cmH2O. Blood gas and hemodynamic data were recorded over 4 h. After sacrifice, protein analysis from lung lavage and histologic evaluation were performed. RESULTS: The oxygenation parameters, protein and histological data were similar, except for the fact that significantly more normal alveoli were observed upon protective ventilation. High frequency ventilation led to lower PaCO2 levels. DISCUSSION: Determination of the lower inflection point of the pressure-volume curve is important for setting the minimum end expiratory pressure needed to keep the airways opened. This is useful when comparing different strategies to treat severe respiratory insufficiency, optimizing conventional ventilation, improving oxygenation and reducing lung injury. CONCLUSIONS: Utilization of the lower inflection point of the pressure-volume curve in the ventilation strategies considered in this study resulted in comparable efficacy with regards to oxygenation and hemodynamics, a high PaCO2 level and a lower pH. In addition, a greater number of normal alveoli were found after protective conventional ventilation in an animal model of acute respiratory distress syndrome.

The effect of positive end-expiratory pressure on pulse pressure ...

African Journals Online (AJOL)

The effect of positive end-expiratory pressure on pulse pressure variation. FJ Smith, M Geyser, I Schreuder, PJ Becker. Abstract. Objectives: To determine the effect of different levels of positive end-expiratory pressure (PEEP) on pulse pressure variation (PPV). Design: An observational study. Setting: Operating theatres of a ...

: ventilators for noninvasive ventilation

OpenAIRE

Fauroux , Brigitte; Leroux , Karl; Desmarais , Gilbert; Isabey , Daniel; Clément , Annick; Lofaso , Frédéric; Louis , Bruno

2008-01-01

International audience; The aim of the present study was to evaluate the performance characteristics of all the ventilators proposed for home noninvasive positive-pressure ventilation in children in France. The ventilators (one volume-targeted, 12 pressure-targeted and four dual) were evaluated on a bench which simulated six different paediatric ventilatory patterns. For each ventilator, the quality of the inspiratory and expiratory trigger and the ability to reach and maintain the preset pre...

A bench study of intensive-care-unit ventilators: new versus old and turbine-based versus compressed gas-based ventilators

Science.gov (United States)

Thille, Arnaud W.; Lyazidi, Aissam; Richard, Jean-Christophe M.; Galia, Fabrice; Brochard, Laurent

2009-01-01

Objective To compare 13 commercially available, new-generation, intensive-care-unit (ICU) ventilators regarding trigger function, pressurization capacity during pressure-support ventilation (PSV), accuracy of pressure measurements and expiratory resistance. Design and Setting Bench study at a research laboratory in a university hospital. Material Four turbine-based ventilators and nine conventional servo-valve compressed-gas ventilators were tested using a two-compartment lung model. Results Three levels of effort were simulated. Each ventilator was evaluated at four PSV levels (5, 10, 15, and 20 cm H2O), with and without positive end-expiratory pressure (5 cm H2O, Trigger function was assessed as the time from effort onset to detectable pressurization. Pressurization capacity was evaluated using the airway pressure-time product computed as the net area under the pressure-time curve over the first 0.3 s after inspiratory effort onset. Expiratory resistance was evaluated by measuring trapped volume in controlled ventilation. Significant differences were found across the ventilators, with a range of triggering-delay from 42 ms to 88 ms for all conditions averaged (Pventilators at PSV5 and three at PSV10, suggesting an inability to unload patient’s effort. On average, turbine-based ventilators performed better than conventional ventilators, which showed no improvement compared to a 2000 bench comparison. Conclusion Technical performances of trigger function, pressurization capacity and expiratory resistance vary considerably across new-generation ICU ventilators. ICU ventilators seem to have reached a technical ceiling in recent years, and some ventilators still perform inadequately. PMID:19352622

Mechanical breath profile of airway pressure release ventilation: the effect on alveolar recruitment and microstrain in acute lung injury.

Science.gov (United States)

Kollisch-Singule, Michaela; Emr, Bryanna; Smith, Bradford; Roy, Shreyas; Jain, Sumeet; Satalin, Joshua; Snyder, Kathy; Andrews, Penny; Habashi, Nader; Bates, Jason; Marx, William; Nieman, Gary; Gatto, Louis A

2014-11-01

Improper mechanical ventilation settings can exacerbate acute lung injury by causing a secondary ventilator-induced lung injury. It is therefore important to establish the mechanism by which the ventilator induces lung injury to develop protective ventilation strategies. It has been postulated that the mechanism of ventilator-induced lung injury is the result of heterogeneous, elevated strain on the pulmonary parenchyma. Acute lung injury has been associated with increases in whole-lung macrostrain, which is correlated with increased pathology. However, the effect of mechanical ventilation on alveolar microstrain remains unknown. To examine whether the mechanical breath profile of airway pressure release ventilation (APRV), consisting of a prolonged pressure-time profile and brief expiratory release phase, reduces microstrain. In a randomized, nonblinded laboratory animal study, rats were randomized into a controlled mandatory ventilation group (n = 3) and an APRV group (n = 3). Lung injury was induced by polysorbate lavage. A thoracotomy was performed and an in vivo microscope was placed on the lungs to measure alveolar mechanics. In the controlled mandatory ventilation group, multiple levels of positive end-expiratory pressure (PEEP; 5, 10, 16, 20, and 24 cm H2O) were tested. In the APRV group, decreasing durations of expiratory release (time at low pressure [T(low)]) were tested. The T(low) was set to achieve ratios of termination of peak expiratory flow rate (T-PEFR) to peak expiratory flow rate (PEFR) of 10%, 25%, 50%, and 75% (the smaller this ratio is [ie, 10%], the more time the lung is exposed to low pressure during the release phase, which decreases end-expiratory lung volume and potentiates derecruitment). Alveolar perimeters were measured at peak inspiration and end expiration using digital image analysis, and strain was calculated by normalizing the change in alveolar perimeter length to the original length. Macrostrain was measured by volume

Influence of Positive End-Expiratory Pressure on Myocardial Strain Assessed by Speckle Tracking Echocardiography in Mechanically Ventilated Patients

Directory of Open Access Journals (Sweden)

Federico Franchi

2013-01-01

Full Text Available Purpose. The effects of mechanical ventilation (MV on speckle tracking echocardiography- (STE-derived variables are not elucidated. The aim of the study was to evaluate the effects of positive end-expiratory pressure (PEEP ventilation on 4-chamber longitudinal strain (LS analysis by STE. Methods. We studied 20 patients admitted to a mixed intensive care unit who required intubation for MV and PEEP titration due to hypoxia. STE was performed at three times: (T1 PEEP = 5 cmH2O; (T2 PEEP = 10 cmH2O; and (T3 PEEP = 15 cmH2O. STE analysis was performed offline using a dedicated software (XStrain MyLab 70 Xvision, Esaote. Results. Left peak atrial-longitudinal strain (LS was significantly reduced from T1 to T2 and from T2 to T3 (. Right peak atrial-LS and right ventricular-LS showed a significant reduction only at T3 (. Left ventricular-LS did not change significantly during titration of PEEP. Cardiac chambers’ volumes showed a significant reduction at higher levels of PEEP (. Conclusions. We demonstrated for the first time that incremental PEEP affects myocardial strain values obtained with STE in intubated critically ill patients. Whenever performing STE in mechanically ventilated patients, care must be taken when PEEP is higher than 10 cmH2O to avoid misinterpreting data and making erroneous decisions.

A new design for high stability pressure-controlled ventilation for small animal lung imaging

International Nuclear Information System (INIS)

Kitchen, M J; Habib, A; Lewis, R A; Fouras, A; Dubsky, S; Wallace, M J; Hooper, S B

2010-01-01

We have developed a custom-designed ventilator to deliver a stable pressure to the lungs of small animals for use in imaging experiments. Our ventilator was designed with independent pressure vessels to separately control the Peak Inspiratory Pressure (PIP) and Positive End Expiratory Pressure (PEEP) to minimise pressure fluctuations during the ventilation process. The ventilator was computer controlled through a LabVIEW interface, enabling experimental manipulations to be performed remotely whilst simultaneously imaging the lungs in situ. Mechanical ventilation was successfully performed on newborn rabbit pups to assess the most effective ventilation strategies for aerating the lungs at birth. Highly stable pressures enabled reliable respiratory gated acquisition of projection radiographs and a stable prolonged (15 minute) breath-hold for high-resolution computed tomography of deceased rabbit pups at different lung volumes.

Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation

International Nuclear Information System (INIS)

Schranz, C; Möller, K; Becher, T; Schädler, D; Weiler, N

2014-01-01

Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (p I ), inspiration and expiration time (t I , t E ) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal p I and adequate t E can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's ‘optimized’ settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end-expiratory

Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation.

Science.gov (United States)

Schranz, C; Becher, T; Schädler, D; Weiler, N; Möller, K

2014-03-01

Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (pI), inspiration and expiration time (tI, tE) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal pI and adequate tE can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's 'optimized' settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end-expiratory pressure.

Partial liquid ventilation improves lung function in ventilation-induced lung injury

NARCIS (Netherlands)

G.F. Vazquez de Anda; R.A. Lachmann; S.J.C. Verbrugge (Serge); D.A.M.P.J. Gommers (Diederik); J.J. Haitsma (Jack); B.F. Lachmann (Burkhard)

2001-01-01

textabstractDisturbances in lung function and lung mechanics are present after ventilation with high peak inspiratory pressures (PIP) and low levels of positive end-expiratory pressure (PEEP). Therefore, the authors investigated whether partial liquid ventilation can re-establish

Positive end-expiratory pressure improves gas exchange and pulmonary mechanics during partial liquid ventilation.

Science.gov (United States)

Kirmse, M; Fujino, Y; Hess, D; Kacmarek, R M

1998-11-01

Partial liquid ventilation (PLV) with perflubron (PFB) has been proposed as an adjunct to the current therapies for the acute respiratory distress syndrome (ARDS). Because PFB has been also referred to as "liquid PEEP," distributing to the most gravity-dependent regions of the lung, less attention has been paid to the amount of applied positive end-expiratory pressure (PEEP). We hypothesized that higher PEEP levels than currently applied are needed to optimize gas exchange, and that the lower inflection point (LIP) of the pressure-volume curve could be used to estimate the amount of PEEP needed when the lung is filled with PFB. Lung injury was induced in 23 sheep by repeated lung lavage with warmed saline until the PaO2/FIO2 ratio fell below 150. Five sheep were used to investigate the change of the LIP when the lung was filled with PFB in increments of 5 ml/kg/body weight to a total of 30 ml/kg/body weight. To evaluate the impact of PEEP set at LIP +1 cm H2O we randomized an additional 15 sheep to three groups with different doses (7.5 ml, 15 ml, 30 ml/kg/body weight) of PFB. In random order a PEEP of 5 cm H2O or PEEP at LIP +1 cm H2O was applied. The LIP decreased with incremental filling of PFB to a minimum at 10 ml (p PFB shifts the LIP to the left, and that setting PEEP at LIP +1 cm H2O improves gas exchange at moderate to high doses of PFB.

Effects of positive end expiratory pressure administration during non-invasive ventilation in patients affected by amyotrophic lateral sclerosis: A randomized crossover study.

Science.gov (United States)

Crescimanno, Grazia; Greco, Francesca; Arrisicato, Salvo; Morana, Noemi; Marrone, Oreste

2016-10-01

No studies have evaluated the impact of different settings of non-invasive ventilation (NIV) in patients affected by amyotrophic lateral sclerosis (ALS). We explored consequences of positive end-expiratory pressure (PEEP) application on effectiveness of ventilation, sleep architecture and heart rate variability (HRV) in patients with ALS naïve to ventilatory treatment. In two consecutive nights, 25 patients received in random order 0 or 4 cm H2 0 of PEEP during nocturnal NIV administration (Idea Ultra ResMed) with the same level of total positive inspiratory pressure. Polysomnographies were performed to evaluate sleep and NIV quality, as well as HRV. HRV was analyzed on 4-h periods and on 5-min segments of stable NREM sleep. We did not observe differences in gas exchanges during NIV with and without PEEP. Conversely, during PEEP application increases in leaks (41.4 ± 29.3% vs 31.0 ± 25.7%, P = 0.0007) and in autotriggerings (4.2 (IQR 1.3-10.0) vs 0.9 (IQR 0.0-3.0) events/h, P NIV was associated with worse NIV and sleep quality and with higher sympathetic activity. © 2016 Asian Pacific Society of Respirology.

Effect of an automatic triggering and cycling system on comfort and patient-ventilator synchrony during pressure support ventilation.

Science.gov (United States)

Vasconcelos, Renata dos S; Melo, Luíz Henrique de P; Sales, Raquel P; Marinho, Liégina S; Deulefeu, Flávio C; Reis, Ricardo C; Alves-de-Almeida, Mirizana; Holanda, Marcelo A

2013-01-01

The digital Auto-Trak™ system is a technology capable of automatically adjusting the triggering and cycling mechanisms during pressure support ventilation (PSV). To compare Auto-Trak with conventional settings in terms of patient-ventilator synchrony and discomfort. Twelve healthy volunteers underwent PSV via the mouth by breathing through an endotracheal tube. In the conventional setting, a pressure support of 8 cm H2O with flow cycling (25% peak inspiratory flow) and a sensitivity of 1 cm H2O was adjusted. In Auto-Trak the triggering and cycling were automatically set. Discomfort, effort of breathing, and the asynchrony index (AI) were assessed. In a complementary bench study, the inspiratory and expiratory time delays were quantified for both settings in three mechanical models: 'normal', obstructive (COPD), and restrictive (ARDS), using the ASL 5000 simulator. In the volunteer study the AI and the discomfort scores did not differ statistically between the two settings. In the bench investigation the use of Auto-Trak was associated with a greater triggering delay in the COPD model and earlier expiratory cycling in the ARDS model but with no asynchronic events. Use of the Auto-Trak system during PSV showed similar results in comparison to the conventional adjustments with respect to patient-ventilator synchrony and discomfort in simulated conditions of invasive mechanical ventilation. Copyright © 2013 S. Karger AG, Basel.

Clinical assessment of auto-positive end-expiratory pressure by diaphragmatic electrical activity during pressure support and neurally adjusted ventilatory assist.

Science.gov (United States)

Bellani, Giacomo; Coppadoro, Andrea; Patroniti, Nicolò; Turella, Marta; Arrigoni Marocco, Stefano; Grasselli, Giacomo; Mauri, Tommaso; Pesenti, Antonio

2014-09-01

Auto-positive end-expiratory pressure (auto-PEEP) may substantially increase the inspiratory effort during assisted mechanical ventilation. Purpose of this study was to assess whether the electrical activity of the diaphragm (EAdi) signal can be reliably used to estimate auto-PEEP in patients undergoing pressure support ventilation and neurally adjusted ventilatory assist (NAVA) and whether NAVA was beneficial in comparison with pressure support ventilation in patients affected by auto-PEEP. In 10 patients with a clinical suspicion of auto-PEEP, the authors simultaneously recorded EAdi, airway, esophageal pressure, and flow during pressure support and NAVA, whereas external PEEP was increased from 2 to 14 cm H2O. Tracings were analyzed to measure apparent "dynamic" auto-PEEP (decrease in esophageal pressure to generate inspiratory flow), auto-EAdi (EAdi value at the onset of inspiratory flow), and IDEAdi (inspiratory delay between the onset of EAdi and the inspiratory flow). The pressure necessary to overcome auto-PEEP, auto-EAdi, and IDEAdi was significantly lower in NAVA as compared with pressure support ventilation, decreased with increase in external PEEP, although the effect of external PEEP was less pronounced in NAVA. Both auto-EAdi and IDEAdi were tightly correlated with auto-PEEP (r = 0.94 and r = 0.75, respectively). In the presence of auto-PEEP at lower external PEEP levels, NAVA was characterized by a characteristic shape of the airway pressure. In patients with auto-PEEP, NAVA, compared with pressure support ventilation, led to a decrease in the pressure necessary to overcome auto-PEEP, which could be reliably monitored by the electrical activity of the diaphragm before inspiratory flow onset (auto-EAdi).

Positive end-expiratory pressure improves survival in a rodent model of cardiopulmonary resuscitation using high-dose epinephrine.

LENUS (Irish Health Repository)

McCaul, Conán

2009-10-01

Multiple interventions have been tested in models of cardiopulmonary resuscitation (CPR) to optimize drug use, chest compressions, and ventilation. None has studied the effects of positive end-expiratory pressure (PEEP) on outcome. We hypothesized that because PEEP can reverse pulmonary atelectasis, lower pulmonary vascular resistance, and potentially improve cardiac output, its use during CPR would increase survival.

Intrinsic positive end-expiratory pressure during one-lung ventilation of patients with pulmonary hyperinflation. Influence of low respiratory rate with unchanged minute volume.

Science.gov (United States)

Szegedi, L L; Barvais, L; Sokolow, Y; Yernault, J C; d'Hollander, A A

2002-01-01

We measured lung mechanics and gas exchange during one-lung ventilation (OLV) of patients with chronic obstructive pulmonary disease, using three respiratory rates (RR) and unchanged minute volume. We studied 15 patients about to undergo lung surgery, during anaesthesia, and placed in the lateral position. Ventilation was with constant minute volume, inspiratory flow and FIO2. For periods of 15 min, RR of 5, 10, and 15 bpm were applied in a random sequence and recordings were made of lung mechanics and an arterial blood gas sample was taken. Data were analysed with the repeated measures ANOVA and paired t-test with Bonferroni correction. PaO2 changes were not significant. At the lowest RR, PaCO2 decreased (from 42 (SD 4) mm Hg at RR 15-41 (4) mm Hg at RR 10 and 39 (4) mm Hg at RR 5, P<0.01), and end-tidal carbon dioxide increased (from 33 (5) mm Hg at RR 15 to 35 (5) mm Hg at RR 10 and 36 (6) mm Hg at RR 5, P<0.01). Intrinsic positive end-expiratory pressure (PEEPi) was reduced even with larger tidal volumes (from 6 (4) cm H2O at RR 15-5 (4) cm H2O at RR 10, and 3 (3) cm H2O at RR 5, P<0.01), most probably caused by increased expiratory time at the lowest RR. A reduction in RR reduces PEEPi and hypercapnia during OLV in anaesthetized patients with chronic obstructive lung disease.

Ventilator-driven xenon ventilation studies

International Nuclear Information System (INIS)

Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

1984-01-01

A modification of a common commercial Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilatory rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration

Effects of recruitment maneuver and positive end-expiratory pressure on respiratory mechanics and transpulmonary pressure during laparoscopic surgery.

Science.gov (United States)

Cinnella, Gilda; Grasso, Salvatore; Spadaro, Savino; Rauseo, Michela; Mirabella, Lucia; Salatto, Potito; De Capraris, Antonella; Nappi, Luigi; Greco, Pantaleo; Dambrosio, Michele

2013-01-01

The authors tested the hypothesis that during laparoscopic surgery, Trendelenburg position and pneumoperitoneum may worsen chest wall elastance, concomitantly decreasing transpulmonary pressure, and that a protective ventilator strategy applied after pneumoperitoneum induction, by increasing transpulmonary pressure, would result in alveolar recruitment and improvement in respiratory mechanics and gas exchange. In 29 consecutive patients, a recruiting maneuver followed by positive end-expiratory pressure 5 cm H(2)O maintained until the end of surgery was applied after pneumoperitoneum induction. Respiratory mechanics, gas exchange, blood pressure, and cardiac index were measured before (T(BSL)) and after pneumoperitoneum with zero positive end-expiratory pressure (T(preOLS)), after recruitment with positive end-expiratory pressure (T(postOLS)), and after peritoneum desufflation with positive end-expiratory pressure (T(end)). Esophageal pressure was used for partitioning respiratory mechanics between lung and chest wall (data are mean ± SD): on T(preOLS), chest wall elastance (E(cw)) and elastance of the lung (E(L)) increased (8.2 ± 0.9 vs. 6.2 ± 1.2 cm H(2)O/L, respectively, on T(BSL); P = 0.00016; and 11.69 ± 1.68 vs. 9.61 ± 1.52 cm H(2)O/L on T(BSL); P = 0.0007). On T(postOLS), both chest wall elastance and E(L) decreased (5.2 ± 1.2 and 8.62 ± 1.03 cm H(2)O/L, respectively; P = 0.00015 vs. T(preOLS)), and Pao(2)/inspiratory oxygen fraction improved (491 ± 107 vs. 425 ± 97 on T(preOLS); P = 0.008) remaining stable thereafter. Recruited volume (the difference in lung volume for the same static airway pressure) was 194 ± 80 ml. Pplat(RS) remained stable while inspiratory transpulmonary pressure increased (11.65 + 1.37 cm H(2)O vs. 9.21 + 2.03 on T(preOLS); P = 0.007). All respiratory mechanics parameters remained stable after abdominal desufflation. Hemodynamic parameters remained stable throughout the study. In patients submitted to laparoscopic surgery in

Positive end expiratory pressure during one-lung ventilation: Selecting ideal patients and ventilator settings with the aim of improving arterial oxygenation

Directory of Open Access Journals (Sweden)

Hoftman Nir

2011-01-01

Full Text Available The efficacy of positive end-expiratory pressure (PEEP in treating intraoperative hypoxemia during one-lung ventilation (OLV remains in question given conflicting results of prior studies. This study aims to (1 evaluate the efficacy of PEEP during OLV, (2 assess the utility of preoperative predictors of response to PEEP, and (3 explore optimal intraoperative settings that would maximize the effects of PEEP on oxygenation. Forty-one thoracic surgery patients from a single tertiary care university center were prospectively enrolled in this observational study. After induction of general anesthesia, a double-lumen endotracheal tube was fiberoptically positioned and OLV initiated. Intraoperatively, PEEP = 5 and 10 cmH 2 O were sequentially applied to the ventilated lung during OLV. Arterial oxygenation, cardiovascular performance parameters, and proposed perioperative variables that could predict or enhance response to PEEP were analysed. T-test and c2 tests were utilized for continuous and categorical variables, respectively. Multivariate analyses were carried out using a classification tree model of binary recursive partitioning. PEEP improved arterial oxygenation by ≥20% in 29% of patients (n = 12 and failed to do so in 71% (n = 29; however, no cardiovascular impact was noted. Among the proposed clinical predictors, only intraoperative tidal volume per kilogram differed significantly between responders to PEEP and non-responders (mean 6.6 vs. 5.7 ml/kg, P = 0.013; no preoperative variable predicted response to PEEP. A multivariate analysis did not yield a clinically significant model for predicting PEEP responsiveness. PEEP improved oxygenation in a subset of patients; larger, although still protective tidal volumes favored a positive response to PEEP. No preoperative variables, however, could be identified as reliable predictors for PEEP responders.

Right ventricular function during one-lung ventilation: effects of pressure-controlled and volume-controlled ventilation.

Science.gov (United States)

Al Shehri, Abdullah M; El-Tahan, Mohamed R; Al Metwally, Roshdi; Qutub, Hatem; El Ghoneimy, Yasser F; Regal, Mohamed A; Zien, Haytham

2014-08-01

To test the effects of pressure-controlled (PCV) and volume-controlled (VCV) ventilation during one-lung ventilation (OLV) for thoracic surgery on right ventricular (RV) function. A prospective, randomized, double-blind, controlled, crossover study. A single university hospital. Fourteen pairs of consecutive patients scheduled for elective thoracotomy. Patients were assigned randomly to ventilate the dependent lung with PCV or VCV mode, each in a randomized crossover order using tidal volume of 6 mL/kg, I: E ratio 1: 2.5, positive end-expiratory pressure (PEEP) of 5 cm H2O and respiratory rate adjusted to maintain normocapnia. Intraoperative changes in RV function (systolic and early diastolic tricuspid annular velocity (TAV), end-systolic volume (ESV), end-diastolic volume (EDV) and fractional area changes (FAC)), airway pressures, compliance and oxygenation index were recorded. The use of PCV during OLV resulted in faster systolic (10.1±2.39 vs. 5.8±1.67 cm/s, respectively), diastolic TAV (9.2±1.99 vs. 4.6±1.42 cm/s, respectively) (prights reserved.

Effects of respiratory rate, plateau pressure, and positive end-expiratory pressure on PaO2 oscillations after saline lavage.

Science.gov (United States)

Baumgardner, James E; Markstaller, Klaus; Pfeiffer, Birgit; Doebrich, Marcus; Otto, Cynthia M

2002-12-15

One of the proposed mechanisms of ventilator-associated lung injury is cyclic recruitment of atelectasis. Collapse of dependent lung regions with every breath should lead to large oscillations in PaO2 as shunt varies throughout the respiratory cycle. We placed a fluorescence-quenching PO2 probe in the brachiocephalic artery of six anesthetized rabbits after saline lavage. Using pressure-controlled ventilation with oxygen, ventilator settings were varied in random order over three levels of positive end-expiratory pressure (PEEP), respiratory rate (RR), and plateau pressure minus PEEP (Delta). Dependence of the amplitude of PaO2 oscillations on PEEP, RR, and Delta was modeled by multiple linear regression. Before lavage, arterial PO2 oscillations varied from 3 to 22 mm Hg. After lavage, arterial PO2 oscillations varied from 5 to 439 mm Hg. Response surfaces showed markedly nonlinear dependence of amplitude on PEEP, RR, and Delta. The large PaO2 oscillations observed provide evidence for cyclic recruitment in this model of lung injury. The important effect of RR on the magnitude of PaO2 oscillations suggests that the static behavior of atelectasis cannot be accurately extrapolated to predict dynamic behavior at realistic breathing frequencies.

Some infant ventilators do not limit peak inspiratory pressure reliably during active expiration.

Science.gov (United States)

Kirpalani, H; Santos-Lyn, R; Roberts, R

1988-09-01

In order to minimize barotrauma in newborn infants with respiratory failure, peak inspiratory pressures should not exceed those required for adequate gas exchange. We examined whether four commonly used pressure-limited, constant flow ventilators limit pressure reliably during simulated active expiration against the inspiratory stroke of the ventilator. Three machines of each type were tested at 13 different expiratory flow rates (2 to 14 L/min). Flow-dependent pressure overshoot above a dialed pressure limit of 20 cm H2O was observed in all machines. However, the magnitude differed significantly between ventilators from different manufacturers (p = .0009). Pressure overshoot above 20 cm H2O was consistently lowest in the Healthdyne (0.8 cm H2O at 2 L/min, 3.6 cm H2O at 14 L/min) and highest in the Bourns BP200 (3.0 cm H2O at 2 L/min, 15.4 cm H2O at 14 L/min). We conclude that peak inspiratory pressure overshoots on pressure-limited ventilators occur during asynchronous expiration. This shortcoming may contribute to barotrauma in newborn infants who "fight" positive-pressure ventilation.

Intratidal recruitment/derecruitment persists at low and moderate positive end-expiratory pressure in paediatric patients.

Science.gov (United States)

Wirth, Steffen; Artner, Lisa; Broß, Tobias; Lozano-Zahonero, Sara; Spaeth, Johannes; Schumann, Stefan

2016-12-01

In paediatric patients positive end-expiratory pressure (PEEP) is traditionally set lower than in adults. We investigated whether moderately higher PEEP improves respiratory mechanics and regional ventilation. Therefore, 40 children were mechanically ventilated with PEEP 2 and 5cmH 2 O. Volume-dependent compliance profiles were analysed as a measure of intratidal recruitment/derecruitment. Regional ventilation was assessed using electrical impedance tomography. Mean compliance was 17.9±9.9mLcmH 2 O -1 (PEEP 2cmH 2 O), and 19.0±10.9mLcmH 2 O -1 (PEEP 5 cmH 2 O, pventilation. In conclusion, mechanically ventilated paediatric patients undergo intratidal recruitment/derecruitment which occurs more prominently in younger than in older children. A PEEP of 5cmH 2 O does not fully prevent intratidal recruitment/derecruitment but homogenizes regional ventilation in comparison to 2cmH 2 O. Copyright © 2016 Elsevier B.V. All rights reserved.

Relationship of end-expiratory pressure, lung volume, and /sup 99m/Tc-DTPA clearance

International Nuclear Information System (INIS)

Cooper, J.A.; van der Zee, H.; Line, B.R.; Malik, A.B.

1987-01-01

We investigated the dose-response effect of positive end-expiratory pressure (PEEP) and increased lung volume on the pulmonary clearance rate of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA). Clearance of lung radioactivity was expressed as percent decrease per minute. Base-line clearance was measured while anesthetized sheep (n = 20) were ventilated with 0 cmH 2 O end-expiratory pressure. Clearance was remeasured during ventilation at 2.5, 5, 10, 15, or 20 cmH 2 O PEEP. Further studies showed stepwise increases in functional residual capacity (FRC) (P less than 0.05) measured at 0, 2.5, 5, 10, 15, and 20 cmH 2 O PEEP. At 2.5 cmH 2 O PEEP, the clearance rate was not different from that at base line (P less than 0.05), although FRC was increased from base line. Clearance rate increased progressively with increasing PEEP at 5, 10, and 15 cmH 2 O (P less than 0.05). Between 15 and 20 cmH 2 O PEEP, clearance rate was again unchanged, despite an increase in FRC. The pulmonary clearance of aerosolized /sup 99m/Tc-DTPA shows a sigmoidal response to increasing FRC and PEEP, having both threshold and maximal effects. This relationship is most consistent with the hypothesis that alveolar epithelial permeability is increased by lung inflation

[Lung protective ventilation. Ventilatory modes and ventilator parameters].

Science.gov (United States)

Schädler, Dirk; Weiler, Norbert

2008-06-01

Mechanical ventilation has a considerable potential for injuring the lung tissue. Therefore, attention has to be paid to the proper choice of ventilatory mode and settings to secure lung-protective ventilation whenever possible. Such ventilator strategy should account for low tidal volume ventilation (6 ml/kg PBW), limited plateau pressure (30 to 35 cm H2O) and positive end-expiratory pressure (PEEP). It is unclear whether pressure controlled or volume controlled ventilation with square flow profile is beneficial. The adjustment of inspiration and expiration time should consider the actual breathing mechanics and anticipate the generation of intrinsic PEEP. Ventilatory modes with the possibility of supporting spontaneous breathing should be used as soon as possible.

Chest compression with a higher level of pressure support ventilation: effects on secretion removal, hemodynamics, and respiratory mechanics in patients on mechanical ventilation

Directory of Open Access Journals (Sweden)

Wagner da Silva Naue

2014-01-01

Full Text Available OBJECTIVE: To determine the efficacy of chest compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation, in comparison with that of aspiration alone, in removing secretions, normalizing hemodynamics, and improving respiratory mechanics in patients on mechanical ventilation. METHODS: This was a randomized crossover clinical trial involving patients on mechanical ventilation for more than 48 h in the ICU of the Porto Alegre Hospital de Clínicas, in the city of Porto Alegre, Brazil. Patients were randomized to receive aspiration alone (control group or compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation (intervention group. We measured hemodynamic parameters, respiratory mechanics parameters, and the amount of secretions collected. RESULTS: We included 34 patients. The mean age was 64.2 ± 14.6 years. In comparison with the control group, the intervention group showed a higher median amount of secretions collected (1.9 g vs. 2.3 g; p = 0.004, a greater increase in mean expiratory tidal volume (16 ± 69 mL vs. 56 ± 69 mL; p = 0.018, and a greater increase in mean dynamic compliance (0.1 ± 4.9 cmH2O vs. 2.8 ± 4.5 cmH2O; p = 0.005. CONCLUSIONS: In this sample, chest compression accompanied by an increase in pressure support significantly increased the amount of secretions removed, the expiratory tidal volume, and dynamic compliance. (ClinicalTrials.gov Identifier:NCT01155648 [http://www.clinicaltrials.gov/

Severe bronchopulmonary dysplasia improved by noninvasive positive pressure ventilation: a case report

Directory of Open Access Journals (Sweden)

Mann Christian

2011-09-01

Full Text Available Abstract Introduction This is the first report to describe the feasibility and effectiveness of noninvasive positive pressure ventilation in the secondary treatment of bronchopulmonary dysplasia. Case presentation A former male preterm of Caucasian ethnicity delivered at 29 weeks gestation developed severe bronchopulmonary dysplasia. At the age of six months he was in permanent tachypnea and dyspnea and in need of 100% oxygen with a flow of 2.0 L/minute via a nasal cannula. Intermittent nocturnal noninvasive positive pressure ventilation was then administered for seven hours daily. The ventilator was set at a positive end-expiratory pressure of 6 cmH2O, with pressure support of 4 cmH2O, trigger at 1.4 mL/second, and a maximum inspiratory time of 0.7 seconds. Over the course of seven weeks, the patient's maximum daytime fraction of inspired oxygen via nasal cannula decreased from 1.0 to 0.75, his respiratory rate from 64 breaths/minute to 50 breaths/minute and carbon dioxide from 58 mmHg to 44 mmHg. Conclusion Noninvasive positive pressure ventilation may be a novel therapeutic option for established severe bronchopulmonary dysplasia. In the case presented, noninvasive positive pressure ventilation achieved sustained improvement in ventilation and thus prepared our patient for safe home oxygen therapy.

Effect of Training Frequency on Maximum Expiratory Pressure

Science.gov (United States)

Anand, Supraja; El-Bashiti, Nour; Sapienza, Christine

2012-01-01

Purpose: To determine the effects of expiratory muscle strength training (EMST) frequency on maximum expiratory pressure (MEP). Method: We assigned 12 healthy participants to 2 groups of training frequency (3 days per week and 5 days per week). They completed a 4-week training program on an EMST trainer (Aspire Products, LLC). MEP was the primary…

Moderately high frequency ventilation with a conventional ventilator allows reduction of tidal volume without increasing mean airway pressure.

Science.gov (United States)

Cordioli, Ricardo Luiz; Park, Marcelo; Costa, Eduardo Leite Vieira; Gomes, Susimeire; Brochard, Laurent; Amato, Marcelo Britto Passos; Azevedo, Luciano Cesar Pontes

2014-12-01

The aim of this study was to explore if positive-pressure ventilation delivered by a conventional ICU ventilator at a moderately high frequency (HFPPV) allows a safe reduction of tidal volume (V T) below 6 mL/kg in a porcine model of severe acute respiratory distress syndrome (ARDS) and at a lower mean airway pressure than high-frequency oscillatory ventilation (HFOV). This is a prospective study. In eight pigs (median weight 34 [29,36] kg), ARDS was induced by pulmonary lavage and injurious ventilation. The animals were ventilated with a randomized sequence of respiratory rates: 30, 60, 90, 120, 150, followed by HFOV at 5 Hz. At each step, V T was adjusted to allow partial pressure of arterial carbon dioxide (PaCO2) to stabilize between 57 and 63 mmHg. Data are shown as median [P25th,P75th]. After lung injury, the PaO2/FiO2 (P/F) ratio was 92 [63,118] mmHg, pulmonary shunt 26 [17,31]%, and static compliance 11 [8,14] mL/cmH2O. Positive end-expiratory pressure (PEEP) was 14 [10,17] cmH2O. At 30 breaths/min, V T was higher than 6 (7.5 [6.8,10.2]) mL/kg, but at all higher frequencies, V T could be reduced and PaCO2 maintained, leading to reductions in plateau pressures and driving pressures. For frequencies of 60 to 150/min, V T progressively fell from 5.2 [5.1,5.9] to 3.8 [3.7,4.2] mL/kg (p mechanics, auto-PEEP generation, hemodynamics, or gas exchange. Mean airway pressure was maintained constant and was increased only during HFOV. During protective mechanical ventilation, HFPPV delivered by a conventional ventilator in a severe ARDS swine model safely allows further tidal volume reductions. This strategy also allowed decreasing airway pressures while maintaining stable PaCO2 levels.

Determination of respiratory system compliance during pressure support ventilation by small variations of pressure support.

Science.gov (United States)

Becher, Tobias; Schädler, Dirk; Rostalski, Philipp; Zick, Günther; Frerichs, Inéz; Weiler, Norbert

2017-09-22

In mechanically ventilated patients, measurement of respiratory system compliance (C rs ) is of high clinical interest. Spontaneous breathing activity during pressure support ventilation (PSV) can impede the correct assessment of C rs and also alter the true C rs by inducing lung recruitment. We describe a method for determination of C rs during PSV and assess its accuracy in a study on 20 mechanically ventilated patients. To assess C rs during pressure support ventilation (C rs,PSV ), we performed repeated changes in pressure support level by ± 2 cmH 2 O. C rs,PSV was calculated from the volume change induced by these changes in pressure support level, taking into account the inspiration time and the expiratory time constant. As reference methods, we used C rs , measured during volume controlled ventilation (C rs,VCV ). In a post-hoc analysis, we assessed C rs during the last 20% of the volume-controlled inflation (C rs,VCV20 ). Values were compared by linear regression and Bland-Altman methods comparison. Comparing C rs,PSV to the reference value C rs,VCV , we found a coefficient of determination (r 2 ) of 0.90, but a relatively high bias of - 7 ml/cm H 2 O (95% limits of agreement - 16.7 to + 2.7 ml/cmH 2 O). Comparison with C rs,VCV20 resulted in a negligible bias (- 1.3 ml/cmH 2 O, 95% limits of agreement - 13.9 to + 11.3) and r 2 of 0.81. We conclude that the novel method provides an estimate of end-inspiratory C rs during PSV. Despite its limited accuracy, it might be useful for non-invasive monitoring of C rs in patients undergoing pressure support ventilation.

Effects of short-term pressure-controlled ventilation on gas exchange, airway pressures, and gas distribution in patients with acute lung injury/ARDS: comparison with volume-controlled ventilation.

Science.gov (United States)

Prella, Maura; Feihl, François; Domenighetti, Guido

2002-10-01

The potential clinical benefits of pressure-controlled ventilation (PCV) over volume-controlled ventilation (VCV) in patients with acute lung injury (ALI) or ARDS still remain debated. We compared PCV with VCV in patients with ALI/ARDS with respect to the following physiologic end points: (1) gas exchange and airway pressures, and (2) CT scan intrapulmonary gas distribution at end-expiration. Prospective, observational study. A multidisciplinary ICU in a nonuniversity, acute-care hospital. Ten patients with ALI or ARDS (9 men and 1 woman; age range, 17 to 80 years). Sequential ventilation in PCV and VCV with a constant inspiratory/expiratory ratio, tidal volume, respiratory rate, and total positive end-expiratory pressure; measurement of gas exchange and airway pressures; and achievement of CT sections at lung base, hilum, and apex for the quantitative analysis of lung densities and of aerated vs nonaerated zones. PaO(2), PaCO(2), and PaO(2)/fraction of inspired oxygen ratio levels did not differ between PCV and VCV. Peak airway pressure (Ppeak) was significantly lower in PCV compared with VCV (26 +/- 2 cm H(2)O vs 31 +/- 2 cm H(2)O; p mean +/- SEM). The surface areas of the nonaerated zones as well as the total areas at each section level were unchanged in PCV compared with VCV, except at the apex level, where there was a significantly greater nonaerated area in VCV (11 +/- 2 cm(2) vs 9 +/- 2 cm(2); p mean CT number of each lung (20 lungs from 10 patients) was similar in the two modes, as were the density values at the basal and apical levels; the hilum mean CT number was - 442 +/- 28 Hounsfield units (HU) in VCV and - 430 +/- 26 HU in PCV (p lower Ppeaks through the precise titration of the lung distending pressure, and might be applied to avoid regional overdistension by means of a more homogeneous gas distribution.

Open-lung protective ventilation with pressure control ventilation, high-frequency oscillation, and intratracheal pulmonary ventilation results in similar gas exchange, hemodynamics, and lung mechanics.

Science.gov (United States)

Sedeek, Khaled A; Takeuchi, Muneyuki; Suchodolski, Klaudiusz; Vargas, Sara O; Shimaoka, Motomu; Schnitzer, Jay J; Kacmarek, Robert M

2003-11-01

Pressure control ventilation (PCV), high-frequency oscillation (HFO), and intratracheal pulmonary ventilation (ITPV) may all be used to provide lung protective ventilation in acute respiratory distress syndrome, but the specific approach that is optimal remains controversial. Saline lavage was used to produce acute respiratory distress syndrome in 21 sheep randomly assigned to receive PCV, HFO, or ITPV as follows: positive end-expiratory pressure (PCV and ITPV) and mean airway pressure (HFO) were set in a pressure-decreasing manner after lung recruitment that achieved a ratio of Pao2/Fio2 > 400 mmHg. Respiratory rates were 30 breaths/min, 120 breaths/min, and 8 Hz, respectively, for PCV, ITPV, and HFO. Eucapnia was targeted with peak carinal pressure of no more than 35 cm H2O. Animals were then ventilated for 4 h. There were no differences among groups in gas exchange, lung mechanics, or hemodynamics. Tidal volume (PCV, 8.9 +/- 2.1 ml/kg; ITPV, 2.7 +/- 0.8 ml/kg; HFO, approximately 2.0 ml/kg) and peak carinal pressure (PCV, 30.6 +/- 2.6 cm H2O; ITPV, 22.3 +/- 4.8 cm H2O; HFO, approximately 24.3 cm H2O) were higher in PCV. Pilot histologic data showed greater interstitial hemorrhage and alveolar septal expansion in PCV than in HFO or ITPV. These data indicate that HFO, ITPV, and PCV when applied with an open-lung protective ventilatory strategy results in the same gas exchange, lung mechanics, and hemodynamic response, but pilot data indicate that lung injury may be greater with PCV.

Bench performance of ventilators during simulated paediatric ventilation.

Science.gov (United States)

Park, M A J; Freebairn, R C; Gomersall, C D

2013-05-01

This study compares the accuracy and capabilities of various ventilators using a paediatric acute respiratory distress syndrome lung model. Various compliance settings and respiratory rate settings were used. The study was done in three parts: tidal volume and FiO2 accuracy; pressure control accuracy and positive end-expiratory pressure (PEEP) accuracy. The parameters set on the ventilator were compared with either or both of the measured parameters by the test lung and the ventilator. The results revealed that none of the ventilators could consistently deliver tidal volumes within 1 ml/kg of the set tidal volume, and the discrepancy between the delivered volume and the volume measured by the ventilator varied greatly. The target tidal volume was 8 ml/kg, but delivered tidal volumes ranged from 3.6-11.4 ml/kg and the volumes measured by the ventilator ranged from 4.1-20.6 ml/kg. All the ventilators maintained pressure within 20% of the set pressure, except one ventilator which delivered pressures of up to 27% higher than the set pressure. Two ventilators maintained PEEP within 10% of the prescribed PEEP. The majority of the readings were also within 10%. However, three ventilators delivered, at times, PEEPs over 20% higher. In conclusion, as lung compliance decreases, especially in paediatric patients, some ventilators perform better than others. This study highlights situations where ventilators may not be able to deliver, nor adequately measure, set tidal volumes, pressure, PEEP or FiO2.

Initial mechanical ventilator settings and lung protective ventilation in the ED.

Science.gov (United States)

Wilcox, Susan R; Richards, Jeremy B; Fisher, Daniel F; Sankoff, Jeffrey; Seigel, Todd A

2016-08-01

Mechanical ventilation with low tidal volumes has been shown to improve outcomes for patients both with and without acute respiratory distress syndrome. This study aims to characterize mechanically ventilated patients in the emergency department (ED), describe the initial ED ventilator settings, and assess for associations between lung protective ventilation strategies in the ED and outcomes. This was a multicenter, prospective, observational study of mechanical ventilation at 3 academic EDs. We defined lung protective ventilation as a tidal volume of less than or equal to 8 mL/kg of predicted body weight and compared outcomes for patients ventilated with lung protective vs non-lung protective ventilation, including inhospital mortality, ventilator days, intensive care unit length of stay, and hospital length of stay. Data from 433 patients were analyzed. Altered mental status without respiratory pathology was the most common reason for intubation, followed by trauma and respiratory failure. Two hundred sixty-one patients (60.3%) received lung protective ventilation, but most patients were ventilated with a low positive end-expiratory pressure, high fraction of inspired oxygen strategy. Patients were ventilated in the ED for a mean of 5 hours and 7 minutes but had few ventilator adjustments. Outcomes were not significantly different between patients receiving lung protective vs non-lung protective ventilation. Nearly 40% of ED patients were ventilated with non-lung protective ventilation as well as with low positive end-expiratory pressure and high fraction of inspired oxygen. Despite a mean ED ventilation time of more than 5 hours, few patients had adjustments made to their ventilators. Copyright © 2016 Elsevier Inc. All rights reserved.

Application of the Novel Ventilation Mode FLow-Controlled EXpiration (FLEX): A Crossover Proof-of-Principle Study in Lung-Healthy Patients.

Science.gov (United States)

Wirth, Steffen; Springer, Sebastian; Spaeth, Johannes; Borgmann, Silke; Goebel, Ulrich; Schumann, Stefan

2017-10-01

Traditionally, mechanical ventilation is achieved via active lung inflation during inspiration and passive lung emptying during expiration. By contrast, the novel FLEX (FLow-controlled EXpiration) ventilator mode actively decreases the rate of lung emptying. We investigated whether FLEX can be used during intraoperative mechanical ventilation of lung-healthy patients. In 30 adult patients scheduled for neurosurgical procedures, we studied respiratory system mechanics, regional ventilation, oxygenation, and hemodynamics during ventilation with and without FLEX at positive end-expiratory pressure (PEEP) of 5 and 7 cm H2O. The FLEX system was integrated into the expiratory limb and modified the expiratory flow profile by continuously changing expiratory resistance according to a computer-controlled algorithm. Mean airway pressure increased with PEEP by 1.9 cm H2O and with FLEX by 1 cm H2O (all P ventilated during general anesthesia. FLEX improves the homogeneous distribution of ventilation in the lungs.

Respiratory System Mechanics During Low Versus High Positive End-Expiratory Pressure in Open Abdominal Surgery: A Substudy of PROVHILO Randomized Controlled Trial.

Science.gov (United States)

D'Antini, Davide; Huhle, Robert; Herrmann, Jacob; Sulemanji, Demet S; Oto, Jun; Raimondo, Pasquale; Mirabella, Lucia; Hemmes, Sabrine N T; Schultz, Marcus J; Pelosi, Paolo; Kaczka, David W; Vidal Melo, Marcos Francisco; Gama de Abreu, Marcelo; Cinnella, Gilda

2018-01-01

In the 2014 PROtective Ventilation using HIgh versus LOw positive end-expiratory pressure (PROVHILO) trial, intraoperative low tidal volume ventilation with high positive end-expiratory pressure (PEEP = 12 cm H2O) and lung recruitment maneuvers did not decrease postoperative pulmonary complications when compared to low PEEP (0-2 cm H2O) approach without recruitment breaths. However, effects of intraoperative PEEP on lung compliance remain poorly understood. We hypothesized that higher PEEP leads to a dominance of intratidal overdistension, whereas lower PEEP results in intratidal recruitment/derecruitment (R/D). To test our hypothesis, we used the volume-dependent elastance index %E2, a respiratory parameter that allows for noninvasive and radiation-free assessment of dominant overdistension and intratidal R/D. We compared the incidence of intratidal R/D, linear expansion, and overdistension by means of %E2 in a subset of the PROVHILO cohort. In 36 patients from 2 participating centers of the PROVHILO trial, we calculated respiratory system elastance (E), resistance (R), and %E2, a surrogate parameter for intratidal overdistension (%E2 > 30%) and R/D (%E2 mechanical ventilation with protective tidal volumes in patients undergoing open abdominal surgery, lung recruitment followed by PEEP of 12 cm H2O decreased the incidence of intratidal R/D and did not worsen overdistension, when compared to PEEP ≤2 cm H2O.

Prospective randomized crossover study of a new closed-loop control system versus pressure support during weaning from mechanical ventilation.

Science.gov (United States)

Clavieras, Noémie; Wysocki, Marc; Coisel, Yannael; Galia, Fabrice; Conseil, Matthieu; Chanques, Gerald; Jung, Boris; Arnal, Jean-Michel; Matecki, Stefan; Molinari, Nicolas; Jaber, Samir

2013-09-01

Intellivent is a new full closed-loop controlled ventilation that automatically adjusts both ventilation and oxygenation parameters. The authors compared gas exchange and breathing pattern variability of Intellivent and pressure support ventilation (PSV). In a prospective, randomized, single-blind design crossover study, 14 patients were ventilated during the weaning phase, with Intellivent or PSV, for two periods of 24 h in a randomized order. Arterial blood gases were obtained after 1, 8, 16, and 24 h with each mode. Ventilatory parameters were recorded continuously in a breath-by-breath basis during the two study periods. The primary endpoint was oxygenation, estimated by the calculation of the difference between the PaO2/FIO2 ratio obtained after 24 h of ventilation and the PaO2/FIO2 ratio obtained at baseline in each mode. The variability in the ventilatory parameters was also evaluated by the coefficient of variation (SD to mean ratio). There were no adverse events or safety issues requiring premature interruption of both modes. The PaO2/FIO2 (mean ± SD) ratio improved significantly from 245 ± 75 at baseline to 294 ± 123 (P = 0.03) after 24 h of Intellivent. The coefficient of variation of inspiratory pressure and positive end-expiratory pressure (median [interquartile range]) were significantly higher with Intellivent, 16 [11-21] and 15 [7-23]%, compared with 6 [5-7] and 7 [5-10]% in PSV. Inspiratory pressure, positive end-expiratory pressure, and FIO2 changes were adjusted significantly more often with Intellivent compared with PSV. Compared with PSV, Intellivent during a 24-h period improved the PaO2/FIO2 ratio in parallel with more variability in the ventilatory support and more changes in ventilation settings.

Protective intraoperative ventilation with higher versus lower levels of positive end-expiratory pressure in obese patients (PROBESE): study protocol for a randomized controlled trial.

Science.gov (United States)

Bluth, T; Teichmann, R; Kiss, T; Bobek, I; Canet, J; Cinnella, G; De Baerdemaeker, L; Gregoretti, C; Hedenstierna, G; Hemmes, S N; Hiesmayr, M; Hollmann, M W; Jaber, S; Laffey, J G; Licker, M J; Markstaller, K; Matot, I; Müller, G; Mills, G H; Mulier, J P; Putensen, C; Rossaint, R; Schmitt, J; Senturk, M; Serpa Neto, A; Severgnini, P; Sprung, J; Vidal Melo, M F; Wrigge, H; Schultz, M J; Pelosi, P; Gama de Abreu, M

2017-04-28

Postoperative pulmonary complications (PPCs) increase the morbidity and mortality of surgery in obese patients. High levels of positive end-expiratory pressure (PEEP) with lung recruitment maneuvers may improve intraoperative respiratory function, but they can also compromise hemodynamics, and the effects on PPCs are uncertain. We hypothesized that intraoperative mechanical ventilation using high PEEP with periodic recruitment maneuvers, as compared with low PEEP without recruitment maneuvers, prevents PPCs in obese patients. The PRotective Ventilation with Higher versus Lower PEEP during General Anesthesia for Surgery in OBESE Patients (PROBESE) study is a multicenter, two-arm, international randomized controlled trial. In total, 2013 obese patients with body mass index ≥35 kg/m 2 scheduled for at least 2 h of surgery under general anesthesia and at intermediate to high risk for PPCs will be included. Patients are ventilated intraoperatively with a low tidal volume of 7 ml/kg (predicted body weight) and randomly assigned to PEEP of 12 cmH 2 O with lung recruitment maneuvers (high PEEP) or PEEP of 4 cmH 2 O without recruitment maneuvers (low PEEP). The occurrence of PPCs will be recorded as collapsed composite of single adverse pulmonary events and represents the primary endpoint. To our knowledge, the PROBESE trial is the first multicenter, international randomized controlled trial to compare the effects of two different levels of intraoperative PEEP during protective low tidal volume ventilation on PPCs in obese patients. The results of the PROBESE trial will support anesthesiologists in their decision to choose a certain PEEP level during general anesthesia for surgery in obese patients in an attempt to prevent PPCs. ClinicalTrials.gov identifier: NCT02148692. Registered on 23 May 2014; last updated 7 June 2016.

Tidal ventilation distribution during pressure-controlled ventilation and pressure support ventilation in post-cardiac surgery patients.

Science.gov (United States)

Blankman, P; VAN DER Kreeft, S M; Gommers, D

2014-09-01

Inhomogeneous ventilation is an important contributor to ventilator-induced lung injury. Therefore, this study examines homogeneity of lung ventilation by means of electrical impedance tomography (EIT) measurements during pressure-controlled ventilation (PCV) and pressure support ventilation (PSV) using the same ventilation pressures. Twenty mechanically ventilated patients were studied after cardiac surgery. On arrival at the intensive care unit, ventilation distribution was measured with EIT just above the diaphragm for 15 min. After awakening, PCV was switched to PSV and EIT measurements were again recorded. Tidal impedance variation, a measure of tidal volume, increased during PSV compared with PCV, despite using the same ventilation pressures (P = 0.045). The distribution of tidal ventilation to the dependent lung region was more pronounced during PSV compared with PCV, especially during the first half of the inspiration. An even distribution of tidal ventilation between the dependent and non-dependent lung regions was seen during PCV at lower tidal volumes (tidal volumes (≥ 8 ml/kg). In addition, the distribution of tidal ventilation was predominantly distributed to the dependent lung during PSV at low tidal volumes. In post-cardiac surgery patients, PSV showed improved ventilation of the dependent lung region due to the contribution of the diaphragm activity, which is even more pronounced during lower assist levels. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Bilevel vs ICU ventilators providing noninvasive ventilation: effect of system leaks: a COPD lung model comparison.

Science.gov (United States)

Ferreira, Juliana C; Chipman, Daniel W; Hill, Nicholas S; Kacmarek, Robert M

2009-08-01

Noninvasive positive-pressure ventilation (NPPV) modes are currently available on bilevel and ICU ventilators. However, little data comparing the performance of the NPPV modes on these ventilators are available. In an experimental bench study, the ability of nine ICU ventilators to function in the presence of leaks was compared with a bilevel ventilator using the IngMar ASL5000 lung simulator (IngMar Medical; Pittsburgh, PA) set at a compliance of 60 mL/cm H(2)O, an inspiratory resistance of 10 cm H(2)O/L/s, an expiratory resistance of 20 cm H(2)O/ L/s, and a respiratory rate of 15 breaths/min. All of the ventilators were set at 12 cm H(2)O pressure support and 5 cm H(2)O positive end-expiratory pressure. The data were collected at baseline and at three customized leaks. At baseline, all of the ventilators were able to deliver adequate tidal volumes, to maintain airway pressure, and to synchronize with the simulator, without missed efforts or auto-triggering. As the leak was increased, all of the ventilators (except the Vision [Respironics; Murrysville, PA] and Servo I [Maquet; Solna, Sweden]) needed adjustment of sensitivity or cycling criteria to maintain adequate ventilation, and some transitioned to backup ventilation. Significant differences in triggering and cycling were observed between the Servo I and the Vision ventilators. The Vision and Servo I were the only ventilators that required no adjustments as they adapted to increasing leaks. There were differences in performance between these two ventilators, although the clinical significance of these differences is unclear. Clinicians should be aware that in the presence of leaks, most ICU ventilators require adjustments to maintain an adequate tidal volume.

Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway.

Directory of Open Access Journals (Sweden)

Samantha Torres Grams

Full Text Available Maximal Inspiratory Pressure (MIP is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway.This study aimed to compare the MIP values assessed by standard method (MIPsta and by unidirectional expiratory valve method (MIPuni in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated.This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B at two moments (Tests 1 and 2 to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1] was used to determine intraobserver and interobserver reproducibility.The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O than the mean values for MIPsta (-102.5 ± 23.9 cmH2O (p<0.001. Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91, and high correlation for Test 2 (ICC[2,1] = 0.88. The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86 and evaluator B (ICC[2,1] = 0.77.MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway.

Current concepts of protective ventilation during general anaesthesia

NARCIS (Netherlands)

Serpa Neto, Ary; Schultz, Marcus J.; Slutsky, Arthur S.

2015-01-01

Mechanical ventilation with high tidal volumes (VT) has been common practice in operating theatres because this strategy recruits collapsed lung tissue and improves ventilation-perfusion mismatch, thus decreasing the need for high inspired oxygen concentrations. Positive end-expiratory pressure

Association between driving pressure and development of postoperative pulmonary complications in patients undergoing mechanical ventilation for general anaesthesia: a meta-analysis of individual patient data.

Science.gov (United States)

Neto, Ary Serpa; Hemmes, Sabrine N T; Barbas, Carmen S V; Beiderlinden, Martin; Fernandez-Bustamante, Ana; Futier, Emmanuel; Gajic, Ognjen; El-Tahan, Mohamed R; Ghamdi, Abdulmohsin A Al; Günay, Ersin; Jaber, Samir; Kokulu, Serdar; Kozian, Alf; Licker, Marc; Lin, Wen-Qian; Maslow, Andrew D; Memtsoudis, Stavros G; Reis Miranda, Dinis; Moine, Pierre; Ng, Thomas; Paparella, Domenico; Ranieri, V Marco; Scavonetto, Federica; Schilling, Thomas; Selmo, Gabriele; Severgnini, Paolo; Sprung, Juraj; Sundar, Sugantha; Talmor, Daniel; Treschan, Tanja; Unzueta, Carmen; Weingarten, Toby N; Wolthuis, Esther K; Wrigge, Hermann; Amato, Marcelo B P; Costa, Eduardo L V; de Abreu, Marcelo Gama; Pelosi, Paolo; Schultz, Marcus J

2016-04-01

Protective mechanical ventilation strategies using low tidal volume or high levels of positive end-expiratory pressure (PEEP) improve outcomes for patients who have had surgery. The role of the driving pressure, which is the difference between the plateau pressure and the level of positive end-expiratory pressure is not known. We investigated the association of tidal volume, the level of PEEP, and driving pressure during intraoperative ventilation with the development of postoperative pulmonary complications. We did a meta-analysis of individual patient data from randomised controlled trials of protective ventilation during general anesthaesia for surgery published up to July 30, 2015. The main outcome was development of postoperative pulmonary complications (postoperative lung injury, pulmonary infection, or barotrauma). We included data from 17 randomised controlled trials, including 2250 patients. Multivariate analysis suggested that driving pressure was associated with the development of postoperative pulmonary complications (odds ratio [OR] for one unit increase of driving pressure 1·16, 95% CI 1·13-1·19; pprotective ventilation on development of pulmonary complications (p=0·027). In two studies that compared low with high PEEP during low tidal volume ventilation, an increase in the level of PEEP that resulted in an increase in driving pressure was associated with more postoperative pulmonary complications (OR 3·11, 95% CI 1·39-6·96; p=0·006). In patients having surgery, intraoperative high driving pressure and changes in the level of PEEP that result in an increase of driving pressure are associated with more postoperative pulmonary complications. However, a randomised controlled trial comparing ventilation based on driving pressure with usual care is needed to confirm these findings. None. Copyright © 2016 Elsevier Ltd. All rights reserved.

The unique contribution of manual chest compression-vibrations to airflow during physiotherapy in sedated, fully ventilated children.

Science.gov (United States)

Gregson, Rachael K; Shannon, Harriet; Stocks, Janet; Cole, Tim J; Peters, Mark J; Main, Eleanor

2012-03-01

This study aimed to quantify the specific effects of manual lung inflations with chest compression-vibrations, commonly used to assist airway clearance in ventilated patients. The hypothesis was that force applied during the compressions made a significant additional contribution to increases in peak expiratory flow and expiratory to inspiratory flow ratio over and above that resulting from accompanying increases in inflation volume. Prospective observational study. Cardiac and general pediatric intensive care. Sedated, fully ventilated children. Customized force-sensing mats and a commercial respiratory monitor recorded force and respiration during physiotherapy. Percentage changes in peak expiratory flow, peak expiratory to inspiratory flow ratios, inflation volume, and peak inflation pressure between baseline and manual inflations with and without compression-vibrations were calculated. Analysis of covariance determined the relative contribution of changes in pressure, volume, and force to influence changes in peak expiratory flow and peak expiratory to inspiratory flow ratio. Data from 105 children were analyzed (median age, 1.3 yrs; range, 1 wk to 15.9 yrs). Force during compressions ranged from 15 to 179 N (median, 46 N). Peak expiratory flow increased on average by 76% during compressions compared with baseline ventilation. Increases in peak expiratory flow were significantly related to increases in inflation volume, peak inflation pressure, and force with peak expiratory flow increasing by, on average, 4% for every 10% increase in inflation volume (p children.

Successful use of non-invasive positive pressure ventilation in a complicated flail chest

International Nuclear Information System (INIS)

Al-Ansari, Mariam A.

2006-01-01

The current advanced trauma life support manual states that patients with significant hypoxia (namely, SaO2<90% on room air) as a result of pulmonary contusion should be intubated and ventilated within the first hour of injury. Recently, several researchers have shown improved outcomes when patients with acute respiratory failure are managed with noninvasive positive pressure ventilation (NIPPV). Trauma patients may also benefit from this therapy. We report a case of 15-year-old boy who isolated flail chest and pulmonary contusion, who was intubated in the emergency room, and was managed successfully with the NIPPV in the intensive care unit (ICU) despite, having had aspiration pneumonia early in the course of her stay. After initial stabilization, he failed a spontaneous breathing trial. Due to absence of contraindications to the use of NIPPV, the patient was extubated on day 7 (from pressure ventilation of 15 cmH2O and positive end expiratory pressure of 8 cm H2O) to immediate NIPPV use. Three days later (after a total of 50 hours of NIPPV use in the ICU) the patient was successfully discharged home. (author)

Protective ventilation reduces Pseudomonas aeruginosa growth in lung tissue in a porcine pneumonia model.

Science.gov (United States)

Sperber, Jesper; Nyberg, Axel; Lipcsey, Miklos; Melhus, Åsa; Larsson, Anders; Sjölin, Jan; Castegren, Markus

2017-08-31

Mechanical ventilation with positive end expiratory pressure and low tidal volume, i.e. protective ventilation, is recommended in patients with acute respiratory distress syndrome. However, the effect of protective ventilation on bacterial growth during early pneumonia in non-injured lungs is not extensively studied. The main objectives were to compare two different ventilator settings on Pseudomonas aeruginosa growth in lung tissue and the development of lung injury. A porcine model of severe pneumonia was used. The protective group (n = 10) had an end expiratory pressure of 10 cm H 2 O and a tidal volume of 6 ml x kg -1 . The control group (n = 10) had an end expiratory pressure of 5 cm H 2 O and a tidal volume of 10 ml x kg -1 . 10 11 colony forming units of Pseudomonas aeruginosa were inoculated intra-tracheally at baseline, after which the experiment continued for 6 h. Two animals from each group received only saline, and served as sham animals. Lung tissue samples from each animal were used for bacterial cultures and wet-to-dry weight ratio measurements. The protective group displayed lower numbers of Pseudomonas aeruginosa (p protective group was unchanged (p protective ventilation with lower tidal volume and higher end expiratory pressure has the potential to reduce the pulmonary bacterial burden and the development of lung injury.

Trigger performance of mid-level ICU mechanical ventilators during assisted ventilation: a bench study.

Science.gov (United States)

Ferreira, Juliana C; Chipman, Daniel W; Kacmarek, Robert M

2008-09-01

To compare the triggering performance of mid-level ICU mechanical ventilators with a standard ICU mechanical ventilator. Experimental bench study. The respiratory care laboratory of a university-affiliated teaching hospital. A computerized mechanical lung model, the IngMar ASL5000. Ten mid-level ICU ventilators were compared to an ICU ventilator at two levels of lung model effort, three combinations of respiratory mechanics (normal, COPD and ARDS) and two modes of ventilation, volume and pressure assist/control. A total of 12 conditions were compared. Performance varied widely among ventilators. Mean inspiratory trigger time was ventilators. The mean inspiratory delay time (time from initiation of the breath to return of airway pressure to baseline) was longer than that for the ICU ventilator for all tested ventilators except one. The pressure drop during triggering (Ptrig) was comparable with that of the ICU ventilator for only two ventilators. Expiratory Settling Time (time for pressure to return to baseline) had the greatest variability among ventilators. Triggering differences among these mid-level ICU ventilators and with the ICU ventilator were identified. Some of these ventilators had a much poorer triggering response with high inspiratory effort than the ICU ventilator. These ventilators do not perform as well as ICU ventilators in patients with high ventilatory demand.

The effects of intraoperative lung protective ventilation with positive end-expiratory pressure on blood loss during hepatic resection surgery: A secondary analysis of data from a published randomised control trial (IMPROVE).

Science.gov (United States)

Neuschwander, Arthur; Futier, Emmanuel; Jaber, Samir; Pereira, Bruno; Eurin, Mathilde; Marret, Emmanuel; Szymkewicz, Olga; Beaussier, Marc; Paugam-Burtz, Catherine

2016-04-01

During high-risk abdominal surgery the use of a multi-faceted lung protective ventilation strategy composed of low tidal volumes, positive end-expiratory pressure (PEEP) and recruitment manoeuvres, has been shown to improve clinical outcomes. It has been speculated, however, that mechanical ventilation using PEEP might increase intraoperative bleeding during liver resection. To study the impact of mechanical ventilation with PEEP on bleeding during hepatectomy. Post-hoc analysis of a randomised controlled trial. Seven French university teaching hospitals from January 2011 to August 2012. Patients scheduled for liver resection surgery. In the Intraoperative Protective Ventilation trial, patients scheduled for major abdominal surgery were randomly assigned to mechanical ventilation using low tidal volume, PEEP between 6 and 8  cmH2O and recruitment manoeuvres (lung protective ventilation strategy) or higher tidal volume, zero PEEP and no recruitment manoeuvres (non-protective ventilation strategy). The primary endpoint was intraoperative blood loss volume. A total of 79 (19.8%) patients underwent liver resections (41 in the lung protective and 38 in the non-protective group). The median (interquartile range) amount of intraoperative blood loss was 500 (200 to 800)  ml and 275 (125 to 800)  ml in the non-protective and lung protective ventilation groups, respectively (P = 0.47). Fourteen (35.0%) and eight (21.5%) patients were transfused in the non-protective and lung protective groups, respectively (P = 0.17), without a statistically significant difference in the median (interquartile range) number of red blood cells units transfused [2.5 (2 to 4) units and 3 (2 to 6) units in the two groups, respectively; P = 0.54]. During hepatic surgery, mechanical ventilation using PEEP within a multi-faceted lung protective strategy was not associated with increased bleeding compared with non-protective ventilation using zero PEEP. The current study was not

Hemodynamic responses to external counterbalancing of auto-positive end-expiratory pressure in mechanically ventilated patients with chronic obstructive pulmonary disease.

Science.gov (United States)

Baigorri, F; de Monte, A; Blanch, L; Fernández, R; Vallés, J; Mestre, J; Saura, P; Artigas, A

1994-11-01

To study the effect of positive end-expiratory pressure (PEEP) on right ventricular hemodynamics and ejection fraction in patients with chronic obstructive pulmonary disease and positive alveolar pressure throughout expiration by dynamic hyperinflation (auto-PEEP). Open, prospective, controlled trial. General intensive care unit of a community hospital. Ten patients sedated and paralyzed with an acute exacerbation of chronic obstructive pulmonary disease undergoing mechanical ventilation. Insertion of a pulmonary artery catheter modified with a rapid response thermistor and a radial arterial catheter. PEEP was then increased from 0 (PEEP 0) to auto-PEEP level (PEEP = auto-PEEP) and 5 cm H2O above that (PEEP = auto-PEEP +5). At each level of PEEP, airway pressures, flow and volume, hemodynamic variables (including right ventricular ejection fraction by thermodilution technique), and blood gas analyses were recorded. The mean auto-PEEP was 6.6 +/- 2.8 cm H2O and the total PEEP reached was 12.2 +/- 2.4 cm H2O. The degree of lung inflation induced by PEEP averaged 145 +/- 87 mL with PEEP = auto-PEEP and 495 +/- 133 mL with PEEP = auto-PEEP + 5. The PEEP = auto-PEEP caused a right ventricular end-diastolic pressure increase, but there was no other significant hemodynamic change. With PEEP = auto-PEEP + 5, there was a significant increase in intravascular pressures; this amount of PEEP reduced cardiac output (from 4.40 +/- 1.38 L/min at PEEP 0 to 4.13 +/- 1.48 L/min; p 10% in only five cases and this group of patients had significantly lower right ventricular volumes than the group with less cardiac output variation (right ventricular end-diastolic volume: 64 +/- 9 vs. 96 +/- 26 mL/m2; right ventricular end-systolic volume: 38 +/- 6 vs. 65 +/- 21 mL/m2; p < .05) without significant difference in the other variables that were measured. Neither right ventricular ejection fraction nor right ventricle volumes changed as PEEP increased, but there were marked interpatient

Gravity predominates over ventilatory pattern in the prevention of ventilator-associated pneumonia.

Science.gov (United States)

Li Bassi, Gianluigi; Marti, Joan Daniel; Saucedo, Lina; Rigol, Montserrat; Roca, Ignasi; Cabanas, Maria; Muñoz, Laura; Ranzani, Otavio Tavares; Giunta, Valeria; Luque, Nestor; Esperatti, Mariano; Gabarrus, Albert; Fernandez, Laia; Rinaudo, Mariano; Ferrer, Miguel; Ramirez, Jose; Vila, Jordi; Torres, Antoni

2014-09-01

In the semirecumbent position, gravity-dependent dissemination of pathogens has been implicated in the pathogenesis of ventilator-associated pneumonia. We compared the preventive effects of a ventilatory strategy, aimed at decreasing pulmonary aspiration and enhancing mucus clearance versus the Trendelenburg position. Prospective randomized animal study. Animal research facility, University of Barcelona, Spain. Twenty-four Large White-Landrace pigs. Pigs were intubated and on mechanical ventilation for 72 hours. Following surgical preparation, pigs were randomized to be positioned: 1) in semirecumbent/prone position, ventilated with a duty cycle (TITTOT) of 0.33 and without positive end-expiratory pressure (control); 2) as in the control group, positive end-expiratory pressure of 5 cm H2O and TITTOT to achieve a mean expiratory-inspiratory flow bias of 10 L/min (treatment); 3) in Trendelenburg/prone position and ventilated as in the control group (Trendelenburg). Following randomization, Pseudomonas aeruginosa was instilled into the oropharynx. Mucus clearance rate was measured through fluoroscopic tracking of tracheal markers. Microspheres were instilled into the subglottic trachea to assess pulmonary aspiration. Ventilator-associated pneumonia was confirmed by histological/microbiological studies. The mean expiratory-inspiratory flow in the treatment, control, and Trendelenburg groups were 10.7 ± 1.7, 1.8 ± 3.7 and 4.3 ± 2.8 L/min, respectively (p gravity-dependent translocation of oropharyngeal pathogens and development of ventilator-associated pneumonia. These findings further substantiate the primary role of gravity in the pathogenesis of ventilator-associated pneumonia.

A historical perspective on ventilator management.

Science.gov (United States)

Shapiro, B A

1994-02-01

Paralysis via neuromuscular blockade in ICU patients requires mechanical ventilation. This review historically addresses the technological advances and scientific information upon which ventilatory management concepts are based, with special emphasis on the influence such concepts have had on the use of neuromuscular blocking agents. Specific reference is made to the scientific information and technological advances leading to the newer concepts of ventilatory management. Information from > 100 major studies in the peer-reviewed medical literature, along with the author's 25 yrs of clinical experience and academic involvement in acute respiratory care is presented. Nomenclature related to ventilatory management is specifically defined and consistently utilized to present and interpret the data. Pre-1970 ventilatory management is traced from the clinically unacceptable pressure-limited devices to the reliable performance of volume-limited ventilators. The scientific data and rationale that led to the concept of relatively large tidal volume delivery are reviewed in the light of today's concerns regarding alveolar overdistention, control-mode dyssynchrony, and auto-positive end-expiratory pressure. Also presented are the post-1970 scientific rationales for continuous positive airway pressure/positive end-expiratory pressure therapy, avoidance of alveolar hyperxia, and partial ventilatory support techniques (intermittent mandatory ventilation/synchronized intermittent mandatory ventilation). The development of pressure-support devices is discussed and the capability of pressure-control techniques is presented. The rationale for more recent concepts of total ventilatory support to avoid ventilator-induced lung injury is presented. The traditional techniques utilizing volume-preset ventilators with relatively large tidal volumes remain valid and desirable for the vast majority of patients requiring mechanical ventilation. Neuromuscular blockade is best avoided in these

Endotracheal tube resistance and inertance in a model of mechanical ventilation of newborns and small infants—the impact of ventilator settings on tracheal pressure swings

International Nuclear Information System (INIS)

Hentschel, Roland; Buntzel, Julia; Guttmann, Josef; Schumann, Stefan

2011-01-01

Resistive properties of endotracheal tubes (ETTs) are particularly relevant in newborns and small infants who are generally ventilated through ETTs with a small inner diameter. The ventilation rate is also high and the inspiratory time (ti) is short. These conditions effectuate high airway flows with excessive flow acceleration, so airway resistance and inertance play an important role. We carried out a model study to investigate the impact of varying ETT size, lung compliance and ventilator settings, such as peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP) and inspiratory time (ti) on the pressure–flow characteristics with respect to the resistive and inertive properties of the ETT. Pressure at the Y piece was compared to direct measurement of intratracheal pressure (P trach ) at the tip of the ETT, and pressure drop (ΔP ETT ) was calculated. Applying published tube coefficients (Rohrer's constants and inertance), P trach was calculated from ventilator readings and compared to measured P trach using the root-mean-square error. The most relevant for ΔP ETT was the ETT size, followed by (in descending order) PIP, compliance, ti and PEEP, with gas flow velocity being the principle in common for all these parameters. Depending on the ventilator settings ΔP ETT exceeded 8 mbar in the smallest 2.0 mm ETT. Consideration of inertance as an additional effect in this setting yielded a better agreement of calculated versus measured P trach than Rohrer's constants alone. We speculate that exact tracheal pressure tracings calculated from ventilator readings by applying Rohrer's equation and the inertance determination to small size ETTs would be helpful. As an integral part of ventilator software this would (1) allow an estimate of work of breathing and implementation of an automatic tube compensation, and (2) be important for gentle ventilation in respiratory care, especially of small infants, since it enables the physician to

Positive expiratory pressure - Common clinical applications and physiological effects.

Science.gov (United States)

Fagevik Olsén, Monika; Lannefors, Louise; Westerdahl, Elisabeth

2015-03-01

Breathing out against resistance, in order to achieve positive expiratory pressure (PEP), is applied by many patient groups. Pursed lips breathing and a variety of devices can be used to create the resistance giving the increased expiratory pressure. Effects on pulmonary outcomes have been discussed in several publications, but the expected underlying physiology of the effect is seldom discussed. The aim of this article is to describe the purpose, performance, clinical application and underlying physiology of PEP when it is used to increase lung volumes, decrease hyperinflation or improve airway clearance. In clinical practice, the instruction how to use an expiratory resistance is of major importance since it varies. Different breathing patterns during PEP increase or reduce expiratory flow, result in movement of EPP centrally or peripherally and can increase or decrease lung volume. It is therefore necessary to give the right instructions to obtain the desired effects. As the different PEP techniques are being used by diverse patient groups it is not possible to give standard instructions. Based on the information given in this article the instructions have to be adjusted to give the optimal effect. There is no consensus regarding optimal treatment frequency and number of cycles included in each treatment session and must also be individualized. In future research, more precise descriptions are needed about physiological aims and specific instructions of how the treatments have been performed to assure as good treatment quality as possible and to be able to evaluate and compare treatment effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lung-protective perioperative mechanical ventilation

NARCIS (Netherlands)

Hemmes, S.N.T.

2015-01-01

Intraoperative ventilation has the potential to cause lung injury and possibly increase risk of pulmonary complications after surgery. Use of large tidal volumes could cause overdistension of lung tissue, which can be aggravated by too high levels of positive end-expiratory pressure (PEEP). Too low

The impact of aerosolized mucolytic agents on the airflow resistance of bacterial filters used in mechanical ventilation

Directory of Open Access Journals (Sweden)

Han-Chung Hu

2015-08-01

Conclusion: This study demonstrated the aerosolized mucolytic agents could increase the pressure drop of the bacterial filters during mechanical ventilation. The pressure drop of the bacterial filters was higher with 10% acetylcysteine. It is critical to continuously monitor the expiration resistance, auto-positive end-expiratory pressure, and ventilator output waveform when aerosolized 10% acetylcysteine was used in mechanical ventilation patients.

Effects of pleural effusion drainage on oxygenation, respiratory mechanics, and hemodynamics in mechanically ventilated patients.

Science.gov (United States)

Razazi, Keyvan; Thille, Arnaud W; Carteaux, Guillaume; Beji, Olfa; Brun-Buisson, Christian; Brochard, Laurent; Mekontso Dessap, Armand

2014-09-01

In mechanically ventilated patients, the effect of draining pleural effusion on oxygenation is controversial. We investigated the effect of large pleural effusion drainage on oxygenation, respiratory function (including lung volumes), and hemodynamics in mechanically ventilated patients after ultrasound-guided drainage. Arterial blood gases, respiratory mechanics (airway, pleural and transpulmonary pressures, end-expiratory lung volume, respiratory system compliance and resistance), and hemodynamics (blood pressure, heart rate, and cardiac output) were recorded before and at 3 and 24 hours (H24) after pleural drainage. The respiratory settings were kept identical during the study period. The mean volume of effusion drained was 1,579 ± 684 ml at H24. Uncomplicated pneumothorax occurred in two patients. Respiratory mechanics significantly improved after drainage, with a decrease in plateau pressure and a large increase in end-expiratory transpulmonary pressure. Respiratory system compliance, end-expiratory lung volume, and PaO2/FiO2 ratio all improved. Hemodynamics were not influenced by drainage. Improvement in the PaO2/FiO2 ratio from baseline to H24 was positively correlated with the increase in end-expiratory lung volume during the same time frame (r = 0.52, P = 0.033), but not with drained volume. A high value of pleural pressure or a highly negative transpulmonary pressure at baseline predicted limited lung expansion following effusion drainage. A lesser improvement in oxygenation occurred in patients with ARDS. Drainage of large (≥500 ml) pleural effusion in mechanically ventilated patients improves oxygenation and end-expiratory lung volume. Oxygenation improvement correlated with an increase in lung volume and a decrease in transpulmonary pressure, but was less so in patients with ARDS.

Experimental intra-abdominal hypertension influences airway pressure limits for lung protective mechanical ventilation.

Science.gov (United States)

Cortes-Puentes, Gustavo A; Cortes-Puentes, Luis A; Adams, Alexander B; Anderson, Christopher P; Marini, John J; Dries, David J

2013-06-01

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) may complicate monitoring of pulmonary mechanics owing to their impact on the respiratory system. However, recommendations for mechanical ventilation of patients with IAH/ACS and the interpretation of thoracoabdominal interactions remain unclear. Our study aimed to characterize the influence of elevated intra-abdominal pressure (IAP) and positive end-expiratory pressure (PEEP) on airway plateau pressure (PPLAT) and bladder pressure (PBLAD). Nine deeply anesthetized swine were mechanically ventilated via tracheostomy: volume-controlled mode at tidal volume (VT) of 10 mL/kg, frequency of 15, inspiratory-expiratory ratio of 1:2, and PEEP of 1 and 10 cm H2O (PEEP1 and PEEP10, respectively). A tracheostomy tube was placed in the peritoneal cavity, and IAP levels of 5, 10, 15, 20, and 25 mm Hg were applied, using a continuous positive airway pressure system. At each IAP level, PBLAD and airway pressure measurements were performed during both PEEP1 and PEEP10. PBLAD increased as experimental IAP rose (y = 0.83x + 0.5; R = 0.98; p < 0.001 at PEEP1). Minimal underestimation of IAP by PBLAD was observed (-2.5 ± 0.8 mm Hg at an IAP of 10-25 mm Hg). Applying PEEP10 did not significantly affect the correlation between experimental IAP and PBLAD. Approximately 50% of the PBLAD (in cm H2O) was reflected by changes in PPLAT, regardless of the PEEP level applied. Increasing IAP did not influence hemodynamics at any level of IAP generated. With minimal underestimation, PBLAD measurements closely correlated with experimentally regulated IAP, independent of the PEEP level applied. For each PEEP level applied, a constant proportion (approximately 50%) of measured PBLAD (in cm H2O) was reflected in PPLAT. A higher safety threshold for PPLAT should be considered in the setting of IAH/ACS as the clinician considers changes in VT. A strategy of reducing VT to cap PPLAT at widely recommended values may not be

Spontaneous breathing during lung-protective ventilation in an experimental acute lung injury model: high transpulmonary pressure associated with strong spontaneous breathing effort may worsen lung injury.

Science.gov (United States)

Yoshida, Takeshi; Uchiyama, Akinori; Matsuura, Nariaki; Mashimo, Takashi; Fujino, Yuji

2012-05-01

We investigated whether potentially injurious transpulmonary pressure could be generated by strong spontaneous breathing and exacerbate lung injury even when plateau pressure is limited to ventilation, each combined with weak or strong spontaneous breathing effort. Inspiratory pressure for low tidal volume ventilation was set at 10 cm H2O and tidal volume at 6 mL/kg. For moderate tidal volume ventilation, the values were 20 cm H2O and 7-9 mL/kg. The groups were: low tidal volume ventilation+spontaneous breathingweak, low tidal volume ventilation+spontaneous breathingstrong, moderate tidal volume ventilation+spontaneous breathingweak, and moderate tidal volume ventilation+spontaneous breathingstrong. Each group had the same settings for positive end-expiratory pressure of 8 cm H2O. Respiratory variables were measured every 60 mins. Distribution of lung aeration and alveolar collapse were histologically evaluated. Low tidal volume ventilation+spontaneous breathingstrong showed the most favorable oxygenation and compliance of respiratory system, and the best lung aeration. By contrast, in moderate tidal volume ventilation+spontaneous breathingstrong, the greatest atelectasis with numerous neutrophils was observed. While we applied settings to maintain plateau pressure at ventilation+spontaneous breathingstrong, transpulmonary pressure rose >33 cm H2O. Both minute ventilation and respiratory rate were higher in the strong spontaneous breathing groups. Even when plateau pressure is limited to mechanical ventilation, transpulmonary pressure and tidal volume should be strictly controlled to prevent further lung injury.

Low pulmonary artery flush perfusion pressure combined with high positive end-expiratory pressure reduces oedema formation in isolated porcine lungs

International Nuclear Information System (INIS)

Schumann, Stefan; Schließmann, Stephan J; Wagner, Giskard; Goebel, Ulrich; Priebe, Hans-Joachim; Guttmann, Josef; Kirschbaum, Andreas

2010-01-01

Flush perfusion of the pulmonary artery with organ protection solution is a standard procedure before lung explantation. However, rapid flush perfusion may cause pulmonary oedema which is deleterious in the lung transplantation setting. In this study we tested the hypotheses that high pulmonary perfusion pressure contributes to the development of pulmonary oedema and positive end-expiratory pressure (PEEP) counteracts oedema formation. We expected oedema formation to increase weight and decrease compliance of the lungs on the basis of a decrease in alveolar volume as fluid replaces alveolar air spaces. The pulmonary artery of 28 isolated porcine lungs was perfused with a low-potassium dextrane solution at low (mean 27 mmHg) or high (mean 40 mmHg) pulmonary artery pressure (PAP) during mechanical ventilation at low (4 cmH 2 O) or high (8 cmH 2 O) PEEP, respectively. Following perfusion and storage, relative increases in lung weight were smaller (p < 0.05) during perfusion at low PAP (62 ± 32% and 42 ± 26%, respectively) compared to perfusion at high PAP (133 ± 54% and 87 ± 30%, respectively). Compared to all other PAP–PEEP combinations, increases in lung weight were smallest (44 ± 9% and 27 ± 12%, respectively), nonlinear intratidal lung compliance was largest (46% and 17% respectively, both p < 0.05) and lung histology showed least infiltration of mononuclear cells in the alveolar septa, and least alveolar destruction during the combination of low perfusion pressure and high PEEP. The findings suggest that oedema formation during pulmonary artery flush perfusion in isolated and ventilated lungs can be reduced by choosing low perfusion pressure and high PEEP. PAP–PEEP titration to minimize pulmonary oedema should be based on lung mechanics and PAP monitoring

High tidal volume ventilation in infant mice.

Science.gov (United States)

Cannizzaro, Vincenzo; Zosky, Graeme R; Hantos, Zoltán; Turner, Debra J; Sly, Peter D

2008-06-30

Infant mice were ventilated with either high tidal volume (V(T)) with zero end-expiratory pressure (HVZ), high V(T) with positive end-expiratory pressure (PEEP) (HVP), or low V(T) with PEEP. Thoracic gas volume (TGV) was determined plethysmographically and low-frequency forced oscillations were used to measure the input impedance of the respiratory system. Inflammatory cells, total protein, and cytokines in bronchoalveolar lavage fluid (BALF) and interleukin-6 (IL-6) in serum were measured as markers of pulmonary and systemic inflammatory response, respectively. Coefficients of tissue damping and tissue elastance increased in all ventilated mice, with the largest rise seen in the HVZ group where TGV rapidly decreased. BALF protein levels increased in the HVP group, whereas serum IL-6 rose in the HVZ group. PEEP keeps the lungs open, but provides high volumes to the entire lungs and induces lung injury. Compared to studies in adult and non-neonatal rodents, infant mice demonstrate a different response to similar ventilation strategies underscoring the need for age-specific animal models.

Differential Effects of Intraoperative Positive End-expiratory Pressure (PEEP) on Respiratory Outcome in Major Abdominal Surgery Versus Craniotomy

DEFF Research Database (Denmark)

de Jong, Myrthe A C; Ladha, Karim S; Melo, Marcos F Vidal

2015-01-01

OBJECTIVES: In this study, we examined whether (1) positive end-expiratory pressure (PEEP) has a protective effect on the risk of major postoperative respiratory complications in a cohort of patients undergoing major abdominal surgeries and craniotomies, and (2) the effect of PEEP is differed......: Within the entire study population (major abdominal surgeries and craniotomies), we found an association between application of PEEP ≥5 cmH2O and a decreased risk of postoperative respiratory complications compared with PEEP 5 cmH2O was associated with a significant lower...... undergoing major abdominal surgery. Our data suggest that default mechanical ventilator settings should include PEEP of 5-10 cmH2O during major abdominal surgery....

Lung recruitability is better estimated according to the Berlin definition of acute respiratory distress syndrome at standard 5 cm H2O rather than higher positive end-expiratory pressure: a retrospective cohort study.

Science.gov (United States)

Caironi, Pietro; Carlesso, Eleonora; Cressoni, Massimo; Chiumello, Davide; Moerer, Onner; Chiurazzi, Chiara; Brioni, Matteo; Bottino, Nicola; Lazzerini, Marco; Bugedo, Guillermo; Quintel, Michael; Ranieri, V Marco; Gattinoni, Luciano

2015-04-01

The Berlin definition of acute respiratory distress syndrome has introduced three classes of severity according to PaO2/FIO2 thresholds. The level of positive end-expiratory pressure applied may greatly affect PaO2/FIO2, thereby masking acute respiratory distress syndrome severity, which should reflect the underlying lung injury (lung edema and recruitability). We hypothesized that the assessment of acute respiratory distress syndrome severity at standardized low positive end-expiratory pressure may improve the association between the underlying lung injury, as detected by CT, and PaO2/FIO2-derived severity. Retrospective analysis. Four university hospitals (Italy, Germany, and Chile). One hundred forty-eight patients with acute lung injury or acute respiratory distress syndrome according to the American-European Consensus Conference criteria. Patients underwent a three-step ventilator protocol (at clinical, 5 cm H2O, or 15 cm H2O positive end-expiratory pressure). Whole-lung CT scans were obtained at 5 and 45 cm H2O airway pressure. Nine patients did not fulfill acute respiratory distress syndrome criteria of the novel Berlin definition. Patients were then classified according to PaO2/FIO2 assessed at clinical, 5 cm H2O, or 15 cm H2O positive end-expiratory pressure. At clinical positive end-expiratory pressure (11±3 cm H2O), patients with severe acute respiratory distress syndrome had a greater lung tissue weight and recruitability than patients with mild or moderate acute respiratory distress syndrome (pBerlin definition of acute respiratory distress syndrome assessed at 5 cm H2O allows a better evaluation of lung recruitability and edema than at higher positive end-expiratory pressure clinically set.

Modes of mechanical ventilation for the operating room.

Science.gov (United States)

Ball, Lorenzo; Dameri, Maddalena; Pelosi, Paolo

2015-09-01

Most patients undergoing surgical procedures need to be mechanically ventilated, because of the impact of several drugs administered at induction and during maintenance of general anaesthesia on respiratory function. Optimization of intraoperative mechanical ventilation can reduce the incidence of post-operative pulmonary complications and improve the patient's outcome. Preoxygenation at induction of general anaesthesia prolongs the time window for safe intubation, reducing the risk of hypoxia and overweighs the potential risk of reabsorption atelectasis. Non-invasive positive pressure ventilation delivered through different interfaces should be considered at the induction of anaesthesia morbidly obese patients. Anaesthesia ventilators are becoming increasingly sophisticated, integrating many functions that were once exclusive to intensive care. Modern anaesthesia machines provide high performances in delivering the desired volumes and pressures accurately and precisely, including assisted ventilation modes. Therefore, the physicians should be familiar with the potential and pitfalls of the most commonly used intraoperative ventilation modes: volume-controlled, pressure-controlled, dual-controlled and assisted ventilation. Although there is no clear evidence to support the advantage of any one of these ventilation modes over the others, protective mechanical ventilation with low tidal volume and low levels of positive end-expiratory pressure (PEEP) should be considered in patients undergoing surgery. The target tidal volume should be calculated based on the predicted or ideal body weight rather than on the actual body weight. To optimize ventilation monitoring, anaesthesia machines should include end-inspiratory and end-expiratory pause as well as flow-volume loop curves. The routine administration of high PEEP levels should be avoided, as this may lead to haemodynamic impairment and fluid overload. Higher PEEP might be considered during surgery longer than 3 h

Mechanical ventilation management during extracorporeal membrane oxygenation for acute respiratory distress syndrome: a retrospective international multicenter study.

Science.gov (United States)

Schmidt, Matthieu; Stewart, Claire; Bailey, Michael; Nieszkowska, Ania; Kelly, Joshua; Murphy, Lorna; Pilcher, David; Cooper, D James; Scheinkestel, Carlos; Pellegrino, Vincent; Forrest, Paul; Combes, Alain; Hodgson, Carol

2015-03-01

To describe mechanical ventilation settings in adult patients treated for an acute respiratory distress syndrome with extracorporeal membrane oxygenation and assess the potential impact of mechanical ventilation settings on ICU mortality. Retrospective observational study. Three international high-volume extracorporeal membrane oxygenation centers. A total of 168 patients treated with extracorporeal membrane oxygenation for severe acute respiratory distress syndrome from January 2007 to January 2013. We analyzed the association between mechanical ventilation settings (i.e. plateau pressure, tidal volume, and positive end-expiratory pressure) on ICU mortality using multivariable logistic regression model and Cox-proportional hazards model. We obtained detailed demographic, clinical, daily mechanical ventilation settings and ICU outcome data. One hundred sixty-eight patients (41 ± 14 years old; PaO2/FIO2 67 ± 19 mm Hg) fulfilled our inclusion criteria. Median duration of extracorporeal membrane oxygenation and ICU stay were 10 days (6-18 d) and 28 days (16-42 d), respectively. Lower positive end-expiratory pressure levels and significantly lower plateau pressures during extracorporeal membrane oxygenation were used in the French center than in both Australian centers (23.9 ± 1.4 vs 27.6 ± 3.7 and 27.8 ± 3.6; p Protective mechanical ventilation strategies were routinely used in high-volume extracorporeal membrane oxygenation centers. However, higher positive end-expiratory pressure levels during the first 3 days on extracorporeal membrane oxygenation support were independently associated with improved survival. Further prospective trials on the optimal mechanical ventilation strategy during extracorporeal membrane oxygenation support are warranted.

Influences of Duration of Inspiratory Effort, Respiratory Mechanics, and Ventilator Type on Asynchrony With Pressure Support and Proportional Assist Ventilation.

Science.gov (United States)

Vasconcelos, Renata S; Sales, Raquel P; Melo, Luíz H de P; Marinho, Liégina S; Bastos, Vasco Pd; Nogueira, Andréa da Nc; Ferreira, Juliana C; Holanda, Marcelo A

2017-05-01

Pressure support ventilation (PSV) is often associated with patient-ventilator asynchrony. Proportional assist ventilation (PAV) offers inspiratory assistance proportional to patient effort, minimizing patient-ventilator asynchrony. The objective of this study was to evaluate the influence of respiratory mechanics and patient effort on patient-ventilator asynchrony during PSV and PAV plus (PAV+). We used a mechanical lung simulator and studied 3 respiratory mechanics profiles (normal, obstructive, and restrictive), with variations in the duration of inspiratory effort: 0.5, 1.0, 1.5, and 2.0 s. The Auto-Trak system was studied in ventilators when available. Outcome measures included inspiratory trigger delay, expiratory trigger asynchrony, and tidal volume (V T ). Inspiratory trigger delay was greater in the obstructive respiratory mechanics profile and greatest with a effort of 2.0 s (160 ms); cycling asynchrony, particularly delayed cycling, was common in the obstructive profile, whereas the restrictive profile was associated with premature cycling. In comparison with PSV, PAV+ improved patient-ventilator synchrony, with a shorter triggering delay (28 ms vs 116 ms) and no cycling asynchrony in the restrictive profile. V T was lower with PAV+ than with PSV (630 mL vs 837 mL), as it was with the single-limb circuit ventilator (570 mL vs 837 mL). PAV+ mode was associated with longer cycling delays than were the other ventilation modes, especially for the obstructive profile and higher effort values. Auto-Trak eliminated automatic triggering. Mechanical ventilation asynchrony was influenced by effort, respiratory mechanics, ventilator type, and ventilation mode. In PSV mode, delayed cycling was associated with shorter effort in obstructive respiratory mechanics profiles, whereas premature cycling was more common with longer effort and a restrictive profile. PAV+ prevented premature cycling but not delayed cycling, especially in obstructive respiratory mechanics

Value and limitations of transpulmonary pressure calculations during intra-abdominal hypertension.

Science.gov (United States)

Cortes-Puentes, Gustavo A; Gard, Kenneth E; Adams, Alexander B; Faltesek, Katherine A; Anderson, Christopher P; Dries, David J; Marini, John J

2013-08-01

To clarify the effect of progressively increasing intra-abdominal pressure on esophageal pressure, transpulmonary pressure, and functional residual capacity. Controlled application of increased intra-abdominal pressure at two positive end-expiratory pressure levels (1 and 10 cm H2O) in an anesthetized porcine model of controlled ventilation. Large animal laboratory of a university-affiliated hospital. Eleven deeply anesthetized swine (weight 46.2 ± 6.2 kg). Air-regulated intra-abdominal hypertension (0-25 mm Hg). Esophageal pressure, tidal compliance, bladder pressure, and end-expiratory lung aeration by gas dilution. Functional residual capacity was significantly reduced by increasing intra-abdominal pressure at both positive end-expiratory pressure levels (p ≤ 0.0001) without corresponding changes of end-expiratory esophageal pressure. Above intra-abdominal pressure 5 mm Hg, plateau airway pressure increased linearly by ~ 50% of the applied intra-abdominal pressure value, associated with commensurate changes of esophageal pressure. With tidal volume held constant, negligible changes occurred in transpulmonary pressure due to intra-abdominal pressure. Driving pressures calculated from airway pressures alone (plateau airway pressure--positive end-expiratory pressure) did not equate to those computed from transpulmonary pressure (tidal changes in transpulmonary pressure). Increasing positive end-expiratory pressure shifted the predominantly negative end-expiratory transpulmonary pressure at positive end-expiratory pressure 1 cm H2O (mean -3.5 ± 0.4 cm H2O) into the positive range at positive end-expiratory pressure 10 cm H2O (mean 0.58 ± 1.2 cm H2O). Despite its insensitivity to changes in functional residual capacity, measuring transpulmonary pressure may be helpful in explaining how different levels of positive end-expiratory pressure influence recruitment and collapse during tidal ventilation in the presence of increased intra-abdominal pressure and in

Surfactant impairment after mechanical ventilation with large alveolar surface area changes and effects of positive end-expiratory pressure

NARCIS (Netherlands)

S.J.C. Verbrugge (Serge); S.H. Bohm; D.A.M.P.J. Gommers (Diederik); L.J.I. Zimmermann (Luc); B.F. Lachmann (Burkhard)

1998-01-01

textabstractWe have assessed the effects of overinflation on surfactant function and composition in rats undergoing ventilation for 20 min with 100% oxygen at a peak inspiratory pressure of 45 cm H2O, with or without PEEP 10 cm H2O (groups 45/10 and 45/0, respectively).

Impact of humidification and nebulization during expiratory limb protection: an experimental bench study.

Science.gov (United States)

Tonnelier, Alexandre; Lellouche, François; Bouchard, Pierre Alexandre; L'Her, Erwan

2013-08-01

Different filtering devices are used during mechanical ventilation to avoid dysfunction of flow and pressure transducers or for airborne microorganisms containment. Water condensates, resulting from the use of humidifiers, but also residual nebulization particles may have a major influence on expiratory limb resistance. To evaluate the influence of nebulization and active humidification on the resistance of expiratory filters. A respiratory system analog was constructed using a test lung, an ICU ventilator, heated humidifiers, and a piezoelectric nebulizer. Humidifiers were connected to different types of circuits (unheated, mono-heated, new-generation and old-generation bi-heated). Five filter types were evaluated: electrostatic, heat-and-moisture exchanger, standard, specific, and internal heated high-efficiency particulate air [HEPA] filter. Baseline characteristics were obtained from each dry filter. Differential pressure measurements were carried out after 24 hours of continuous in vitro use for each condition, and after 24 hours of use with an old-generation bi-heated circuit without nebulization. While using unheated circuits, measurements had to be interrupted before 24 hours for all the filtering devices except the internal heated HEPA filter. The heat-and-moisture exchangers occluded before 24 hours with the unheated and mono-heated circuits. The circuit type, nebulization practice, and duration of use did not influence the internal heated HEPA filter resistance. Expiratory limb filtration is likely to induce several major adverse events. Expiratory filter resistance increase is due mainly to the humidification circuit type, rather than to nebulization. If filtration is mandatory while using an unheated circuit, a dedicated filter should be used for ≤ 24 hours, or a heated HEPA for a longer duration.

An expiratory assist during spontaneous breathing can compensate for endotracheal tube resistance.

Science.gov (United States)

Uchiyama, Akinori; Chang, Cheng; Suzuki, Shinya; Mashimo, Takashi; Fujino, Yuji

2009-08-01

Although inspiratory assist of spontaneous breathing in intubated patients is common, expiratory assist functions have rarely been reported. Effective expiratory support (ES) could be used to compensate for endotracheal tube (ETT) resistance during spontaneous breathing. In this study, we examined the performance of a new system designed to provide both inspiratory support (IS) and ES during spontaneous breathing with the goal of reducing the effective resistance of the ETT. The ES system consisted of a ventilator demand valve and a computer-controlled piston cylinder, which aspirated gas from the respiratory circuit during the expiratory phase. The movement of the piston was synchronized with spontaneous breathing. We compared the pressures at the tip of the ETT and in the breathing circuit during spontaneous breathing through an ETT of internal diameter (ID) 5 mm with that of an ETT with ID 8 mm in nine healthy adult male volunteers. The ventilatory mode was set to maintain a continuous airway pressure of 0 cm H(2)O. Three ventilator settings (no support, IS only, and IS plus ES) were compared using ID 5 mm ETT. We monitored pressure in the breathing circuit (P(aw)), ETT tip pressure (P(tip)), and respiratory flow. The P(tip) of the ID 5 mm ETT showed a large negative deflection during inspiration and a positive deflection during expiration without support. IS alone did not improve the respiratory pattern through the small ETT. However, IS plus ES resulted in negative P(aw) during expiration in addition to positive deflection of P(aw) during inspiration, making the pressure characteristics of P(tip) similar to those of ID 8 mm ETT. Moreover, IS plus ES produced a respiratory pattern through the ID 5 mm ETT that was similar to that through the ID 8 mm ETT. In this study of healthy volunteers, IS plus ES compensated for the airway resistance imposed by a ID 5.0 mm ETT to create pressure changes at the tip of the ETT similar to those of an ID 8.0 mm ETT.

Intra-operative protective mechanical ventilation in lung transplantation: a randomised, controlled trial.

Science.gov (United States)

Verbeek, G L; Myles, P S; Westall, G P; Lin, E; Hastings, S L; Marasco, S F; Jaffar, J; Meehan, A C

2017-08-01

Primary graft dysfunction occurs in up to 25% of patients after lung transplantation. Contributing factors include ventilator-induced lung injury, cardiopulmonary bypass, ischaemia-reperfusion injury and excessive fluid administration. We evaluated the feasibility, safety and efficacy of an open-lung protective ventilation strategy aimed at reducing ventilator-induced lung injury. We enrolled adult patients scheduled to undergo bilateral sequential lung transplantation, and randomly assigned them to either a control group (volume-controlled ventilation with 5 cmH 2 O, positive end-expiratory pressure, low tidal volumes (two-lung ventilation 6 ml.kg -1 , one-lung ventilation 4 ml.kg -1 )) or an alveolar recruitment group (regular step-wise positive end-expiratory pressure-based alveolar recruitment manoeuvres, pressure-controlled ventilation set at 16 cmH 2 O with 10 cmH 2 O positive end-expiratory pressure). Ventilation strategies were commenced from reperfusion of the first lung allograft and continued for the duration of surgery. Regular PaO 2 /F I O 2 ratios were calculated and venous blood samples collected for inflammatory marker evaluation during the procedure and for the first 24 h of intensive care stay. The primary end-point was the PaO 2 /F I O 2 ratio at 24 h after first lung reperfusion. Thirty adult patients were studied. The primary outcome was not different between groups (mean (SD) PaO 2 /F I O 2 ratio control group 340 (111) vs. alveolar recruitment group 404 (153); adjusted p = 0.26). Patients in the control group had poorer mean (SD) PaO 2 /F I O 2 ratios at the end of the surgical procedure and a longer median (IQR [range]) time to tracheal extubation compared with the alveolar recruitment group (308 (144) vs. 402 (154) (p = 0.03) and 18 (10-27 [5-468]) h vs. 15 (11-36 [5-115]) h (p = 0.01), respectively). An open-lung protective ventilation strategy during surgery for lung transplantation is feasible, safe and achieves favourable

Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study.

Science.gov (United States)

Nakamura, Maria Aparecida Miyuki; Costa, Eduardo Leite Vieira; Carvalho, Carlos Roberto Ribeiro; Tucci, Mauro Roberto

2014-01-01

Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM. This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization. Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly. The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM.

Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study* **

Science.gov (United States)

Nakamura, Maria Aparecida Miyuki; Costa, Eduardo Leite Vieira; Carvalho, Carlos Roberto Ribeiro; Tucci, Mauro Roberto

2014-01-01

Objective: Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM. Methods: This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization. Results: Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly. Conclusions: The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM. PMID:25029653

The effect of entrainment site and inspiratory pressure on the delivery of oxygen therapy during non-invasive mechanical ventilation (NIMV in acute COPD patients

Directory of Open Access Journals (Sweden)

Sundeep Kaul

2006-12-01

Full Text Available Supplemental O2 is frequently added to bi-level non-invasive ventilation circuits to maintain Sa,O2 >90%. Oxygen can be added at several points & in the presence of different inspiratory pressures. The effect of varying entrainment sites and inspiratory pressures (IPAP on PO2, PCO2, Fio2, inspiratory triggering and expiratory triggering in COPD patients is unknown. 18 patients with stable COPD (mean FEV1 47% participated in the study. Oxygen was added at 4 sites in the ventilatory circuit (site 1: between mask and exhalation port; site 2: just distal to exhalation port; site 3: at ventilator outlet; site 4: directly into the mask via an inlet. The effect of varying entrainment sites and inspiratory pressures on arterial PO2, PCO2, FIO2, was recorded at 3 mins. The same full face mask (Respironics, Image 3 & ventilator (Respironics, BIPAP ST 30 was used.

A sigmoidal fit for pressure-volume curves of idiopathic pulmonary fibrosis patients on mechanical ventilation: clinical implications

Directory of Open Access Journals (Sweden)

Juliana C. Ferreira

2011-01-01

Full Text Available OBJECTIVE: Respiratory pressure-volume curves fitted to exponential equations have been used to assess disease severity and prognosis in spontaneously breathing patients with idiopathic pulmonary fibrosis. Sigmoidal equations have been used to fit pressure-volume curves for mechanically ventilated patients but not for idiopathic pulmonary fibrosis patients. We compared a sigmoidal model and an exponential model to fit pressure-volume curves from mechanically ventilated patients with idiopathic pulmonary fibrosis. METHODS: Six idiopathic pulmonary fibrosis patients and five controls underwent inflation pressure-volume curves using the constant-flow technique during general anesthesia prior to open lung biopsy or thymectomy. We identified the lower and upper inflection points and fit the curves with an exponential equation, V = A-B.e-k.P, and a sigmoid equation, V = a+b/(1+e-(P-c/d. RESULTS: The mean lower inflection point for idiopathic pulmonary fibrosis patients was significantly higher (10.5 ± 5.7 cm H2O than that of controls (3.6 ± 2.4 cm H2O. The sigmoidal equation fit the pressure-volume curves of the fibrotic and control patients well, but the exponential equation fit the data well only when points below 50% of the inspiratory capacity were excluded. CONCLUSION: The elevated lower inflection point and the sigmoidal shape of the pressure-volume curves suggest that respiratory system compliance is decreased close to end-expiratory lung volume in idiopathic pulmonary fibrosis patients under general anesthesia and mechanical ventilation. The sigmoidal fit was superior to the exponential fit for inflation pressure-volume curves of anesthetized patients with idiopathic pulmonary fibrosis and could be useful for guiding mechanical ventilation during general anesthesia in this condition.

Accuracy of automatic tube compensation in new-generation mechanical ventilators.

Science.gov (United States)

Elsasser, Serge; Guttmann, Josef; Stocker, Reto; Mols, Georg; Priebe, Hans-Joachim; Haberthür, Christoph

2003-11-01

To compare performance of flow-adapted compensation of endotracheal tube resistance (automatic tube compensation, ATC) between the original ATC system and ATC systems incorporated in commercially available ventilators. Bench study. University research laboratory. The original ATC system, Dräger Evita 2 prototype, Dräger Evita 4, Puritan-Bennett 840. The four ventilators under investigation were alternatively connected via different sized endotracheal tubes and an artificial trachea to an active lung model. Test conditions consisted of two ventilatory modes (ATC vs. continuous positive airway pressure), three different sized endotracheal tubes (inner diameter 7.0, 8.0, and 9.0 mm), two ventilatory rates (15/min and 30/min), and four levels of positive end-expiratory pressure (0, 5, 10, and 15 cm H2O). Performance of tube compensation was assessed by the amount of tube-related (additional) work of breathing (WOBadd), which was calculated on the basis of pressure gradient across the endotracheal tube. Compared with continuous positive airway pressure, ATC reduced inspiratory WOBadd by 58%, 68%, 50%, and 97% when using the Evita 4, the Evita 2 prototype, the Puritan-Bennett 840, and the original ATC system, respectively. Depending on endotracheal tube diameter and ventilatory pattern, inspiratory WOBadd was 0.12-5.2 J/L with the original ATC system, 1.5-28.9 J/L with the Puritan-Bennett 840, 10.4-21.0 J/L with the Evita 2 prototype, and 10.1-36.1 J/L with the Evita 4 (difference between each ventilator at identical test situations, p ventilator (p <.025). Flow-adapted tube compensation by the original ATC system significantly reduced tube-related inspiratory and expiratory work of breathing. The commercially available ATC modes investigated here may be adequate for inspiratory but probably not for expiratory tube compensation.

Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel

Science.gov (United States)

Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei

2018-03-01

In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.

Neopuff T-piece resuscitator mask ventilation: Does mask leak vary with different peak inspiratory pressures in a manikin model?

Science.gov (United States)

Maheshwari, Rajesh; Tracy, Mark; Hinder, Murray; Wright, Audrey

2017-08-01

The aim of this study was to compare mask leak with three different peak inspiratory pressure (PIP) settings during T-piece resuscitator (TPR; Neopuff) mask ventilation on a neonatal manikin model. Participants were neonatal unit staff members. They were instructed to provide mask ventilation with a TPR with three PIP settings (20, 30, 40 cm H 2 O) chosen in a random order. Each episode was for 2 min with 2-min rest period. Flow rate and positive end-expiratory pressure (PEEP) were kept constant. Airway pressure, inspiratory and expiratory tidal volumes, mask leak, respiratory rate and inspiratory time were recorded. Repeated measures analysis of variance was used for statistical analysis. A total of 12 749 inflations delivered by 40 participants were analysed. There were no statistically significant differences (P > 0.05) in the mask leak with the three PIP settings. No statistically significant differences were seen in respiratory rate and inspiratory time with the three PIP settings. There was a significant rise in PEEP as the PIP increased. Failure to achieve the desired PIP was observed especially at the higher settings. In a neonatal manikin model, the mask leak does not vary as a function of the PIP when the flow rate is constant. With a fixed rate and inspiratory time, there seems to be a rise in PEEP with increasing PIP. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

Effect of Positive End-Expiratory Pressure on Central Venous Pressure in Patients under Mechanical Ventilation.

Science.gov (United States)

Shojaee, Majid; Sabzghabaei, Anita; Alimohammadi, Hossein; Derakhshanfar, Hojjat; Amini, Afshin; Esmailzadeh, Bahareh

2017-01-01

Finding the probable governing pattern of PEEP and CVP changes is an area of interest for in-charge physicians and researchers. Therefore, the present study was designed with the aim of evaluating the relationship between the mentioned pressures. In this quasi-experimental study, patients under mechanical ventilation were evaluated with the aim of assessing the effect of PEEP change on CVP. Non-trauma patients, over 18 years of age, who were under mechanical ventilation and had stable hemodynamics, with inserted CV line were entered. After gathering demographic data, patients underwent 0, 5, and 10 cmH 2 O PEEPs and the respective CVPs of the mentioned points were recorded. The relationship of CVP and PEEP in different cut points were measured using SPSS 21.0 statistical software. 60 patients with the mean age of 73.95 ± 11.58 years were evaluated (68.3% male). The most frequent cause of ICU admission was sepsis with 45.0%. 5 cmH 2 O increase in PEEP led to 2.47 ± 1.53 mean difference in CVP level. If the PEEP baseline is 0 at the time of 5 cmH 2 O increase, it leads to a higher raise in CVP compared to when the baseline is 5 cmH 2 O (2.47 ± 1.53 vs. 1.57 ± 1.07; p = 0.039). The relationship between CVP and 5 cmH 2 O (p = 0.279), and 10 cmH 2 O (p = 0.292) PEEP changes were not dependent on the baseline level of CVP. The findings of this study revealed the direct relationship between PEEP and CVP. Approximately, a 5 cmH 2 O increase in PEEP will be associated with about 2.5 cmH 2 O raise in CVP. When applying a 5 cmH 2 O PEEP increase, if the baseline PEEP is 0, it leads to a significantly higher raise in CVP compared to when it is 5 cmH 2 O (2.5 vs. 1.6). It seems that sex, history of cardiac failure, baseline CVP level, and hypertension do not have a significant effect in this regard.

Effect of Positive End-Expiratory Pressure on Central Venous Pressure in Patients under Mechanical Ventilation

Directory of Open Access Journals (Sweden)

Majid Shojaee

2016-12-01

Full Text Available Introduction: Finding the probable governing pattern of PEEP and CVP changes is an area of interest for in-charge physicians and researchers. Therefore, the present study was designed with the aim of evaluating the relationship between the mentioned pressures. Methods: In this quasi-experimental study, patients under mechanical ventilation were evaluated with the aim of assessing the effect of PEEP change on CVP. Non-trauma patients, over 18 years of age, who were under mechanical ventilation and had stable hemodynamics, with inserted CV line were entered. After gathering demographic data, patients underwent 0, 5, and 10 cmH2O PEEPs and the respective CVPs of the mentioned points were recorded. The relationship of CVP and PEEP in different cut points were measured using SPSS 21.0 statistical software. Results: 60 patients with the mean age of 73.95 ± 11.58 years were evaluated (68.3% male. The most frequent cause of ICU admission was sepsis with 45.0%. 5 cmH2O increase in PEEP led to 2.47 ± 1.53 mean difference in CVP level. If the PEEP baseline is 0 at the time of 5 cmH2O increase, it leads to a higher raise in CVP compared to when the baseline is 5 cmH2O (2.47 ± 1.53 vs. 1.57 ± 1.07; p = 0.039. The relationship between CVP and 5 cmH2O (p = 0.279, and 10 cmH2O (p = 0.292 PEEP changes were not dependent on the baseline level of CVP. Conclusion: The findings of this study revealed the direct relationship between PEEP and CVP. Approximately, a 5 cmH2O increase in PEEP will be associated with about 2.5 cmH2O raise in CVP. When applying a 5 cmH2O PEEP increase, if the baseline PEEP is 0, it leads to a significantly higher raise in CVP compared to when it is 5 cmH2O (2.5 vs. 1.6. It seems that sex, history of cardiac failure, baseline CVP level, and hypertension do not have a significant effect in this regard.

Expiratory timing in obstructive sleep apnoeas.

Science.gov (United States)

Cibella, F; Marrone, O; Sanci, S; Bellia, V; Bonsignore, G

1990-03-01

Diaphragmatic electromyogram was recorded during NREM sleep in 4 patients affected by obstructive sleep apnoea (OSA) syndrome in order to evaluate the behaviour of expiratory time (TE) in the course of the obstructive apnoea-ventilation cycle. The two components of TE, i.e. time of post-inspiratory inspiratory activity (TPIIA) and time of expiratory phase 2 (TE2) were separately analysed. TPIIA showed a short duration, with only minor variations, within the apnoea, while its duration was more variable and longer in the interapnoeic periods: the longest TPIIA values were associated with the highest inspiratory volumes in the same breaths. This behaviour seemed regulated according to the need of a more or less effective expiratory flow braking, probably as a result of pulmonary stretch receptors discharge. Conversely TE2 showed a continuous gradual modulation, progressively increasing in the pre-apnoeic period, decreasing during the apnoea and increasing in the post-apnoeic period: these TE2 variations seemed related to oscillations in chemical drive. These data show that TE in the obstructive apnoea-ventilation cycle results from a different modulation in its two components and suggest that both mechanical and chemical influences play a role in its overall duration.

The effect of pressure-controlled inverse ratio ventilation on lung protection in obese patients undergoing gynecological laparoscopic surgery.

Science.gov (United States)

Xu, Lili; Shen, Jianjun; Yan, Min

2017-10-01

To examine the effects of pressure-controlled inverse ratio ventilation (PCIRV) and volume-control ventilation (VCV) on arterial oxygenation, pulmonary function, hemodynamics, levels of surfactant protein A (SP-A), and tumor necrosis factor-α (TNF-α) in obese patients undergoing gynecological laparoscopic surgery. Sixty patients, body mass index (BMI) ≥30 kg/m 2 , scheduled for elective gynecological laparoscopic surgery were enrolled in the study. Patients were randomly allocated to receive either PCIRV with an inspiratory-expiratory (I:E) ratio of 1.5:1 (PCIRV group n = 30) or VCV with an I:E ratio of 1:2 (VCV group n = 30). Ventilation variables, viz. tidal volume (V T ), dynamic respiratory-system compliance (C RS ), driving pressure (ΔP = V T /C RS ), arterial blood oxygen partial pressure/fraction of inspiration oxygen (PaO 2 /FiO 2 ) and arterial blood carbon dioxide partial pressure (PaCO 2 ), were measured. Hemodynamic variables, viz. mean arterial pressure (MAP), heart rate (HR), and serum levels of SP-A and TNF-α, were also measured. When compared to patients in the VCV group, patients in the PCIRV group had higher V T , dynamic C RS , and PaO 2 /FiO 2 , and lower ΔP and PaCO 2 at 20 and 60 min after the start of pneumoperitoneum (p ventilation, promote gas exchange and oxygenation, and is associated with decreased levels of SP-A and TNF-α. These effects demonstrate improved lung protection provided by PCIRV in this patient population.

Airway pressure release ventilation and biphasic positive airway pressure: a systematic review of definitional criteria.

Science.gov (United States)

Rose, Louise; Hawkins, Martyn

2008-10-01

The objective of this study was to identify the definitional criteria for the pressure-limited and time-cycled modes: airway pressure release ventilation (APRV) and biphasic positive airway pressure (BIPAP) available in the published literature. Systematic review. Medline, PubMed, Cochrane, and CINAHL databases (1982-2006) were searched using the following terms: APRV, BIPAP, Bilevel and lung protective strategy, individually and in combination. Two independent reviewers determined the paper eligibility and abstracted data from 50 studies and 18 discussion articles. Of the 50 studies, 39 (78%) described APRV, and 11 (22%) described BIPAP. Various study designs, populations, or outcome measures were investigated. Compared to BIPAP, APRV was described more frequently as extreme inverse inspiratory:expiratory ratio [18/39 (46%) vs. 0/11 (0%), P = 0.004] and used rarely as a noninverse ratio [2/39 (5%) vs. 3/11 (27%), P = 0.06]. One (9%) BIPAP and eight (21%) APRV studies used mild inverse ratio (>1:1 to branding may further add to confusion. Generic naming of modes and consistent definitional parameters may improve consistency of patient response for a given mode and assist with clinical implementation.

Work of breathing using different interfaces in spontaneous positive pressure ventilation: helmet, face-mask, and endotracheal tube.

Science.gov (United States)

Oda, Shinya; Otaki, Kei; Yashima, Nozomi; Kurota, Misato; Matsushita, Sachiko; Kumasaka, Airi; Kurihara, Hutaba; Kawamae, Kaneyuki

2016-08-01

Noninvasive positive pressure ventilation (NPPV) using a helmet is expected to cause inspiratory trigger delay due to the large collapsible and compliant chamber. We compared the work of breathing (WOB) of NPPV using a helmet or a full face-mask with that of invasive ventilation by tracheal intubation. We used a lung model capable of simulating spontaneous breathing (LUNGOO; Air Water Inc., Japan). LUNGOO was set at compliance (C) = 50 mL/cmH2O and resistance (R) = 5 cmH2O/L/s for normal lung simulation, C = 20 mL/cmH2O and R = 5 cmH2O/L/s for restrictive lung, and C = 50 mL/cmH2O and R = 20 cmH2O/L/s for obstructive lung. Muscle pressure was fixed at 25 cmH2O and respiratory rate at 20 bpm. Pressure support ventilation and continuous positive airway pressure were performed with each interface placed on a dummy head made of reinforced plastic that was connected to LUNGOO. We tested the inspiratory WOB difference between the interfaces with various combinations of ventilator settings (positive end-expiratory pressure 5 cmH2O; pressure support 0, 5, and 10 cmH2O). In the normal lung and restrictive lung models, WOB decreased more with the face-mask than the helmet, especially when accompanied by the level of pressure support. In the obstructive lung model, WOB with the helmet decreased compared with the other two interfaces. In the mixed lung model, there were no significant differences in WOB between the three interfaces. NPPV using a helmet is more effective than the other interfaces for WOB in obstructive lung disease.

Hyperinflation and intrinsic positive end-expiratory pressure: less room to breathe.

Science.gov (United States)

Krieger, Bruce P

2009-01-01

Clinically, the symptoms and limited exercise capabilities of patients with chronic obstructive pulmonary disease (COPD) correlate better with changes in lung volumes than with airflow measurements. The realization of the clinical importance of hyperinflation has been overshadowed for decades by the use of forced expiratory volume during 1 s (FEV(1)) and the ratio of the FEV(1) to the forced expiratory vital capacity (FEV(1)/FVC) to categorize the severity and progression of COPD. Hyperinflation is defined as an elevation in the end-expiratory lung volume or functional residual capacity. When severe hyperinflation encroaches upon inspiratory capacity and limits vital capacity, it results in elevated intrinsic positive end-expiratory pressure (PEEPi) that places the diaphragm at a mechanical disadvantage and increases the work of breathing. Severe hyperinflation is the major physiologic cause of the resulting hypercarbic respiratory failure and patients' inability to transition (i.e. wean) from mechanical ventilatory support to spontaneous breathing. This paper reviews the basic physiologic principles of hyperinflation and its clinical manifestations as demonstrated by PEEPi. Also reviewed are the adverse effects of hyperinflation and PEEPi in critically ill patients with COPD, and methods for minimizing or counterbalancing these effects. Copyright 2009 S. Karger AG, Basel.

Ventilation practices in subarachnoid hemorrhage: a cohort study exploring the use of lung protective ventilation.

Science.gov (United States)

Marhong, Jonathan D; Ferguson, Niall D; Singh, Jeffrey M

2014-10-01

Acute respiratory distress syndrome (ARDS) is common following aneurysmal subarachnoid hemorrhage (SAH), but the influence of mechanical ventilator settings on its development is unclear. We sought to determine adherence to lung protective thresholds in ventilated patients with SAH and describe the association between ventilator settings and subsequent development of ARDS. We conducted a retrospective cohort study of consecutive patients receiving mechanical ventilation within 72 h of SAH at a single academic center. Ventilator settings and blood gas data were collected twice daily for the first 7 days of ventilation along with ICU and hospital outcomes. Lung protective ventilation was defined as follows: tidal volume ≤8 mL/kg of predicted body weight, positive end-expiratory pressure (PEEP) ≥5 cm H(2)O, and peak or plateau pressure ≤30 cm H(2)O. The development of ARDS was ascertained retrospectively by PaO(2)/FiO(2) ≤300 with new bilateral lung opacities on chest X-ray within one day of hypoxemia. We identified 62 patients who underwent early mechanical ventilation following SAH. PS and Continuous Positive Airway Pressure were common ventilator modes with a median tidal volume of 7.8 mL/kg [interquartile range 6.8-8.8], median peak pressure of 14 cm H(2)O [IQR 12-17], and median PEEP of 5 cm H(2)O [IQR 5-6]. Adherence to tidal volumes ≤8 mL/kg was seen in 64 % of all observations and peak pressures protective criteria were seen in 58 % of all observations. Thirty-one patients (50 %) were determined to have ARDS. ARDS patients were more frequently ventilated with a peak pressure >30 cm H(2)O (11.3 % of ARDS ventilation days vs. 0 % of non-ARDS ventilation days; p mechanical ventilation frequently breathe spontaneously, generating tidal volumes above usual protective thresholds regardless of meeting ARDS criteria. In patients with SAH, the presence of an additional ARDS risk factor should prompt close screening for the development of ARDS and

A randomized comparison of different ventilator strategies during thoracotomy for pulmonary resection.

Science.gov (United States)

Maslow, Andrew D; Stafford, Todd S; Davignon, Kristopher R; Ng, Thomas

2013-07-01

Protective lung ventilation is reported to benefit patients with acute respiratory distress syndrome. It is not known whether protective lung ventilation is also beneficial to patients undergoing single-lung ventilation for elective pulmonary resection. In an institutional review board-approved prospective randomized trial, 34 patients undergoing elective pulmonary resection requiring single-lung ventilation were enrolled. Informed consent was obtained. Patients were randomized to 1 of 2 groups: (1) high tidal volume (Hi-TV) of 10 mL/kg, rate of 7 breaths/min, and zero positive end-expiratory pressure or (2) low tidal volume (Lo-TV) of 5 mL/kg, rate of 14 breaths/min, and 5 cmH2O positive end-expiratory pressure. Ventilator settings were continued during both double- and single-lung ventilation. Pulmonary functions, hemodynamics, and postoperative outcomes were recorded. Patient demographics, operative characteristics, intraoperative hemodynamics, and postoperative pain and sedation scores were similar between the 2 groups. During most time periods, airway pressures (peak and plateau) were significantly higher in the Hi-TV group; however, plateau pressures remained less than 30 cmH2O at all times for all patients. The Hi-TV group had significantly lower arterial carbon dioxide tension, less arterial carbon dioxide tension-end-tidal carbon dioxide gradient, lower alveolar dead space ratio, and higher dynamic pulmonary compliance. There were no differences in postoperative morbidity and hospital days between the 2 groups, but atelectasis scores on postoperative days 1 and 2 were lower in the Hi-TV group. The use of Hi-TV during single-lung ventilation for pulmonary resection resulted in no increase in morbidity and was associated with less hypercarbia, less dead space ventilation, better dynamic compliance, and less postoperative atelectasis. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

[Effects of noninvasive proportional assist vs pressure support ventilation on respiratory work in chronic obstructive pulmonary disease patients with hypercapnia].

Science.gov (United States)

Zhang, J H; Luo, Q; Zhang, H J; Chen, R C

2017-06-12

Objective: To investigate the effect of noninvasive proportional assist ventilation (PAV) on respiratory work in chronic obstructive pulmonary disease(COPD) patients, in comparison to noninvasive pressure support ventilation(PSV). Methods: Ten severe COPD patients with hypercapnia during acute exacerbation were examined. The baseline inspiratory pressure of PSV (PS) and the assistance level of PAV(PA) were titrated by patients' tolerance. In addition to the baseline PS and PA, an additional decrease by 25% (PS-=75% PS, PA-=75% PA) or increase by 25% (PS+ =125% PS, PA+ =125% PA) of the assist level were applied to the patients. After the assessment of unassisted spontaneous breathing (SB), the patient was placed on the 6 levels of noninvasive-PSV and noninvasive-PAV in random sequence. Each level lasted at least 20 minutes. Respiratory rate (RR), tidal volume (Vt), and respiratory work(Wex, Wip and Wv) were measured. Asynchrony index (AI) was calculated. Results: During ventilation, Vt was significantly higher with each assist level than with SB. The Vt was significant increased with PS+ than with PA+ . An increase in expiratory work(Wex) and decrease in inspiratory work(Wip) were observed respectively, with the increasing assist level. The inspiratory muscles assessed by Wip were more unloaded at PS compared with PA [PS: (1.59±1.27) J/min vs PA: (4.99±3.48) J/min P increased with the increasing assist level of PSV [PS-: (0.46±0.57)%, PS: (1.36±1.24)% PS+ : (5.26±4.77)]. No asynchrony events were observed at PA- and PA. "Runaway" (expiratory asynchrony) was observed during PA+ [AI: (2.62±2.72)%]. Conclusions: Noninvasive-PAV can increase the Vt and decrease the Wip of the COPD patients with hypercapnia and avoid the over-assistance. The "Runaway" will occur at assist level higher than that set by tolerance. Physiological data can monitor the patient's responses and the ventilator-patient interaction, which may provide objective criteria for ventilator setting.

[Effectiveness of nasal positive pressure ventilation in the management of acute refractory left ventricular insufficiency].

Science.gov (United States)

Chesi, G; Pinelli, G; Galimberti, D; Navazio, A; Montanari, P

1994-04-01

Ehen refractory to optimal medical treatment cardiogenic pulmonary edema requires mechanical ventilation as a last therapeutic resource. In recent years an increasing number of authors reported their experience in the management of acute or subacute respiratory failure with non-invasive mechanical ventilation by nasal mask. Encouraged by the first promising results reported in literature we experimented this new therapeutic tool in a first group of seven elderly patients (mean age: 76.57--range: 65-89); they all had been admitted for severe cardiogenic pulmonary edema unresponsive to maximal doses of the conventional drugs available for treating acute decompensated heart failure. The enrolled patients were treated with intermittent ventilation administered by nasal mask at selected values of inspiratory positive airway pressure (IPAP) that were comprised between 10 and 20 cm H2O. At the same time an expiratory positive airway pressure (EPAP) at values comprised between 3 and 8 cm H2O was applied. Ventilation was continued for variable periods of 3-24 hours until acceptable values of PaO2 and PaCO2 were obtained. The ventilation modality was spontaneous, spontaneous-time or timed depending on the patients' level of consciousness at starting time. A good short-term outcome was achieved in all the patients regardless of the ventilation modality applied. The main blood gas alteration was severe hypercapnia with acidosis in three patients, while the other four presented critical hypoxemia unresponsive to simple oxygen supply even if delivered by high-flow Venturi mask. Four of our seven patients were discharged from hospital in satisfactory haemodynamic conditions; the remaining three died during hospitalization from refractory heart failure. In this our preliminary experience the therapeutic approach with nasal positive pressure ventilation (NPPV) and EPAP proved to be very effective to improve the signs and symptoms of acute refractory cardiogenic pulmonary edema as

Effects of positive end-expiratory pressure on arthroscopic shoulder surgery under general anesthesia.

Science.gov (United States)

Ersoy, Ayşın; Çakırgöz, Mensure; Ervatan, Zekeriya; Kıran, Özlem; Türkmen, Aygen; Esenyel, Cem Zeki

2016-01-01

Our study is a prospective, randomized study on patients undergoing arthroscopic shoulder surgery in the beach-chair position to evaluate the effects of positive end-expiratory pressure (PEEP) on hemodynamic stability, providing a bloodless surgical field and surgical satisfaction. Fifty patients were divided into two groups. Group I (n=25) had zero end-expiratory pressure (ZEEP) administered under general anesthesia, and group II (n=25) had +5 PEEP administered. During surgery, intraarticular hemorrhage and surgical satisfaction were evaluated on a scale of 0-10. During surgery, at the 5th, 30th, 60th, and 90th minutes and at the end of surgery, heart rate, mean arterial pressure (MAP), and positive inspiratory pressure were recorded. At the end of the surgery, the amount of bleeding and duration of the operation were recorded. In group I, the duration of operation and amount of bleeding were found to be significantly greater than those in group II (pshoulder surgery in the beach-chair position reduces the amount of hemorrhage in the surgical field and thus increases surgical satisfaction without requiring the creation of controlled hypotension.

Mathematics of Ventilator-induced Lung Injury.

Science.gov (United States)

Rahaman, Ubaidur

2017-08-01

Ventilator-induced lung injury (VILI) results from mechanical disruption of blood-gas barrier and consequent edema and releases of inflammatory mediators. A transpulmonary pressure (P L ) of 17 cmH 2 O increases baby lung volume to its anatomical limit, predisposing to VILI. Viscoelastic property of lung makes pulmonary mechanics time dependent so that stress (P L ) increases with respiratory rate. Alveolar inhomogeneity in acute respiratory distress syndrome acts as a stress riser, multiplying global stress at regional level experienced by baby lung. Limitation of stress (P L ) rather than strain (tidal volume [V T ]) is the safe strategy of mechanical ventilation to prevent VILI. Driving pressure is the noninvasive surrogate of lung strain, but its relations to P L is dependent on the chest wall compliance. Determinants of lung stress (V T , driving pressure, positive end-expiratory pressure, and inspiratory flow) can be quantified in terms of mechanical power, and a safe threshold can be determined, which can be used in decision-making between safe mechanical ventilation and extracorporeal lung support.

Key considerations on nebulization of antimicrobial agents to mechanically ventilated patients.

Science.gov (United States)

Rello, J; Rouby, J J; Sole-Lleonart, C; Chastre, J; Blot, S; Luyt, C E; Riera, J; Vos, M C; Monsel, A; Dhanani, J; Roberts, J A

2017-09-01

Nebulized antibiotics have an established role in patients with cystic fibrosis or bronchiectasis. Their potential benefit to treat respiratory infections in mechanically ventilated patients is receiving increasing interest. In this consensus statement of the European Society of Clinical Microbiology and Infectious Diseases, the body of evidence of the therapeutic utility of aerosolized antibiotics in mechanically ventilated patients was reviewed and resulted in the following recommendations: Vibrating-mesh nebulizers should be preferred to jet or ultrasonic nebulizers. To decrease turbulence and limit circuit and tracheobronchial deposition, we recommend: (a) the use of specifically designed respiratory circuits avoiding sharp angles and characterized by smooth inner surfaces, (b) the use of specific ventilator settings during nebulization including use of a volume controlled mode using constant inspiratory flow, tidal volume 8 mL/kg, respiratory frequency 12 to 15 bpm, inspiratory:expiratory ratio 50%, inspiratory pause 20% and positive end-expiratory pressure 5 to 10 cm H 2 O and (c) the administration of a short-acting sedative agent if coordination between the patient and the ventilator is not obtained, to avoid patient's flow triggering and episodes of peak decelerating inspiratory flow. A filter should be inserted on the expiratory limb to protect the ventilator flow device and changed between each nebulization to avoid expiratory flow obstruction. A heat and moisture exchanger and/or conventional heated humidifier should be stopped during the nebulization period to avoid a massive loss of aerosolized particles through trapping and condensation. If these technical requirements are not followed, there is a high risk of treatment failure and adverse events in mechanically ventilated patients receiving nebulized antibiotics for pneumonia. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights

Ventilation distribution measured with EIT at varying levels of pressure support and Neurally Adjusted Ventilatory Assist in patients with ALI.

Science.gov (United States)

Blankman, Paul; Hasan, Djo; van Mourik, Martijn S; Gommers, Diederik

2013-06-01

The purpose of this study was to compare the effect of varying levels of assist during pressure support (PSV) and Neurally Adjusted Ventilatory Assist (NAVA) on the aeration of the dependent and non-dependent lung regions by means of Electrical Impedance Tomography (EIT). We studied ten mechanically ventilated patients with Acute Lung Injury (ALI). Positive-End Expiratory Pressure (PEEP) and PSV levels were both 10 cm H₂O during the initial PSV step. Thereafter, we changed the inspiratory pressure to 15 and 5 cm H₂O during PSV. The electrical activity of the diaphragm (EAdi) during pressure support ten was used to define the initial NAVA gain (100 %). Thereafter, we changed NAVA gain to 150 and 50 %, respectively. After each step the assist level was switched back to PSV 10 cm H₂O or NAVA 100 % to get a new baseline. The EIT registration was performed continuously. Tidal impedance variation significantly decreased during descending PSV levels within patients, whereas not during NAVA. The dorsal-to-ventral impedance distribution, expressed according to the center of gravity index, was lower during PSV compared to NAVA. Ventilation contribution of the dependent lung region was equally in balance with the non-dependent lung region during PSV 5 cm H₂O, NAVA 50 and 100 %. Neurally Adjusted Ventilatory Assist ventilation had a beneficial effect on the ventilation of the dependent lung region and showed less over-assistance compared to PSV in patients with ALI.

Pressure dynamic characteristics of pressure controlled ventilation system of a lung simulator.

Science.gov (United States)

Shi, Yan; Ren, Shuai; Cai, Maolin; Xu, Weiqing; Deng, Qiyou

2014-01-01

Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems.

Intraoperative mechanical ventilation for the pediatric patient.

Science.gov (United States)

Kneyber, Martin C J

2015-09-01

Invasive mechanical ventilation is required when children undergo general anesthesia for any procedure. It is remarkable that one of the most practiced interventions such as pediatric mechanical ventilation is hardly supported by any scientific evidence but rather based on personal experience and data from adults, especially as ventilation itself is increasingly recognized as a harmful intervention that causes ventilator-induced lung injury. The use of low tidal volume and higher levels of positive end-expiratory pressure became an integral part of lung-protective ventilation following the outcomes of clinical trials in critically ill adults. This approach has been readily adopted in pediatric ventilation. However, a clear association between tidal volume and mortality has not been ascertained in pediatrics. In fact, experimental studies have suggested that young children might be less susceptible to ventilator-induced lung injury. As such, no recommendations on optimal lung-protective ventilation strategy in children with or without lung injury can be made. Copyright © 2015 Elsevier Ltd. All rights reserved.

Monitoring of noninvasive ventilation by built-in software of home bilevel ventilators: a bench study.

Science.gov (United States)

Contal, Olivier; Vignaux, Laurence; Combescure, Christophe; Pepin, Jean-Louis; Jolliet, Philippe; Janssens, Jean-Paul

2012-02-01

Current bilevel positive-pressure ventilators for home noninvasive ventilation (NIV) provide physicians with software that records items important for patient monitoring, such as compliance, tidal volume (Vt), and leaks. However, to our knowledge, the validity of this information has not yet been independently assessed. Testing was done for seven home ventilators on a bench model adapted to simulate NIV and generate unintentional leaks (ie, other than of the mask exhalation valve). Five levels of leaks were simulated using a computer-driven solenoid valve (0-60 L/min) at different levels of inspiratory pressure (15 and 25 cm H(2)O) and at a fixed expiratory pressure (5 cm H(2)O), for a total of 10 conditions. Bench data were compared with results retrieved from ventilator software for leaks and Vt. For assessing leaks, three of the devices tested were highly reliable, with a small bias (0.3-0.9 L/min), narrow limits of agreement (LA), and high correlations (R(2), 0.993-0.997) when comparing ventilator software and bench results; conversely, for four ventilators, bias ranged from -6.0 L/min to -25.9 L/min, exceeding -10 L/min for two devices, with wide LA and lower correlations (R(2), 0.70-0.98). Bias for leaks increased markedly with the importance of leaks in three devices. Vt was underestimated by all devices, and bias (range, 66-236 mL) increased with higher insufflation pressures. Only two devices had a bias ventilation must be aware of differences in the estimation of leaks and Vt by ventilator software. Also, leaks are reported in different ways according to the device used.

Performance of current intensive care unit ventilators during pressure and volume ventilation.

Science.gov (United States)

Marchese, Andrew D; Sulemanji, Demet; Chipman, Daniel; Villar, Jesús; Kacmarek, Robert M

2011-07-01

Intensive-care mechanical ventilators regularly enter the market, but the gas-delivery capabilities of many have never been assessed. We evaluated 6 intensive-care ventilators in the pressure support (PS), pressure assist/control (PA/C), and volume assist/control (VA/C) modes, with lung-model mechanics combinations of compliance and resistance of 60 mL/cm H(2)O and 10 cm H(2)O/L/s, 60 mL/cm H(2)O and 5 cm H(2)O/L/s, and 30 mL/cm H(2)O and 10 cm H(2)O/L/s, and inspiratory muscle effort of 5 and 10 cm H(2)O. PS and PA/C were set to 15 cm H(2)O, and PEEP to 5 and 15 cm H(2)O in all modes. During VA/C, tidal volume was set at 500 mL and inspiratory time was set at 0.8 second. Rise time and termination criteria were set at the manufacturers' defaults, and to an optimal level during PS and PA/C. There were marked differences in ventilator performance in all 3 modes. VA/C had the greatest difficulty meeting lung model demand and the greatest variability across all tested scenarios and ventilators. From high to low inspiratory muscle effort, pressure-to-trigger, time for pressure to return to baseline, and triggering pressure-time product decreased in all modes. With increasing resistance and decreasing compliance, tidal volume, pressure-to-trigger, time-to-trigger, time for pressure to return to baseline, time to 90% of peak pressure, and pressure-time product decreased. There were large differences between the default and optimal settings for all the variables in PS and PA/C. Performance was not affected by PEEP. Most of the tested ventilators performed at an acceptable level during the majority of evaluations, but some ventilators performed inadequately during specific settings. Bedside clinical evaluation is needed.

Using an expiratory resistor, arterial pulse pressure variations predict fluid responsiveness during spontaneous breathing: an experimental porcine study.

Science.gov (United States)

Dahl, Michael K; Vistisen, Simon T; Koefoed-Nielsen, Jacob; Larsson, Anders

2009-01-01

Fluid responsiveness prediction is difficult in spontaneously breathing patients. Because the swings in intrathoracic pressure are minor during spontaneous breathing, dynamic parameters like pulse pressure variation (PPV) and systolic pressure variation (SPV) are usually small. We hypothesized that during spontaneous breathing, inspiratory and/or expiratory resistors could induce high arterial pressure variations at hypovolemia and low variations at normovolemia and hypervolemia. Furthermore, we hypothesized that SPV and PPV could predict fluid responsiveness under these conditions. Eight prone, anesthetized and spontaneously breathing pigs (20 to 25 kg) were subjected to a sequence of 30% hypovolemia, normovolemia, and 20% and 40% hypervolemia. At each volemic level, the pigs breathed in a randomized order either through an inspiratory and/or an expiratory threshold resistor (7.5 cmH2O) or only through the tracheal tube without any resistor. Hemodynamic and respiratory variables were measured during the breathing modes. Fluid responsiveness was defined as a 15% increase in stroke volume (DeltaSV) following fluid loading. Stroke volume was significantly lower at hypovolemia compared with normovolemia, but no differences were found between normovolemia and 20% or 40% hypervolemia. Compared with breathing through no resistor, SPV was magnified by all resistors at hypovolemia whereas there were no changes at normovolemia and hypervolemia. PPV was magnified by the inspiratory resistor and the combined inspiratory and expiratory resistor. Regression analysis of SPV or PPV versus DeltaSV showed the highest R2 (0.83 for SPV and 0.52 for PPV) when the expiratory resistor was applied. The corresponding sensitivity and specificity for prediction of fluid responsiveness were 100% and 100%, respectively, for SPV and 100% and 81%, respectively, for PPV. Inspiratory and/or expiratory threshold resistors magnified SPV and PPV in spontaneously breathing pigs during hypovolemia

21 CFR 868.5935 - External negative pressure ventilator.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External negative pressure ventilator. 868.5935 Section 868.5935 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... ventilator. (a) Identification. An external negative pressure ventilator (e.g., iron lung, cuirass) is a...

Effects of Pressure Support Ventilation May Be Lost at High Exercise Intensities in People with COPD.

Science.gov (United States)

Anekwe, David; de Marchie, Michel; Spahija, Jadranka

2017-06-01

Pressure support ventilation (PSV) may be used for exercise training in chronic obstructive pulmonary disease (COPD), but its acute effect on maximum exercise capacity is not fully known. The objective of this study was to evaluate the effect of 10 cm H 2 O PSV and a fixed PSV level titrated to patient comfort at rest on maximum exercise workload (WLmax), breathing pattern and metabolic parameters during a symptom-limited incremental bicycle test in individuals with COPD. Eleven individuals with COPD (forced expiratory volume in one second: 49 ± 16%; age: 64 ± 7 years) performed three exercise tests: without a ventilator, with 10 cm H 2 O of PSV and with a fixed level titrated to comfort at rest, using a SERVO-i ventilator. Tests were performed in randomized order and at least 48 hours apart. The WLmax, breathing pattern, metabolic parameters, and mouth pressure (Pmo) were compared using repeated measures analysis of variance. Mean PSV during titration was 8.2 ± 4.5 cm H 2 O. There was no difference in the WLmax achieved during the three tests. At rest, PSV increased the tidal volume, minute ventilation, and mean inspiratory flow with a lower end-tidal CO 2 ; this was not sustained at peak exercise. Pmo decreased progressively (decreased unloading) with PSV at workloads close to peak, suggesting the ventilator was unable to keep up with the increased ventilatory demand at high workloads. In conclusion, with a Servo-i ventilator, 10 cm H 2 O of PSV and a fixed level of PSV established by titration to comfort at rest, is ineffective for the purpose of achieving higher exercise workloads as the acute physiological effects may not be sustained at peak exercise.

Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

Directory of Open Access Journals (Sweden)

Yan Shi

2014-01-01

Full Text Available Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems.

Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

Science.gov (United States)

Shi, Yan; Ren, Shuai; Cai, Maolin; Xu, Weiqing; Deng, Qiyou

2014-01-01

Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems. PMID:25197318

Adaptive support ventilation may deliver unwanted respiratory rate-tidal volume combinations in patients with acute lung injury ventilated according to an open lung concept.

Science.gov (United States)

Dongelmans, Dave A; Paulus, Frederique; Veelo, Denise P; Binnekade, Jan M; Vroom, Margreeth B; Schultz, Marcus J

2011-05-01

With adaptive support ventilation, respiratory rate and tidal volume (V(T)) are a function of the Otis least work of breathing formula. We hypothesized that adaptive support ventilation in an open lung ventilator strategy would deliver higher V(T)s to patients with acute lung injury. Patients with acute lung injury were ventilated according to a local guideline advising the use of lower V(T) (6-8 ml/kg predicted body weight), high concentrations of positive end-expiratory pressure, and recruitment maneuvers. Ventilation parameters were recorded when the ventilator was switched to adaptive support ventilation, and after recruitment maneuvers. If V(T) increased more than 8 ml/kg predicted body weight, airway pressure was limited to correct for the rise of V(T). Ten patients with a mean (±SD) Pao(2)/Fio(2) of 171 ± 86 mmHg were included. After a switch from pressure-controlled ventilation to adaptive support ventilation, respiratory rate declined (from 31 ± 5 to 21 ± 6 breaths/min; difference = 10 breaths/min, 95% CI 3-17 breaths/min, P = 0.008) and V(T) increased (from 6.5 ± 0.8 to 9.0 ± 1.6 ml/kg predicted body weight; difference = 2.5 ml, 95% CI 0.4-4.6 ml/kg predicted body weight, P = 0.02). Pressure limitation corrected for the rise of V(T), but minute ventilation declined, forcing the user to switch back to pressure-controlled ventilation. Adaptive support ventilation, compared with pressure-controlled ventilation in an open lung strategy setting, delivers a lower respiratory rate-higher V(T) combination. Pressure limitation does correct for the rise of V(T), but leads to a decline in minute ventilation.

Human versus Computer Controlled Selection of Ventilator Settings: An Evaluation of Adaptive Support Ventilation and Mid-Frequency Ventilation

Directory of Open Access Journals (Sweden)

Eduardo Mireles-Cabodevila

2012-01-01

Full Text Available Background. There are modes of mechanical ventilation that can select ventilator settings with computer controlled algorithms (targeting schemes. Two examples are adaptive support ventilation (ASV and mid-frequency ventilation (MFV. We studied how different clinician-chosen ventilator settings are from these computer algorithms under different scenarios. Methods. A survey of critical care clinicians provided reference ventilator settings for a 70 kg paralyzed patient in five clinical/physiological scenarios. The survey-derived values for minute ventilation and minute alveolar ventilation were used as goals for ASV and MFV, respectively. A lung simulator programmed with each scenario’s respiratory system characteristics was ventilated using the clinician, ASV, and MFV settings. Results. Tidal volumes ranged from 6.1 to 8.3 mL/kg for the clinician, 6.7 to 11.9 mL/kg for ASV, and 3.5 to 9.9 mL/kg for MFV. Inspiratory pressures were lower for ASV and MFV. Clinician-selected tidal volumes were similar to the ASV settings for all scenarios except for asthma, in which the tidal volumes were larger for ASV and MFV. MFV delivered the same alveolar minute ventilation with higher end expiratory and lower end inspiratory volumes. Conclusions. There are differences and similarities among initial ventilator settings selected by humans and computers for various clinical scenarios. The ventilation outcomes are the result of the lung physiological characteristics and their interaction with the targeting scheme.

Protective mechanical ventilation, why use it?

Science.gov (United States)

Seiberlich, Emerson; Santana, Jonas Alves; Chaves, Renata de Andrade; Seiberlich, Raquel Carvalho

2011-01-01

Mechanical ventilation (MV) strategies have been modified over the last decades with a tendency for increasingly lower tidal volumes (VT). However, in patients without acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) the use of high VTs is still very common. Retrospective studies suggest that this practice can be related to mechanical ventilation-associated ALI. The objective of this review is to search for evidence to guide protective MV in patients with healthy lungs and to suggest strategies to properly ventilate lungs with ALI/ARDS. A review based on the main articles that focus on the use of strategies of mechanical ventilation was performed. Consistent studies to determine which would be the best way to ventilate a patient with healthy lungs are lacking. Expert recommendations and current evidence presented in this article indicate that the use of a VT lower than 10 mL.kg(-1), associated with positive end-expiratory pressure (PEEP) ≥ 5 cmH(2)O without exceeding a pressure plateau of 15 to 20 cmH(2)O could minimize alveolar stretching at the end of inspiration and avoid possible inflammation or alveolar collapse. Copyright © 2011 Elsevier Editora Ltda. All rights reserved.

Defining a Ventilation Strategy for Flexible Bronchoscopy on Mechanically Ventilated Patients in the Medical Intensive Care Unit.

Science.gov (United States)

Greenstein, Yonatan Y; Shakespeare, Eric; Doelken, Peter; Mayo, Paul H

2017-07-01

Flexible bronchoscopy (FB) in intubated patients on mechanical ventilation increases airway resistance. During FB, two ventilatory strategies are possible: maintaining tidal volume (VT) while maintaining baseline CO2 or allowing reduction of VT. The former strategy carries risk of hyperinflation due to expiratory flow limitation with FB. The aim of the authors was too study end expiratory lung volume (EELV) during FB of intubated subjects while limiting VT. We studied 16 subjects who were intubated on mechanical ventilation and required FB. Changes in EELV were measured by respiratory inductance plethysmography. Ventilator mechanics, EELV, and arterial blood gases, were measured. FB insertions decreased EELV in 64% of cases (-325±371 mL) and increased it in 32% of cases (65±59 mL). Suctioning decreased EELV in 76% of cases (-120±104 mL) and increased it in 16% of cases (29±33 mL). Respiratory mechanics were unchanged. Pre-FB and post-FB, PaO2 decreased by 61±96 mm Hg and PaCO2 increased by 15±7 mm Hg. There was no clinically significant increase in EELV in any subject during FB. Decreases in EELV coincided with FB-suctioning maneuvers. Peak pressure limiting ventilation protected the subject against hyperinflation with a consequent, well-tolerated reduction in VT, and hypercapnea. Suctioning should be limited, especially in patients vulnerable to derecruitment effect.

Implementation of a Goal-Directed Mechanical Ventilation Order Set Driven by Respiratory Therapists Improves Compliance With Best Practices for Mechanical Ventilation.

Science.gov (United States)

Radosevich, Misty A; Wanta, Brendan T; Meyer, Todd J; Weber, Verlin W; Brown, Daniel R; Smischney, Nathan J; Diedrich, Daniel A

2017-01-01

Data regarding best practices for ventilator management strategies that improve outcomes in acute respiratory distress syndrome (ARDS) are readily available. However, little is known regarding processes to ensure compliance with these strategies. We developed a goal-directed mechanical ventilation order set that included physician-specified lung-protective ventilation and oxygenation goals to be implemented by respiratory therapists (RTs). We sought as a primary outcome to determine whether an RT-driven order set with predefined oxygenation and ventilation goals could be implemented and associated with improved adherence with best practice. We evaluated 1302 patients undergoing invasive mechanical ventilation (1693 separate episodes of invasive mechanical ventilation) prior to and after institution of a standardized, goal-directed mechanical ventilation order set using a controlled before-and-after study design. Patient-specific goals for oxygenation partial pressure of oxygen in arterial blood (Pao 2 ), ARDS Network [Net] positive end-expiratory pressure [PEEP]/fraction of inspired oxygen [Fio 2 ] table use) and ventilation (pH, partial pressure of carbon dioxide) were selected by prescribers and implemented by RTs. Compliance with the new mechanical ventilation order set was high: 88.2% compliance versus 3.8% before implementation of the order set ( P mechanical ventilation, intensive care unit (ICU) length of stay, and in-hospital or ICU mortality. A standardized best practice mechanical ventilation order set can be implemented by a multidisciplinary team and is associated with improved compliance to written orders and adherence to the ARDSNet PEEP/Fio 2 table.

Protective mechanical ventilation in United Kingdom critical care units: A multicentre audit.

Science.gov (United States)

Newell, Christopher P; Martin, Matthew J; Richardson, Neil; Bourdeaux, Christopher P

2017-05-01

Lung protective ventilation is becoming increasingly used for all critically ill patients being mechanically ventilated on a mandatory ventilator mode. Compliance with the universal application of this ventilation strategy in intensive care units in the United Kingdom is unknown. This 24-h audit of ventilation practice took place in 16 intensive care units in two regions of the United Kingdom. The mean tidal volume for all patients being ventilated on a mandatory ventilator mode was 7.2(±1.4) ml kg -1 predicted body weight and overall compliance with low tidal volume ventilation (≤6.5 ml kg -1 predicted body weight) was 34%. The mean tidal volume for patients ventilated with volume-controlled ventilation was 7.0(±1.2) ml kg -1 predicted body weight and 7.9(±1.8) ml kg -1 predicted body weight for pressure-controlled ventilation ( P  < 0.0001). Overall compliance with recommended levels of positive end-expiratory pressure was 72%. Significant variation in practice existed both at a regional and individual unit level.

Increasing the inspiratory time and I:E ratio during mechanical ventilation aggravates ventilator-induced lung injury in mice.

Science.gov (United States)

Müller-Redetzky, Holger C; Felten, Matthias; Hellwig, Katharina; Wienhold, Sandra-Maria; Naujoks, Jan; Opitz, Bastian; Kershaw, Olivia; Gruber, Achim D; Suttorp, Norbert; Witzenrath, Martin

2015-01-28

Lung-protective ventilation reduced acute respiratory distress syndrome (ARDS) mortality. To minimize ventilator-induced lung injury (VILI), tidal volume is limited, high plateau pressures are avoided, and positive end-expiratory pressure (PEEP) is applied. However, the impact of specific ventilatory patterns on VILI is not well defined. Increasing inspiratory time and thereby the inspiratory/expiratory ratio (I:E ratio) may improve oxygenation, but may also be harmful as the absolute stress and strain over time increase. We thus hypothesized that increasing inspiratory time and I:E ratio aggravates VILI. VILI was induced in mice by high tidal-volume ventilation (HVT 34 ml/kg). Low tidal-volume ventilation (LVT 9 ml/kg) was used in control groups. PEEP was set to 2 cm H2O, FiO2 was 0.5 in all groups. HVT and LVT mice were ventilated with either I:E of 1:2 (LVT 1:2, HVT 1:2) or 1:1 (LVT 1:1, HVT 1:1) for 4 hours or until an alternative end point, defined as mean arterial blood pressure below 40 mm Hg. Dynamic hyperinflation due to the increased I:E ratio was excluded in a separate group of animals. Survival, lung compliance, oxygenation, pulmonary permeability, markers of pulmonary and systemic inflammation (leukocyte differentiation in lung and blood, analyses of pulmonary interleukin-6, interleukin-1β, keratinocyte-derived chemokine, monocyte chemoattractant protein-1), and histopathologic pulmonary changes were analyzed. LVT 1:2 or LVT 1:1 did not result in VILI, and all individuals survived the ventilation period. HVT 1:2 decreased lung compliance, increased pulmonary neutrophils and cytokine expression, and evoked marked histologic signs of lung injury. All animals survived. HVT 1:1 caused further significant worsening of oxygenation, compliance and increased pulmonary proinflammatory cytokine expression, and pulmonary and blood neutrophils. In the HVT 1:1 group, significant mortality during mechanical ventilation was observed. According to the "baby lung

The 30-year evolution of airway pressure release ventilation (APRV).

Science.gov (United States)

Jain, Sumeet V; Kollisch-Singule, Michaela; Sadowitz, Benjamin; Dombert, Luke; Satalin, Josh; Andrews, Penny; Gatto, Louis A; Nieman, Gary F; Habashi, Nader M

2016-12-01

Airway pressure release ventilation (APRV) was first described in 1987 and defined as continuous positive airway pressure (CPAP) with a brief release while allowing the patient to spontaneously breathe throughout the respiratory cycle. The current understanding of the optimal strategy to minimize ventilator-induced lung injury is to "open the lung and keep it open". APRV should be ideal for this strategy with the prolonged CPAP duration recruiting the lung and the minimal release duration preventing lung collapse. However, APRV is inconsistently defined with significant variation in the settings used in experimental studies and in clinical practice. The goal of this review was to analyze the published literature and determine APRV efficacy as a lung-protective strategy. We reviewed all original articles in which the authors stated that APRV was used. The primary analysis was to correlate APRV settings with physiologic and clinical outcomes. Results showed that there was tremendous variation in settings that were all defined as APRV, particularly CPAP and release phase duration and the parameters used to guide these settings. Thus, it was impossible to assess efficacy of a single strategy since almost none of the APRV settings were identical. Therefore, we divided all APRV studies divided into two basic categories: (1) fixed-setting APRV (F-APRV) in which the release phase is set and left constant; and (2) personalized-APRV (P-APRV) in which the release phase is set based on changes in lung mechanics using the slope of the expiratory flow curve. Results showed that in no study was there a statistically significant worse outcome with APRV, regardless of the settings (F-ARPV or P-APRV). Multiple studies demonstrated that P-APRV stabilizes alveoli and reduces the incidence of acute respiratory distress syndrome (ARDS) in clinically relevant animal models and in trauma patients. In conclusion, over the 30 years since the mode's inception there have been no strict

Haemodynamics and oxygenation improvement induced by high frequency percussive ventilation in a patient with hypoxia following cardiac surgery: a case report

Directory of Open Access Journals (Sweden)

Persi Bruno

2010-10-01

Full Text Available Abstract Introduction High frequency percussive ventilation is a ventilatory technique that delivers small bursts of high flow respiratory gas into the lungs at high rates. It is classified as a pneumatically powered, pressure-regulated, time-cycled, high-frequency flow interrupter modality of ventilation. High frequency percussive ventilation improves the arterial partial pressure of oxygen with the same positive end expiratory pressure and fractional inspiratory oxygen level as conventional ventilation using a minor mean airway pressure in an open circuit. It reduces the barotraumatic events in a hypoxic patient who has low lung-compliance. To the best of our knowledge, there have been no papers published about this ventilation modality in patients with severe hypoxaemia after cardiac surgery. Case presentation A 75-year-old Caucasian man with an ejection fraction of 27 percent, developed a lung infection with severe hypoxaemia [partial pressure of oxygen/fractional inspiratory oxygen of 90] ten days after cardiac surgery. Conventional ventilation did not improve the gas exchange. He was treated with high frequency percussive ventilation for 12 hours with a low conventional respiratory rate (five per minute. His cardiac output and systemic and pulmonary pressures were monitored. Compared to conventional ventilation, high frequency percussive ventilation gives an improvement of the partial pressure of oxygen from 90 to 190 mmHg with the same fractional inspiratory oxygen and positive end expiratory pressure level. His right ventricular stroke work index was lowered from 19 to seven g-m/m2/beat; his pulmonary vascular resistance index from 267 to 190 dynes•seconds/cm5/m2; left ventricular stroke work index from 28 to 16 gm-m/m2/beat; and his pulmonary arterial wedge pressure was lowered from 32 to 24 mmHg with a lower mean airway pressure compared to conventional ventilation. His cardiac index (2.7 L/min/m2 and ejection fraction (27 percent

Mask Ventilation during Induction of General Anesthesia: Influences of Obstructive Sleep Apnea.

Science.gov (United States)

Sato, Shin; Hasegawa, Makoto; Okuyama, Megumi; Okazaki, Junko; Kitamura, Yuji; Sato, Yumi; Ishikawa, Teruhiko; Sato, Yasunori; Isono, Shiroh

2017-01-01

Depending on upper airway patency during anesthesia induction, tidal volume achieved by mask ventilation may vary. In 80 adult patients undergoing general anesthesia, the authors tested a hypothesis that tidal volume during mask ventilation is smaller in patients with sleep-disordered breathing priorly defined as apnea hypopnea index greater than 5 per hour. One-hand mask ventilation with a constant ventilator setting (pressure-controlled ventilation) was started 20 s after injection of rocuronium and maintained for 1 min during anesthesia induction. Mask ventilation efficiency was assessed by the breath number needed to initially exceed 5 ml/kg ideal body weight of expiratory tidal volume (primary outcome) and tidal volumes (secondary outcomes) during initial 15 breaths (UMIN000012494). Tidal volume progressively increased by more than 70% in 1 min and did not differ between sleep-disordered breathing (n = 42) and non-sleep-disordered breathing (n = 38) patients. In post hoc subgroup analyses, the primary outcome breath number (mean [95% CI], 5.7 [4.1 to 7.3] vs. 1.7 [0.2 to 3.2] breath; P = 0.001) and mean tidal volume (6.5 [4.6 to 8.3] vs. 9.6 [7.7 to 11.4] ml/kg ideal body weight; P = 0.032) were significantly smaller in 20 sleep-disordered breathing patients with higher apnea hypopnea index (median [25th to 75th percentile]: 21.7 [17.6 to 31] per hour) than in 20 non-sleep disordered breathing subjects with lower apnea hypopnea index (1.0 [0.3 to 1.5] per hour). Obesity and occurrence of expiratory flow limitation during one-hand mask ventilation independently explained the reduction of efficiency of mask ventilation, while the use of two hands effectively normalized inefficient mask ventilation during one-hand mask ventilation. One-hand mask ventilation is difficult in patients with obesity and severe sleep-disordered breathing particularly when expiratory flow limitation occurs during mask ventilation.

High altitude pulmonary edema and exercise at 4,400 meters on Mount McKinley. Effect of expiratory positive airway pressure.

Science.gov (United States)

Schoene, R B; Roach, R C; Hackett, P H; Harrison, G; Mills, W J

1985-03-01

Breathing against positive expiratory pressure has been used to improve gas exchange in many forms of pulmonary edema, and forced expiration against resistance during exercise has been advocated for climbing at high altitude as a method to optimize performance. To evaluate the effect of expiratory positive airway pressure (EPAP) on climbers with high altitude pulmonary edema (HAPE) and on exercise at high altitude, we studied four climbers with HAPE at rest and 13 healthy climbers during exercise on a bicycle ergometer at 4400 m. We measured minute ventilation (VI, L/min), arterial oxygen saturation (SaO2 percent), end-tidal carbon dioxide (PACO2, mm Hg), respiratory rate (RR), and heart rate (HR) during the last minute of a five minute interval at rest in the climbers with HAPE, and at rest, 300, and 600 kpm/minute workloads on a bicycle ergometer in the healthy subjects. The HAPE subjects demonstrated an increased SaO2 percent, no change in HR or VI, and a decrease in RR on EPAP as compared to control. In normal subjects, SaO2 percent, VI, and heart rate were significantly higher on EPAP 10 cm H2O than 0 cm H2O control (p less than 0.01, 0.01, and 0.05, respectively). The RR and PaCO2 were not significantly different. In summary, EPAP improves gas exchange in HAPE subjects at rest. The EPAP in normal subjects at high altitude resulted in a higher SaO2 percent at the expense of a higher VI and higher HR. These results suggest that the work of breathing is higher and the stroke volume lower on EPAP. The positive pressure mask may be an effective temporizing measure for victims of HAPE who cannot immediately go to a lower altitude.

Ventilation therapy for patients suffering from obstructive lung diseases.

Science.gov (United States)

Jungblut, Sven A; Heidelmann, Lena M; Westerfeld, Andreas; Frickmann, Hagen; Körber, Mareike K; Zautner, Andreas E

2014-01-01

Severe bronchial obstruction due to one of the major pulmonary diseases: asthma, COPD, or emphysema often requires mechanical ventilation support. Otherwise, patients are at risk of severe hypooxygenation with consecutive overloading and dilatation of the right cardiac ventricle with subsequent failure. This review focuses on how to manage a calculated ventilation therapy of patients suffering from bronchial obstruction and relevant patents. Options and pitfalls of invasive and non-invasive ventilation in the intensive care setting regarding clinical improvement and final outcome are discussed. The non-invasive ventilation is very efficient in treating acute or chronic respiratory failure in COPD patients and is capable of shortening the duration of hospitalization. Further non-invasive ventilation can successfully support the weaning after a long-lasting ventilation therapy and improve the prognosis of COPD patients. "Permissive hypercapnia" is unequivocally established in invasive ventilation therapy of severe bronchial obstruction in situations of limited ventilation. When intrinsic positive end-expiratory pressure (PEEP) and elevated airways resistance are present PEEP may be useful although external-PEEP application relieves over-inflation only in selected patients with airway obstruction during controlled mechanical ventilation. Upper limit of airways peak pressure used in "protective ventilation" of adult respiratory distress syndrome (ARDS) patients can be exceeded under certain circumstances.

Tidal volume delivery from ICU ventilators at BTPS conditions: a bench study.

Science.gov (United States)

Duchateau, Paul; Guérin, Claude

2013-04-01

Even though it is not a common practice, an external filter to the expiratory limb of the breathing circuit may protect the expiratory valve from water saturation in case of nebulization, or from the environment in case of lung infection with multi-drug-resistant micro-organisms or H1N1 influenza. We added an external filter to the expiratory limb and measured tidal volume (VT) from 6 ICU ventilators: 2 with built-in expiratory filter (Avea, Puritan Bennett 840), and 4 without (Engström Carestation, Evita XL, Evita V500, and Servo-i), set in volume controlled mode, at BTPS (body temperature and pressure saturated) condition, with a heated humidifier and a lung model (compliance 16 mL/cm H2O, resistance 20 cm H2O/L/s) placed inside a neonatal incubator. The temperature was targeted at 37°C for both the heated humidifier and the incubator. The setup was run continuously for 24 hours. In the latter 4 ICU ventilators, a Hygrobac or Sterivent S external filter was placed upstream from the expiratory valve for an additional 24-hour period for each. At the end of this period, VT was measured at 4 nominal VT values (300, 400, 500, and 800 mL) with a pneumotachograph. The volume error computed from the ratio of set to measured VT (% set VT) was the primary end point. In these warm and wet conditions, volume error averaged 96 ± 3% for Avea, 100 ± 7% for Puritan Bennett 840, 90 ± 2% for Evita XL, 100 ± 7% for Evita V500, 105 ± 2% for Servo-i, and 108 ± 4% for Engström Carestation (P ventilators for VT delivery, with further significant changes occurring after addition of a filter at the distal expiratory limb.

Rationale and study design of PROVHILO - a worldwide multicenter randomized controlled trial on protective ventilation during general anesthesia for open abdominal surgery.

Science.gov (United States)

Hemmes, Sabrine N T; Severgnini, Paolo; Jaber, Samir; Canet, Jaume; Wrigge, Hermann; Hiesmayr, Michael; Tschernko, Edda M; Hollmann, Markus W; Binnekade, Jan M; Hedenstierna, Göran; Putensen, Christian; de Abreu, Marcelo Gama; Pelosi, Paolo; Schultz, Marcus J

2011-05-06

Post-operative pulmonary complications add to the morbidity and mortality of surgical patients, in particular after general anesthesia >2 hours for abdominal surgery. Whether a protective mechanical ventilation strategy with higher levels of positive end-expiratory pressure (PEEP) and repeated recruitment maneuvers; the "open lung strategy", protects against post-operative pulmonary complications is uncertain. The present study aims at comparing a protective mechanical ventilation strategy with a conventional mechanical ventilation strategy during general anesthesia for abdominal non-laparoscopic surgery. The PROtective Ventilation using HIgh versus LOw positive end-expiratory pressure ("PROVHILO") trial is a worldwide investigator-initiated multicenter randomized controlled two-arm study. Nine hundred patients scheduled for non-laparoscopic abdominal surgery at high or intermediate risk for post-operative pulmonary complications are randomized to mechanical ventilation with the level of PEEP at 12 cmH(2)O with recruitment maneuvers (the lung-protective strategy) or mechanical ventilation with the level of PEEP at maximum 2 cmH(2)O without recruitment maneuvers (the conventional strategy). The primary endpoint is any post-operative pulmonary complication. The PROVHILO trial is the first randomized controlled trial powered to investigate whether an open lung mechanical ventilation strategy in short-term mechanical ventilation prevents against postoperative pulmonary complications. ISRCTN: ISRCTN70332574.

Monitoring tidal volumes in preterm infants at birth: mask versus endotracheal ventilation.

Science.gov (United States)

van Vonderen, Jeroen J; Hooper, Stuart B; Krabbe, Vera B; Siew, Melissa L; Te Pas, Arjan B

2015-01-01

Upper airway distention during mask ventilation could reduce gas volumes entering the lung compared with ventilation via an endotracheal tube. Therefore, respiratory tract volumes were measured in lambs and tidal volumes were compared in preterm infants before and after intubation. In seven preterm lambs, volumes of the airways (oropharynx, trachea, lungs) were assessed. In 10 preterm infants, delta pressures, tidal volumes and leak were measured during ventilation 2 min before (mask ventilation) and 2 min after intubation (endotracheal ventilation). Inflations coinciding with breaths were excluded. Amount of upper airway distention in lambs and differences in inspiratory and expiratory tidal volume before and after intubation. In lambs, the combined trachea and oropharynx contributed to 14 (12-21) % (median (IQR), whereas the oropharynx contributed to 9 (7-10) % of the total tidal volume measured at the mouth. In preterm infants, inspiratory (11.1 (7.9-22.6) mL/kg vs 5.8 (3.9-9.6) mL/kg (p=0.01)) and expiratory (8.3 (6.8-15.4) mL/kg vs 4.9 (3.9-9.6) mL/kg (p=0.02)) tidal volumes were significantly larger during mask ventilation compared with endotracheal ventilation. Leak was 18.7 (3.3-28.7) % before versus 0 (0-2.3) % after intubation (p0.05). During mask ventilation, expiratory tidal volume increased from 10.0 (5.4-15.6) mL/kg to 11.3 (7.6-17.0) mL/kg (p=0.01), but remained unchanged during endotracheal ventilation. During neonatal mask ventilation, distention of the upper respiratory tract contributes to the tidal volumes measured and should be taken into account when targeting tidal volumes during mask ventilation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

High-Frequency Percussive Ventilation and Low Tidal Volume Ventilation in Burns: A Randomized Controlled Trial

Science.gov (United States)

2010-01-01

incidence of ventilator-associated pneumonia ( VAP ) in patients with inha- lation injury when supported with HFPV compared with conventional modes of...mean ratio of PaO2 to FIO2 was 58 6 with a mean positive end- expiratory pressure of 22 2 cm H2O before rescue. Two of these patients were...a sample size of 110 patients in each arm would have been required to detect a difference in VAP with 80% power. A multicentered study would be

Critical evaluation of emergency stockpile ventilators in an in vitro model of pediatric lung injury.

Science.gov (United States)

Custer, Jason W; Watson, Christopher M; Dwyer, Joe; Kaczka, David W; Simon, Brett A; Easley, R Blaine

2011-11-01

Modern health care systems may be inadequately prepared for mass casualty respiratory failure requiring mechanical ventilation. Current health policy has focused on the "stockpiling" of emergency ventilators, though little is known about the performance of these ventilators under conditions of respiratory failure in adults and children. In this study, we seek to compare emergency ventilator performance characteristics using a test lung simulating pediatric lung injury. Evaluation of ventilator performance using a test lung. Laboratory. None. Six transport/emergency ventilators capable of adult/child application were chosen on the basis of manufacturer specifications, Autovent 3000, Eagle Univent 754, EPV 100, LP-10, LTV 1200, and Parapac 200D. Manufacturer specifications for each ventilator were reviewed and compared with known standards for alarms and functionality for surge capacity ventilators. The delivered tidal volume, gas flow characteristics, and airway pressure waveforms were evaluated in vitro using a mechanical test lung to model pediatric lung injury and integrated software. Test lung and flow meter recordings were analyzed over a range of ventilator settings. Of the six ventilators assessed, only two had the minimum recommended alarm capability. Four of the six ventilators tested were capable of being set to deliver a tidal volume of less than 200 mL. The delivered tidal volume for all ventilators was within 8% of the nominal setting at a positive end expiratory pressure of zero but was reduced significantly with the addition of positive end expiratory pressure (range, ±10% to 30%; p ventilators tested performed comparably at higher set tidal volumes; however, only three of the ventilators tested delivered a tidal volume across the range of ventilator settings that was comparable to that of a standard intensive care unit ventilator. Multiple ventilators are available for the provision of ventilation to children with respiratory failure in a mass

Comparison of airway pressure release ventilation to conventional mechanical ventilation in the early management of smoke inhalation injury in swine.

Science.gov (United States)

Batchinsky, Andriy I; Burkett, Samuel E; Zanders, Thomas B; Chung, Kevin K; Regn, Dara D; Jordan, Bryan S; Necsoiu, Corina; Nguyen, Ruth; Hanson, Margaret A; Morris, Michael J; Cancio, Leopoldo C

2011-10-01

The role of airway pressure release ventilation in the management of early smoke inhalation injury has not been studied. We compared the effects of airway pressure release ventilation and conventional mechanical ventilation on oxygenation in a porcine model of acute respiratory distress syndrome induced by wood smoke inhalation. Prospective animal study. Government laboratory animal intensive care unit. Thirty-three Yorkshire pigs. Smoke inhalation injury. Anesthetized female Yorkshire pigs (n = 33) inhaled room-temperature pine-bark smoke. Before injury, the pigs were randomized to receive conventional mechanical ventilation (n = 15) or airway pressure release ventilation (n = 12) for 48 hrs after smoke inhalation. As acute respiratory distress syndrome developed (PaO2/Fio2 ratio conventional mechanical ventilation for 48 hrs and served as time controls. Changes in PaO2/Fio2 ratio, tidal volume, respiratory rate, mean airway pressure, plateau pressure, and hemodynamic variables were recorded. Survival was assessed using Kaplan-Meier analysis. PaO2/Fio2 ratio was lower in airway pressure release ventilation vs. conventional mechanical ventilation pigs at 12, 18, and 24 hrs (p conventional mechanical ventilation animals between 30 and 48 hrs post injury (p animals between 6 and 48 hrs (p conventional mechanical ventilation and airway pressure release ventilation pigs. In this model of acute respiratory distress syndrome caused by severe smoke inhalation in swine, airway pressure release ventilation-treated animals developed acute respiratory distress syndrome faster than conventional mechanical ventilation-treated animals, showing a lower PaO2/Fio2 ratio at 12, 18, and 24 hrs after injury. At other time points, PaO2/Fio2 ratio was not different between conventional mechanical ventilation and airway pressure release ventilation.

Lung-protective ventilation in abdominal surgery.

Science.gov (United States)

Futier, Emmanuel; Jaber, Samir

2014-08-01

To provide the most recent and relevant clinical evidence regarding the use of prophylactic lung-protective mechanical ventilation in abdominal surgery. Evidence is accumulating, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary complications in patients undergoing abdominal surgery. Nonprotective ventilator settings, especially high tidal volume (>10-12 ml/kg), very low level of positive end-expiratory pressure (PEEP, ventilator-associated lung injury in patients with healthy lungs. Stimulated by the previous findings in patients with acute respiratory distress syndrome, the use of lower tidal volume ventilation is becoming increasingly more common in the operating room. However, lowering tidal volume, though important, is only part of the overall multifaceted approach of lung-protective mechanical ventilation. Recent data provide compelling evidence that prophylactic lung-protective mechanical ventilation using lower tidal volume (6-8 ml/kg of predicted body weight), moderate PEEP (6-8 cm H2O), and recruitment maneuvers is associated with improved functional or physiological and clinical postoperative outcome in patients undergoing abdominal surgery. The use of prophylactic lung-protective ventilation can help in improving the postoperative outcome.

Noninvasive Positive Pressure Ventilation or Conventional Mechanical Ventilation for Neonatal Continuous Positive Airway Pressure Failure

Directory of Open Access Journals (Sweden)

Zohreh Badiee

2014-01-01

Full Text Available Background: The aim of this study was to assess the success rate of nasal intermittent positive pressure ventilation (NIPPV for treatment of continuous positive airway pressure (CPAP failure and prevention of conventional ventilation (CV in preterm neonates. Methods: Since November 2012 to April 2013, a total number of 55 consecutive newborns with gestational ages of 26-35 weeks who had CPAP failure were randomly assigned to one of the two groups. The NIPPV group received NIPPV with the initial peak inspiratory pressure (PIP of 16-20 cmH 2 O and frequency of 40-60 breaths/min. The CV group received PIP of 12-20 cmH 2 O and frequency of 40-60 breaths/min. Results: About 74% of newborns who received NIPPV for management of CPAP failure responded to NIPPV and did not need intubation and mechanical ventilation. Newborns with lower postnatal age at entry to the study and lower 5 min Apgar score more likely had NIPPV failure. In addition, treatment failure was higher in newborns who needed more frequent doses of surfactant. Duration of oxygen therapy was 9.28 days in CV group and 7.77 days in NIPPV group (P = 0.050. Length of hospital stay in CV group and NIPPV groups were 48.7 and 41.7 days, respectively (P = 0.097. Conclusions: NIPPV could decrease the need for intubation and mechanical ventilation in preterm infants with CPAP failure.

Randomized, controlled trial comparing synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in preterm infants.

Science.gov (United States)

Reyes, Zenaida C; Claure, Nelson; Tauscher, Markus K; D'Ugard, Carmen; Vanbuskirk, Silvia; Bancalari, Eduardo

2006-10-01

Prolonged mechanical ventilation is associated with lung injury in preterm infants. In these infants, weaning from synchronized intermittent mandatory ventilation may be delayed by their inability to cope with increased respiratory loads. The addition of pressure support to synchronized intermittent mandatory ventilation can offset these loads and may facilitate weaning. The purpose of this work was to compare synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in weaning from mechanical ventilation and the duration of supplemental oxygen dependency in preterm infants with respiratory failure. Preterm infants weighing 500 to 1000 g at birth who required mechanical ventilation during the first postnatal week were randomly assigned to synchronized intermittent mandatory ventilation or synchronized intermittent mandatory ventilation plus pressure support. In both groups, weaning followed a set protocol during the first 28 days. Outcomes were assessed during the first 28 days and until discharge or death. There were 107 infants enrolled (53 synchronized intermittent mandatory ventilation plus pressure support and 54 synchronized intermittent mandatory ventilation). Demographic and perinatal data, mortality, and morbidity did not differ between groups. During the first 28 days, infants in the synchronized intermittent mandatory ventilation plus pressure support group reached minimal ventilator settings and were extubated earlier than infants in the synchronized intermittent mandatory ventilation group. Total duration of mechanical ventilation, duration of oxygen dependency, and oxygen need at 36 weeks' postmenstrual age alone or combined with death did not differ between groups. However, infants in synchronized intermittent mandatory ventilation plus pressure support within the 700- to 1000-g birth weight strata had a shorter oxygen dependency. The results of this study suggest that the addition of

[Possibilities of bi-level positive pressure ventilation in chronic hypoventilation].

Science.gov (United States)

Saaresranta, Tarja; Anttalainen, Ulla; Polo, Olli

2011-01-01

During the last decade, noninvasive bi-level positive pressure ventilation has enabled respiratory support in inpatient wards and at home. In many cases, a bi-level airway pressure ventilator can be used to avoid artificial airway and respirator therapy, and may shorten hospital stay and save costs. The treatment alleviates the patient's dyspnea and fatigue, whereby the quality of life improves, and in certain situations also the life span increases. The implementation of bi-level positive pressure ventilation by the physician requires knowledge of the basics of respiratory physiology and familiarization with the bi-level airway pressure ventilator.

Comparison of devices for newborn ventilation in the delivery room.

Science.gov (United States)

Szyld, Edgardo; Aguilar, Adriana; Musante, Gabriel A; Vain, Nestor; Prudent, Luis; Fabres, Jorge; Carlo, Waldemar A

2014-08-01

To evaluate the effectiveness and safety of a T-piece resuscitator compared with a self-inflating bag for providing mask ventilation to newborns at birth. Newborns at ≥26 weeks gestational age receiving positive-pressure ventilation at birth were included in this multicenter cluster-randomized 2-period crossover trial. Positive-pressure ventilation was provided with either a self-inflating bag (self-inflating bag group) with or without a positive end-expiratory pressure valve or a T-piece with a positive end-expiratory pressure valve (T-piece group). Delivery room management followed American Academy of Pediatrics and International Liaison Committee on Resuscitation guidelines. The primary outcome was the proportion of newborns with heart rate (HR)≥100 bpm at 2 minutes after birth. A total of 1027 newborns were included. There was no statistically significant difference in the incidence of HR≥100 bpm at 2 minutes after birth between the T-piece and self-inflating bag groups: 94% (479 of 511) and 90% (466 of 516), respectively (OR, 0.65; 95% CI, 0.41-1.05; P=.08). A total of 86 newborns (17%) in the T-piece group and 134 newborns (26%) in the self-inflating bag group were intubated in the delivery room (OR, 0.58; 95% CI, 0.4-0.8; P=.002). The mean±SD maximum positive inspiratory pressure was 26±2 cm H2O in the T-piece group vs 28±5 cm H2O in the self-inflating bag group (P<.001). Air leaks, use of drugs/chest compressions, mortality, and days on mechanical ventilation did not differ significantly between groups. There was no difference between the T-piece resuscitator and a self-inflating bag in achieving an HR of ≥100 bpm at 2 minutes in newborns≥26 weeks gestational age resuscitated at birth. However, use of the T-piece decreased the intubation rate and the maximum pressures applied. Copyright © 2014 Elsevier Inc. All rights reserved.

Automatic detection of AutoPEEP during controlled mechanical ventilation

Directory of Open Access Journals (Sweden)

Nguyen Quang-Thang

2012-06-01

Full Text Available Abstract Background Dynamic hyperinflation, hereafter called AutoPEEP (auto-positive end expiratory pressure with some slight language abuse, is a frequent deleterious phenomenon in patients undergoing mechanical ventilation. Although not readily quantifiable, AutoPEEP can be recognized on the expiratory portion of the flow waveform. If expiratory flow does not return to zero before the next inspiration, AutoPEEP is present. This simple detection however requires the eye of an expert clinician at the patient’s bedside. An automatic detection of AutoPEEP should be helpful to optimize care. Methods In this paper, a platform for automatic detection of AutoPEEP based on the flow signal available on most of recent mechanical ventilators is introduced. The detection algorithms are developed on the basis of robust non-parametric hypothesis testings that require no prior information on the signal distribution. In particular, two detectors are proposed: one is based on SNT (Signal Norm Testing and the other is an extension of SNT in the sequential framework. The performance assessment was carried out on a respiratory system analog and ex-vivo on various retrospectively acquired patient curves. Results The experiment results have shown that the proposed algorithm provides relevant AutoPEEP detection on both simulated and real data. The analysis of clinical data has shown that the proposed detectors can be used to automatically detect AutoPEEP with an accuracy of 93% and a recall (sensitivity of 90%. Conclusions The proposed platform provides an automatic early detection of AutoPEEP. Such functionality can be integrated in the currently used mechanical ventilator for continuous monitoring of the patient-ventilator interface and, therefore, alleviate the clinician task.

[The clinical effect of airway pressure release ventilation for acute lung injury/acute respiratory distress syndrome].

Science.gov (United States)

Song, Shaohua; Tian, Huiyu; Yang, Xiufen; Hu, Zhenjie

2016-01-01

To evaluate the effect of airway pressure release ventilation (APRV) in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS), to evaluate the extent of ventilator-induced lung injury (VILI), and to explore its possible mechanism. A prospective study was conducted in the Department of Critical Care Medicine of the First Hospital of Hebei Medical University from December 2010 to February 2012. The patients with ALI/ARDS were enrolled. They were randomly divided into two groups. The patients in APRV group were given APRV pattern, while those in control group were given lung protection ventilation, synchronized intermittent mandatory ventilation with positive end-expiratory pressure (SIMV+PEEP). All patients were treated with AVEA ventilator. The parameters such as airway peak pressure (Ppeak), mean airway pressure (Pmean), pulse oxygen saturation (SpO2), mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), arterial blood gas, urine output (UO), the usage of sedation and muscle relaxation drugs were recorded. AVEA ventilator "turning point (Pflex) operation" was used to describe the quasi-static pressure volume curve (P-V curve). High and low inflection point (UIP, LIP) and triangular Pflex volume (Vdelta) were automatically measured and calculated. The ventilation parameters were set, and the 24-hour P-V curve was recorded again in order to be compared with subsequent results. Venous blood was collected before treatment, 24 hours and 48 hours after ventilation to measure lung surfactant protein D (SP-D) and large molecular mucus in saliva (KL-6) by enzyme linked immunosorbent assay (ELISA), and the correlation between the above two parameters and prognosis on 28 days was analyzed by multinomial logistic regression. Twenty-six patients with ALI/ARDS were enrolled, and 22 of them completed the test with 10 in APRV group and 12 in control group. The basic parameters and P-V curves between two groups were similar before

Early postoperative alterations of ventilation parameters after tracheostomy in major burn injuries

Directory of Open Access Journals (Sweden)

Mailänder, Peter

2010-01-01

Full Text Available Purpose: In patients with major burn injuries mechanical ventilation is often required for longer periods. Tracheostomy (TS plays an integral role in airway management. We investigated the effect of TS on ventilation parameters within 8 hours after TS. Materials: A retrospective analysis of severely burned patients admitted to the burn unit of a German University Hospital was performed. Ventilation parameters 8 hours before and after TS were registered. Results: A retrospective analysis of 20 patients which received surgical TS was performed. Mean age was 52±19 years. Mean abbreviated burned severity index (ABSI was 8.3±2.2. A mechanical ventilation was required for 14.3±4.8 days. TS was performed on day 7±4. Inspiratory oxygen concentration (FiO2 (p<0.001, peak inspiratory pressure (p<0.001, positive end-expiratory pressure (p=0.003 and pulmonary resistance (p<0.001 were reduced significantly after TS. The arterial partial pressure of oxygen/FiO2-ratio increased significantly after TS (p<0.001. Conclusions: We demonstrate that TS reduces invasiveness of ventilation in severely burned patients and by this can optimize lung protective ventilation strategy.

Respiratory effects of low versus high tidal volume with or without positive end-expiratory pressure in anesthetized dogs with healthy lungs.

Science.gov (United States)

De Monte, Valentina; Bufalari, Antonello; Grasso, Salvatore; Ferrulli, Fabienne; Crovace, Alberto Maria; Lacitignola, Luca; Staffieri, Francesco

2018-05-01

OBJECTIVE To evaluate the impact of 2 tidal volumes (T V s) with or without positive end-expiratory pressure (PEEP) on lung mechanics, aeration, and gas exchange in healthy anesthetized dogs. ANIMALS 40 mixed-breed dogs with healthy lungs. PROCEDURES Anesthetized dogs were randomly assigned to 4 groups (n = 10/group) with different ventilatory settings: T V of 8 mL/kg and PEEP of 0 cm H 2 O (low T V group), T V of 8 mL/kg and PEEP of 5 cm H 2 O (low T V plus PEEP group), T V of 15 mL/kg and PEEP of 0 cm H 2 O (high T V group), or T V of 15 mL/kg and PEEP of 5 cm H 2 O (high T V plus PEEP group). Expired CO 2 and respiratory rate were titrated on the basis of a predetermined stepwise protocol. Gas exchange, respiratory mechanics, and pulmonary aeration were evaluated by means of CT 30 minutes after starting mechanical ventilation at the assigned setting. RESULTS Partial pressures of arterial and expired CO 2 were higher in the low T V and low T V plus PEEP groups than in the high T V and high T V plus PEEP groups. Peak and plateau airway pressures were higher in the PEEP group than in the other groups. Static lung compliance was higher in the high T V plus PEEP group than in the low T V group. Relative percentages of atelectatic and poorly aerated lung were lower in the high T V plus PEEP group than in the other groups. Oxygenation was similar among groups. CONCLUSIONS AND CLINICAL RELEVANCE Differences in T V and PEEP application during mechanical ventilation may affect respiratory function in anesthetized dogs with healthy lungs. Ventilation with a T V of 15 mL/kg and PEEP of 5 cm H 2 O significantly improved lung compliance and reduced the amount of atelectatic and poorly aerated lung.

Recent advances in mechanical ventilation in patients with acute respiratory distress syndrome

Directory of Open Access Journals (Sweden)

Nuttapol Rittayamai

2015-03-01

Full Text Available Acute respiratory distress syndrome (ARDS is characterised by different degrees of severity and different stages. Understanding these differences can help to better adapt the ventilatory settings to protect the lung from ventilator-induced lung injury by reducing hyperinflation or keeping the lung open when it is possible. The same therapies may be useful and beneficial in certain forms of ARDS, and risky or harmful at other stages: this includes high positive end-expiratory pressure, allowance of spontaneous breathing activity or use of noninvasive ventilation. The severity of the disease is the primary indicator to individualise treatment. Monitoring tools such as oesophageal pressure or lung volume measurements may also help to set the ventilator. At an earlier stage, an adequate lung protective strategy may also help to prevent the development of ARDS.

Nasal mask ventilation is better than face mask ventilation in edentulous patients.

Science.gov (United States)

Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

2016-01-01

Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients.

Rationale and study design of PROVHILO - a worldwide multicenter randomized controlled trial on protective ventilation during general anesthesia for open abdominal surgery

Directory of Open Access Journals (Sweden)

Hedenstierna Göran

2011-05-01

Full Text Available Abstract Background Post-operative pulmonary complications add to the morbidity and mortality of surgical patients, in particular after general anesthesia >2 hours for abdominal surgery. Whether a protective mechanical ventilation strategy with higher levels of positive end-expiratory pressure (PEEP and repeated recruitment maneuvers; the "open lung strategy", protects against post-operative pulmonary complications is uncertain. The present study aims at comparing a protective mechanical ventilation strategy with a conventional mechanical ventilation strategy during general anesthesia for abdominal non-laparoscopic surgery. Methods The PROtective Ventilation using HIgh versus LOw positive end-expiratory pressure ("PROVHILO" trial is a worldwide investigator-initiated multicenter randomized controlled two-arm study. Nine hundred patients scheduled for non-laparoscopic abdominal surgery at high or intermediate risk for post-operative pulmonary complications are randomized to mechanical ventilation with the level of PEEP at 12 cmH2O with recruitment maneuvers (the lung-protective strategy or mechanical ventilation with the level of PEEP at maximum 2 cmH2O without recruitment maneuvers (the conventional strategy. The primary endpoint is any post-operative pulmonary complication. Discussion The PROVHILO trial is the first randomized controlled trial powered to investigate whether an open lung mechanical ventilation strategy in short-term mechanical ventilation prevents against postoperative pulmonary complications. Trial registration ISRCTN: ISRCTN70332574

Effect of different breathing aids on ventilation distribution in adults with cystic fibrosis.

Directory of Open Access Journals (Sweden)

Markus Wettstein

Full Text Available BACKGROUND AND OBJECTIVES: We investigated the effect of different breathing aids on ventilation distribution in healthy adults and subjects with cystic fibrosis (CF. METHODS: In 11 healthy adults and 9 adults with CF electrical impedance tomography measurements were performed during spontaneous breathing, continuous positive airway pressure (CPAP and positive expiratory pressure (PEP therapy randomly applied in upright and lateral position. Spatial and temporal ventilation distribution was assessed. RESULTS: The proportion of ventilation directed to the dependent lung significantly increased in lateral position compared to upright in healthy and CF. This effect was enhanced with CPAP but neutralised with PEP, whereas the effect of PEP was larger in the healthy group. Temporal ventilation distribution showed exactly the opposite with homogenisation during CPAP and increased inhomogeneity with PEP. CONCLUSIONS: PEP shows distinct differences to CPAP with respect to its impact on ventilation distribution in healthy adults and CF subjects EIT might be used to individualise respiratory physiotherapy.

Controlled invasive mechanical ventilation strategies in obese patients undergoing surgery.

Science.gov (United States)

Maia, Lígia de Albuquerque; Silva, Pedro Leme; Pelosi, Paolo; Rocco, Patricia Rieken Macedo

2017-06-01

The obesity prevalence is increasing in surgical population. As the number of obese surgical patients increases, so does the demand for mechanical ventilation. Nevertheless, ventilatory strategies in this population are challenging, since obesity results in pathophysiological changes in respiratory function. Areas covered: We reviewed the impact of obesity on respiratory system and the effects of controlled invasive mechanical ventilation strategies in obese patients undergoing surgery. To date, there is no consensus regarding the optimal invasive mechanical ventilation strategy for obese surgical patients, and no evidence that possible intraoperative beneficial effects on oxygenation and mechanics translate into better postoperative pulmonary function or improved outcomes. Expert commentary: Before determining the ideal intraoperative ventilation strategy, it is important to analyze the pathophysiology and comorbidities of each obese patient. Protective ventilation with low tidal volume, driving pressure, energy, and mechanical power should be employed during surgery; however, further studies are required to clarify the most effective ventilation strategies, such as the optimal positive end-expiratory pressure and whether recruitment maneuvers minimize lung injury. In this context, an ongoing trial of intraoperative ventilation in obese patients (PROBESE) should help determine the mechanical ventilation strategy that best improves clinical outcome in patients with body mass index≥35kg/m 2 .

MEASUREMENT OF FRICTIONAL PRESSURE DIFFERENTIALS DURING A VENTILATION SURVEY

International Nuclear Information System (INIS)

B.S. Prosser, PE; I.M. Loomis, PE, PhD

2003-01-01

During the course of a ventilation survey, both airflow quantity and frictional pressure losses are measured and quantified. The measurement of airflow has been extensively studied as the vast majority of ventilation standards/regulations are tied to airflow quantity or velocity. However, during the conduct of a ventilation survey, measurement of airflow only represents half of the necessary parameters required to directly calculate the airway resistance. The measurement of frictional pressure loss is an often misunderstood and misapplied part of the ventilation survey. This paper compares the two basic methods of frictional pressure drop measurements; the barometer and the gauge and tube. Personal experiences with each method will be detailed along with the authors' opinions regarding the applicability and conditions favoring each method

A Case of Shunting Postoperative Patent Foramen Ovale Under Mechanical Ventilation Controlled by Different Ventilator Settings.

Science.gov (United States)

Pragliola, Claudio; Di Michele, Sara; Galzerano, Domenico

2017-06-07

A 56-year old male with ischemic heart disease and an unremarkable preoperative echocardiogram underwent surgical coronary revascularization. An intraoperative post pump trans-esophageal echocardiogram (TOE) performed while the patient was being ventilated at a positive end expiratory pressure (PEEP) of 8 cm H 2 O demonstrated a right to left interatrial shunt across a patent foramen ovale (PFO). Whereas oxygen saturation was normal, a reduction of the PEEP to 3 cm H 2 O led to the complete resolution of the shunt with no change in arterial blood gases. Attempts to increase the PEEP level above 3 mmHg resulted in recurrence of the interatrial shunt. The remaining of the TEE was unremarkable. Mechanical ventilation, particularly with PEEP, causes an increase in intrathoracic pressure. The resulting rise in right atrial pressure, mostly during inspiration, may unveil and pop open an unrecognized PFO, thus provoking a right to left shunt across a seemingly intact interatrial septum. This phenomenon increases the risk of paradoxical embolism and can lead to hypoxemia. The immediate management would be to adjust the ventilatory settings to a lower PEEP level. A routine search for a PFO should be performed in ventilated patients who undergo a TEE.

A case of shunting postoperative patent foramen ovale under mechanical ventilation controlled by different ventilator settings

Directory of Open Access Journals (Sweden)

Claudio Pragliola

2017-08-01

Full Text Available A 56-year old male with ischemic heart disease and an unremarkable preoperative echocardiogram underwent surgical coronary revascularization. An intraoperative post pump trans-esophageal echocardiogram (TOE performed while the patient was being ventilated at a positive end expiratory pressure (PEEP of 8 cm H2O demonstrated a right to left interatrial shunt across a patent foramen ovale (PFO. Whereas oxygen saturation was normal, a reduction of the PEEP to 3 cm H2O led to the complete resolution of the shunt with no change in arterial blood gases. Attempts to increase the PEEP level above 3 mmHg resulted in recurrence of the interatrial shunt. The remaining of the TEE was unremarkable. Mechanical ventilation, particularly with PEEP, causes an increase in intrathoracic pressure. The resulting rise in right atrial pressure, mostly during inspiration, may unveil and pop open an unrecognized PFO, thus provoking a right to left shunt across a seemingly intact interatrial septum. This phenomenon increases the risk of paradoxical embolism and can lead to hypoxemia. The immediate management would be to adjust the ventilatory settings to a lower PEEP level. A routine search for a PFO should be performed in ventilated patients who undergo a TEE.

Patients with uninjured lungs may also benefit from lung-protective ventilator settings [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Roger Alencar

2017-11-01

Full Text Available Although mechanical ventilation is a life-saving strategy in critically ill patients and an indispensable tool in patients under general anesthesia for surgery, it also acts as a double-edged sword. Indeed, ventilation is increasingly recognized as a potentially dangerous intrusion that has the potential to harm lungs, in a condition known as ‘ventilator-induced lung injury’ (VILI. So-called ‘lung-protective’ ventilator settings aiming at prevention of VILI have been shown to improve outcomes in patients with acute respiratory distress syndrome (ARDS, and, over the last few years, there has been increasing interest in possible benefit of lung-protective ventilation in patients under ventilation for reasons other than ARDS. Patients without ARDS could benefit from tidal volume reduction during mechanical ventilation. However, it is uncertain whether higher levels of positive end-expiratory pressure could benefit these patients as well. Finally, recent evidence suggests that patients without ARDS should receive low driving pressures during ventilation.

Mechanical ventilation during extracorporeal membrane oxygenation.

Science.gov (United States)

Schmidt, Matthieu; Pellegrino, Vincent; Combes, Alain; Scheinkestel, Carlos; Cooper, D Jamie; Hodgson, Carol

2014-01-21

The timing of extracorporeal membrane oxygenation (ECMO) initiation and its outcome in the management of respiratory and cardiac failure have received considerable attention, but very little attention has been given to mechanical ventilation during ECMO. Mechanical ventilation settings in non-ECMO studies have been shown to have an effect on survival and may also have contributed to a treatment effect in ECMO trials. Protective lung ventilation strategies established for non-ECMO-supported respiratory failure patients may not be optimal for more severe forms of respiratory failure requiring ECMO support. The influence of positive end-expiratory pressure on the reduction of the left ventricular compliance may be a matter of concern for patients receiving ECMO support for cardiac failure. The objectives of this review were to describe potential mechanisms for lung injury during ECMO for respiratory or cardiac failure, to assess the possible benefits from the use of ultra-protective lung ventilation strategies and to review published guidelines and expert opinions available on mechanical ventilation-specific management of patients requiring ECMO, including mode and ventilator settings. Articles were identified through a detailed search of PubMed, Ovid, Cochrane databases and Google Scholar. Additional references were retrieved from the selected studies. Growing evidence suggests that mechanical ventilation settings are important in ECMO patients to minimize further lung damage and improve outcomes. An ultra-protective ventilation strategy may be optimal for mechanical ventilation during ECMO for respiratory failure. The effects of airway pressure on right and left ventricular afterload should be considered during venoarterial ECMO support of cardiac failure. Future studies are needed to better understand the potential impact of invasive mechanical ventilation modes and settings on outcomes.

Respiratory mechanics to understand ARDS and guide mechanical ventilation.

Science.gov (United States)

Mauri, Tommaso; Lazzeri, Marta; Bellani, Giacomo; Zanella, Alberto; Grasselli, Giacomo

2017-11-30

As precision medicine is becoming a standard of care in selecting tailored rather than average treatments, physiological measurements might represent the first step in applying personalized therapy in the intensive care unit (ICU). A systematic assessment of respiratory mechanics in patients with the acute respiratory distress syndrome (ARDS) could represent a step in this direction, for two main reasons. Approach and Main results: On the one hand, respiratory mechanics are a powerful physiological method to understand the severity of this syndrome in each single patient. Decreased respiratory system compliance, for example, is associated with low end expiratory lung volume and more severe lung injury. On the other hand, respiratory mechanics might guide protective mechanical ventilation settings. Improved gravitationally dependent regional lung compliance could support the selection of positive end-expiratory pressure and maximize alveolar recruitment. Moreover, the association between driving airway pressure and mortality in ARDS patients potentially underlines the importance of sizing tidal volume on respiratory system compliance rather than on predicted body weight. The present review article aims to describe the main alterations of respiratory mechanics in ARDS as a potent bedside tool to understand severity and guide mechanical ventilation settings, thus representing a readily available clinical resource for ICU physicians.

The role of high airway pressure and dynamic strain on ventilator-induced lung injury in a heterogeneous acute lung injury model.

Science.gov (United States)

Jain, Sumeet V; Kollisch-Singule, Michaela; Satalin, Joshua; Searles, Quinn; Dombert, Luke; Abdel-Razek, Osama; Yepuri, Natesh; Leonard, Antony; Gruessner, Angelika; Andrews, Penny; Fazal, Fabeha; Meng, Qinghe; Wang, Guirong; Gatto, Louis A; Habashi, Nader M; Nieman, Gary F

2017-12-01

Acute respiratory distress syndrome causes a heterogeneous lung injury with normal and acutely injured lung tissue in the same lung. Improperly adjusted mechanical ventilation can exacerbate ARDS causing a secondary ventilator-induced lung injury (VILI). We hypothesized that a peak airway pressure of 40 cmH 2 O (static strain) alone would not cause additional injury in either the normal or acutely injured lung tissue unless combined with high tidal volume (dynamic strain). Pigs were anesthetized, and heterogeneous acute lung injury (ALI) was created by Tween instillation via a bronchoscope to both diaphragmatic lung lobes. Tissue in all other lobes was normal. Airway pressure release ventilation was used to precisely regulate time and pressure at both inspiration and expiration. Animals were separated into two groups: (1) over-distension + high dynamic strain (OD + H DS , n = 6) and (2) over-distension + low dynamic strain (OD + L DS , n = 6). OD was caused by setting the inspiratory pressure at 40 cmH 2 O and dynamic strain was modified by changing the expiratory duration, which varied the tidal volume. Animals were ventilated for 6 h recording hemodynamics, lung function, and inflammatory mediators followed by an extensive necropsy. In normal tissue (N T ), OD + L DS caused minimal histologic damage and a significant reduction in BALF total protein (p < 0.05) and MMP-9 activity (p < 0.05), as compared with OD + H DS . In acutely injured tissue (ALI T ), OD + L DS resulted in reduced histologic injury and pulmonary edema (p < 0.05), as compared with OD + H DS . Both N T and ALI T are resistant to VILI caused by OD alone, but when combined with a H DS , significant tissue injury develops.

Protective mechanical ventilation during general anesthesia for open abdominal surgery improves postoperative pulmonary function.

Science.gov (United States)

Severgnini, Paolo; Selmo, Gabriele; Lanza, Christian; Chiesa, Alessandro; Frigerio, Alice; Bacuzzi, Alessandro; Dionigi, Gianlorenzo; Novario, Raffaele; Gregoretti, Cesare; de Abreu, Marcelo Gama; Schultz, Marcus J; Jaber, Samir; Futier, Emmanuel; Chiaranda, Maurizio; Pelosi, Paolo

2013-06-01

The impact of intraoperative ventilation on postoperative pulmonary complications is not defined. The authors aimed at determining the effectiveness of protective mechanical ventilation during open abdominal surgery on a modified Clinical Pulmonary Infection Score as primary outcome and postoperative pulmonary function. Prospective randomized, open-label, clinical trial performed in 56 patients scheduled to undergo elective open abdominal surgery lasting more than 2 h. Patients were assigned by envelopes to mechanical ventilation with tidal volume of 9 ml/kg ideal body weight and zero-positive end-expiratory pressure (standard ventilation strategy) or tidal volumes of 7 ml/kg ideal body weight, 10 cm H2O positive end-expiratory pressure, and recruitment maneuvers (protective ventilation strategy). Modified Clinical Pulmonary Infection Score, gas exchange, and pulmonary functional tests were measured preoperatively, as well as at days 1, 3, and 5 after surgery. Patients ventilated protectively showed better pulmonary functional tests up to day 5, fewer alterations on chest x-ray up to day 3 and higher arterial oxygenation in air at days 1, 3, and 5 (mmHg; mean ± SD): 77.1 ± 13.0 versus 64.9 ± 11.3 (P = 0.0006), 80.5 ± 10.1 versus 69.7 ± 9.3 (P = 0.0002), and 82.1 ± 10.7 versus 78.5 ± 21.7 (P = 0.44) respectively. The modified Clinical Pulmonary Infection Score was lower in the protective ventilation strategy at days 1 and 3. The percentage of patients in hospital at day 28 after surgery was not different between groups (7 vs. 15% respectively, P = 0.42). A protective ventilation strategy during abdominal surgery lasting more than 2 h improved respiratory function and reduced the modified Clinical Pulmonary Infection Score without affecting length of hospital stay.

Positional effects on distribution of ventilation in chronic obstructive pulmonary disease

International Nuclear Information System (INIS)

Shim, C.; Chun, K.J.; Williams, M.H. Jr.; Blaufox, M.D.

1986-01-01

Ventilation is distributed predominantly to the dependent lung in normal persons in the decubitus position. We evaluated the distribution of ventilation in four patients with mild-to-moderate chronic obstructive pulmonary disease using 81mKr gas. Patients were tested in the sitting and right and left decubitus positions with and without the application of positive end expiratory pressure (PEEP). In contrast to findings in controls, ventilation was predominantly distributed to the nondependent lung in patients in the decubitus position. Mean ventilation in the right lung decreased from 51% of the total in the sitting position to 31% in the right decubitus position; it increased with the application of 10 cm PEEP. Reduced ventilation in the dependent lung most likely is caused by closure of the airways after a decrease in volume. Application of PEEP resulted in increased lung volume and preferential distribution of ventilation to the dependent lung

An advanced expiratory circuit for the recovery of perfluorocarbon liquid from non-saturated perfluorocarbon vapour during partial liquid ventilation: an experimental model

Directory of Open Access Journals (Sweden)

Davies Mark W

2006-02-01

Full Text Available Abstract Background The loss of perfluorocarbon (PFC vapour in the expired gases during partial liquid ventilation should be minimized both to prevent perfluorocarbon vapour entering the atmosphere and to re-use the recovered PFC liquid. Using a substantially modified design of our previously described condenser, we aimed to determine how much perfluorocarbon liquid could be recovered from gases containing PFC and water vapour, at concentrations found during partial liquid ventilation, and to determine if the amount recovered differed with background flow rate (at flow rates suitable for use in neonates. Methods The expiratory line of a standard ventilator circuit set-up was mimicked, with the addition of two condensers. Perfluorocarbon (30 mL of FC-77 and water vapour, at concentrations found during partial liquid ventilation, were passed through the circuit at a number of flow rates and the percentage recovery of the liquids measured. Results From 14.2 mL (47% to 27.3 mL (91% of the infused 30 mL of FC-77 was recovered at the flow rates studied. Significantly higher FC-77 recovery was obtained at lower flow rates (ANOVA with Bonferroni's multiple comparison test, p -1 (ANOVA with Bonferroni's multiple comparison test, p -1, respectively. Conclusion Using two condensers in series 47% to 91% of perfluorocarbon liquid can be recovered, from gases containing perfluorocarbon and water vapour, at concentrations found during partial liquid ventilation.

Pressure analysis in ventilation ducts at bituminization facility

International Nuclear Information System (INIS)

Kikuchi, Naoki; Iimura, Masato; Takahashi, Yuki; Omori, Eiichi; Yamanouchi, Takamichi

1997-09-01

Pressure analysis in cell ventilation ducts at bituminization facility where the fire and explosion accident occured was carried out. This report also describes the results of bench mark calculations for computer code EVENT84 which was used for the accident analysis. The bench mark calculations were performed by comparing the analytical results by EVENT84 code with the experimental data of safety demonstration tests of ventilation system which were carried out by JAERI. We confirmed the applicability of EVENT84 code with the conservative results. The pressure analysis in cell ventilation ducts at bituminization facility were performed by comparing the analytical results of duct pressure by EVENT84 code with the yield stress of destroyed ducts by explosion, in order to estimate the scale of explosion. As a result, we could not explain the damage of ducts quantitatively, but we found the local pressure peaks analytically in downstream ducts where the serious damages were observed. (author)

Spatial distribution of sequential ventilation during mechanical ventilation of the uninjured lung: an argument for cyclical airway collapse and expansion

Directory of Open Access Journals (Sweden)

Altemeier William A

2010-05-01

Full Text Available Abstract Background Ventilator-induced lung injury (VILI is a recognized complication of mechanical ventilation. Although the specific mechanism by which mechanical ventilation causes lung injury remains an active area of study, the application of positive end expiratory pressure (PEEP reduces its severity. We have previously reported that VILI is spatially heterogeneous with the most severe injury in the dorsal-caudal lung. This regional injury heterogeneity was abolished by the application of PEEP = 8 cm H2O. We hypothesized that the spatial distribution of lung injury correlates with areas in which cyclical airway collapse and recruitment occurs. Methods To test this hypothesis, rabbits were mechanically ventilated in the supine posture, and regional ventilation distribution was measured under four conditions: tidal volumes (VT of 6 and 12 ml/kg with PEEP levels of 0 and 8 cm H2O. Results We found that relative ventilation was sequentially redistributed towards dorsal-caudal lung with increasing tidal volume. This sequential ventilation redistribution was abolished with the addition of PEEP. Conclusions These results suggest that cyclical airway collapse and recruitment is regionally heterogeneous and spatially correlated with areas most susceptible to VILI.

Ventilator respiratory graphic diagnosis of hiccupping in non-ketotic hyperglycinaemia.

Science.gov (United States)

Panayiotou, Eliana; Spike, Kelly; Morley, Colin; Belteki, Gusztav

2017-08-09

A neonate presented with early encephalopathy deteriorated and was intubated and ventilated. Ventilator data were monitored and recorded at 100 Hz for 24 hours.The infant had many sudden deep inspirations during this time which were initially thought to be seizures. These were characterised by short, rapid, large inspirations when the airway pressure was reduced well below the positive end expiratory pressure level. Analysis of the ventilator data showed that these were hiccupping episodes misinterpreted by the ventilator as spontaneous breaths and triggering ventilator inflations. The expired tidal volumes during the hiccupping episodes were more than double the set 4.5 mL/kg. During these episodes, there was no change in the level of consciousness or in the amplitude-integrated electroencephalogram signal. Detailed respiratory recording of pathological hiccups has not been reported.Metabolic screening diagnosed non-ketotic hyperglycinaemia. Hiccups commonly occur in this condition and should not be misinterpreted as seizures, spontaneous breaths or gasps. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effect of nasal continuous and biphasic positive airway pressure on lung volume in preterm infants

NARCIS (Netherlands)

Miedema, Martijn; van der Burg, Pauline S.; Beuger, Sabine; de Jongh, Frans H.; Frerichs, Inez; van Kaam, Anton H.

2013-01-01

To monitor regional changes in end-expiratory lung volume (EELV), tidal volumes, and their ventilation distribution during different levels of nasal continuous positive airway pressure (nCPAP) and nasal biphasic positive airway pressure (BiPAP) in stable preterm infants. By using electrical

Rationale and study design of PROVHILO - a worldwide multicenter randomized controlled trial on protective ventilation during general anesthesia for open abdominal surgery

NARCIS (Netherlands)

Hemmes, S.N.T.; Severgnini, P.; Jaber, S.; Canet, J.; Wrigge, H.; Hiesmayr, M.; Tschernko, E.M.; Hollmann, M.W.; Binnekade, J.M.; Hedenstierna, G.; Putensen, C.; Gama de Abreu, M.; Pelosi, P.; Schultz, M.J.

2011-01-01

ABSTRACT: BACKGROUND: Post-operative pulmonary complications add to the morbidity and mortality of surgical patients, in particular after general anesthesia > 2 hours for abdominal surgery. Whether a protective mechanical ventilation strategy with higher levels of positive end-expiratory pressure

Ventilation and gas exchange management after cardiac arrest.

Science.gov (United States)

Sutherasan, Yuda; Raimondo, Pasquale; Pelosi, Paolo

2015-12-01

For several decades, physicians had integrated several interventions aiming to improve the outcomes in post-cardiac arrest patients. However, the mortality rate after cardiac arrest is still as high as 50%. Post-cardiac arrest syndrome is associated with high morbidity and mortality due to not only poor neurological outcome and cardiovascular failure but also respiratory dysfunction. To minimize ventilator-associated lung injury, protective mechanical ventilation by using low tidal volume ventilation and driving pressure may decrease pulmonary complications and improve survival. Low level of positive end-expiratory pressure (PEEP) can be initiated and titrated with careful cardiac output and respiratory mechanics monitoring. Furthermore, optimizing gas exchange by avoiding hypoxia and hyperoxia as well as maintaining normocarbia may improve neurological and survival outcome. Early multidisciplinary cardiac rehabilitation intervention is recommended. Minimally invasive monitoring techniques, that is, echocardiography, transpulmonary thermodilution method measuring extravascular lung water, as well as transcranial Doppler ultrasound, might be useful to improve appropriate management of post-cardiac arrest patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Pressure support ventilation and proportional assist ventilation during weaning from mechanical ventilation].

Science.gov (United States)

Aguirre-Bermeo, H; Bottiroli, M; Italiano, S; Roche-Campo, F; Santos, J A; Alonso, M; Mancebo, J

2014-01-01

To compare tolerance, duration of mechanical ventilation (MV) and clinical outcomes during weaning from MV in patients subjected to either pressure support ventilation (PSV) or proportional assist ventilation (PAV). A prospective, observational study was carried out. Intensive Care Unit. A total of 40 consecutive subjects were allocated to either the PSV or the PAV group until each group contained 20 patients. Patients were included in the study when they met the criteria to begin weaning and the attending physician decided to initiate the weaning process. The physician selected the modality and set the ventilatory parameters. None. Demographic data, respiratory mechanics, ventilatory parameters, duration of MV, and clinical outcomes (reintubation, tracheostomy, mortality). Baseline characteristics were similar in both groups. No significant differences were observed between the PSV and PAV groups in terms of the total duration of MV (10 [5-18] vs. 9 [7-19] days; P=.85), reintubation (5 [31%] vs. 3 [19%]; P=.69), or mortality (4 [20%] vs. 5 [25%] deaths; P=1). Eight patients (40%) in the PSV group and 6 patients (30%) in the PAV group (P=.74) required a return to volume assist-control ventilation due to clinical deterioration. Tolerance, duration of MV and clinical outcomes during weaning from mechanical ventilation were similar in PSV and PAV. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

Respiratory mechanics in infants with severe bronchiolitis on controlled mechanical ventilation.

Science.gov (United States)

Cruces, Pablo; González-Dambrauskas, Sebastián; Quilodrán, Julio; Valenzuela, Jorge; Martínez, Javier; Rivero, Natalia; Arias, Pablo; Díaz, Franco

2017-10-06

Analysis of respiratory mechanics during mechanical ventilation (MV) is able to estimate resistive, elastic and inertial components of the working pressure of the respiratory system. Our aim was to discriminate the components of the working pressure of the respiratory system in infants on MV with severe bronchiolitis admitted to two PICU's. Infants younger than 1 year old with acute respiratory failure caused by severe bronchiolitis underwent neuromuscular blockade, tracheal intubation and volume controlled MV. Shortly after intubation studies of pulmonary mechanics were performed using inspiratory and expiratory breath hold. The maximum inspiratory and expiratory flow (QI and QE) as well as peak inspiratory (PIP), plateau (PPL) and total expiratory pressures (tPEEP) were measured. Inspiratory and expiratory resistances (RawI and RawE) and Time Constants (K TI and K TE ) were calculated. We included 16 patients, of median age 2.5 (1-5.8) months. Bronchiolitis due to respiratory syncytial virus was the main etiology (93.8%) and 31.3% had comorbidities. Measured respiratory pressures were PIP 29 (26-31), PPL 24 (20-26), tPEEP 9 [8-11] cmH2O. Elastic component of the working pressure was significantly higher than resistive and both higher than threshold (tPEEP - PEEP) (P mechanics of infants with severe bronchiolitis receiving MV shows that the elastic component of the working pressure of the respiratory system is the most important. The elastic and resistive components in conjunction with flow profile are characteristic of restrictive diseases. A better understanding of lung mechanics in this group of patients may lead to change the traditional ventilatory approach to severe bronchiolitis.

Protective lung ventilation in operating room: a systematic review.

Science.gov (United States)

Futier, E; Constantin, J M; Jaber, S

2014-06-01

Postoperative pulmonary and extrapulmonary complications adversely affect clinical outcomes and healthcare utilization, so that prevention has become a measure of the quality of perioperative care. Mechanical ventilation is an essential support therapy to maintain adequate gas exchange during general anesthesia for surgery. Mechanical ventilation using high tidal volume (VT) (between 10 and 15 mL/kg) has been historically encouraged to prevent hypoxemia and atelectasis formation in anesthetized patients undergoing abdominal and thoracic surgery. However, there is accumulating evidence from both experimental and clinical studies that mechanical ventilation, especially the use of high VT and plateau pressure, may potentially aggravate or even initiate lung injury. Ventilator-associated lung injury can result from cyclic alveolar overdistension of non-dependent lung tissue, and repetitive opening and closing of dependent lung tissue resulting in ultrastructural damage at the junction of closed and open alveoli. Lung-protective ventilation, which refers to the use of lower VT and limited plateau pressure to minimize overdistension, and positive end-expiratory pressure to prevent alveolar collapse at end-expiration, was shown to improve outcome in critically ill patients with acute respiratory distress syndrome (ARDS). It has been recently suggested that this approach might also be beneficial in a broader population, especially in critically ill patients without ARDS at the onset of mechanical ventilation. There is, however, little evidence regarding a potential beneficial effect of lung protective ventilation during surgery, especially in patients with healthy lungs. Although surgical patients are frequently exposed to much shorter periods of mechanical ventilation, this is an important gap in knowledge given the number of patients receiving mechanical ventilation in the operating room. This review developed the benefits of lung protective ventilation during surgery

Linking Ventilator Injury-Induced Leak across the Blood-Gas Barrier to Derangements in Murine Lung Function

Directory of Open Access Journals (Sweden)

Bradford J. Smith

2017-07-01

Full Text Available Mechanical ventilation is vital to the management of acute respiratory distress syndrome, but it frequently leads to ventilator-induced lung injury (VILI. Understanding the pathophysiological processes involved in the development of VILI is an essential prerequisite for improving lung-protective ventilation strategies. The goal of this study was to relate the amount and nature of material accumulated in the airspaces to biomarkers of injury and the derecruitment behavior of the lung in VILI. Forty-nine BALB/c mice were mechanically ventilated with combinations of tidal volume and end-expiratory pressures to produce varying degrees of overdistension and atelectasis while lung function was periodically assessed. Total protein, serum protein, and E-Cadherin levels were measured in bronchoalveolar lavage fluid (BALF. Tissue injury was assessed by histological scoring. We found that both high tidal volume and zero positive end-expiratory pressure were necessary to produce significant VILI. Increased BALF protein content was correlated with increased lung derecruitability, elevated peak pressures, and histological evidence of tissue injury. Blood derived molecules were present in the BALF in proportion to histological injury scores and epithelial injury, reflected by E-Cadherin levels in BALF. We conclude that repetitive recruitment is an important factor in the pathogenesis of VILI that exacerbates injury associated with tidal overdistension. Furthermore, the dynamic mechanical behavior of the injured lung provides a means to assess both the degree of tissue injury and the nature and amount of blood-derived fluid and proteins that accumulate in the airspaces.

Lung-Protective Ventilation Strategies for Relief from Ventilator-Associated Lung Injury in Patients Undergoing Craniotomy: A Bicenter Randomized, Parallel, and Controlled Trial

Directory of Open Access Journals (Sweden)

Chaoliang Tang

2017-01-01

Full Text Available Current evidence indicates that conventional mechanical ventilation often leads to lung inflammatory response and oxidative stress, while lung-protective ventilation (LPV minimizes the risk of ventilator-associated lung injury (VALI. This study evaluated the effects of LPV on relief of pulmonary injury, inflammatory response, and oxidative stress among patients undergoing craniotomy. Sixty patients undergoing craniotomy received either conventional mechanical (12 mL/kg tidal volume [VT] and 0 cm H2O positive end-expiratory pressure [PEEP]; CV group or protective lung (6 mL/kg VT and 10 cm H2O PEEP; PV group ventilation. Hemodynamic variables, lung function indexes, and inflammatory and oxidative stress markers were assessed. The PV group exhibited greater dynamic lung compliance and lower respiratory index than the CV group during surgery (P0.05. Patients receiving LPV during craniotomy exhibited low perioperative inflammatory response, oxidative stress, and VALI.

Evaluation of Pressure Generated by Resistors From Different Positive Expiratory Pressure Devices.

Science.gov (United States)

Fagevik Olsén, Monika; Carlsson, Maria; Olsén, Erik; Westerdahl, Elisabeth

2015-10-01

Breathing exercises with positive expiratory pressure (PEP) are used to improve pulmonary function and airway clearance. Different PEP devices are available, but there have been no studies that describe the pressure generated by different resistors. The purpose of this study was to compare pressures generated from the proprietary resistor components of 4 commercial flow-dependent PEP valves with all other parameters kept constant. Resistors from 4 flow-regulated PEP devices (Pep/Rmt system, Wellspect HealthCare; Pipe P breathing exerciser, Koo Medical Equipment; Mini-PEP, Philips Respironics [including resistors by Rüsch]; and 15-mm endo-adapter, VBM Medizintechnik) were tested randomly by a blinded tester at constant flows of 10 and 18 L/min from an external gas system. All resistors were tested 3 times. Resistors with a similar diameter produced statistically significant different pressures at the same flow. The differences were smaller when the flow was 10 L/min compared with 18 L/min. The differences were also smaller when the diameter of the resistor was increased. The pressures produced by the 4 resistors of the same size were all significantly different when measuring 1.5- and 2.0-mm resistors at a flow of 10 L/min and 2.0-mm resistors at a flow of 18 L/min (P < .001). There were no significant differences between any of the resistors when testing sizes of 4.5 and 5.0 mm at either flow. The Mini-PEP and adapter resistors gave the highest pressures. Pressures generated by the different proprietary resistor components of 4 commercial PEP devices were not comparable, even though the diameter of the resistors is reported to be the same. The pressures generated were significantly different, particularly when using small-diameter resistors at a high flow. Therefore, the resistors may not be interchangeable. This is important information for clinicians, particularly when considering PEP for patients who do not tolerate higher pressures. Copyright © 2015 by

Closed-loop mechanical ventilation for lung injury: a novel physiological-feedback mode following the principles of the open lung concept.

Science.gov (United States)

Schwaiberger, David; Pickerodt, Philipp A; Pomprapa, Anake; Tjarks, Onno; Kork, Felix; Boemke, Willehad; Francis, Roland C E; Leonhardt, Steffen; Lachmann, Burkhard

2018-06-01

Adherence to low tidal volume (V T ) ventilation and selected positive end-expiratory pressures are low during mechanical ventilation for treatment of the acute respiratory distress syndrome. Using a pig model of severe lung injury, we tested the feasibility and physiological responses to a novel fully closed-loop mechanical ventilation algorithm based on the "open lung" concept. Lung injury was induced by surfactant washout in pigs (n = 8). Animals were ventilated following the principles of the "open lung approach" (OLA) using a fully closed-loop physiological feedback algorithm for mechanical ventilation. Standard gas exchange, respiratory- and hemodynamic parameters were measured. Electrical impedance tomography was used to quantify regional ventilation distribution during mechanical ventilation. Automatized mechanical ventilation provided strict adherence to low V T -ventilation for 6 h in severely lung injured pigs. Using the "open lung" approach, tidal volume delivery required low lung distending pressures, increased recruitment and ventilation of dorsal lung regions and improved arterial blood oxygenation. Physiological feedback closed-loop mechanical ventilation according to the principles of the open lung concept is feasible and provides low tidal volume ventilation without human intervention. Of importance, the "open lung approach"-ventilation improved gas exchange and reduced lung driving pressures by opening atelectasis and shifting of ventilation to dorsal lung regions.

Deep breathing exercises with positive expiratory pressure in patients with multiple sclerosis - a randomized controlled trial.

Science.gov (United States)

Westerdahl, Elisabeth; Wittrin, Anna; Kånåhols, Margareta; Gunnarsson, Martin; Nilsagård, Ylva

2016-11-01

Breathing exercises with positive expiratory pressure are often recommended to patients with advanced neurological deficits, but the potential benefit in multiple sclerosis (MS) patients with mild and moderate symptoms has not yet been investigated in randomized controlled trials. To study the effects of 2 months of home-based breathing exercises for patients with mild to moderate MS on respiratory muscle strength, lung function, and subjective breathing and health status outcomes. Forty-eight patients with MS according to the revised McDonald criteria were enrolled in a randomized controlled trial. Patients performing breathing exercises (n = 23) were compared with a control group (n = 25) performing no breathing exercises. The breathing exercises were performed with a positive expiratory pressure device (10-15 cmH 2 O) and consisted of 30 slow deep breaths performed twice a day for 2 months. Respiratory muscle strength (maximal inspiratory and expiratory pressure at the mouth), spirometry, oxygenation, thoracic excursion, subjective perceptions of breathing and self-reported health status were evaluated before and after the intervention period. Following the intervention, there was a significant difference between the breathing group and the control group regarding the relative change in lung function, favoring the breathing group (vital capacity: P < 0.043; forced vital capacity: P < 0.025). There were no other significant differences between the groups. Breathing exercises may be beneficial in patients with mild to moderate stages of MS. However, the clinical significance needs to be clarified, and it remains to be seen whether a sustainable effect in delaying the development of respiratory dysfunction in MS can be obtained. © 2015 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.

Effects of sevoflurane on ventilator induced lung injury in a healthy lung experimental model.

Science.gov (United States)

Romero, A; Moreno, A; García, J; Sánchez, C; Santos, M; García, J

2016-01-01

Ventilator-induced lung injury (VILI) causes a systemic inflammatory response in tissues, with an increase in IL-1, IL-6 and TNF-α in blood and tissues. Cytoprotective effects of sevoflurane in different experimental models are well known, and this protective effect can also be observed in VILI. The objective of this study was to assess the effects of sevoflurane in VILI. A prospective, randomized, controlled study was designed. Twenty female rats were studied. The animals were mechanically ventilated, without sevoflurane in the control group and sevoflurane 3% in the treated group (SEV group). VILI was induced applying a maximal inspiratory pressure of 35 cmH2O for 20 min without any positive end-expiratory pressure for 20 min (INJURY time). The animals were then ventilated 30 min with a maximal inspiratory pressure of 12 cmH2O and 3 cmH2O positive end-expiratory pressure (time 30 min POST-INJURY), at which time the animals were euthanized and pathological and biomarkers studies were performed. Heart rate, invasive blood pressure, pH, PaO2, and PaCO2 were recorded. The lung wet-to-dry weight ratio was used as an index of lung edema. No differences were found in the blood gas analysis parameters or heart rate between the 2 groups. Blood pressure was statistically higher in the control group, but still within the normal clinical range. The percentage of pulmonary edema and concentrations of TNF-α and IL-6 in lung tissue in the SEV group were lower than in the control group. Sevoflurane attenuates VILI in a previous healthy lung in an experimental subclinical model in rats. Copyright © 2015 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Mechanical ventilation in abdominal surgery.

Science.gov (United States)

Futier, E; Godet, T; Millot, A; Constantin, J-M; Jaber, S

2014-01-01

One of the key challenges in perioperative care is to reduce postoperative morbidity and mortality. Patients who develop postoperative morbidity but survive to leave hospital have often reduced functional independence and long-term survival. Mechanical ventilation provides a specific example that may help us to shift thinking from treatment to prevention of postoperative complications. Mechanical ventilation in patients undergoing surgery has long been considered only as a modality to ensure gas exchange while allowing maintenance of anesthesia with delivery of inhaled anesthetics. Evidence is accumulating, however, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary function and clinical outcome in patients undergoing abdominal surgery. Non-protective ventilator settings, especially high tidal volume (VT) (>10-12mL/kg) and the use of very low level of positive end-expiratory pressure (PEEP) (PEEPventilator-associated lung injury in patients with healthy lungs. Stimulated by previous findings in patients with acute respiratory distress syndrome, the use of lower tidal volume ventilation is becoming increasingly more common in the operating room. However, lowering tidal volume, though important, is only part of the overall multifaceted approach of lung protective mechanical ventilation. In this review, we aimed at providing the most recent and relevant clinical evidence regarding the use of mechanical ventilation in patients undergoing abdominal surgery. Copyright © 2014 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.

Data on respiratory variables in critically ill patients with acute respiratory failure placed on proportional assist ventilation with load adjustable gain factors (PAV+

Directory of Open Access Journals (Sweden)

Dimitris Georgopoulos

2016-09-01

Full Text Available The data show respiratory variables in 108 critically ill patients with acute respiratory failure placed on proportional assist ventilation with load adjustable gain factors (PAV+ after at least 36 h on passive mechanical ventilation. PAV+ was continued for 48 h until the patients met pre-defined criteria either for switching to controlled modes or for breathing without ventilator assistance. Data during passive mechanical ventilation and during PAV+ are reported. Data are acquired from the whole population, as well as from patients with and without acute respiratory distress syndrome. The reported variables are tidal volume, driving pressure (ΔP, the difference between static end-inspiratory plateau pressure and positive end-expiratory airway pressure, respiratory system compliance and resistance, and arterial blood gasses. The data are supplemental to our original research article, which described individual ΔP in these patients and examined how it related to ΔP when the same patients were ventilated with passive mechanical ventilation using the currently accepted lung-protective strategy “Driving pressure during assisted mechanical ventilation. Is it controlled by patient brain?” [1]. Keywords: Tidal volume, Compliance, Driving pressure

Feasibility of Protective Ventilation During Elective Supratentorial Neurosurgery: A Randomized, Crossover, Clinical Trial.

Science.gov (United States)

Ruggieri, Francesco; Beretta, Luigi; Corno, Laura; Testa, Valentina; Martino, Enrico A; Gemma, Marco

2017-06-30

Traditional ventilation approaches, providing high tidal volumes (Vt), produce excessive alveolar distention and lung injury. Protective ventilation, employing lower Vt and positive end-expiratory pressure (PEEP), is an attractive alternative also for neuroanesthesia, when prolonged mechanical ventilation is needed. Nevertheless, protective ventilation during intracranial surgery may exert dangerous effects on intracranial pressure (ICP). We tested the feasibility of a protective ventilation strategy in neurosurgery. Our monocentric, double-blind, 1:1 randomized, 2×2 crossover study aimed at studying the effect size and variability of ICP in patients undergoing elective supratentorial brain tumor removal and alternatively ventilated with Vt 9 mL/kg-PEEP 0 mm Hg and Vt 7 mL/kg-PEEP 5 mm Hg. Respiratory rate was adjusted to maintain comparable end-tidal carbon dioxide between ventilation modes. ICP was measured through a subdural catheter inserted before dural opening. Forty patients were enrolled; 8 (15%) were excluded after enrollment. ICP did not differ between traditional and protective ventilation (11.28±5.37, 11 [7 to 14.5] vs. 11.90±5.86, 11 [8 to 15] mm Hg; P=0.541). End-tidal carbon dioxide (28.91±2.28, 29 [28 to 30] vs. 28.00±2.17, 28 [27 to 29] mm Hg; Pprotective ventilation. Blood pressure, heart rate, and body temperature did not differ between ventilation modes. Dural tension was "acceptable for surgery" in all cases. ICP differences between ventilation modes were not affected by ICP values under traditional ventilation (coefficient=0.067; 95% confidence interval, -0.278 to 0.144; P=0.523). Protective ventilation is a feasible alternative to traditional ventilation during elective neurosurgery.

Positive expiratory pressure in patients with chronic obstructive pulmonary disease--a systematic review.

Science.gov (United States)

Fagevik Olsén, Monika; Westerdahl, Elisabeth

2009-01-01

Breathing exercises against a resistance during expiration are often used as treatment for patients with chronic obstructive pulmonary disease (COPD). Controversy still exists regarding the clinical application and efficacy. The aim of this systematic review was to determine the effects of chest physiotherapy techniques with positive expiratory pressure (PEP) for the prevention and treatment of pulmonary impairment in adults with COPD. The review was conducted on randomised, controlled clinical trials in which breathing exercises with positive expiratory pressure were compared with other chest physical therapy techniques or with no treatment, in adult patients with COPD. A computer-assisted literature search of available databases from 1970 to January 2008 was performed. Two reviewers extracted data independently and assessed the trials systematically with an instrument for measuring methodological quality. In total, 11 trials met the inclusion criteria, of which 5 reached an adequate level of internal validity. Several kinds of PEP techniques with a diversity of intensities and durations of treatment have been evaluated with different outcome measures and follow-up periods. Benefits of PEP were found in isolated outcome measures in separate studies with a follow-up period <1 month. Concerning long-term effects, the results are contradictory. Prior to widespread prescription of long-term PEP treatment, more research is required to establish the benefit of the technique in patients with COPD. (c) 2008 S. Karger AG, Basel.

Mechanical ventilators in the hot zone: effects of a CBRN filter on patient protection and battery life.

Science.gov (United States)

Blakeman, Thomas C; Toth, Peter; Rodriquez, Dario; Branson, Richard D

2010-09-01

In a contaminated environment, respiratory protection for ventilator dependent patients can be achieved by attaching a chemical, biological, radiological, or nuclear (CBRN) filter to the air intake port of a portable ventilator. We evaluated the effect of the filter on battery performance of four portable ventilators in a laboratory setting. Each ventilator was attached to a test lung. Ventilator settings were: assist control (AC) mode, respiratory rate 35 bpm, tidal volume 450 ml, positive end-expiratory pressure (PEEP) 10 cm H(2)O, inspiratory time 0.8 s, and FIO(2) 0.21. Ventilators were operated until the battery was fully discharged. We also evaluated the ventilators' ability to deliver all the gas through the CBRN filter and analyzed the pressures required to breathe through the anti-asphyxiation valve of a failed device. The range of battery life varied widely across different ventilator models (99.8-562.6 min). There was no significant difference in battery life (pventilator dependent patients when environmental contamination is present, although conditions exist where all gas does not pass through the filter with some ventilators under normal operating conditions. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Nebulized hypertonic saline via positive expiratory pressure versus via jet nebulizer in patients with severe cystic fibrosis.

LENUS (Irish Health Repository)

O'Connell, Oisin J

2011-06-01

Nebulized hypertonic saline is a highly effective therapy for patients with cystic fibrosis (CF), yet 10% of patients are intolerant of hypertonic saline administered via jet nebulizer. Positive expiratory pressure (PEP) nebulizers splint open the airways and offers a more controlled rate of nebulization.

Lung ventilation injures areas with discrete alveolar flooding, in a surface tension-dependent fashion.

Science.gov (United States)

Wu, You; Kharge, Angana Banerjee; Perlman, Carrie E

2014-10-01

With proteinaceous-liquid flooding of discrete alveoli, a model of the edema pattern in the acute respiratory distress syndrome, lung inflation over expands aerated alveoli adjacent to flooded alveoli. Theoretical considerations suggest that the overexpansion may be proportional to surface tension, T. Yet recent evidence indicates proteinaceous edema liquid may not elevate T. Thus whether the overexpansion is injurious is not known. Here, working in the isolated, perfused rat lung, we quantify fluorescence movement from the vasculature to the alveolar liquid phase as a measure of overdistension injury to the alveolar-capillary barrier. We label the perfusate with fluorescence; micropuncture a surface alveolus and instill a controlled volume of nonfluorescent liquid to obtain a micropunctured-but-aerated region (control group) or a region with discrete alveolar flooding; image the region at a constant transpulmonary pressure of 5 cmH2O; apply five ventilation cycles with a positive end-expiratory pressure of 0-20 cmH2O and tidal volume of 6 or 12 ml/kg; return the lung to a constant transpulmonary pressure of 5 cmH2O; and image for an additional 10 min. In aerated areas, ventilation is not injurious. With discrete alveolar flooding, all ventilation protocols cause sustained injury. Greater positive end-expiratory pressure or tidal volume increases injury. Furthermore, we determine T and find injury increases with T. Inclusion of either plasma proteins or Survanta in the flooding liquid does not alter T or injury. Inclusion of 2.7-10% albumin and 1% Survanta together, however, lowers T and injury. Contrary to expectation, albumin inclusion in our model facilitates exogenous surfactant activity. Copyright © 2014 the American Physiological Society.

Physiologically based indices of volumetric capnography in patients receiving mechanical ventilation.

Science.gov (United States)

Romero, P V; Lucangelo, U; Lopez Aguilar, J; Fernandez, R; Blanch, L

1997-06-01

Several indices of ventilatory heterogeneity can be identified from the expiratory CO2 partial pressure or CO2 elimination versus volume curves. The aims of this study were: 1) to analyse several computerizable indices of volumetric capnography in order to detect ventilatory disturbances; and 2) to establish the relationship between those indices and respiratory system mechanics in subjects with normal lungs and in patients with acute respiratory distress syndrome (ARDS), both receiving mechanical ventilation. We studied six normal subjects and five patients with early ARDS mechanically ventilated at three levels of tidal volume (VT). Respiratory system mechanics were assessed by end-expiratory and end-inspiratory occlusion methods, respectively. We determined Phase III slopes, Fletcher's efficiency index, Bohr's dead space (VD,Bohr/VT), and the ratio of alveolar ejection volume to tidal volume (VAE/VT) from expiratory capnograms, as a function of expired volume. Differences between normal subjects and ARDS patients were significant both for capnographic and mechanical parameters. Changes in VT significantly altered capnographic indices in normal subjects, but failed to change ventilatory mechanics and VAE/VT in ARDS patients. After adjusting for breathing pattern, VAE/VT exhibited the best correlation with the mechanical parameters. In conclusion, volumetric capnography, and, specifically, the ratio of alveolar ejection volume to tidal volume allows evaluation and monitoring of ventilatory disturbances in patients with adult respiratory distress syndrome.

Performance potential of mechanical ventilation systems with minimized pressure loss

DEFF Research Database (Denmark)

Terkildsen, Søren; Svendsen, Svend

2013-01-01

simulations that quantify fan power consumption, heating demand and indoor environmental conditions. The system was designed with minimal pressure loss in the duct system and heat exchanger. Also, it uses state-of-the-art components such as electrostatic precipitators, diffuse ceiling inlets and demand......In many locations mechanical ventilation has been the most widely used principle of ventilation over the last 50 years but the conventional system design must be revised to comply with future energy requirements. This paper examines the options and describes a concept for the design of mechanical...... ventilation systems with minimal pressure loss and minimal energy use. This can provide comfort ventilation and avoid overheating through increased ventilation and night cooling. Based on this concept, a test system was designed for a fictive office building and its performance was documented using building...

Sensitivity and specificity of hypopnoea detection using nasal pressure in the presence of a nasal expiratory resistive device (Provent®)

International Nuclear Information System (INIS)

Milne, Stephen; Amis, Terence C; Wheatley, John R; Kairaitis, Kristina

2014-01-01

Nasal expiratory resistive valves (Provent ® ) have been proposed as novel therapy for obstructive sleep apnea. We compared pressure measurements from a standard nasal pressure catheter used to assess nasal airflow during sleep with those from nasal expiratory resistive device with attached proprietary nasal pressure cannula. Nasal pressure cannula or Provent ® + proprietary nasal pressure cannula were attached to a bench model of human anterior nares and nasal passages, and pressure measured (P). Respiratory airflows generated by a subject breathing were applied to rear of model and airflow ( V-dot ) measured via pneumotachograph. Airflow amplitude (Δ V-dot ) was plotted against pressure amplitude (ΔP). Hypopnoea detection (<50% Δ V-dot ) sensitivity and specificity was tested by expressing ΔP in terms of two reference breaths: reference breath 1, Δ V-dot 0.55 L s −1  = 100%; and reference breath 2, Δ V-dot 0.45 L s −1  = 100%. ΔP/Δ V-dot relationships were linear for Δ V-dot  ≤ 0.55 L s −1 ; ΔP = 0.37ΔV + 0.16 (nasal pressure cannula), ΔP = 2.7ΔV + 0.12 (Provent ® + proprietary nasal pressure cannula); both R 2  > 0.65, p < 0.0001; p < 0.0001 for between slope difference). For nasal pressure cannula, specificity of hypopnoea detection differed between reference breaths one and two (80.2% and 40.0%, respectively), and Provent ® + proprietary nasal pressure cannula (30.3% and 74.2%, respectively). Quantification of airflow obstruction in the presence of Provent ® + proprietary nasal pressure cannula is greatly influenced by the reference breath chosen to determine a reduction in nasal airflow. Reported variability in therapeutic response to nasal expiratory resistive devices may relate to differences in measurement technique specificity used to quantify the severity of sleep disordered breathing. (paper)

Mobile communication devices causing interference in invasive and noninvasive ventilators.

Science.gov (United States)

Dang, Bao P; Nel, Pierre R; Gjevre, John A

2007-06-01

The aim of this study was to assess if common mobile communication systems would cause significant interference on mechanical ventilation devices and at what distances would such interference occur. We tested all the invasive and noninvasive ventilatory devices used within our region. This consisted of 2 adult mechanical ventilators, 1 portable ventilator, 2 pediatric ventilators, and 2 noninvasive positive pressure ventilatory devices. We operated the mobile devices from the 2 cellular communication systems (digital) and 1 2-way radio system used in our province at varying distances from the ventilators and looked at any interference they created. We tested the 2-way radio system, which had a fixed operation power output of 3.0 watts, the Global Systems for Mobile Communication cellular system, which had a maximum power output of 2.0 watts and the Time Division Multiple Access cellular system, which had a maximum power output of 0.2 watts on our ventilators. The ventilators were ventilating a plastic lung at fixed settings. The mobile communication devices were tested at varying distances starting at zero meter from the ventilator and in all operation modes. The 2-way radio caused the most interference on some of the ventilators, but the maximum distance of interference was 1.0 m. The Global Systems for Mobile Communication system caused significant interference only at 0 m and minor interference at 0.5 m on only 1 ventilator. The Time Division Multiple Access system caused no interference at all. Significant interference consisted of a dramatic rise and fluctuation of the respiratory rate, pressure, and positive end-expiratory pressure of the ventilators with no normalization when the mobile device was removed. From our experiment on our ventilators with the communication systems used in our province, we conclude that mobile communication devices such as cellular phones and 2-way radios are safe and cause no interference unless operated at very close distances of

Comparison of nasal continuous positive airway pressure delivered by seven ventilators using simulated neonatal breathing.

Science.gov (United States)

Drevhammar, Thomas; Nilsson, Kjell; Zetterström, Henrik; Jonsson, Baldvin

2013-05-01

Nasal continuous positive airway pressure (NCPAP) is an established treatment for respiratory distress in neonates. Most modern ventilators are able to provide NCPAP. There have been no large studies examining the properties of NCPAP delivered by ventilators. The aim of this study was to compare pressure stability and imposed work of breathing (iWOB) for NCPAP delivered by ventilators using simulated neonatal breathing. Experimental in vitro study. Research laboratory in Sweden. None. Neonatal breathing was simulated using a mechanical lung simulator. Seven ventilators were tested at different CPAP levels using two breath profiles. Pressure stability and iWOB were determined. Results from three ventilators revealed that they provided a slight pressure support. For these ventilators, iWOB could not be calculated. There were large differences in pressure stability and iWOB between the tested ventilators. For simulations using the 3.4-kg breath profile, the pressure swings around the mean pressure were more than five times greater, and iWOB more than four times higher, for the system with the highest measured values compared with the system with the lowest. Overall, the Fabian ventilator was the most pressure stable system. Evita XL and SERVO-i were found more pressure stable than Fabian in some simulations. The results for iWOB were in accordance with pressure stability for systems that allowed determination of this variable. Some of the tested ventilators unexpectedly provided a minor degree of pressure support. In terms of pressure stability, we have not found any advantages of ventilators as a group compared with Bubble CPAP, Neopuff, and variable flow generators that were tested in our previous study. The variation between individual systems is great within both categories. The clinical importance of these findings needs further investigation.

Gadolinium prevents high airway pressure-induced permeability increases in isolated rat lungs.

Science.gov (United States)

Parker, J C; Ivey, C L; Tucker, J A

1998-04-01

To determine the initial signaling event in the vascular permeability increase after high airway pressure injury, we compared groups of lungs ventilated at different peak inflation pressures (PIPs) with (gadolinium group) and without (control group) infusion of 20 microM gadolinium chloride, an inhibitor of endothelial stretch-activated cation channels. Microvascular permeability was assessed by using the capillary filtration coefficient (Kfc), a measure of capillary hydraulic conductivity. Kfc was measured after ventilation for 30-min periods with 7, 20, and 30 cmH2O PIP with 3 cmH2O positive end-expiratory pressure and with 35 cmH2O PIP with 8 cmH2O positive end-expiratory pressure. In control lungs, Kfc increased significantly to 1.8 and 3.7 times baseline after 30 and 35 cmH2O PIP, respectively. In the gadolinium group, Kfc was unchanged from baseline (0.060 +/- 0.010 ml . min-1 . cmH2O-1 . 100 g-1) after any PIP ventilation period. Pulmonary vascular resistance increased significantly from baseline in both groups before the last Kfc measurement but was not different between groups. These results suggest that microvascular permeability is actively modulated by a cellular response to mechanical injury and that stretch-activated cation channels may initiate this response through increases in intracellular calcium concentration.

Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Patients with Acute Severe Respiratory Failure.

Science.gov (United States)

Zhang, Zhongheng; Gu, Wan-Jie; Chen, Kun; Ni, Hongying

2017-01-01

Conventionally, a substantial number of patients with acute respiratory failure require mechanical ventilation (MV) to avert catastrophe of hypoxemia and hypercapnia. However, mechanical ventilation per se can cause lung injury, accelerating the disease progression. Extracorporeal membrane oxygenation (ECMO) provides an alternative to rescue patients with severe respiratory failure that conventional mechanical ventilation fails to maintain adequate gas exchange. The physiology behind ECMO and its interaction with MV were reviewed. Next, we discussed the timing of ECMO initiation based on the risks and benefits of ECMO. During the running of ECMO, the protective ventilation strategy can be employed without worrying about catastrophic hypoxemia and carbon dioxide retention. There is a large body of evidence showing that protective ventilation with low tidal volume, high positive end-expiratory pressure, and prone positioning can provide benefits on mortality outcome. More recently, there is an increasing popularity on the use of awake and spontaneous breathing for patients undergoing ECMO, which is thought to be beneficial in terms of rehabilitation.

Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Patients with Acute Severe Respiratory Failure

Directory of Open Access Journals (Sweden)

Zhongheng Zhang

2017-01-01

Full Text Available Conventionally, a substantial number of patients with acute respiratory failure require mechanical ventilation (MV to avert catastrophe of hypoxemia and hypercapnia. However, mechanical ventilation per se can cause lung injury, accelerating the disease progression. Extracorporeal membrane oxygenation (ECMO provides an alternative to rescue patients with severe respiratory failure that conventional mechanical ventilation fails to maintain adequate gas exchange. The physiology behind ECMO and its interaction with MV were reviewed. Next, we discussed the timing of ECMO initiation based on the risks and benefits of ECMO. During the running of ECMO, the protective ventilation strategy can be employed without worrying about catastrophic hypoxemia and carbon dioxide retention. There is a large body of evidence showing that protective ventilation with low tidal volume, high positive end-expiratory pressure, and prone positioning can provide benefits on mortality outcome. More recently, there is an increasing popularity on the use of awake and spontaneous breathing for patients undergoing ECMO, which is thought to be beneficial in terms of rehabilitation.

Mild hypothermia attenuates changes in respiratory system mechanics and modifies cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation.

Science.gov (United States)

Dostál, P; Senkeřík, M; Pařízková, R; Bareš, D; Zivný, P; Zivná, H; Cerný, V

2010-01-01

Hypothermia was shown to attenuate ventilator-induced lung injury due to large tidal volumes. It is unclear if the protective effect of hypothermia is maintained under less injurious mechanical ventilation in animals without previous lung injury. Tracheostomized rats were randomly allocated to non-ventilated group (group C) or ventilated groups of normothermia (group N) and mild hypothermia (group H). After two hours of mechanical ventilation with inspiratory fraction of oxygen 1.0, respiratory rate 60 min(-1), tidal volume 10 ml x kg(-1), positive end-expiratory pressure (PEEP) 2 cm H2O or immediately after tracheostomy in non-ventilated animals inspiratory pressures were recorded, rats were sacrificed, pressure-volume (PV) curve of respiratory system constructed, bronchoalveolar lavage (BAL) fluid and aortic blood samples obtained. Group N animals exhibited a higher rise in peak inspiratory pressures in comparison to group H animals. Shift of the PV curve to right, higher total protein and interleukin-6 levels in BAL fluid were observed in normothermia animals in comparison with hypothermia animals and non-ventilated controls. Tumor necrosis factor-alpha was lower in the hypothermia group in comparison with normothermia and non-ventilated groups. Mild hypothermia attenuated changes in respiratory system mechanics and modified cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation in animals without previous lung injury.

The deflation limb of the pressure-volume relationship in infants during high-frequency ventilation.

Science.gov (United States)

Tingay, David G; Mills, John F; Morley, Colin J; Pellicano, Anastasia; Dargaville, Peter A

2006-02-15

The importance of applying high-frequency oscillatory ventilation with a high lung volume strategy in infants is well established. Currently, a lack of reliable methods for assessing lung volume limits clinicians' ability to achieve the optimum volume range. To map the pressure-volume relationship of the lung during high-frequency oscillatory ventilation in infants, to determine at what point ventilation is being applied clinically, and to describe the relationship between airway pressure, lung volume, and oxygenation. In 12 infants, a partial inflation limb and the deflation limb of the pressure-volume relationship were mapped using a quasi-static lung volume optimization maneuver. This involved stepwise airway pressure increments to total lung capacity, followed by decrements until the closing pressure of the lung was identified. Lung volume and oxygen saturation were recorded at each airway pressure. Lung volume was measured using respiratory inductive plethysmography. A distinct deflation limb could be mapped in each infant. Overall, oxygenation and lung volume were improved by applying ventilation on the deflation limb. Maximal lung volume and oxygenation occurred on the deflation limb at a mean airway pressure of 3 and 5 cm H(2)O below the airway pressure approximating total lung capacity, respectively. Using current ventilation strategies, all infants were being ventilated near the inflation limb. It is possible to delineate the deflation limb in infants receiving high-frequency oscillatory ventilation; in doing so, greater lung volume and oxygenation can be achieved, often at lower airway pressures.

Mechanical ventilation with lower tidal volumes and positive end-expiratory pressure prevents pulmonary inflammation in patients without preexisting lung injury

NARCIS (Netherlands)

Wolthuis, Esther K.; Choi, Goda; Dessing, Mark C.; Bresser, Paul; Lutter, Rene; Dzoljic, Misa; van der Poll, Tom; Vroom, Margreeth B.; Hollmann, Markus; Schultz, Marcus J.

2008-01-01

Background: Mechanical ventilation with high tidal volumes aggravates lung injury in patients with acute lung injury or acute respiratory distress syndrome. The authors sought to determine the effects of short-term mechanical ventilation on local inflammatory responses in patients without

Mechanical ventilation during extracorporeal membrane oxygenation. An international survey.

Science.gov (United States)

Marhong, Jonathan D; Telesnicki, Teagan; Munshi, Laveena; Del Sorbo, Lorenzo; Detsky, Michael; Fan, Eddy

2014-07-01

In patients with severe, acute respiratory failure undergoing venovenous extracorporeal membrane oxygenation (VV-ECMO), the optimal strategy for mechanical ventilation is unclear. Our objective was to describe ventilation practices used in centers registered with the Extracorporeal Life Support Organization (ELSO). We conducted an international cross-sectional survey of medical directors and ECMO program coordinators from all ELSO-registered centers. The survey was distributed using a commercial website that collected information on center characteristics, the presence of a mechanical ventilator protocol, ventilator settings, and weaning practices. E-mails were sent out to medical directors or coordinators at each ELSO center and their responses were pooled for analysis. We analyzed 141 (50%) individual responses from the 283 centers contacted across 28 countries. Only 27% of centers reported having an explicit mechanical ventilation protocol for ECMO patients. The majority of these centers (77%) reported "lung rest" to be the primary goal of mechanical ventilation, whereas 9% reported "lung recruitment" to be their ventilation strategy. A tidal volume of 6 ml/kg or less was targeted by 76% of respondents, and 58% targeted a positive end-expiratory pressure of 6-10 cm H2O while ventilating patients on VV-ECMO. Centers prioritized weaning VV-ECMO before mechanical ventilation. Although ventilation practices in patients supported by VV-ECMO vary across ELSO centers internationally, the majority of centers used a strategy that targeted lung-protective thresholds and prioritized weaning VV-ECMO over mechanical ventilation.

[Alveolar ventilation and recruitment under lung protective ventilation].

Science.gov (United States)

Putensen, Christian; Muders, Thomas; Kreyer, Stefan; Wrigge, Hermann

2008-11-01

Goal of mechanical ventilation is to improve gas exchange and reduce work of breathing without contributing to further lung injury. Besides providing adequate EELV and thereby arterial oxygenation PEEP in addition to a reduction in tidal volume is required to prevent cyclic alveolar collapse and tidal recruitment and hence protective mechanical ventilation. Currently, there is no consensus if and if yes at which price alveolar recruitment with high airway pressures should be intended ("open up the lung"), or if it is more important to reduce the mechanical stress and strain to the lungs as much as possible ("keep the lung closed"). Potential of alveolar recruitment differs from patient to patient but also between lung regions. Potential for recruitment depends probably more on regional lung mechanics - especially on lung elastance - than on the underlying disease. Based on available data neither high PEEP nor other methods used for alveolar recruitment could demonstrate a survival benefit in patients with ARDS. These results may support an individualized titration of PEEP or other manoeuvres used for recruitment taking into consideration the regional effects. Bedside imaging techniques allowing titration of PEEP or other manoeuvres to prevent end-expiratory alveolar collapse (tidal recruitment) and inspiratory overinflation may be a promising development.

Physiological techniques for detecting expiratory flow limitation during tidal breathing

Directory of Open Access Journals (Sweden)

N.G. Koulouris

2011-09-01

Full Text Available Patients with severe chronic obstructive pulmonary disease (COPD often exhale along the same flow–volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFLT. Therefore, EFLT, namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFLT leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFLT occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage, in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFLT are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique.

Static end-expiratory and dynamic forced expiratory tracheal collapse in COPD

International Nuclear Information System (INIS)

O'Donnell, C.R.; Bankier, A.A.; O'Donnell, D.H.; Loring, S.H.; Boiselle, P.M.

2014-01-01

Aim: To determine the range of tracheal collapse at end-expiration among chronic obstructive pulmonary disease (COPD) patients and to compare the extent of tracheal collapse between static end-expiratory and dynamic forced-expiratory multidetector-row computed tomography (MDCT). Materials and methods: After institutional review board approval and obtaining informed consent, 67 patients meeting the National Heart, Lung, and Blood Institute (NHLBI)/World Health Organization (WHO) Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD were sequentially imaged using a 64-detector-row CT machine at end-inspiration, during forced expiration, and at end-expiration. Standardized respiratory coaching and spirometric monitoring were employed. Mean percentage tracheal collapse at end-expiration and forced expiration were compared using correlation analysis, and the power of end-expiratory cross-sectional area to predict excessive forced-expiratory tracheal collapse was computed following construction of receiver operating characteristic (ROC) curves. Results: Mean percentage expiratory collapse among COPD patients was 17 ± 18% at end-expiration compared to 62 ± 16% during forced expiration. Over the observed range of end-expiratory tracheal collapse (approximately 10–50%), the positive predictive value of end-expiratory collapse to predict excessive (≥80%) forced expiratory tracheal collapse was <0.3. Conclusion: COPD patients demonstrate a wide range of end-expiratory tracheal collapse. The magnitude of static end-expiratory tracheal collapse does not predict excessive dynamic expiratory tracheal collapse

Variability in the Use of Protective Mechanical Ventilation During General Anesthesia.

Science.gov (United States)

Ladha, Karim S; Bateman, Brian T; Houle, Timothy T; De Jong, Myrthe A C; Vidal Melo, Marcos F; Huybrechts, Krista F; Kurth, Tobias; Eikermann, Matthias

2018-02-01

The purpose of this study was to determine whether significant variation exists in the use of protective ventilation across individual anesthesia providers and whether this difference can be explained by patient, procedure, and provider-related characteristics. The cohort consisted of 262 anesthesia providers treating 57,372 patients at a tertiary care hospital between 2007 and 2014. Protective ventilation was defined as a median positive end-expiratory pressure of 5 cm H2O or more, tidal volume of protective ventilation was modified in sensitivity analyses. In unadjusted analysis, the mean probability of administering protective ventilation was 53.8% (2.5th percentile of provider 19.9%, 97.5th percentile 80.8%). After adjustment for a large number of covariates, there was little change in the results with a mean probability of 51.1% (2.5th percentile 24.7%, 97.5th percentile 77.2%). The variations persisted when the thresholds for protective ventilation were changed. There was significant variability across individual anesthesia providers in the use of intraoperative protective mechanical ventilation. Our data suggest that this variability is highly driven by individual preference, rather than patient, procedure, or provider-related characteristics.

Alveolar Tidal recruitment/derecruitment and Overdistension During Four Levels of End-Expiratory Pressure with Protective Tidal Volume During Anesthesia in a Murine Lung-Healthy Model.

Science.gov (United States)

Soares, Joao Henrique Neves; Carvalho, Alysson Roncally; Bergamini, Bruno Curty; Gress, Maria Alice Kuster; Jandre, Frederico Caetano; Zin, Walter Araujo; Giannella-Neto, Antonio

2018-06-01

We compared respiratory mechanics between the positive end-expiratory pressure of minimal respiratory system elastance (PEEP minErs ) and three levels of PEEP during low-tidal-volume (6 mL/kg) ventilation in rats. Twenty-four rats were anesthetized, paralyzed, and mechanically ventilated. Airway pressure (P aw ), flow (F), and volume (V) were fitted by a linear single compartment model (LSCM) P aw (t) = E rs  × V(t) + R rs  × F(t) + PEEP or a volume- and flow-dependent SCM (VFDSCM) P aw (t) = (E 1  + E 2  × V(t)) × V(t) + (K 1  + K 2  × |F(t)|) × F(t) + PEEP, where E rs and R rs are respiratory system elastance and resistance, respectively; E 1 and E 2 × V are volume-independent and volume-dependent E rs , respectively; and K 1 and K 2  × F are flow-independent and flow-dependent R rs , respectively. Animals were ventilated for 1 h at PEEP 0 cmH 2 O (ZEEP); PEEP minErs ; 2 cmH 2 O above PEEP minErs (PEEP minErs+2 ); or 4 cmH 2 O above PEEP minErs (PEEP minErs+4 ). Alveolar tidal recruitment/derecruitment and overdistension were assessed by the index %E 2  = 100 × [(E 2  × V T )/(E 1  + |E 2 | × V T )], and alveolar stability by the slope of E rs (t). %E 2 varied between 0 and 30% at PEEP minErs in most respiratory cycles. Alveolar Tidal recruitment/derecruitment (%E 2   30) were predominant in the absence of PEEP and in PEEP levels higher than PEEP minErs , respectively. The slope of E rs (t) was different from zero in all groups besides PEEP minErs+4 . PEEP minErs presented the best compromise between alveolar tidal recruitment/derecruitment and overdistension, during 1 h of low-V T mechanical ventilation.

Is increased positive end-expiratory pressure the culprit? Autoresuscitation in a 44-year-old man after prolonged cardiopulmonary resuscitation: a case report.

Science.gov (United States)

Hagmann, Henning; Oelmann, Katrin; Stangl, Robert; Michels, Guido

2016-12-20

The phenomenon of autoresuscitation is rare, yet it is known to most emergency physicians. However, the pathophysiology of the delayed return of spontaneous circulation remains enigmatic. Among other causes hyperinflation of the lungs and excessively high positive end-expiratory pressure have been suggested, but reports including cardiopulmonary monitoring during cardiopulmonary resuscitation are scarce to support this hypothesis. We report a case of autoresuscitation in a 44-year-old white man after 80 minutes of advanced cardiac life support accompanied by continuous capnometry and repeated evaluation by ultrasound and echocardiography. After prolonged cardiopulmonary resuscitation, refractory electromechanical dissociation on electrocardiogram and ventricular akinesis were recorded. In addition, a precipitous drop in end-tidal partial pressure of carbon dioxide was noted and cardiopulmonary resuscitation was discontinued. Five minutes after withdrawal of all supportive measures his breathing resumed and a perfusing rhythm ensued. Understanding the underlying pathophysiology of autoresuscitation is hampered by a lack of reports including extensive cardiopulmonary monitoring during cardiopulmonary resuscitation in a preclinical setting. In this case, continuous capnometry was combined with repetitive ultrasound evaluation, which ruled out most assumed causes of autoresuscitation. Our observation of a rapid decline in end-tidal partial pressure of carbon dioxide supports the hypothesis of increased intrathoracic pressure. Continuous capnometry can be performed easily during cardiopulmonary resuscitation, also in a preclinical setting. Knowledge of the pathophysiologic mechanisms may lead to facile interventions to be incorporated into cardiopulmonary resuscitation algorithms. A drop in end-tidal partial pressure of carbon dioxide, for example, might prompt disconnection of the ventilation to allow left ventricular filling. Further reports and research on this topic

Actual performance of mechanical ventilators in ICU: a multicentric quality control study.

Science.gov (United States)

Govoni, Leonardo; Dellaca', Raffaele L; Peñuelas, Oscar; Bellani, Giacomo; Artigas, Antonio; Ferrer, Miquel; Navajas, Daniel; Pedotti, Antonio; Farré, Ramon

2012-01-01

Even if the performance of a given ventilator has been evaluated in the laboratory under very well controlled conditions, inappropriate maintenance and lack of long-term stability and accuracy of the ventilator sensors may lead to ventilation errors in actual clinical practice. The aim of this study was to evaluate the actual performances of ventilators during clinical routines. A resistance (7.69 cmH(2)O/L/s) - elastance (100 mL/cmH(2)O) test lung equipped with pressure, flow, and oxygen concentration sensors was connected to the Y-piece of all the mechanical ventilators available for patients in four intensive care units (ICUs; n = 66). Ventilators were set to volume-controlled ventilation with tidal volume = 600 mL, respiratory rate = 20 breaths/minute, positive end-expiratory pressure (PEEP) = 8 cmH(2)O, and oxygen fraction = 0.5. The signals from the sensors were recorded to compute the ventilation parameters. The average ± standard deviation and range (min-max) of the ventilatory parameters were the following: inspired tidal volume = 607 ± 36 (530-723) mL, expired tidal volume = 608 ± 36 (530-728) mL, peak pressure = 20.8 ± 2.3 (17.2-25.9) cmH(2)O, respiratory rate = 20.09 ± 0.35 (19.5-21.6) breaths/minute, PEEP = 8.43 ± 0.57 (7.26-10.8) cmH(2)O, oxygen fraction = 0.49 ± 0.014 (0.41-0.53). The more error-prone parameters were the ones related to the measure of flow. In several cases, the actual delivered mechanical ventilation was considerably different from the set one, suggesting the need for improving quality control procedures for these machines.

A knowledge- and model-based system for automated weaning from mechanical ventilation: technical description and first clinical application.

Science.gov (United States)

Schädler, Dirk; Mersmann, Stefan; Frerichs, Inéz; Elke, Gunnar; Semmel-Griebeler, Thomas; Noll, Oliver; Pulletz, Sven; Zick, Günther; David, Matthias; Heinrichs, Wolfgang; Scholz, Jens; Weiler, Norbert

2014-10-01

To describe the principles and the first clinical application of a novel prototype automated weaning system called Evita Weaning System (EWS). EWS allows an automated control of all ventilator settings in pressure controlled and pressure support mode with the aim of decreasing the respiratory load of mechanical ventilation. Respiratory load takes inspired fraction of oxygen, positive end-expiratory pressure, pressure amplitude and spontaneous breathing activity into account. Spontaneous breathing activity is assessed by the number of controlled breaths needed to maintain a predefined respiratory rate. EWS was implemented as a knowledge- and model-based system that autonomously and remotely controlled a mechanical ventilator (Evita 4, Dräger Medical, Lübeck, Germany). In a selected case study (n = 19 patients), ventilator settings chosen by the responsible physician were compared with the settings 10 min after the start of EWS and at the end of the study session. Neither unsafe ventilator settings nor failure of the system occurred. All patients were successfully transferred from controlled ventilation to assisted spontaneous breathing in a mean time of 37 ± 17 min (± SD). Early settings applied by the EWS did not significantly differ from the initial settings, except for the fraction of oxygen in inspired gas. During the later course, EWS significantly modified most of the ventilator settings and reduced the imposed respiratory load. A novel prototype automated weaning system was successfully developed. The first clinical application of EWS revealed that its operation was stable, safe ventilator settings were defined and the respiratory load of mechanical ventilation was decreased.

Design and Construction of a Microcontroller-Based Ventilator Synchronized with Pulse Oximeter.

Science.gov (United States)

Gölcük, Adem; Işık, Hakan; Güler, İnan

2016-07-01

This study aims to introduce a novel device with which mechanical ventilator and pulse oximeter work in synchronization. Serial communication technique was used to enable communication between the pulse oximeter and the ventilator. The SpO2 value and the pulse rate read on the pulse oximeter were transmitted to the mechanical ventilator through transmitter (Tx) and receiver (Rx) lines. The fuzzy-logic-based software developed for the mechanical ventilator interprets these values and calculates the percentage of oxygen (FiO2) and Positive End-Expiratory Pressure (PEEP) to be delivered to the patient. The fuzzy-logic-based software was developed to check the changing medical states of patients and to produce new results (FiO2 ve PEEP) according to each new state. FiO2 and PEEP values delivered from the ventilator to the patient can be calculated in this way without requiring any arterial blood gas analysis. Our experiments and the feedbacks from physicians show that this device makes it possible to obtain more successful results when compared to the current practices.

Performance of portable ventilators at altitude.

Science.gov (United States)

Blakeman, Thomas; Britton, Tyler; Rodriquez, Dario; Branson, Richard

2014-09-01

Aeromedical transport of critically ill patients requires continued, accurate performance of equipment at altitude. Changes in barometric pressure can affect the performance of mechanical ventilators calibrated for operation at sea level. Deploying ventilators that can maintain a consistent tidal volume (VT) delivery at various altitudes is imperative for lung protection when transporting wounded war fighters to each echelon of care. Three ventilators (Impact 731, Hamilton T1, and CareFusion Revel) were tested at pediatric (50 and 100 mL) and adult (250-750 mL) tidal VTs at 0 and 20 cm H₂O positive end expiratory pressure and at inspired oxygen of 0.21 and 1.0. Airway pressure, volume, and flow were measured at sea level as well as at 8,000, 16,000, and 22,000 ft (corresponding to barometric pressures of 760, 564, 412, and 321 mm Hg) using a calibrated pneumotachograph connected to a training test lung in an altitude chamber. Set VT and delivered VT as well as changes in VT at each altitude were compared by t test. The T1 delivered VT within 10% of set VT at 8,000 ft. The mean VT was less than set VT at sea level as a result of circuit compressible volume with the Revel and the 731. Changes in VT varied widely among the devices at sea level and at altitude. Increasing altitudes resulted in larger VT than set for the Revel and the T1. The 731 compensated for changes in altitude delivered VT within 10% at the adult settings at all altitudes. Altitude compensation is an active software algorithm. Only the 731 actively accounts for changes in barometric pressure to maintain the set VT at all tested altitudes.

Double-lumen tubes and auto-PEEP during one-lung ventilation.

Science.gov (United States)

Spaeth, J; Ott, M; Karzai, W; Grimm, A; Wirth, S; Schumann, S; Loop, T

2016-01-01

Double-lumen tubes (DLT) are routinely used to enable one-lung-ventilation (OLV) during thoracic anaesthesia. The flow-dependent resistance of the DLT's bronchial limb may be high as a result of its narrow inner diameter and length, and thus potentially contribute to an unintended increase in positive end-expiratory pressure (auto-PEEP). We therefore studied the impact of adult sized DLTs on the dynamic auto-PEEP during OLV. In this prospective clinical study, dynamic auto-PEEP was determined in 72 patients undergoing thoracic surgery, with right- and left-sided DLTs of various sizes. During OLV, air trapping was provoked by increasing inspiration to expiration ratio from 1:2 to 2:1 (five steps). Based on measured flow rate, airway pressure (Paw) and bronchial pressure (Pbronch), the pressure gradient across the DLT (ΔPDLT) and the total auto-PEEP in the respiratory system (i.e. the lungs, the DLT and the ventilator circuit) were determined. Subsequently the DLT's share in total auto-PEEP was calculated. ΔPDLT was 2.3 (0.7) cm H2O over the entire breathing cycle. At the shortest expiratory time the mean total auto-PEEP was 2.9 (1.5) cm H2O (range 0-5.9 cm H2O). The DLT caused 27 to 31% of the total auto-PEEP. Size and side of the DLT's bronchial limb did not impact auto-PEEP significantly. Although the DLT contributes to the overall auto-PEEP, its contribution is small and independent of size and side of the DLT's bronchial limb. The choice of DLT does not influence the risk of auto-PEEP during OLV to a clinically relevant extent. DRKS00005648. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Evaluation of the monitor cursor-line method for measuring pulmonary artery and central venous pressures.

Science.gov (United States)

Pasion, Editha; Good, Levell; Tizon, Jisebelle; Krieger, Staci; O'Kier, Catherine; Taylor, Nicole; Johnson, Jennifer; Horton, Carrie M; Peterson, Mary

2010-11-01

To determine if the monitor cursor-line feature on bedside monitors is accurate for measuring central venous and pulmonary artery pressures in cardiac surgery patients. Central venous and pulmonary artery pressures were measured via 3 methods (end-expiratory graphic recording, monitor cursor-line display, and monitor digital display) in a convenience sample of postoperative cardiac surgery patients. Pressures were measured twice during both mechanical ventilation and spontaneous breathing. Analysis of variance was used to determine differences between measurement methods and the percentage of monitor pressures that differed by 4 mm Hg or more from the measurement obtained from the graphic recording. Significance level was set at P less than .05. Twenty-five patients were studied during mechanical ventilation (50 measurements) and 21 patients during spontaneous breathing (42 measurements). Measurements obtained via the 3 methods did not differ significantly for either type of pressure (P > .05). Graphically recorded pressures and measurements obtained via the monitor cursor-line or digital display methods differed by 4 mm Hg or more in 4% and 6% of measurements, respectively, during mechanical ventilation and 4% and 11%, respectively, during spontaneous breathing. The monitor cursor-line method for measuring central venous and pulmonary artery pressures may be a reasonable alternative to the end-expiratory graphic recording method in hemodynamically stable, postoperative cardiac surgery patients. Use of the digital display on the bedside monitor may result in larger discrepancies from the graphically recorded pressures than when the cursor-line method is used, particularly in spontaneously breathing patients.

Simulation of static pressure reset control in comfort ventilation

DEFF Research Database (Denmark)

Koulani, Chrysanthi Sofia; Prunescu, Remus Mihail; Hviid, Christian Anker

2014-01-01

Variable air volume (VAV) ventilation systems reduce fan power consumption compared to constant air volume (CAV) systems because they supply air according to the airflow demand. However VAV ventilation systems do not take fully into account the potential energy savings as the control strategy...... management system. In this way the operation of central plant equipment is adjusted in real time according to the actual pressure demand; this control scheme can be implemented by the static pressure reset (SPR) method. The SPR control method ensures that at least one damper remains fully opened; thus...... of the art is represented by the method of trim and respond based on pressure alarms. This study investigates the operation of the SPR control method of trim and respond based on pressure alarms in a CO2 demand application where large air volumes are provided to three classrooms. The investigation was based...

[Clinical research of using optimal compliance to determine positive end-expiratory pressure].

Science.gov (United States)

Xu, Lei; Feng, Quan-sheng; Lian, Fu; Shao, Xin-hua; Li, Zhi-bo; Wang, Zhi-yong; Li, Jun

2012-07-01

To observe the availability and security of optimal compliance strategy to titrate the optimal positive end-expiratory pressure (PEEP), compared with quasi-static pressure-volume curve (P-V curve) traced by low-flow method. Fourteen patients received mechanical ventilation with acute respiratory distress syndrome (ARDS) admitted in intensive care unit (ICU) of Tianjin Third Central Hospital from November 2009 to December 2010 were divided into two groups(n = 7). The quasi-static P-V curve method and the optimal compliance titration were used to set the optimal PEEP respectively, repeated 3 times in a row. The optimal PEEP and the consistency of repeated experiments were compared between groups. The hemodynamic parameters, oxygenation index (OI), lung compliance (C), cytokines and pulmonary surfactant-associated protein D (SP-D) concentration in plasma before and 2, 4, and 6 hours after the experiment were observed in each group. (1) There were no significant differences in gender, age and severity of disease between two groups. (2)The optimal PEEP [cm H(2)O, 1 cm H(2)O=0.098 kPa] had no significant difference between quasi-static P-V curve method group and the optimal compliance titration group (11.53 ± 2.07 vs. 10.57 ± 0.87, P>0.05). The consistency of repeated experiments in quasi-static P-V curve method group was poor, the slope of the quasi-static P-V curve in repeated experiments showed downward tendency. The optimal PEEP was increasing in each measure. There was significant difference between the first and the third time (10.00 ± 1.58 vs. 12.80 ± 1.92, P vs. 93.71 ± 5.38, temperature: 38.05 ± 0.73 vs. 36.99 ± 1.02, IL-6: 144.84 ± 23.89 vs. 94.73 ± 5.91, TNF-α: 151.46 ± 46.00 vs. 89.86 ± 13.13, SP-D: 33.65 ± 8.66 vs. 16.63 ± 5.61, MAP: 85.47 ± 9.24 vs. 102.43 ± 8.38, CCI: 3.00 ± 0.48 vs. 3.81 ± 0.81, OI: 62.00 ± 21.45 vs. 103.40 ± 37.27, C: 32.10 ± 2.92 vs. 49.57 ± 7.18, all P safety and usability.

Are there benefits or harm from pressure targeting during lung-protective ventilation?

Science.gov (United States)

MacIntyre, Neil R; Sessler, Curtis N

2010-02-01

Mechanically, breath design is usually either flow/volume-targeted or pressure-targeted. Both approaches can effectively provide lung-protective ventilation, but they prioritize different ventilation parameters, so their responses to changing respiratory-system mechanics and patient effort are different. These different response behaviors have advantages and disadvantages that can be important in specific circumstances. Flow/volume targeting guarantees a set minute ventilation but sometimes may be difficult to synchronize with patient effort, and it will not limit inspiratory pressure. In contrast, pressure targeting, with its variable flow, may be easier to synchronize and will limit inspiratory pressure, but it provides no control over delivered volume. Skilled clinicians can maximize benefits and minimize problems with either flow/volume targeting or pressure targeting. Indeed, as is often the case in managing complex life-support devices, it is operator expertise rather than the device design features that most impacts patient outcomes.

Are tidal volume measurements in neonatal pressure-controlled ventilation accurate?

Science.gov (United States)

Chow, Lily C; Vanderhal, Andre; Raber, Jorge; Sola, Augusto

2002-09-01

Bedside pulmonary mechanics monitors (PMM) have become useful in ventilatory management in neonates. These monitors are used more frequently due to recent improvements in data-processing capabilities. PMM devices are often part of the ventilator or are separate units. The accuracy and reliability of these systems have not been carefully evaluated. We compared a single ventilatory parameter, tidal volume (V(t)), as measured by several systems. We looked at two freestanding PMMs: the Ventrak Respiratory Monitoring System (Novametrix, Wallingford, CT) and the Bicore CP-100 Neonatal Pulmonary Monitor (Allied Health Care Products, Riverside, CA), and three ventilators with built-in PMM: the VIP Bird Ventilator (Bird Products Corp., Palm Springs, CA), Siemens Servo 300A (Siemens-Elema AB, Solna, Sweden), and Drager Babylog 8000 (Drager, Inc., Chantilly, VA). A calibrated syringe (Hans Rudolph, Inc., Kansas City, MO) was used to deliver tidal volumes of 4, 10, and 20 mL to each ventilator system coupled with a freestanding PMM. After achieving steady state, six consecutive V(t) readings were taken simultaneously from the freestanding PMM and each ventilator. In a second portion of the bench study, we used pressure-control ventilation and measured exhaled tidal volume (V(te)) while ventilating a Bear Test Lung with the same three ventilators. We adjusted peak inspiratory pressure (PIP) under controlled conditions to achieve the three different targeted tidal volumes on the paired freestanding PMM. Again, six V(te) measurements were recorded for each tidal volume. Means and standard deviations were calculated.The percentage difference in measurement of V(t) delivered by calibrated syringe varied greatly, with the greatest discrepancy seen in the smallest tidal volumes, by up to 28%. In pressure control mode, V(te) as measured by the Siemens was significantly overestimated by 20-95%, with the biggest discrepancy at the smallest V(te), particularly when paired with the Bicore

Does Regional Lung Strain Correlate With Regional Inflammation in Acute Respiratory Distress Syndrome During Nonprotective Ventilation? An Experimental Porcine Study.

Science.gov (United States)

Retamal, Jaime; Hurtado, Daniel; Villarroel, Nicolás; Bruhn, Alejandro; Bugedo, Guillermo; Amato, Marcelo Britto Passos; Costa, Eduardo Leite Vieira; Hedenstierna, Göran; Larsson, Anders; Borges, João Batista

2018-06-01

It is known that ventilator-induced lung injury causes increased pulmonary inflammation. It has been suggested that one of the underlying mechanisms may be strain. The aim of this study was to investigate whether lung regional strain correlates with regional inflammation in a porcine model of acute respiratory distress syndrome. Retrospective analysis of CT images and positron emission tomography images using [F]fluoro-2-deoxy-D-glucose. University animal research laboratory. Seven piglets subjected to experimental acute respiratory distress syndrome and five ventilated controls. Acute respiratory distress syndrome was induced by repeated lung lavages, followed by 210 minutes of injurious mechanical ventilation using low positive end-expiratory pressures (mean, 4 cm H2O) and high inspiratory pressures (mean plateau pressure, 45 cm H2O). All animals were subsequently studied with CT scans acquired at end-expiration and end-inspiration, to obtain maps of volumetric strain (inspiratory volume - expiratory volume)/expiratory volume, and dynamic positron emission tomography imaging. Strain maps and positron emission tomography images were divided into 10 isogravitational horizontal regions-of-interest, from which spatial correlation was calculated for each animal. The acute respiratory distress syndrome model resulted in a decrease in respiratory system compliance (20.3 ± 3.4 to 14.0 ± 4.9 mL/cm H2O; p < 0.05) and oxygenation (PaO2/FIO2, 489 ± 80 to 92 ± 59; p < 0.05), whereas the control animals did not exhibit changes. In the acute respiratory distress syndrome group, strain maps showed a heterogeneous distribution with a greater concentration in the intermediate gravitational regions, which was similar to the distribution of [F]fluoro-2-deoxy-D-glucose uptake observed in the positron emission tomography images, resulting in a positive spatial correlation between both variables (median R = 0.71 [0.02-0.84]; p < 0.05 in five of seven animals

Effects of Inhaled Fenoterol and Positive End-Expiratory Pressure on the Respiratory Mechanics of Patients with Chronic Obstructive Pulmonary Disease

Directory of Open Access Journals (Sweden)

Claude Guerin

2005-01-01

Full Text Available BACKGROUND: During acute ventilatory failure in patients with chronic obstructive pulmonary disease (COPD, applying external positive end-expiratory pressure (PEEPe will reopen small airways and, thus, may enhance peripheral deposition as well as the physiological effects of inhaled beta-2 agonists.

High frequency jet ventilation and intermittent positive pressure ventilation. Effect of cerebral blood flow in patients after open heart surgery

International Nuclear Information System (INIS)

Pittet, J.F.; Forster, A.; Suter, P.M.

1990-01-01

Attenuation of ventilator-synchronous pressure fluctuations of intracranial pressure has been demonstrated during high frequency ventilation in animal and human studies, but the consequences of this effect on cerebral blood flow have not been investigated in man. We compared the effects of high frequency jet ventilation and intermittent positive pressure ventilation on CBF in 24 patients investigated three hours after completion of open-heart surgery. The patients were investigated during three consecutive periods with standard sedation (morphine, pancuronium): a. IPPV; b. HFJV; c. IPPV. Partial pressure of arterial CO 2 (PaCO 2 : 4.5-5.5 kPa) and rectal temperature (35.5 to 37.5 degree C) were maintained constant during the study. The CBF was measured by intravenous 133 Xe washout technique. The following variables were derived from the cerebral clearance of 133 Xe: the rapid compartment flow, the initial slope index, ie, a combination of the rapid and the slow compartment flows, and the ratio of fast compartment flow over total CBF (FF). Compared to IPPV, HFJV applied to result in the same mean airway pressure did not produce any change in pulmonary gas exchange, mean systemic arterial pressure, and cardiac index. Similarly, CBF was not significantly altered by HFJV. However, important variations of CBF values were observed in three patients, although the classic main determinants of CBF (PaCO 2 , cerebral perfusion pressure, Paw, temperature) remained unchanged. Our results suggest that in patients with normal systemic hemodynamics, the effects of HFJV and IPPV on CBF are comparable at identical levels of mean airway pressure

The Society for Translational Medicine: clinical practice guidelines for mechanical ventilation management for patients undergoing lobectomy.

Science.gov (United States)

Gao, Shugeng; Zhang, Zhongheng; Brunelli, Alessandro; Chen, Chang; Chen, Chun; Chen, Gang; Chen, Haiquan; Chen, Jin-Shing; Cassivi, Stephen; Chai, Ying; Downs, John B; Fang, Wentao; Fu, Xiangning; Garutti, Martínez I; He, Jianxing; He, Jie; Hu, Jian; Huang, Yunchao; Jiang, Gening; Jiang, Hongjing; Jiang, Zhongmin; Li, Danqing; Li, Gaofeng; Li, Hui; Li, Qiang; Li, Xiaofei; Li, Yin; Li, Zhijun; Liu, Chia-Chuan; Liu, Deruo; Liu, Lunxu; Liu, Yongyi; Ma, Haitao; Mao, Weimin; Mao, Yousheng; Mou, Juwei; Ng, Calvin Sze Hang; Petersen, René H; Qiao, Guibin; Rocco, Gaetano; Ruffini, Erico; Tan, Lijie; Tan, Qunyou; Tong, Tang; Wang, Haidong; Wang, Qun; Wang, Ruwen; Wang, Shumin; Xie, Deyao; Xue, Qi; Xue, Tao; Xu, Lin; Xu, Shidong; Xu, Songtao; Yan, Tiansheng; Yu, Fenglei; Yu, Zhentao; Zhang, Chunfang; Zhang, Lanjun; Zhang, Tao; Zhang, Xun; Zhao, Xiaojing; Zhao, Xuewei; Zhi, Xiuyi; Zhou, Qinghua

2017-09-01

Patients undergoing lobectomy are at significantly increased risk of lung injury. One-lung ventilation is the most commonly used technique to maintain ventilation and oxygenation during the operation. It is a challenge to choose an appropriate mechanical ventilation strategy to minimize the lung injury and other adverse clinical outcomes. In order to understand the available evidence, a systematic review was conducted including the following topics: (I) protective ventilation (PV); (II) mode of mechanical ventilation [e.g., volume controlled (VCV) versus pressure controlled (PCV)]; (III) use of therapeutic hypercapnia; (IV) use of alveolar recruitment (open-lung) strategy; (V) pre-and post-operative application of positive end expiratory pressure (PEEP); (VI) Inspired Oxygen concentration; (VII) Non-intubated thoracoscopic lobectomy; and (VIII) adjuvant pharmacologic options. The recommendations of class II are non-intubated thoracoscopic lobectomy may be an alternative to conventional one-lung ventilation in selected patients. The recommendations of class IIa are: (I) Therapeutic hypercapnia to maintain a partial pressure of carbon dioxide at 50-70 mmHg is reasonable for patients undergoing pulmonary lobectomy with one-lung ventilation; (II) PV with a tidal volume of 6 mL/kg and PEEP of 5 cmH 2 O are reasonable methods, based on current evidence; (III) alveolar recruitment [open lung ventilation (OLV)] may be beneficial in patients undergoing lobectomy with one-lung ventilation; (IV) PCV is recommended over VCV for patients undergoing lung resection; (V) pre- and post-operative CPAP can improve short-term oxygenation in patients undergoing lobectomy with one-lung ventilation; (VI) controlled mechanical ventilation with I:E ratio of 1:1 is reasonable in patients undergoing one-lung ventilation; (VII) use of lowest inspired oxygen concentration to maintain satisfactory arterial oxygen saturation is reasonable based on physiologic principles; (VIII) Adjuvant drugs

Optimized damper control of pressure and airflow in ventilation systems

DEFF Research Database (Denmark)

Koulani, Chrysanthi Sofia; Hviid, Christian Anker; Terkildsen, Søren

2014-01-01

Conventional control strategies in variable air volume (VAV) ventilation systems do not take fully into advantage the potential energy savings since the system operation is based on maintaining a constant static pressure (CSP) set point in the main duct irrespective of the actual pressure demand...... by using the Simulink programming tool which is addon software to MATLAB mathematical programming language. A model of a VAV ventilation system was created in Simulink based on the International Building Physics Toolbox (IBPT); the IBPT thermal zone was remodelled in order to calculate dynamically...... the airflow demand according to the zone air temperature. The performance of the Simulink model was evaluated based on the experimental setup of the ventilation system. The SPR control method established stable system operation and was proven efficient to maintain comfortable space conditions while reducing...

Predicting the lung compliance of mechanically ventilated patients via statistical modeling

International Nuclear Information System (INIS)

Ganzert, Steven; Kramer, Stefan; Guttmann, Josef

2012-01-01

To avoid ventilator associated lung injury (VALI) during mechanical ventilation, the ventilator is adjusted with reference to the volume distensibility or ‘compliance’ of the lung. For lung-protective ventilation, the lung should be inflated at its maximum compliance, i.e. when during inspiration a maximal intrapulmonary volume change is achieved by a minimal change of pressure. To accomplish this, one of the main parameters is the adjusted positive end-expiratory pressure (PEEP). As changing the ventilator settings usually produces an effect on patient's lung mechanics with a considerable time delay, the prediction of the compliance change associated with a planned change of PEEP could assist the physician at the bedside. This study introduces a machine learning approach to predict the nonlinear lung compliance for the individual patient by Gaussian processes, a probabilistic modeling technique. Experiments are based on time series data obtained from patients suffering from acute respiratory distress syndrome (ARDS). With a high hit ratio of up to 93%, the learned models could predict whether an increase/decrease of PEEP would lead to an increase/decrease of the compliance. However, the prediction of the complete pressure–volume relation for an individual patient has to be improved. We conclude that the approach is well suitable for the given problem domain but that an individualized feature selection should be applied for a precise prediction of individual pressure–volume curves. (paper)

Variability in Usual Care Mechanical Ventilation for Pediatric Acute Respiratory Distress Syndrome: Time for a Decision Support Protocol?

Science.gov (United States)

Newth, Christopher J L; Sward, Katherine A; Khemani, Robinder G; Page, Kent; Meert, Kathleen L; Carcillo, Joseph A; Shanley, Thomas P; Moler, Frank W; Pollack, Murray M; Dalton, Heidi J; Wessel, David L; Berger, John T; Berg, Robert A; Harrison, Rick E; Holubkov, Richard; Doctor, Allan; Dean, J Michael; Jenkins, Tammara L; Nicholson, Carol E

2017-11-01

Although pediatric intensivists philosophically embrace lung protective ventilation for acute lung injury and acute respiratory distress syndrome, we hypothesized that ventilator management varies. We assessed ventilator management by evaluating changes to ventilator settings in response to blood gases, pulse oximetry, or end-tidal CO2. We also assessed the potential impact that a pediatric mechanical ventilation protocol adapted from National Heart Lung and Blood Institute acute respiratory distress syndrome network protocols could have on reducing variability by comparing actual changes in ventilator settings to those recommended by the protocol. Prospective observational study. Eight tertiary care U.S. PICUs, October 2011 to April 2012. One hundred twenty patients (age range 17 d to 18 yr) with acute lung injury/acute respiratory distress syndrome. Two thousand hundred arterial and capillary blood gases, 3,964 oxygen saturation by pulse oximetry, and 2,757 end-tidal CO2 values were associated with 3,983 ventilator settings. Ventilation mode at study onset was pressure control 60%, volume control 19%, pressure-regulated volume control 18%, and high-frequency oscillatory ventilation 3%. Clinicians changed FIO2 by ±5 or ±10% increments every 8 hours. Positive end-expiratory pressure was limited at ~10 cm H2O as oxygenation worsened, lower than would have been recommended by the protocol. In the first 72 hours of mechanical ventilation, maximum tidal volume/kg using predicted versus actual body weight was 10.3 (8.5-12.9) (median [interquartile range]) versus 9.2 mL/kg (7.6-12.0) (p Ventilator management varies substantially in children with acute respiratory distress syndrome. Opportunities exist to minimize variability and potentially injurious ventilator settings by using a pediatric mechanical ventilation protocol offering adequately explicit instructions for given clinical situations. An accepted protocol could also reduce confounding by mechanical

A comparison of synchronized intermittent mandatory ventilation and pressure-regulated volume control ventilation in elderly patients with acute exacerbations of COPD and respiratory failure.

Science.gov (United States)

Chang, Suchi; Shi, Jindong; Fu, Cuiping; Wu, Xu; Li, Shanqun

2016-01-01

COPD is the third leading cause of death worldwide. Acute exacerbations of COPD may cause respiratory failure, requiring intensive care unit admission and mechanical ventilation. Intensive care unit patients with acute exacerbations of COPD requiring mechanical ventilation have higher mortality rates than other hospitalized patients. Although mechanical ventilation is the most effective intervention for these conditions, invasive ventilation techniques have yielded variable effects. We evaluated pressure-regulated volume control (PRVC) ventilation treatment efficacy and preventive effects on pulmonary barotrauma in elderly COPD patients with respiratory failure. Thirty-nine intubated patients were divided into experimental and control groups and treated with the PRVC and synchronized intermittent mandatory ventilation - volume control methods, respectively. Vital signs, respiratory mechanics, and arterial blood gas analyses were monitored for 2-4 hours and 48 hours. Both groups showed rapidly improved pH, partial pressure of oxygen (PaO2), and PaO2 per fraction of inspired O2 levels and lower partial pressure of carbon dioxide (PaCO2) levels. The pH and PaCO2 levels at 2-4 hours were lower and higher, respectively, in the test group than those in the control group (P0.05). Vital signs during 2-4 hours and 48 hours of treatment showed no statistical difference in either group (P>0.05). The level of peak inspiratory pressure in the experimental group after mechanical ventilation for 2-4 hours and 48 hours was significantly lower than that in the control group (P0.05). Among elderly COPD patients with respiratory failure, application of PRVC resulted in rapid improvement in arterial blood gas analyses while maintaining a low peak inspiratory pressure. PRVC can reduce pulmonary barotrauma risk, making it a safer protective ventilation mode than synchronized intermittent mandatory ventilation - volume control.

CDC releases ventilator-associated events criteria

Directory of Open Access Journals (Sweden)

Robbins RA

2017-01-01

Full Text Available No abstract available. Article truncated at 150 words. A new term has been coined by the CDC, ventilator-associated events (VAEs (1. In 2011, the CDC convened a working group composed of members of several stakeholder organizations to address the limitations of the definition of ventilator-associated pneumonia (VAP definition (2. The organizations represented in the Working Group include: the Critical Care Societies Collaborative (the American Association of Critical-Care Nurses, the American College of Chest Physicians, the American Thoracic Society, and the Society for Critical Care Medicine; the American Association for Respiratory Care; the Association of Professionals in Infection Control and Epidemiology; the Council of State and Territorial Epidemiologists; the Healthcare Infection Control Practices Advisory Committee’s Surveillance Working Group; the Infectious Diseases Society of America; and the Society for Healthcare Epidemiology of America. VAEs are defined by an increase oxygen (>0.2 in FiO2 or positive end-expiratory pressure (PEEP (≥3 cm H2O, after a previous stable baseline of at least 2 …

A Quasi-Experimental, Before-After Trial Examining the Impact of an Emergency Department Mechanical Ventilator Protocol on Clinical Outcomes and Lung-Protective Ventilation in Acute Respiratory Distress Syndrome.

Science.gov (United States)

Fuller, Brian M; Ferguson, Ian T; Mohr, Nicholas M; Drewry, Anne M; Palmer, Christopher; Wessman, Brian T; Ablordeppey, Enyo; Keeperman, Jacob; Stephens, Robert J; Briscoe, Cristopher C; Kolomiets, Angelina A; Hotchkiss, Richard S; Kollef, Marin H

2017-04-01

To evaluate the impact of an emergency department mechanical ventilation protocol on clinical outcomes and adherence to lung-protective ventilation in patients with acute respiratory distress syndrome. Quasi-experimental, before-after trial. Emergency department and ICUs of an academic center. Mechanically ventilated emergency department patients experiencing acute respiratory distress syndrome while in the emergency department or after admission to the ICU. An emergency department ventilator protocol which targeted variables in need of quality improvement, as identified by prior work: 1) lung-protective tidal volume, 2) appropriate setting of positive end-expiratory pressure, 3) oxygen weaning, and 4) head-of-bed elevation. A total of 229 patients (186 preintervention group, 43 intervention group) were studied. In the emergency department, the intervention was associated with significant changes (p protective ventilation from 11.1% to 61.5%, p value of less than 0.01. The intervention was associated with a reduction in mortality from 54.8% to 39.5% (odds ratio, 0.38; 95% CI, 0.17-0.83; p = 0.02) and a 3.9 day increase in ventilator-free days, p value equals to 0.01. This before-after study of mechanically ventilated patients with acute respiratory distress syndrome demonstrates that implementing a mechanical ventilator protocol in the emergency department is feasible and associated with improved clinical outcomes.

Impact of Different Ventilation Strategies on Driving Pressure, Mechanical Power, and Biological Markers During Open Abdominal Surgery in Rats.

Science.gov (United States)

Maia, Lígia de A; Samary, Cynthia S; Oliveira, Milena V; Santos, Cintia L; Huhle, Robert; Capelozzi, Vera L; Morales, Marcelo M; Schultz, Marcus J; Abreu, Marcelo G; Pelosi, Paolo; Silva, Pedro L; Rocco, Patricia Rieken Macedo

2017-10-01

Intraoperative mechanical ventilation may yield lung injury. To date, there is no consensus regarding the best ventilator strategy for abdominal surgery. We aimed to investigate the impact of the mechanical ventilation strategies used in 2 recent trials (Intraoperative Protective Ventilation [IMPROVE] trial and Protective Ventilation using High versus Low PEEP [PROVHILO] trial) on driving pressure (ΔPRS), mechanical power, and lung damage in a model of open abdominal surgery. Thirty-five Wistar rats were used, of which 28 were anesthetized, and a laparotomy was performed with standardized bowel manipulation. Postoperatively, animals (n = 7/group) were randomly assigned to 4 hours of ventilation with: (1) tidal volume (VT) = 7 mL/kg and positive end-expiratory pressure (PEEP) = 1 cm H2O without recruitment maneuvers (RMs) (low VT/low PEEP/RM-), mimicking the low-VT/low-PEEP strategy of PROVHILO; (2) VT = 7 mL/kg and PEEP = 3 cm H2O with RMs before laparotomy and hourly thereafter (low VT/moderate PEEP/4 RM+), mimicking the protective ventilation strategy of IMPROVE; (3) VT = 7 mL/kg and PEEP = 6 cm H2O with RMs only before laparotomy (low VT/high PEEP/1 RM+), mimicking the strategy used after intubation and before extubation in PROVHILO; or (4) VT = 14 mL/kg and PEEP = 1 cm H2O without RMs (high VT/low PEEP/RM-), mimicking conventional ventilation used in IMPROVE. Seven rats were not tracheotomized, operated, or mechanically ventilated, and constituted the healthy nonoperated and nonventilated controls. Low VT/moderate PEEP/4 RM+ and low VT/high PEEP/1 RM+, compared to low VT/low PEEP/RM- and high VT/low PEEP/RM-, resulted in lower ΔPRS (7.1 ± 0.8 and 10.2 ± 2.1 cm H2O vs 13.9 ± 0.9 and 16.9 ± 0.8 cm H2O, respectively; Pmechanical power (63 ± 7 and 79 ± 20 J/min vs 110 ± 10 and 120 ± 20 J/min, respectively; P = .007). Low VT/high PEEP/1 RM+ was associated with less alveolar collapse than low VT/low PEEP/RM- (P = .03). E-cadherin expression was higher in

Intraoperative protective mechanical ventilation and risk of postoperative respiratory complications: hospital based registry study.

Science.gov (United States)

Ladha, Karim; Vidal Melo, Marcos F; McLean, Duncan J; Wanderer, Jonathan P; Grabitz, Stephanie D; Kurth, Tobias; Eikermann, Matthias

2015-07-14

To evaluate the effects of intraoperative protective ventilation on major postoperative respiratory complications and to define safe intraoperative mechanical ventilator settings that do not translate into an increased risk of postoperative respiratory complications. Hospital based registry study. Academic tertiary care hospital and two affiliated community hospitals in Massachusetts, United States. 69,265 consecutively enrolled patients over the age of 18 who underwent a non-cardiac surgical procedure between January 2007 and August 2014 and required general anesthesia with endotracheal intubation. Protective ventilation, defined as a median positive end expiratory pressure (PEEP) of 5 cmH2O or more, a median tidal volume of less than 10 mL/kg of predicted body weight, and a median plateau pressure of less than 30 cmH2O. Composite outcome of major respiratory complications, including pulmonary edema, respiratory failure, pneumonia, and re-intubation. Of the 69,265 enrolled patients 34,800 (50.2%) received protective ventilation and 34,465 (49.8%) received non-protective ventilation intraoperatively. Protective ventilation was associated with a decreased risk of postoperative respiratory complications in multivariable regression (adjusted odds ratio 0.90, 95% confidence interval 0.82 to 0.98, P=0.013). The results were similar in the propensity score matched cohort (odds ratio 0.89, 95% confidence interval 0.83 to 0.97, P=0.004). A PEEP of 5 cmH2O and median plateau pressures of 16 cmH2O or less were associated with the lowest risk of postoperative respiratory complications. Intraoperative protective ventilation was associated with a decreased risk of postoperative respiratory complications. A PEEP of 5 cmH2O and a plateau pressure of 16 cmH2O or less were identified as protective mechanical ventilator settings. These findings suggest that protective thresholds differ for intraoperative ventilation in patients with normal lungs compared with those used for patients

Early application of airway pressure release ventilation may reduce the duration of mechanical ventilation in acute respiratory distress syndrome.

Science.gov (United States)

Zhou, Yongfang; Jin, Xiaodong; Lv, Yinxia; Wang, Peng; Yang, Yunqing; Liang, Guopeng; Wang, Bo; Kang, Yan

2017-11-01

Experimental animal models of acute respiratory distress syndrome (ARDS) have shown that the updated airway pressure release ventilation (APRV) methodologies may significantly improve oxygenation, maximize lung recruitment, and attenuate lung injury, without circulatory depression. This led us to hypothesize that early application of APRV in patients with ARDS would allow pulmonary function to recover faster and would reduce the duration of mechanical ventilation as compared with low tidal volume lung protective ventilation (LTV). A total of 138 patients with ARDS who received mechanical ventilation for mechanical ventilation from enrollment to day 28. The secondary endpoints included oxygenation, P plat , respiratory system compliance, and patient outcomes. Compared with the LTV group, patients in the APRV group had a higher median number of ventilator-free days {19 [interquartile range (IQR) 8-22] vs. 2 (IQR 0-15); P mechanical ventilation and ICU stay.

Intrathoracic pressure regulation during cardiopulmonary resuscitation: a feasibility case-series.

Science.gov (United States)

Segal, Nicolas; Parquette, Brent; Ziehr, Jonathon; Yannopoulos, Demetris; Lindstrom, David

2013-04-01

Intrathoracic pressure regulation (IPR) is a novel, noninvasive therapy intended to increase cardiac output and blood pressure in hypotensive states by generating a negative end expiratory pressure of -12 cm H2O between positive pressure ventilations. In this first feasibility case-series, we tested the hypothesis that IPR improves End tidal (ET) CO2 during cardiopulmonary resuscitation (CPR). ETCO2 was used as a surrogate measure for circulation. All patients were treated initially with manual CPR and an impedance threshold device (ITD). When IPR-trained medics arrived on scene the ITD was removed and an IPR device (CirQLATOR™) was attached to the patient's advanced airway (intervention group). The IPR device lowered airway pressures to -9 mmHg after each positive pressure ventilation for the duration of the expiratory phase. ETCO2, was measured using a capnometer incorporated into the defibrillator system (LifePak™). Values are expressed as mean ± SEM. Results were compared using paired and unpaired Student's t test. p values of <0.05 were considered statistically significant. ETCO2 values in 11 patients in the case series were compared pre and during IPR therapy and also compared to 74 patients in the control group not treated with the new IPR device. ETCO2 values increased from an average of 21 ± 1 mmHg immediately before IPR application to an average value of 32 ± 5 mmHg and to a maximum value of 45 ± 5mmHg during IPR treatment (p<0.001). In the control group ETCO2 values did not change significantly. Return of spontaneous circulation (ROSC) rates were 46% (34/74) with standard CPR and ITD versus 73% (8/11) with standard CPR and the IPR device (p<0.001). ETCO2 levels and ROSC rates were significantly higher in the study intervention group. These findings demonstrate that during CPR circulation may be significantly augmented by generation of a negative end expiratory pressure between each breath. Copyright © 2012 Elsevier Ireland Ltd. All rights

Injurious mechanical ventilation in the normal lung causes a progressive pathologic change in dynamic alveolar mechanics.

Science.gov (United States)

Pavone, Lucio A; Albert, Scott; Carney, David; Gatto, Louis A; Halter, Jeffrey M; Nieman, Gary F

2007-01-01

Acute respiratory distress syndrome causes a heterogeneous lung injury, and without protective mechanical ventilation a secondary ventilator-induced lung injury can occur. To ventilate noncompliant lung regions, high inflation pressures are required to 'pop open' the injured alveoli. The temporal impact, however, of these elevated pressures on normal alveolar mechanics (that is, the dynamic change in alveolar size and shape during ventilation) is unknown. In the present study we found that ventilating the normal lung with high peak pressure (45 cmH(2)0) and low positive end-expiratory pressure (PEEP of 3 cmH(2)O) did not initially result in altered alveolar mechanics, but alveolar instability developed over time. Anesthetized rats underwent tracheostomy, were placed on pressure control ventilation, and underwent sternotomy. Rats were then assigned to one of three ventilation strategies: control group (n = 3, P control = 14 cmH(2)O, PEEP = 3 cmH(2)O), high pressure/low PEEP group (n = 6, P control = 45 cmH(2)O, PEEP = 3 cmH(2)O), and high pressure/high PEEP group (n = 5, P control = 45 cmH(2)O, PEEP = 10 cmH(2)O). In vivo microscopic footage of subpleural alveolar stability (that is, recruitment/derecruitment) was taken at baseline and than every 15 minutes for 90 minutes following ventilator adjustments. Alveolar recruitment/derecruitment was determined by measuring the area of individual alveoli at peak inspiration (I) and end expiration (E) by computer image analysis. Alveolar recruitment/derecruitment was quantified by the percentage change in alveolar area during tidal ventilation (%I - E Delta). Alveoli were stable in the control group for the entire experiment (low %I - E Delta). Alveoli in the high pressure/low PEEP group were initially stable (low %I - E Delta), but with time alveolar recruitment/derecruitment developed. The development of alveolar instability in the high pressure/low PEEP group was associated with histologic lung injury. A large change in

Liquid- and air-filled catheters without balloon as an alternative to the air-filled balloon catheter for measurement of esophageal pressure.

Science.gov (United States)

Beda, Alessandro; Güldner, Andreas; Carvalho, Alysson R; Zin, Walter Araujo; Carvalho, Nadja C; Huhle, Robert; Giannella-Neto, Antonio; Koch, Thea; de Abreu, Marcelo Gama

2014-01-01

Measuring esophageal pressure (Pes) using an air-filled balloon catheter (BC) is the common approach to estimate pleural pressure and related parameters. However, Pes is not routinely measured in mechanically ventilated patients, partly due to technical and practical limitations and difficulties. This study aimed at comparing the conventional BC with two alternative methods for Pes measurement, liquid-filled and air-filled catheters without balloon (LFC and AFC), during mechanical ventilation with and without spontaneous breathing activity. Seven female juvenile pigs (32-42 kg) were anesthetized, orotracheally intubated, and a bundle of an AFC, LFC, and BC was inserted in the esophagus. Controlled and assisted mechanical ventilation were applied with positive end-expiratory pressures of 5 and 15 cmH2O, and driving pressures of 10 and 20 cmH2O, in supine and lateral decubitus. Cardiogenic noise in BC tracings was much larger (up to 25% of total power of Pes signal) than in AFC and LFC (<3%). Lung and chest wall elastance, pressure-time product, inspiratory work of breathing, inspiratory change and end-expiratory value of transpulmonary pressure were estimated. The three catheters allowed detecting similar changes in these parameters between different ventilation settings. However, a non-negligible and significant bias between estimates from BC and those from AFC and LFC was observed in several instances. In anesthetized and mechanically ventilated pigs, the three catheters are equivalent when the aim is to detect changes in Pes and related parameters between different conditions, but possibly not when the absolute value of the estimated parameters is of paramount importance. Due to a better signal-to-noise ratio, and considering its practical advantages in terms of easier calibration and simpler acquisition setup, LFC may prove interesting for clinical use.

Liquid- and air-filled catheters without balloon as an alternative to the air-filled balloon catheter for measurement of esophageal pressure.

Directory of Open Access Journals (Sweden)

Alessandro Beda

Full Text Available BACKGROUND: Measuring esophageal pressure (Pes using an air-filled balloon catheter (BC is the common approach to estimate pleural pressure and related parameters. However, Pes is not routinely measured in mechanically ventilated patients, partly due to technical and practical limitations and difficulties. This study aimed at comparing the conventional BC with two alternative methods for Pes measurement, liquid-filled and air-filled catheters without balloon (LFC and AFC, during mechanical ventilation with and without spontaneous breathing activity. Seven female juvenile pigs (32-42 kg were anesthetized, orotracheally intubated, and a bundle of an AFC, LFC, and BC was inserted in the esophagus. Controlled and assisted mechanical ventilation were applied with positive end-expiratory pressures of 5 and 15 cmH2O, and driving pressures of 10 and 20 cmH2O, in supine and lateral decubitus. MAIN RESULTS: Cardiogenic noise in BC tracings was much larger (up to 25% of total power of Pes signal than in AFC and LFC (<3%. Lung and chest wall elastance, pressure-time product, inspiratory work of breathing, inspiratory change and end-expiratory value of transpulmonary pressure were estimated. The three catheters allowed detecting similar changes in these parameters between different ventilation settings. However, a non-negligible and significant bias between estimates from BC and those from AFC and LFC was observed in several instances. CONCLUSIONS: In anesthetized and mechanically ventilated pigs, the three catheters are equivalent when the aim is to detect changes in Pes and related parameters between different conditions, but possibly not when the absolute value of the estimated parameters is of paramount importance. Due to a better signal-to-noise ratio, and considering its practical advantages in terms of easier calibration and simpler acquisition setup, LFC may prove interesting for clinical use.

Mask pressure effects on the nasal bridge during short-term noninvasive ventilation

Science.gov (United States)

Brill, Anne-Kathrin; Pickersgill, Rachel; Moghal, Mohammad; Morrell, Mary J.; Simonds, Anita K.

2018-01-01

The aim of this study was to assess the influence of different masks, ventilator settings and body positions on the pressure exerted on the nasal bridge by the mask and subjective comfort during noninvasive ventilation (NIV). We measured the pressure over the nasal bridge in 20 healthy participants receiving NIV via four different NIV masks (three oronasal masks, one nasal mask) at three different ventilator settings and in the seated or supine position. Objective pressure measurements were obtained with an I-Scan pressure-mapping system. Subjective comfort of the mask fit was assessed with a visual analogue scale. The masks exerted mean pressures between 47.6±29 mmHg and 91.9±42.4 mmHg on the nasal bridge. In the supine position, the pressure was lower in all masks (57.1±31.9 mmHg supine, 63.9±37.3 mmHg seated; pmasks, a change of inspiratory positive airway pressure (IPAP) did not influence the objective pressure over the nasal bridge. Subjective discomfort was associated with higher IPAP and positively correlated with the pressure on the skin. Objective measurement of pressure on the skin during mask fitting might be helpful for mask selection. Mask fitting in the supine position should be considered in the clinical routine. PMID:29637077

Bi-level positive pressure ventilation and adaptive servo ventilation in patients with heart failure and Cheyne-Stokes respiration.

Science.gov (United States)

Fietze, Ingo; Blau, Alexander; Glos, Martin; Theres, Heinz; Baumann, Gert; Penzel, Thomas

2008-08-01

Nocturnal positive pressure ventilation (PPV) has been shown to be effective in patients with impaired left ventricular ejection fraction (LVEF) and Cheyne-Stokes respiration (CSR). We investigated the effect of a bi-level PPV and adaptive servo ventilation on LVEF, CSR, and quantitative sleep quality. Thirty-seven patients (New York heart association [NYHA] II-III) with LVEFCSR were investigated by electrocardiography (ECG), echocardiography and polysomnography. The CSR index (CSRI) was 32.3+/-16.2/h. Patients were randomly treated with bi-level PPV using the standard spontaneous/timed (S/T) mode or with adaptive servo ventilation mode (AutoSetCS). After 6 weeks, 30 patients underwent control investigations with ECG, echocardiography, and polysomnography. The CSRI decreased significantly to 13.6+/-13.4/h. LVEF increased significantly after 6 weeks of ventilation (from 25.1+/-8.5 to 28.8+/-9.8%, plevel PPV and adaptive servo ventilation: the CSRI decreased more in the AutoSetCS group while the LVEF increased more in the bi-level PPV group. Administration of PPV can successfully attenuate CSA. Reduced CSA may be associated with improved LVEF; however, this may depend on the mode of PPV. Changed LVEF is evident even in the absence of significant changes in blood pressure.

[Treatment of acute respiratory distress syndrome using pressure and volume controlled ventilation with lung protective strategy].

Science.gov (United States)

Ge, Ying; Wan, Yong; Wang, Da-qing; Su, Xiao-lin; Li, Jun-ying; Chen, Jing

2004-07-01

To investigate the significance and effect of pressure controlled ventilation (PCV) as well as volume controlled ventilation (VCV) by lung protective strategy on respiratory mechanics, blood gas analysis and hemodynamics in patients with acute respiratory distress syndrome (ARDS). Fifty patients with ARDS were randomly divided into PCV and VCV groups with permissive hypercapnia and open lung strategy. Changes in respiratory mechanics, blood gas analysis and hemodynamics were compared between two groups. Peak inspiration pressure (PIP) in PCV group was significantly lower than that in VCV group, while mean pressure of airway (MPaw) was significantly higher than that in VCV after 24 hours mechanical ventilation. After 24 hours mechanical ventilation, there were higher central venous pressure (CVP) and slower heart rate (HR) in two groups, CVP was significantly higher in VCV compared with PCV, and PCV group had slower HR than VCV group, the two groups had no differences in mean blood pressure (MBP) at various intervals. All patients showed no ventilator-induced lung injury. Arterial blood oxygenations were obviously improved in two groups after 24 hours mechanical ventilation, PCV group had better partial pressure of oxygen in artery (PaO2) than VCV group. Both PCV and VCV can improve arterial blood oxygenations, prevent ventilator-induced lung injury, and have less disturbance in hemodynamic parameters. PCV with lung protective ventilatory strategy should be early use for patients with ARDS.

A comparison of volume control and pressure-regulated volume control ventilation in acute respiratory failure

Science.gov (United States)

Guldager, Henrik; Nielsen, Soeren L; Carl, Peder; Soerensen, Mogens B

1997-01-01

Background: The aim of this study was to test the hypothesis that a new mode of ventilation (pressure-regulated volume control; PRVC) is associated with improvements in respiratory mechanics and outcome when compared with conventional volume control (VC) ventilation in patients with acute respiratory failure. We conducted a randomised, prospective, open, cross over trial on 44 patients with acute respiratory failure in the general intensive care unit of a university hospital. After a stabilization period of 8 h, a cross over trial of 2 × 2 h was conducted. Apart from the PRVC/VC mode, ventilator settings were comparable. The following parameters were recorded for each patient: days on ventilator, failure in the assigned mode of ventilation (peak inspiratory pressure > 50 cmH2O) and survival. Results: In the crossover trial, peak inspiratory pressure was significantly lower using PRVC than with VC (20 cmH2O vs 24 cmH2O, P < 0.0001). No other statistically significant differences were found. Conclusions: Peak inspiratory pressure was significantly lower during PRVC ventilation than during VC ventilation, and thus PRVC may be superior to VC in certain patients. However, in this small group of patients, we could not demonstrate that PRVC improved outcome. PMID:11056699

Ventilator flow data predict bronchopulmonary dysplasia in extremely premature neonates

Directory of Open Access Journals (Sweden)

Mariann H. Bentsen

2018-03-01

Full Text Available Early prediction of bronchopulmonary dysplasia (BPD may facilitate tailored management for neonates at risk. We investigated whether easily accessible flow data from a mechanical ventilator can predict BPD in neonates born extremely premature (EP. In a prospective population-based study of EP-born neonates, flow data were obtained from the ventilator during the first 48 h of life. Data were logged for >10 min and then converted to flow–volume loops using custom-made software. Tidal breathing parameters were calculated and averaged from ≥200 breath cycles, and data were compared between those who later developed moderate/severe and no/mild BPD. Of 33 neonates, 18 developed moderate/severe and 15 no/mild BPD. The groups did not differ in gestational age, surfactant treatment or ventilator settings. The infants who developed moderate/severe BPD had evidence of less airflow obstruction, significantly so for tidal expiratory flow at 50% of tidal expiratory volume (TEF50 expressed as a ratio of peak tidal expiratory flow (PTEF (p=0.007. A compound model estimated by multiple logistic regression incorporating TEF50/PTEF, birthweight z-score and sex predicted moderate/severe BPD with good accuracy (area under the curve 0.893, 95% CI 0.735–0.973. This study suggests that flow data obtained from ventilators during the first hours of life may predict later BPD in premature neonates. Future and larger studies are needed to validate these findings and to determine their clinical usefulness.

Spontaneous blood pressure oscillations in mechanically ventilated patients with sepsis

DEFF Research Database (Denmark)

Berg, Ronan M G; Plovsing, Ronni R; Greve, Anders M

2016-01-01

OBJECTIVE: In the present hypothesis-generating study, we investigated whether spontaneous blood pressure oscillations are suppressed to lower frequencies, and whether abolished oscillations are associated with an adverse outcome in mechanically ventilated patients with sepsis. METHODS: We...... retrospectively subjected invasive steady-state blood pressure recordings from 65 mechanically ventilated patients with sepsis to spectral analysis. Modified spectral bands were visually identified by plotting spectral power against frequency. RESULTS: Modified middle-frequency and low-frequency (MF' and LF......') oscillations were absent in 9% and 22% of the patients, respectively. In patients in whom spontaneous blood pressure oscillations were preserved, the MF' oscillations occurred at 0.021 Hz (median, interquartile range 0.013-0.030), whereas the LF' oscillations occurred at 0.009 Hz (median, interquartile range 0...

Impact of expiratory strength training in amyotrophic lateral sclerosis.

Science.gov (United States)

Plowman, Emily K; Watts, Stephanie A; Tabor, Lauren; Robison, Raele; Gaziano, Joy; Domer, Amanda S; Richter, Joel; Vu, Tuan; Gooch, Clifton

2016-06-01

We evaluated the feasibility and impact of expiratory muscle strength training (EMST) on respiratory and bulbar function in persons with amyotrophic lateral sclerosis (ALS). Twenty-five ALS patients participated in this delayed intervention open-label clinical trial. Following a lead-in period, patients completed a 5-week EMST protocol. Outcome measures included: maximum expiratory pressure (MEP); physiologic measures of swallow and cough; and penetration-aspiration scale (PAS) scores. Of participants who entered the active phase of the study (n = 15), EMST was well tolerated and led to significant increases in MEPs and maximum hyoid displacement during swallowing post-EMST (P < 0.05). No significant differences were observed for PAS scores or cough spirometry measures. EMST was feasible and well tolerated in this small cohort of ALS patients and led to improvements in expiratory force-generating pressures and swallow kinematics. Further investigation is warranted to confirm these preliminary findings. Muscle Nerve 54: 48-53, 2016. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Low tidal volume mechanical ventilation against no ventilation during cardiopulmonary bypass heart surgery (MECANO): study protocol for a randomized controlled trial.

Science.gov (United States)

Nguyen, Lee S; Merzoug, Messaouda; Estagnasie, Philippe; Brusset, Alain; Law Koune, Jean-Dominique; Aubert, Stephane; Waldmann, Thierry; Grinda, Jean-Michel; Gibert, Hadrien; Squara, Pierre

2017-12-02

Postoperative pulmonary complications are a leading cause of morbidity and mortality after cardiac surgery. There are no recommendations on mechanical ventilation associated with cardiopulmonary bypass (CPB) during surgery and anesthesiologists perform either no ventilation (noV) at all during CPB or maintain low tidal volume (LTV) ventilation. Indirect evidence points towards better pulmonary outcomes when LTV is performed but no large-scale prospective trial has yet been published in cardiac surgery. The MECANO trial is a single-center, double-blind, randomized, controlled trial comparing two mechanical ventilation strategies, noV and LTV, during cardiac surgery with CPB. In total, 1500 patients are expected to be included, without any restrictions. They will be randomized between noV and LTV on a 1:1 ratio. The noV group will receive no ventilation during CPB. The LTV group will receive 5 breaths/minute with a tidal volume of 3 mL/kg and positive end-expiratory pressure of 5 cmH2O. The primary endpoint will be a composite of all-cause mortality, early respiratory failure defined as a ratio of partial pressure of oxygen/fraction of inspired oxygen ventilation, mechanical ventilation or high-flow oxygen) at 2 days after arrival in the ICU or ventilator-acquired pneumonia defined by the Center of Disease Control. Lung recruitment maneuvers will be performed in the noV and LTV groups at the end of surgery and at arrival in ICU with an insufflation at +30 cmH20 for 5 seconds. Secondary endpoints are those composing the primary endpoint with the addition of pneumothorax, CPB duration, quantity of postoperative bleeding, red blood cell transfusions, revision surgery requirements, length of stay in the ICU and in the hospital and total hospitalization costs. Patients will be followed until hospital discharge. The MECANO trial is the first of its kind to compare in a double-blind design, a no-ventilation to a low-tidal volume strategy for mechanical ventilation during

Face mask ventilation--the dos and don'ts.

Science.gov (United States)

Wood, Fiona E; Morley, Colin J

2013-12-01

Face mask ventilation provides respiratory support to newly born or sick infants. It is a challenging technique and difficult to ensure that an appropriate tidal volume is delivered because large and variable leaks occur between the mask and face; airway obstruction may also occur. Technique is more important than the mask shape although the size must appropriately fit the face. The essence of the technique is to roll the mask on to the face from the chin while avoiding the eyes, with a finger and thumb apply a strong even downward pressure to the top of the mask, away from the stem and sloped sides or skirt of the mask, place the other fingers under the jaw and apply a similar upward pressure. Preterm infants require continuous end-expiratory pressure to facilitate lung aeration and maintain lung volume. This is best done with a T-piece device, not a self-inflating or flow-inflating bag. Copyright © 2013 Elsevier Ltd. All rights reserved.

Respiratory polygraphy monitoring of intensive care patients receiving non-invasive ventilation

Directory of Open Access Journals (Sweden)

Eduardo Borsini

Full Text Available Introduction: Patients that started on Non-Invasive Ventilation (NIV need to define several parameters selected on the basis of diurnal arterial blood gas and underlying disease. We hypothesize that respiratory polygraphy (RP could be useful to monitor NIV. This retrospective work describes RP findings and their impact on the setting of continuous flow ventilators from patients on NIV of Intensive Care Unit (ICU. Material and Methods: Patient's data on NIV from at the ICU of Hospital Británico were included in this study. RP recordings were performed in all of them. Respiratory events, such as ventilatory pattern changes, impact on oximetry or tidal volume, were observed to modify the ventilatory mode after RP. Results: The RP findings have contributes to change the ventilatory mode for one third of the patients. The mean values of expiratory positive airway pressure (EPAP and inspiratory positive airway pressure (IPAP were not significantly different across all the population before or after RP: 8.7±0.3 vs. 8.6±0.4; p 2 cmH2O pressure value changes after RP. Conclusions: RP recordings could contribute to broad range of data useful to make decisions about changes in programming and allowed to identify adverse events related to positive pressure.

Developing a new, national approach to surveillance for ventilator-associated events*.

Science.gov (United States)

Magill, Shelley S; Klompas, Michael; Balk, Robert; Burns, Suzanne M; Deutschman, Clifford S; Diekema, Daniel; Fridkin, Scott; Greene, Linda; Guh, Alice; Gutterman, David; Hammer, Beth; Henderson, David; Hess, Dean; Hill, Nicholas S; Horan, Teresa; Kollef, Marin; Levy, Mitchell; Septimus, Edward; VanAntwerpen, Carole; Wright, Don; Lipsett, Pamela

2013-11-01

To develop and implement an objective, reliable approach to surveillance for ventilator-associated events in adult patients. The Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group in September 2011. Working Group members included representatives of stakeholder societies and organizations and federal partners. The Working Group finalized a three-tier, adult surveillance definition algorithm for ventilator-associated events. The algorithm uses objective, readily available data elements and can identify a broad range of conditions and complications occurring in mechanically ventilated adult patients, including but not limited to VAP. The first tier definition, ventilator-associated condition (VAC), identifies patients with a period of sustained respiratory deterioration following a sustained period of stability or improvement on the ventilator, defined by changes in the daily minimum fraction of inspired oxygen or positive end-expiratory pressure. The second tier definition, infection-related ventilator-associated complication (IVAC), requires that patients with VAC also have an abnormal temperature or white blood cell count, and be started on a new antimicrobial agent. The third tier definitions, possible and probable VAP, require that patients with IVAC also have laboratory and/or microbiological evidence of respiratory infection. Ventilator-associated events surveillance was implemented in January 2013 in the CDC's National Healthcare Safety Network. Modifications to improve surveillance may be made as additional data become available and users gain experience with the new definitions.

Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study

Directory of Open Access Journals (Sweden)

Thomas Berlet

2016-01-01

Full Text Available This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, airway pressures, temperatures, and simulated static lung compliance settings on leakage characteristics was assessed. We observed substantial differences in transfenestration pressures and transfenestration leakage rates. The leakage rates of the best performing tubes were <3.5% of the delivered minute volume. At body temperature, the leakage rates of these tracheostomy tubes were <1%. The tracheal tube design was the main factor that determined the leakage characteristics. Careful tracheostomy tube selection permits the use of fenestrated tracheostomy tubes in patients receiving positive pressure ventilation immediately after stoma formation and minimises the risk of complications caused by transfenestration gas leakage, for example, subcutaneous emphysema.

Diagnostic methods to assess inspiratory and expiratory muscle strength

Directory of Open Access Journals (Sweden)

Pedro Caruso

2015-04-01

Full Text Available Impairment of (inspiratory and expiratory respiratory muscles is a common clinical finding, not only in patients with neuromuscular disease but also in patients with primary disease of the lung parenchyma or airways. Although such impairment is common, its recognition is usually delayed because its signs and symptoms are nonspecific and late. This delayed recognition, or even the lack thereof, occurs because the diagnostic tests used in the assessment of respiratory muscle strength are not widely known and available. There are various methods of assessing respiratory muscle strength during the inspiratory and expiratory phases. These methods are divided into two categories: volitional tests (which require patient understanding and cooperation; and non-volitional tests. Volitional tests, such as those that measure maximal inspiratory and expiratory pressures, are the most commonly used because they are readily available. Non-volitional tests depend on magnetic stimulation of the phrenic nerve accompanied by the measurement of inspiratory mouth pressure, inspiratory esophageal pressure, or inspiratory transdiaphragmatic pressure. Another method that has come to be widely used is ultrasound imaging of the diaphragm. We believe that pulmonologists involved in the care of patients with respiratory diseases should be familiar with the tests used in order to assess respiratory muscle function.Therefore, the aim of the present article is to describe the advantages, disadvantages, procedures, and clinical applicability of the main tests used in the assessment of respiratory muscle strength.

Radon mitigation with mechanical supply and exhaust ventilation adjusted by a pressure control unit

International Nuclear Information System (INIS)

Kokotti, H.; Keskikuru, T.; Kalliokoski, P.

1993-01-01

Effective ventilation and positive or low negative pressure indoors are suggested to low indoor radon levels. The aim of this study is to develop and to test an equipment, which makes it possible to achieve simultaneously effective ventilation and minimum outdoor-pressure difference. The unit includes mechanical supply and exhaust air fans, a exchanger and a pressure control unit in direct digital control (DDC), which adjusts continuously air exchange based on the pressure difference transmitter information. (orig.). (8 refs., 6 figs.)

Auto-trilevel versus bilevel positive airway pressure ventilation for hypercapnic overlap syndrome patients.

Science.gov (United States)

Su, Mei; Huai, De; Cao, Juan; Ning, Ding; Xue, Rong; Xu, Meijie; Huang, Mao; Zhang, Xilong

2018-03-01

Although bilevel positive airway pressure (Bilevel PAP) therapy is usually used for overlap syndrome (OS), there is still a portion of OS patients in whom Bilevel PAP therapy could not simultaneously eliminate residual apnea events and hypercapnia. The current study was expected to explore whether auto-trilevel positive airway pressure (auto-trilevel PAP) therapy with auto-adjusting end expiratory positive airway pressure (EEPAP) can serve as a better alternative for these patients. From January of 2014 to June of 2016, 32 hypercapnic OS patients with stable chronic obstructive pulmonary diseases (COPD) and moderate-to-severe obstructive sleep apnea syndrome (OSAS) were recruited. Three variable modes of positive airway pressure (PAP) from the ventilator (Prisma25ST, Weinmann Inc., Germany) were applicated for 8 h per night. We performed the design of each mode at each night with an interval of two nights with no PAP treatment as a washout period among different modes. In Bilevel-1 mode (Bilevel-1), the expiratory positive airway pressure (EPAP) delivered from Bilevel PAP was always set as the lowest PAP for abolishment of snoring. For each patient, the inspiratory positive airway pressure (IPAP) was constantly set the same as the minimal pressure for keeping end-tidal CO 2 (ETCO 2 ) ≤45 mmHg for all three modes. However, the EPAP issued by Bilevel PAP in Bilevel-2 mode (Bilevel-2) was kept 3 cmH 2 O higher than that in Bilevel-1. In auto-trilevel mode (auto-trilevel) with auto-trilevel PAP, the initial part of EPAP was fixed at the same PAP as that in Bilevel-1 while the EEPAP was automatically regulated to rise at a range of ≤4 cmH 2 O based on nasal airflow wave changes. Comparisons were made for parameters before and during or following treatment as well as among different PAP therapy modes. The following parameters were compared such as nocturnal apnea hypopnea index (AHI), minimal SpO 2 (minSpO 2 ), arousal index, sleep structure and efficiency

Respiratory mechanics by least squares fitting in mechanically ventilated patients: application on flow-limited COPD patients.

Science.gov (United States)

Volta, Carlo A; Marangoni, Elisabetta; Alvisi, Valentina; Capuzzo, Maurizia; Ragazzi, Riccardo; Pavanelli, Lina; Alvisi, Raffaele

2002-01-01

Although computerized methods of analyzing respiratory system mechanics such as the least squares fitting method have been used in various patient populations, no conclusive data are available in patients with chronic obstructive pulmonary disease (COPD), probably because they may develop expiratory flow limitation (EFL). This suggests that respiratory mechanics be determined only during inspiration. Eight-bed multidisciplinary ICU of a teaching hospital. Eight non-flow-limited postvascular surgery patients and eight flow-limited COPD patients. Patients were sedated, paralyzed for diagnostic purposes, and ventilated in volume control ventilation with constant inspiratory flow rate. Data on resistance, compliance, and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) obtained by applying the least squares fitting method during inspiration, expiration, and the overall breathing cycle were compared with those obtained by the traditional method (constant flow, end-inspiratory occlusion method). Our results indicate that (a) the presence of EFL markedly decreases the precision of resistance and compliance values measured by the LSF method, (b) the determination of respiratory variables during inspiration allows the calculation of respiratory mechanics in flow limited COPD patients, and (c) the LSF method is able to detect the presence of PEEPi,dyn if only inspiratory data are used.

Improved oxygenation during standing performance of deep breathing exercises with positive expiratory pressure after cardiac surgery: A randomized controlled trial.

Science.gov (United States)

Pettersson, Henrik; Faager, Gun; Westerdahl, Elisabeth

2015-09-01

Breathing exercises after cardiac surgery are often performed in a sitting position. It is unknown whether oxygenation would be better in the standing position. The aim of this study was to evaluate oxygenation and subjective breathing ability during sitting vs standing performance of deep breathing exercises on the second day after cardiac surgery. Patients undergoing coronary artery bypass grafting (n = 189) were randomized to sitting (controls) or standing. Both groups performed 3 × 10 deep breaths with a positive expiratory pressure device. Peripheral oxygen saturation was measured before, directly after, and 15 min after the intervention. Subjective breathing ability, blood pressure, heart rate, and pain were assessed. Oxygenation improved significantly in the standing group compared with controls directly after the breathing exercises (p < 0.001) and after 15 min rest (p = 0.027). The standing group reported better deep breathing ability compared with controls (p = 0.004). A slightly increased heart rate was found in the standing group (p = 0.047). After cardiac surgery, breathing exercises with positive expiratory pressure, performed in a standing position, significantly improved oxygenation and subjective breathing ability compared with sitting performance. Performance of breathing exercises in the standing position is feasible and could be a valuable treatment for patients with postoperative hypoxaemia.

Extubation success in premature infants with respiratory distress syndrome treated with bi-level nasal continuous positive airway pressure versus nasal intermittent positive pressure ventilation.

Science.gov (United States)

Thomas, Patricia E; LeFlore, Judy

2013-01-01

Infants born prematurely with respiratory distress syndrome are at high risk for complications from mechanical ventilation. Strategies are needed to minimize their days on the ventilator. The purpose of this study was to compare extubation success rates in infants treated with 2 different types of continuous positive airway pressure devices. A retrospective cohort study design was used. Data were retrieved from electronic medical records for patients in a large, metropolitan, level III neonatal intensive care unit. A sample of 194 premature infants with respiratory distress syndrome was selected, 124 of whom were treated with nasal intermittent positive pressure ventilation and 70 with bi-level variable flow nasal continuous positive airway pressure (bi-level nasal continuous positive airway pressure). Infants in both groups had high extubation success rates (79% of nasal intermittent positive pressure ventilation group and 77% of bi-level nasal continuous positive airway pressure group). Although infants in the bi-level nasal continuous positive airway pressure group were extubated sooner, there was no difference in duration of oxygen therapy between the 2 groups. Promoting early extubation and extubation success is a vital strategy to reduce complications of mechanical ventilation that adversely affect premature infants with respiratory distress syndrome.

Relationship between pre-extubation positive endexpiratory pressure and oxygenation after coronary artery bypass grafting

Directory of Open Access Journals (Sweden)

Reijane Oliveira Lima

2015-08-01

Full Text Available Abstract Introduction After removal of endotracheal tube and artificial ventilation, ventilatory support should be continued, offering oxygen supply to ensure an arterial oxygen saturation close to physiological. Objective: The aim of this study was to investigate the effects of positive-end expiratory pressure before extubation on the oxygenation indices of patients undergoing coronary artery bypass grafting. Methods: A randomized clinical trial with seventy-eight patients undergoing coronary artery bypass grafting divided into three groups and ventilated with different positive-end expiratory pressure levels prior to extubation: Group A, 5 cmH2O (n=32; Group B, 8 cmH2O (n=26; and Group C, 10 cmH2O (n=20. Oxygenation index data were obtained from arterial blood gas samples collected at 1, 3, and 6 h after extubation. Patients with chronic pulmonary disease and those who underwent off-pump, emergency, or combined surgeries were excluded. For statistical analysis, we used Shapiro-Wilk, G, Kruskal-Wallis, and analysis of variance tests and set the level of significance at P<0.05. Results Groups were homogenous with regard to demographic, clinical, and surgical variables. There were no statistically significant differences between groups in the first 6 h after extubation with regard to oxygenation indices and oxygen therapy utilization. Conclusion: In this sample of patients undergoing coronary artery bypass grafting, the use of different positive-end expiratory pressure levels before extubation did not affect gas exchange or oxygen therapy utilization in the first 6 h after endotracheal tube removal.

The Society for Translational Medicine: clinical practice guidelines for mechanical ventilation management for patients undergoing lobectomy

Science.gov (United States)

Zhang, Zhongheng; Brunelli, Alessandro; Chen, Chang; Chen, Chun; Chen, Gang; Chen, Haiquan; Chen, Jin-Shing; Cassivi, Stephen; Chai, Ying; Downs, John B.; Fang, Wentao; Fu, Xiangning; Garutti, Martínez I.; He, Jianxing; Hu, Jian; Huang, Yunchao; Jiang, Gening; Jiang, Hongjing; Jiang, Zhongmin; Li, Danqing; Li, Gaofeng; Li, Hui; Li, Qiang; Li, Xiaofei; Li, Yin; Li, Zhijun; Liu, Chia-Chuan; Liu, Deruo; Liu, Lunxu; Liu, Yongyi; Ma, Haitao; Mao, Weimin; Mao, Yousheng; Mou, Juwei; Ng, Calvin Sze Hang; Petersen, René H.; Qiao, Guibin; Rocco, Gaetano; Ruffini, Erico; Tan, Lijie; Tan, Qunyou; Tong, Tang; Wang, Haidong; Wang, Qun; Wang, Ruwen; Wang, Shumin; Xie, Deyao; Xue, Qi; Xue, Tao; Xu, Lin; Xu, Shidong; Xu, Songtao; Yan, Tiansheng; Yu, Fenglei; Yu, Zhentao; Zhang, Chunfang; Zhang, Lanjun; Zhang, Tao; Zhang, Xun; Zhao, Xiaojing; Zhao, Xuewei; Zhi, Xiuyi; Zhou, Qinghua

2017-01-01

Patients undergoing lobectomy are at significantly increased risk of lung injury. One-lung ventilation is the most commonly used technique to maintain ventilation and oxygenation during the operation. It is a challenge to choose an appropriate mechanical ventilation strategy to minimize the lung injury and other adverse clinical outcomes. In order to understand the available evidence, a systematic review was conducted including the following topics: (I) protective ventilation (PV); (II) mode of mechanical ventilation [e.g., volume controlled (VCV) versus pressure controlled (PCV)]; (III) use of therapeutic hypercapnia; (IV) use of alveolar recruitment (open-lung) strategy; (V) pre-and post-operative application of positive end expiratory pressure (PEEP); (VI) Inspired Oxygen concentration; (VII) Non-intubated thoracoscopic lobectomy; and (VIII) adjuvant pharmacologic options. The recommendations of class II are non-intubated thoracoscopic lobectomy may be an alternative to conventional one-lung ventilation in selected patients. The recommendations of class IIa are: (I) Therapeutic hypercapnia to maintain a partial pressure of carbon dioxide at 50–70 mmHg is reasonable for patients undergoing pulmonary lobectomy with one-lung ventilation; (II) PV with a tidal volume of 6 mL/kg and PEEP of 5 cmH2O are reasonable methods, based on current evidence; (III) alveolar recruitment [open lung ventilation (OLV)] may be beneficial in patients undergoing lobectomy with one-lung ventilation; (IV) PCV is recommended over VCV for patients undergoing lung resection; (V) pre- and post-operative CPAP can improve short-term oxygenation in patients undergoing lobectomy with one-lung ventilation; (VI) controlled mechanical ventilation with I:E ratio of 1:1 is reasonable in patients undergoing one-lung ventilation; (VII) use of lowest inspired oxygen concentration to maintain satisfactory arterial oxygen saturation is reasonable based on physiologic principles; (VIII) Adjuvant drugs

[Preventing Facial Pressure Injuries in Patients Who Use Noninvasive Positive Pressure Ventilators: The Efficiency of Dressings].

Science.gov (United States)

Tai, Chia-Hua; Hsu, Mei-Yu

2016-10-01

Noninvasive positive pressure ventilation (NPPV) provides ventilation without tracheal intubation. Facial pressure injury is a recognized complication of this technique, making the prevention of facial pressure injuries an important issue for NPPV patients. The present study compared the effects of foam dressing and hydrocolloid dressing in preventing facial pressure injuries in NPPV patients. A randomized clinical trial was used to evaluate participants that were referred from the intensive care unit of a medical center in eastern Taiwan. Participants were randomized into two groups: the foam dressing group and the hydrocolloid dressing group. Statistics used in analysis were: analysis mean, standard deviation, chi-square, independent t-test, and the generalized estimating equation. Sixty participants were enrolled as participants. The incidence rate of facial pressure injury was 11.7% (7/60). No significant difference was found between the two groups in terms of duration of NPPV use, incidence of facial pressure injury, and occurrence time of facial pressure injury. However, the hydrocolloid dressing group had a higher usage amount than the foam dressing group (p < .05). Foam and hydrocolloid dressings are both helpful in preventing facial pressure injury when used in conjunction with regular skin assessments.

[Anesthesia ventilators].

Science.gov (United States)

Otteni, J C; Beydon, L; Cazalaà, J B; Feiss, P; Nivoche, Y

1997-01-01

To review anaesthesia ventilators in current use in France by categories of ventilators. References were obtained from computerized bibliographic search. (Medline), recent review articles, the library of the service and personal files. Anaesthesia ventilators can be allocated into three groups, depending on whether they readminister expired gases or not or allow both modalities. Contemporary ventilators provide either constant volume ventilation, or constant pressure ventilation, with or without a pressure plateau. Ventilators readministering expired gases after CO2 absorption, or closed circuit ventilators, are either of a double- or a single-circuit design. Double-circuit ventilators, or pneumatical bag or bellows squeezers, or bag-in-bottle or bellows-in-bottle (or box) ventilators, consist of a primary, or driving circuit (bottle or box) and a secondary or patient circuit (including a bag or a bellows or membrane chambers). Bellows-in-bottle ventilators have either standing bellows ascending at expiration, or hanging bellows, descending at expiration. Ascending bellows require a positive pressure of about 2 cmH2O throughout exhalation to allow the bellows to refill. The expired gas volume is a valuable indicator for leak and disconnection. Descending bellows generate a slight negative pressure during exhalation. In case of leak or disconnection they aspirate ambient air and cannot act therefore as an indicator for integrity of the circuit and the patient connection. Closed circuit ventilators with a single-circuit (patient circuit) include a insufflating device consisting either in a bellows or a cylinder with a piston, operated by a electric or pneumatic motor. As the hanging bellows of the double circuit ventilators, they generate a slight negative pressure during exhalation and aspirate ambient air in case of leak or disconnection. Ventilators not designed for the readministration of expired gases, or open circuit ventilators, are generally stand

Mechanical ventilation with lower tidal volumes and positive end-expiratory pressure prevents alveolar coagulation in patients without lung injury

NARCIS (Netherlands)

Choi, Goda; Wolthuis, Esther K.; Bresser, Paul; Levi, Marcel; van der Poll, Tom; Dzoljic, Misa; Vroom, Margreeth B.; Schultz, Marcus J.

2006-01-01

BACKGROUND: Alveolar fibrin deposition is a hallmark of acute lung injury, resulting from activation of coagulation and inhibition of fibrinolysis. Previous studies have shown that mechanical ventilation with high tidal volumes may aggravate lung injury in patients with sepsis and acute lung injury.

Ventilation is unstable during drowsiness before sleep onset.

Science.gov (United States)

Thomson, Stuart; Morrell, Mary J; Cordingley, Jeremy J; Semple, Stephen J

2005-11-01

Ventilation is unstable during drowsiness before sleep onset. We have studied the effects of transitory changes in cerebral state during drowsiness on breath duration and lung volume in eight healthy subjects in the absence of changes in airway resistance and fluctuations of ventilation and CO2 tension, characteristic of the onset of non-rapid eye movement sleep. A volume-cycled ventilator in the assist control mode was used to maintain CO2 tension close to that when awake. Changes in cerebral state were determined by the EEG on a breath-by-breath basis and classified as alpha or theta breaths. Breath duration and the pause in gas flow between the end of expiratory airflow and the next breath were computed for two alpha breaths which preceded a theta breath and for the theta breath itself. The group mean (SD) results for this alpha-to-theta transition was associated with a prolongation in breath duration from 5.2 (SD 1.3) to 13.0 s (SD 2.1) and expiratory pause from 0.7 (SD 0.4) to 7.5 s (SD 2.2). Because the changes in arterial CO2 tension (PaCO2) are unknown during the theta breaths, we made in two subjects a continuous record of PaCO2 in the radial artery. PaCO2 remained constant from the alpha breaths through to the expiratory period of the theta breath by which time the duration of breath was already prolonged, representing an immediate and altered ventilatory response to the prevailing PaCO2. In the eight subjects, the CO2 tension awake was 39.6 Torr (SD 2.3) and on assisted ventilation 38.0 Torr (1.4). We conclude that the ventilatory instability recorded in the present experiments is due to the apneic threshold for CO2 being at or just below that when awake.

Patient-ventilator asynchrony affects pulse pressure variation prediction of fluid responsiveness.

Science.gov (United States)

Messina, Antonio; Colombo, Davide; Cammarota, Gianmaria; De Lucia, Marta; Cecconi, Maurizio; Antonelli, Massimo; Corte, Francesco Della; Navalesi, Paolo

2015-10-01

During partial ventilatory support, pulse pressure variation (PPV) fails to adequately predict fluid responsiveness. This prospective study aims to investigate whether patient-ventilator asynchrony affects PPV prediction of fluid responsiveness during pressure support ventilation (PSV). This is an observational physiological study evaluating the response to a 500-mL fluid challenge in 54 patients receiving PSV, 27 without (Synch) and 27 with asynchronies (Asynch), as assessed by visual inspection of ventilator waveforms by 2 skilled blinded physicians. The area under the curve was 0.71 (confidence interval, 0.57-0.83) for the overall population, 0.86 (confidence interval, 0.68-0.96) in the Synch group, and 0.53 (confidence interval, 0.33-0.73) in the Asynch group (P = .018). Sensitivity and specificity of PPV were 78% and 89% in the Synch group and 36% and 46% in the Asynch group. Logistic regression showed that the PPV prediction was influenced by patient-ventilator asynchrony (odds ratio, 8.8 [2.0-38.0]; P < .003). Of the 27 patients without asynchronies, 12 had a tidal volume greater than or equal to 8 mL/kg; in this subgroup, the rate of correct classification was 100%. Patient-ventilator asynchrony affects PPV performance during partial ventilatory support influencing its efficacy in predicting fluid responsiveness. Copyright © 2015 Elsevier Inc. All rights reserved.

[A comparative study between inflation and deflation pressure-volume curve in determining the optimal positive end-expiratory pressure].

Science.gov (United States)

Gang, Li; Sun, Xiao-yi; Xu, Jin-quan; Zhang, Xin-li; Kou, Lu-xin; Jiang, Zhi-hong; Zhang, Lei

2012-02-01

To determine the optimal positive end-expiratory pressure (PEEP) according to inflation and deflation pressure-volume curve (P-V curve) in patients with acute respiratory distress syndrome (ARDS). ARDS models were reproduced in 20 dogs, and they were randomly divided into two groups. In both groups, Levenberg-Marquardt iterative algorithm was employed using software to explore parameters fitting with Boltzmann formula, by which the real inflection point of pressure (Pinf d) in deflation limb or lower inflection point pressure (PLip) in inflation limb on P-V curve were defined. For the control group (inflation curve) P-V curve of PLip + 2 cm H(2)O [1 cm H(2)O = 0.098 kPa] was applied as the best PEEP value. In the experimental group (deflation curve) the Pinf d was taken as the best PEEP value. The heart rate (HR), blood pressure (BP), fingertip pulse oxygen saturation [SpO(2)], static lung compliance (Cst), arterial partial pressure of oxygen [PaO(2)] and arterial partial pressure of carbon dioxide [PaCO(2)] were monitored at 0, 2, 6, 12, 24 and 48 hours. Oxygenation index increased significantly both in control and experimental groups. In experimental group, oxygenation index (mm Hg, 1 mm Hg = 0.133 kPa) of 12, 24 and 48 hours was respectively significantly higher than that of the control group (12 hours: 177.63 ± 8.94 vs. 165.60 ± 8.90, 24 hours: 194.19 ± 10.67 vs. 168.70 ± 10.60, 48 hours: 203.15 ± 13.21 vs. 171.26 ± 9.21, all P deflation P-V curve was better than that of inflation curve.

Theoretical study of inspiratory flow waveforms during mechanical ventilation on pulmonary blood flow and gas exchange.

Science.gov (United States)

Niranjan, S C; Bidani, A; Ghorbel, F; Zwischenberger, J B; Clark, J W

1999-08-01

A lumped two-compartment mathematical model of respiratory mechanics incorporating gas exchange and pulmonary circulation is utilized to analyze the effects of square, descending and ascending inspiratory flow waveforms during mechanical ventilation. The effects on alveolar volume variation, alveolar pressure, airway pressure, gas exchange rate, and expired gas species concentration are evaluated. Advantages in ventilation employing a certain inspiratory flow profile are offset by corresponding reduction in perfusion rates, leading to marginal effects on net gas exchange rates. The descending profile provides better CO2 exchange, whereas the ascending profile is more advantageous for O2 exchange. Regional disparities in airway/lung properties create maldistribution of ventilation and a concomitant inequality in regional alveolar gas composition and gas exchange rates. When minute ventilation is maintained constant, for identical time constant disparities, inequalities in compliance yield pronounced effects on net gas exchange rates at low frequencies, whereas the adverse effects of inequalities in resistance are more pronounced at higher frequencies. Reduction in expiratory air flow (via increased airway resistance) reduces the magnitude of upstroke slope of capnogram and oxigram time courses without significantly affecting end-tidal expired gas compositions, whereas alterations in mechanical factors that result in increased gas exchanges rates yield increases in CO2 and decreases in O2 end-tidal composition values. The model provides a template for assessing the dynamics of cardiopulmonary interactions during mechanical ventilation by combining concurrent descriptions of ventilation, capillary perfusion, and gas exchange. Copyright 1999 Academic Press.

A comparison of synchronized intermittent mandatory ventilation and pressure-regulated volume control ventilation in elderly patients with acute exacerbations of COPD and respiratory failure

Directory of Open Access Journals (Sweden)

Chang SC

2016-05-01

Full Text Available Suchi Chang,1 Jindong Shi,2 Cuiping Fu,1 Xu Wu,1 Shanqun Li1 1Department of Respiratory Medicine, Zhongshan Hospital, Fudan University, Shanghai, 2Department of Respiratory Medicine, The Fifth People’s Hospital of Shanghai, Fudan University, Shanghai, People’s Republic of China Background: COPD is the third leading cause of death worldwide. Acute exacerbations of COPD may cause respiratory failure, requiring intensive care unit admission and mechanical ventilation. Intensive care unit patients with acute exacerbations of COPD requiring mechanical ventilation have higher mortality rates than other hospitalized patients. Although mechanical ventilation is the most effective intervention for these conditions, invasive ventilation techniques have yielded variable effects. Objective: We evaluated pressure-regulated volume control (PRVC ventilation treatment efficacy and preventive effects on pulmonary barotrauma in elderly COPD patients with respiratory failure. Patients and methods: Thirty-nine intubated patients were divided into experimental and control groups and treated with the PRVC and synchronized intermittent mandatory ventilation – volume control methods, respectively. Vital signs, respiratory mechanics, and arterial blood gas analyses were monitored for 2–4 hours and 48 hours. Results: Both groups showed rapidly improved pH, partial pressure of oxygen (PaO2, and PaO2 per fraction of inspired O2 levels and lower partial pressure of carbon dioxide (PaCO2 levels. The pH and PaCO2 levels at 2–4 hours were lower and higher, respectively, in the test group than those in the control group (P<0.05 for both; after 48 hours, blood gas analyses showed no statistical difference in any marker (P>0.05. Vital signs during 2–4 hours and 48 hours of treatment showed no statistical difference in either group (P>0.05. The level of peak inspiratory pressure in the experimental group after mechanical ventilation for 2–4 hours and 48�

Methylene Blue in Ventilator-Induced Lung Injury after Pneumonectomy: an Experimental Study

Directory of Open Access Journals (Sweden)

Ye. V Suborov

2007-01-01

Full Text Available Objective: to study the expediency and efficiency of using methylene blue (MB on a model of pneumectomy (PE and subsequent ventilator-induced lung injury (VILI in sheep. Materials and methods. The study was conducted at the Research Laboratory of University of Tromse. The experiment included 23 sheep weighing 41.0±4.9 kg. Thoracotomy and right-sided pneumonectomy were performed in the animals under general anesthesia and controlled artificial ventilation. After measurement of the parameters of systemic hemodynamics and extravascular water of the lung (EVWL, the animals were divided into 3 groups: 1 a control group (CG, n=7 with a tidal volume (TV of 6 ml/kg and an end-expiratory positive pressure (PEEP of 2 cm H2O; 2 a VILI group (n=9 with a TV of 12 ml/kg and a PEEP of 0 cm H2O; 3 a group of MB (n=7 that was given in parallel with a damaging ventilation mode. The thermodilution technique (using a Cold Z-021 monitor, (Pulsion, Germany was employed to measure volumetric parameters and EVWL. The parameters of pulmonary hemodynamics, respiratory mechanics, and blood gas composition were recorded. Results: After its reduction at PE, EVWL index increased during damaging ventilation in the VILI and MB groups. In addition, there was an increase in pulmonary artery wedge pressure after PE in the MB and VILI groups. In the latter group, arterial hypoxemia was observed at the end of the experiment. Along with this, after PE pulmonary compliance decreased and airway pressure elevated in the VILI and MB groups. Conclusion: In the presented model of VILI, MB does not prevent the development of postp-neumectomic edema of the lung. Key words: thermochromodilution, acute lung injury, pneumectomy, ventilator-induced lung injury, postpneumectomic edema of the lung, methylene blue.

Backrest position in prevention of pressure ulcers and ventilator-associated pneumonia: conflicting recommendations.

Science.gov (United States)

Burk, Ruth Srednicki; Grap, Mary Jo

2012-01-01

Pressure ulcers and ventilator-associated pneumonia (VAP) are both common in acute and critical care settings and are considerable sources of morbidity, mortality, and health care costs. To prevent pressure ulcers, guidelines limit bed backrest elevation to less than 30 degrees, whereas recommendations to reduce VAP include use of backrest elevations of 30 degrees or more. Although a variety of risk factors beyond patient position have been identified for both pressure ulcers and VAP, this article will focus on summarizing the major evidence for each of these apparently conflicting positioning strategies and discuss implications for practice in managing mechanically ventilated patients with risk factors for both pressure ulcers and VAP. Copyright © 2012 Elsevier Inc. All rights reserved.

Noninvasive ventilation.

Science.gov (United States)

Rabatin, J T; Gay, P C

1999-08-01

Noninvasive ventilation refers to the delivery of assisted ventilatory support without the use of an endotracheal tube. Noninvasive positive pressure ventilation (NPPV) can be delivered by using a volume-controlled ventilator, a pressure-controlled ventilator, a bilevel positive airway pressure ventilator, or a continuous positive airway pressure device. During the past decade, there has been a resurgence in the use of noninvasive ventilation, fueled by advances in technology and clinical trials evaluating its use. Several manufacturers produce portable devices that are simple to operate. This review describes the equipment, techniques, and complications associated with NPPV and also the indications for both short-term and long-term applications. NPPV clearly represents an important addition to the techniques available to manage patients with respiratory failure. Future clinical trials evaluating its many clinical applications will help to define populations of patients most apt to benefit from this type of treatment.

Positive end-expiratory pressure increases pulmonary clearance of inhaled 99mTc-DTPA in nonsmokers but not in healthy smokers

International Nuclear Information System (INIS)

Nolop, K.B.; Braude, S.; Royston, D.; Maxwell, D.L.; Hughes, J.M.B.

1987-01-01

Positive end-expiratory pressure (PEEP) is widely used in the treatment of severe pulmonary oedema, although its effects on the clearance of water and small solutes from alveolus to blood are not well characterized. We studied the effect of the application of 10 cmH 2 O of PEEP on the flux of inhaled 99 mTc-diethylene-triamine-penta-acetic acid (DTPA) from lung to blood in six healthy smoking and six nonsmoking subjects. The rate of flux was corrected for possible changes in pulmonary blood volume during PEEP by use of an intravenous injection of 99m Tc-DTPA. The baseline clearance rate (K,%.min -1 ) for nonsmokers was 1.48±0.12 (mean±SE) and increased to 2.40±0.29 during PEEP (p<0.05). In contrast, the mean clearance rate for smokers was 3.26±0.82 at baseline and 3.03±0.82 during PEEP (p=NS). The application of positive end-expiratory pressure appears to increase alveolar solute flux in nonsmokers but not in smokers, suggesting that the pathway for solute clearance in smokers is governed by different rate-limiting steps to those of nonsmokers

Noninvasive ventilation in patients with acute cardiogenic pulmonary edema

Directory of Open Access Journals (Sweden)

Andrea Bellone

2013-07-01

Full Text Available The term noninvasive ventilation (NIV encompasses two different modes of delivering positive airway pressure, namely continuous positive airway pressure (CPAP and bilevel positive airway pressure (bilevel-PAP. The two modes are different since CPAP does not actively assist inspiration whereas bilevel-PAP does. Bilevel-PAP is a type of noninvasive ventilation that helps keep the upper airways of the lungs open by providing a flow of air delivered through a face mask. The air is pressurized by a machine, which delivers it to the face mask through long, plastic hosing. With bilevel-PAP, the doctor prescribes specific alternating pressures: a higher pressure is used to breathe in (inspiratory positive airway pressure and a lower pressure is used to breath out (expiratory positive airway pressure. Noninvasive ventilation has been shown to reduce the rate of tracheal intubation. The main indications are exacerbation of chronic obstructive pulmonary disease and acute cardiogenic pulmonary edema (ACPE. This last is a common cause of respiratory failure with high incidence and high mortality rate. Clinical findings of ACPE are related to the increased extra-vascular water in the lungs and the resulting reduced lung compliance, increased airway resistance and elevated inspiratory muscle load which generates a depression in pleural pressure. These large pleural pressure swings are responsible for hemodynamic changes by increasing left ventricular afterload, myocardial transmural pressure, and venous return. These alterations can be detrimental to patients with left ventricular systolic dysfunction. Under these circumstances, NIV, either by CPAP or bilevel-PAP, improves vital signs, gas exchange, respiratory mechanics and hemodynamics by reducing left ventricular afterload and preload. In the first randomized study which compared the effectiveness of CPAP plus medical treatment vs medical treatment alone, the CPAP group showed a significant decrease in its

Functional Magnetic Stimulation of Inspiratory and Expiratory Muscles in Subjects With Tetraplegia.

Science.gov (United States)

Zhang, Xiaoming; Plow, Ela; Ranganthan, Vinoth; Huang, Honglian; Schmitt, Melissa; Nemunaitis, Gregory; Kelly, Clay; Frost, Frederick; Lin, Vernon

2016-07-01

Respiratory complications are major causes of morbidity and mortality in persons with a spinal cord injury, partly because of respiratory muscle paralysis. Earlier investigation has demonstrated that functional magnetic stimulation (FMS) can be used as a noninvasive technology for activating expiratory muscles, thus producing useful expiratory functions (simulated cough) in subjects with spinal cord injury. To evaluate the effectiveness of FMS for conditioning inspiratory and expiratory muscles in persons with tetraplegia. A prospective before and after trial. FMS Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, OH. Six persons with tetraplegia. Each subject participated in a 6-week FMS protocol for conditioning the inspiratory and expiratory muscles. A magnetic stimulator was used with the center of a magnetic coil placed at the C7-T1 and T9-T10 spinous processes, respectively. Pulmonary function tests were performed before, during, and after the protocol. Respiratory variables included maximal inspiratory pressure (MIP), inspiratory reserve volume (IRV), peak inspiratory flow (PIF), maximal expiratory pressure (MEP), expiratory reserve volume (ERV), and peak expiratory flow (PEF). After 6 weeks of conditioning, the main outcome measurements (mean ± standard error) were as follows: MIP, 89.6 ± 7.3 cm H2O; IRV, 1.90 ± 0.34 L; PIF, 302.4 ± 36.3 L/min; MEP, 67.4 ± 11.1 cm H2O; ERV, 0.40 ± 0.06 L; and PEF, 372.4 ± 31.9 L/min. These values corresponded to 117%, 107%, 136%, 109%, 130%, and 124% of pre-FMS conditioning values, respectively. Significant improvements were observed in MIP (P = .022), PIF (P = .0001), and PEF (P = .0006), respectively. When FMS was discontinued for 4 weeks, these values showed decreases from their values at the end of the conditioning protocol, which suggests that continual FMS may be necessary to maintain improved respiratory functions. FMS conditioning of the inspiratory and expiratory muscles improved

Dynamic airway pressure-time curve profile (Stress Index): a systematic review.

Science.gov (United States)

Terragni, Pierpaolo; Bussone, Guido; Mascia, Luciana

2016-01-01

The assessment of respiratory mechanics at the bedside is necessary in order to identify the most protective ventilatory strategy. Indeed in the last 20 years, adverse effects of positive ventilation to the lung structures have led to a reappraisal of the objectives of mechanical ventilation. The ventilator setting requires repeated readjustment over the period of mechanical ventilation dependency and careful respiratory monitoring to minimize the risks, preventing further injury and permitting the lung and airways healing. Among the different methods that have been proposed and validated, the analysis of dynamic P-t curve (named Stress Index, SI) represents an adequate tool available at the bedside, repeatable and, therefore, able to identify the amount of overdistension occurring in the daily clinical practice, when modifying positive end-expiratory pressure. In this review we will analyze the evidence that supports respiratory mechanics assessment at the bedside and the application of the dynamic P/t curve profile (SI) to optimize protective ventilation in patients with acute respiratory failure.

Nonassociative learning promotes respiratory entrainment to mechanical ventilation.

Directory of Open Access Journals (Sweden)

Shawna M MacDonald

Full Text Available BACKGROUND: Patient-ventilator synchrony is a major concern in critical care and is influenced by phasic lung-volume feedback control of the respiratory rhythm. Routine clinical application of positive end-expiratory pressure (PEEP introduces a tonic input which, if unopposed, might disrupt respiratory-ventilator entrainment through sustained activation of the vagally-mediated Hering-Breuer reflex. We suggest that this potential adverse effect may be averted by two differentiator forms of nonassociative learning (habituation and desensitization of the Hering-Breuer reflex via pontomedullary pathways. METHODOLOGY/PRINCIPAL FINDINGS: We tested these hypotheses in 17 urethane-anesthetized adult Sprague-Dawley rats under controlled mechanical ventilation. Without PEEP, phrenic discharge was entrained 1:1 to the ventilator rhythm. Application of PEEP momentarily dampened the entrainment to higher ratios but this effect was gradually adapted by nonassociative learning. Bilateral electrolytic lesions of the pneumotaxic center weakened the adaptation to PEEP, whereas sustained stimulation of the pneumotaxic center weakened the entrainment independent of PEEP. In all cases, entrainment was abolished after vagotomy. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate an important functional role for pneumotaxic desensitization and extra-pontine habituation of the Hering-Breuer reflex elicited by lung inflation: acting as buffers or high-pass filters against tonic vagal volume input, these differentiator forms of nonassociative learning help to restore respiratory-ventilator entrainment in the face of PEEP. Such central sites-specific habituation and desensitization of the Hering-Breuer reflex provide a useful experimental model of nonassociative learning in mammals that is of particular significance in understanding respiratory rhythmogenesis and coupled-oscillator entrainment mechanisms, and in the clinical management of mechanical ventilation in

Data-driven classification of ventilated lung tissues using electrical impedance tomography

International Nuclear Information System (INIS)

Gómez-Laberge, Camille; Hogan, Matthew J; Elke, Gunnar; Weiler, Norbert; Frerichs, Inéz; Adler, Andy

2011-01-01

Current methods for identifying ventilated lung regions utilizing electrical impedance tomography images rely on dividing the image into arbitrary regions of interest (ROI), manually delineating ROI, or forming ROI with pixels whose signal properties surpass an arbitrary threshold. In this paper, we propose a novel application of a data-driven classification method to identify ventilated lung ROI based on forming k clusters from pixels with correlated signals. A standard first-order model for lung mechanics is then applied to determine which ROI correspond to ventilated lung tissue. We applied the method in an experimental study of 16 mechanically ventilated swine in the supine position, which underwent changes in positive end-expiratory pressure (PEEP) and fraction of inspired oxygen (F I O 2 ). In each stage of the experimental protocol, the method performed best with k = 4 and consistently identified 3 lung tissue ROI and 1 boundary tissue ROI in 15 of the 16 subjects. When testing for changes from baseline in lung position, tidal volume, and respiratory system compliance, we found that PEEP displaced the ventilated lung region dorsally by 2 cm, decreased tidal volume by 1.3%, and increased the respiratory system compliance time constant by 0.3 s. F I O 2 decreased tidal volume by 0.7%. All effects were tested at p < 0.05 with n = 16. These findings suggest that the proposed ROI detection method is robust and sensitive to ventilation dynamics in the experimental setting

Use of dynamic CT in acute respiratory distress syndrome (ARDS) with comparison of positive and negative pressure ventilation

Energy Technology Data Exchange (ETDEWEB)

Helm, Emma; Babyn, Paul [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Talakoub, Omid; Alirezaie, Javad [Ryerson University, Department of Electrical and Computer Engineering, Toronto, ON (Canada); Grasso, Francesco; Engelberts, Doreen; Kavanagh, Brian P. [Hospital for Sick Children and the University of Toronto, Departments of Anesthesia and Critical Care Medicine and the Program in Pulmonary and Experimental Medicine, Toronto (Canada)

2009-01-15

Negative pressure ventilation via an external device ('iron lung') has the potential to provide better oxygenation with reduced barotrauma in patients with ARDS. This study was designed to see if oxygenation differences between positive and negative ventilation could be explained by CT. Six anaesthetized rabbits had ARDS induced by repeated saline lavage. Rabbits were ventilated with positive pressure ventilation (PPV) and negative pressure ventilation (NPV) in turn. Dynamic CT images were acquired over the respiratory cycle. A computer-aided method was used to segment the lung and calculate the range of CT densities within each slice. Volumes of ventilated lung and atelectatic lung were measured over the respiratory cycle. NPV was associated with an increased percentage of ventilated lung and decreased percentage of atelectatic lung. The most significant differences in ventilation and atelectasis were seen at mid-inspiration and mid-expiration (ventilated lung NPV=61%, ventilated lung PPV=47%, p<0.001; atelectatic lung NPV=10%, atelectatic lung PPV 19%, p<0.001). Aeration differences were not significant at end-inspiration. Dynamic CT can show differences in lung aeration between positive and negative ventilation in ARDS. These differences would not be appreciated if only static breath-hold CT was used. (orig.)

Potential risk for bacterial contamination in conventional reused ventilator systems and disposable closed ventilator-suction systems.

Science.gov (United States)

Li, Ya-Chi; Lin, Hui-Ling; Liao, Fang-Chun; Wang, Sing-Siang; Chang, Hsiu-Chu; Hsu, Hung-Fu; Chen, Sue-Hsien; Wan, Gwo-Hwa

2018-01-01

Few studies have investigated the difference in bacterial contamination between conventional reused ventilator systems and disposable closed ventilator-suction systems. The aim of this study was to investigate the bacterial contamination rates of the reused and disposable ventilator systems, and the association between system disconnection and bacterial contamination of ventilator systems. The enrolled intubated and mechanically ventilated patients used a conventional reused ventilator system and a disposable closed ventilator-suction system, respectively, for a week; specimens were then collected from the ventilator circuit systems to evaluate human and environmental bacterial contamination. The sputum specimens from patients were also analyzed in this study. The detection rate of bacteria in the conventional reused ventilator system was substantially higher than that in the disposable ventilator system. The inspiratory and expiratory limbs of the disposable closed ventilator-suction system had higher bacterial concentrations than the conventional reused ventilator system. The bacterial concentration in the heated humidifier of the reused ventilator system was significantly higher than that in the disposable ventilator system. Positive associations existed among the bacterial concentrations at different locations in the reused and disposable ventilator systems, respectively. The predominant bacteria identified in the reused and disposable ventilator systems included Acinetobacter spp., Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan) maltophilia. Both the reused and disposable ventilator systems had high bacterial contamination rates after one week of use. Disconnection of the ventilator systems should be avoided during system operation to decrease the risks of environmental pollution and human exposure, especially for the disposable ventilator system. ClinicalTrials.gov PRS / NCT03359148.

Effect of driving pressure on mortality in ARDS patients during lung protective mechanical ventilation in two randomized controlled trials.

Science.gov (United States)

Guérin, Claude; Papazian, Laurent; Reignier, Jean; Ayzac, Louis; Loundou, Anderson; Forel, Jean-Marie

2016-11-29

Driving pressure (ΔPrs) across the respiratory system is suggested as the strongest predictor of hospital mortality in patients with acute respiratory distress syndrome (ARDS). We wonder whether this result is related to the range of tidal volume (V T ). Therefore, we investigated ΔPrs in two trials in which strict lung-protective mechanical ventilation was applied in ARDS. Our working hypothesis was that ΔPrs is a risk factor for mortality just like compliance (Crs) or plateau pressure (Pplat,rs) of the respiratory system. We performed secondary analysis of data from 787 ARDS patients enrolled in two independent randomized controlled trials evaluating distinct adjunctive techniques while they were ventilated as in the low V T arm of the ARDSnet trial. For this study, we used V T , positive end-expiratory pressure (PEEP), Pplat,rs, Crs, ΔPrs, and respiratory rate recorded 24 hours after randomization, and compared them between survivors and nonsurvivors at day 90. Patients were followed for 90 days after inclusion. Cox proportional hazard modeling was used for mortality at day 90. If colinearity between ΔPrs, Crs, and Pplat,rs was verified, specific Cox models were used for each of them. Both trials enrolled 805 patients of whom 787 had day-1 data available, and 533 of these survived. In the univariate analysis, ΔPrs averaged 13.7 ± 3.7 and 12.8 ± 3.7 cmH 2 O (P = 0.002) in nonsurvivors and survivors, respectively. Colinearity between ΔPrs, Crs and Pplat,rs, which was expected as these variables are mathematically coupled, was statistically significant. Hazard ratios from the Cox models for day-90 mortality were 1.05 (1.02-1.08) (P = 0.005), 1.05 (1.01-1.08) (P = 0.008) and 0.985 (0.972-0.985) (P = 0.029) for ΔPrs, Pplat,rs and Crs, respectively. PEEP and V T were not associated with death in any model. When ventilating patients with low V T , ΔPrs is a risk factor for death in ARDS patients, as is Pplat,rs or Crs. As our data

Control study of pulmonary surfactant combined with CPAP and BIPAP ventilation modes respectively in treatment of neonatal NRDS

Directory of Open Access Journals (Sweden)

Yao Liu

2016-04-01

Full Text Available Objective: To analyze the differences in effect of pulmonary surfactant combined with CPAP and BIPAP ventilation modes respectively in treatment of neonatal NRDS. Methods: A total of 50 cases of children with neonatal respiratory distress syndrome (NRDS born and receiving treatment in our hospital from August 2012 to January 2015 were selected as research subjects and randomly divided into observation group and control group, each with 25 cases. Control group received pulmonary surfactant combined with CPAP ventilation mode treatment, observation group received pulmonary surfactant combined with BIPAP ventilation mode treatment, and then differences in blood gas indicators and mechanical ventilation parameters, pulmonary artery pressure, endothelin and nitric oxide levels, blood coagulation and anticoagulation indicators and protein expression levels of CD24, TNF-α, IL-6 and IL-17A of two groups after treatment were compared. Results: PaO2, PH value and oxygenation index of observation group after treatment were higher than those of control group, and PaCO2, positive end-expiratory pressure, peak inspiratory pressure and inspired oxygen concentration were lower than those of control group; pulmonary artery pressure and EF-1 level of observation group after treatment were lower than those of control group, and NO level was higher than that of control group; PC, TPS and AT-Ⅲ levels of observation group after treatment were higher than those of control group, and D-D and vWF levels were lower than those of control group; protein expression of CD24 and IL-6 of observation group after treatment were lower than those of control group, and protein expression of TNF-α and IL-17A were higher than those of control group. Conclusion: Pulmonary surfactant combined with BIPAP ventilation mode treatment of children with NRDS can effectively optimize ventilation function and realize homeostasis, and it has active clinical significance.

In-vitro characterisation of the nebulised dose during non-invasive ventilation.

Science.gov (United States)

Abdelrahim, Mohamed E; Plant, Paul; Chrystyn, Henry

2010-08-01

Non-invasive ventilation (NIV) with nebulised bronchodilators helps some patients to maintain effective ventilation. However, the position of the nebuliser in the ventilation circuit may affect lung delivery. We placed the nebuliser proximal (A) and distal (B) to a breathing simulator in a standard NIV circuit with inspiratory (I) and expiratory (E) pressures of 20 and 5 cm H(2)O, 1 : 3 I : E ratio, 15 breaths/min and a tidal volume of 500 ml. Five milligrams of terbutaline solution was nebulised using an Aeroneb Pro (AERO) and a Sidestream (SIDE) nebuliser. The fate of the nebulised dose was determined and the aerodynamic droplet characteristics were measured using a cooled Next Generation Impactor. More terbutaline was entrained on the inhalation filter in position A than in position B (P AEROB, SIDEA and SIDEB were 1.31 (0.2), 1.13 (0.14), 0.56 (0.03) and 0.39 (0.13) mg. These amounts from AEROA were significantly greater (P < 0.001) than those of the other three methods. The results highlight the differences between nebulisers and the influence on the placement of the nebuliser in the NIV circuit.

Evaluation of a computerized system for mechanical ventilation of infants.

Science.gov (United States)

Tehrani, Fleur T; Abbasi, Soraya

2009-04-01

To evaluate a computerized system for mechanical ventilation of infants. FLEX is a computerized system that includes the features of a patented mode known as adaptive-support ventilation (ASV). In addition, it has many other features including adjustment of positive end-expiratory pressure (PEEP), fraction of inspired oxygen (F(IO2)), minute ventilation, and control of weaning. It is used as an open-loop decision support system or as a closed-loop technique. Blood gas and ventilation data were collected from 12 infants in the neonatal intensive care at baseline and at the next round of evaluation. This data were input to open-loop version of FLEX. The system recommendations were compared to clinical determinations. FLEX recommended values for ventilation were on the average within 25% and 16.5% of the measured values at baseline and at the next round of evaluation, respectively. For F(IO2) and PEEP, FLEX recommended values were in general agreement with the clinical settings. FLEX recommendations for weaning were the same as the clinical determinations 50% of the time at baseline and 55% of the time at the next round of evaluation. FLEX did not recommend weaning for infants with weak spontaneous breathing effort or those who showed signs of dyspnea. A computerized system for mechanical ventilation is evaluated for treatment of infants. The results of the study show that the system has good potential for use in neonatal ventilatory care. Further refinements can be made in the system for very low-birth-weight infants.

Impact of ventilation/pressurization on indoor air contaminants in schools

International Nuclear Information System (INIS)

Shaughnessy, R.J.; Levetin, E.; Fisher, E.J.; Ligman, B.K.

1993-01-01

As part of a continuing technology development effort to control radon in schools, The U.S. Environmental Protection Agency's (EPA) School Evaluation Program (SEP) team in cooperation with U.S. EPA's Region 6 office has performed radon mitigation in two Southwestern United States schools utilizing the method of ventilation/pressurization control technology. Schools were inspected and IAQ measurements made with respect to carbon dioxide, bioaerosols, volatile organic compounds, and respirable particles. Premitigation results indicated poor ventilation conditions existed throughout the school buildings. Elevated levels of respirable particles were measured, yet no conclusions with respect to health could be implied. Post-mitigation results support, but do not prove the hypothesis that improved ventilation to control radon will also reduce other indicator indoor air contaminants. (orig.). (9 refs., 4 tabs.)

Respiratory training during rehabilitation of acute organic fluorine-poisoned patients treated by non-invasive positive pressure ventilation.

Science.gov (United States)

Liu, L; Liu, D Z; Wang, Q P; Zhu, Z L; Li, H M; Lu, X Y

2017-01-01

This paper aimed to analyze the effects of respiratory training on pulmonary function during the rehabilitation period for acute organic fluorine-poisoned patients treated by non-invasive positive pressure ventilation (NIPPV). Sixty-two acute organic fluorine-poisoned patients admitted to the Xinxiang Central Hospital, Xinxiang City, China, from May 2012 to March 2016 were selected and randomly divided into an observation group and a control group, with 31 cases in each. Both groups received NIPPV. The patients in the control group exercised daily, while the patients in the observation group received contracting lips-abdominal breathing training. The therapeutic effects, pulmonary ventilation function, serum levels of α-antitrypsin1 (α-AT1), surfactant protein D (SP-D), neutrophil elastase (NE), transforming growth factor beta 1 (TGF-β1), and quality of life were analyzed and compared between the two groups both before and after the administration of treatment. The total effective rate of the observation group was 93.55%, which was significantly higher when compared with the control group (74.19%) (P less than 0.05). The levels of forced expiratory volume in one second (FEV1), FEV1/FVC ratio, vital capacity (VC), carbon monoxide diffusion capacity (DLco), and maximal voluntary ventilation (MVV) of the observation group were better when compared with the control group and had statistical significance (P less than 0.05). Before treatment, the serum levels of α-AT1, SP-D, NE, and TGF-β1, and quality of life had no statistical significance in either group (P>0.05); after treatment, these indexes and the quality of life for the observation group were significantly higher when compared with the control group, with statistical significance (P less than 0.05). The respiratory training in acute organic fluorine-poisoned patients treated by NIPPV can improve the serum indexes, dilute toxicity, and recover pulmonary function, which play key roles in improving the

A novel fiber-optic measurement system for the evaluation of performances of neonatal pulmonary ventilators

International Nuclear Information System (INIS)

Battista, L; Scorza, A; Botta, F; Sciuto, S A

2016-01-01

Published standards for the performance evaluation of pulmonary ventilators are mainly directed to manufacturers rather than to end-users and often considered inadequate or not comprehensive. In order to contribute to overcome the problems above, a novel measurement system was proposed and tested with waveforms of mechanical ventilation by means of experimental trials carried out with infant ventilators typically used in neonatal intensive care units: the main quantities of mechanical ventilation in newborns are monitored, i.e. air flow rate, differential pressure and volume from infant ventilator are measured by means of two novel fiber-optic sensors (OFSs) developed and characterized by the authors, while temperature and relative humidity of air mass are obtained by two commercial transducers. The proposed fiber-optic sensors (flow sensor Q-OFS, pressure sensor P-OFS) showed measurement ranges of air flow and pressure typically encountered in neonatal mechanical ventilation, i.e. the air flow rate Q ranged from 3 l min −1 to 18 l min −1 (inspiratory) and from  −3 l min −1 to  −18 l min −1 (expiratory), the differential pressure ΔP ranged from  −15 cmH 2 O to 15 cmH2O. In each experimental trial carried out with different settings of the ventilator, outputs of the OFSs are compared with data from two reference sensors (reference flow sensor RF, reference pressure sensor RP) and results are found consistent: flow rate Q showed a maximum error between Q-OFS and RF up to 13 percent, with an output ratio Q RF /Q OFS of not more than 1.06  ±  0.09 (least square estimation, 95 percent confidence level, R 2 between 0.9822 and 0.9931). On the other hand the maximum error between P-OFS and RP on differential pressure ΔP was lower than 10 percent, with an output ratio ΔP RP /ΔP OFS between 0.977  ±  0.022 and 1.0  ±  0.8 (least square estimation, 95 percent confidence level, R 2 between 0.9864 and 0.9876). Despite the

A novel fiber-optic measurement system for the evaluation of performances of neonatal pulmonary ventilators

Science.gov (United States)

Battista, L.; Scorza, A.; Botta, F.; Sciuto, S. A.

2016-02-01

Published standards for the performance evaluation of pulmonary ventilators are mainly directed to manufacturers rather than to end-users and often considered inadequate or not comprehensive. In order to contribute to overcome the problems above, a novel measurement system was proposed and tested with waveforms of mechanical ventilation by means of experimental trials carried out with infant ventilators typically used in neonatal intensive care units: the main quantities of mechanical ventilation in newborns are monitored, i.e. air flow rate, differential pressure and volume from infant ventilator are measured by means of two novel fiber-optic sensors (OFSs) developed and characterized by the authors, while temperature and relative humidity of air mass are obtained by two commercial transducers. The proposed fiber-optic sensors (flow sensor Q-OFS, pressure sensor P-OFS) showed measurement ranges of air flow and pressure typically encountered in neonatal mechanical ventilation, i.e. the air flow rate Q ranged from 3 l min-1 to 18 l min-1 (inspiratory) and from  -3 l min-1 to  -18 l min-1 (expiratory), the differential pressure ΔP ranged from  -15 cmH2O to 15 cmH2O. In each experimental trial carried out with different settings of the ventilator, outputs of the OFSs are compared with data from two reference sensors (reference flow sensor RF, reference pressure sensor RP) and results are found consistent: flow rate Q showed a maximum error between Q-OFS and RF up to 13 percent, with an output ratio Q RF/Q OFS of not more than 1.06  ±  0.09 (least square estimation, 95 percent confidence level, R 2 between 0.9822 and 0.9931). On the other hand the maximum error between P-OFS and RP on differential pressure ΔP was lower than 10 percent, with an output ratio ΔP RP/ΔP OFS between 0.977  ±  0.022 and 1.0  ±  0.8 (least square estimation, 95 percent confidence level, R 2 between 0.9864 and 0.9876). Despite the possible improvements

Neurally Adjusted Ventilatory Assist After Pediatric Cardiac Surgery: Clinical Experience and Impact on Ventilation Pressures.

Science.gov (United States)

Crulli, Benjamin; Khebir, Mariam; Toledano, Baruch; Vobecky, Suzanne; Poirier, Nancy; Emeriaud, Guillaume

2018-02-01

After pediatric cardiac surgery, ventilation with high airway pressures can be detrimental to right ventricular function and pulmonary blood flow. Neurally adjusted ventilatory assist (NAVA) improves patient-ventilator interactions, helping maintain spontaneous ventilation. This study reports our experience with the use of NAVA in children after a cardiac surgery. We hypothesize that using NAVA in this population is feasible and allows for lower ventilation pressures. We retrospectively studied all children ventilated with NAVA (invasively or noninvasively) after undergoing cardiac surgery between January 2013 and May 2015 in our pediatric intensive care unit. The number and duration of NAVA episodes were described. For the first period of invasive NAVA in each subject, detailed clinical and ventilator data in the 4 h before and after the start of NAVA were extracted. 33 postoperative courses were included in 28 subjects with a median age of 3 [interquartile range (IQR) 1-12] months. NAVA was used invasively in 27 courses for a total duration of 87 (IQR 15-334) h per course. Peak inspiratory pressures and mean airway pressures decreased significantly after the start of NAVA (mean differences of 5.8 cm H 2 O (95% CI 4.1-7.5) and 2.0 cm H 2 O (95% CI 1.2-2.8), respectively, P < .001 for both). There was no significant difference in vital signs or blood gas values. NAVA was used noninvasively in 14 subjects, over 79 (IQR 25-137) h. NAVA could be used in pediatric subjects after cardiac surgery. The significant decrease in airway pressures observed after transition to NAVA could have a beneficial impact in this specific population, which should be investigated in future interventional studies. Copyright © 2018 by Daedalus Enterprises.

Continuous monitoring of natural ventilation pressure at the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Loomis, I.M.; Wallace, K.G.

1993-01-01

The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy research and development facility designed to demonstrate the permanent, safe disposal of US defense-generated transuranic waste. The waste storage horizon is 655 m (2150 ft) below surface in bedded salt. To date the WIPP project has not emplaced any waste. There are three intake shafts used to supply air to the underground. All air is exhausted through a single return shaft. The total design airflow during normal operations is 200 m 3 /s (424,000 cfm). The ventilation system is designed to provide separate air splits to construction, experimental, and storage activities. Separation is achieved by isolating the storage circuit from the construction or experimental circuits with bulkheads. Any air leakage must be towards the storage area of the facility. Field studies have shown that the pressure differential necessary to maintain the correct leakage direction is susceptible to the effects of natural ventilation; therefore, extensive studies and analyses have been conducted to quantify the natural ventilation effects on the WIPP underground airflow system. A component of this work is a monitoring system designed to measure the air properties necessary for calculation of the natural ventilation pressure (NVP). This monitoring system consists of measuring dry bulb temperature, relative humidity, and barometric pressure at strategic location on surface and underground. The psychometric parameters of the air are measured every fifteen minutes. From these data, trends can be determined showing the impact of NVP on the ventilation system during diurnal variations in surface climate. Both summer and winter conditions have been studied. To the author's knowledge this is the first reported instance of automatic and continuous production of time and temperature variant NVPs. This paper describes the results of the initial monitoring study

Pressure support ventilation vs Continuous positive airway pressure for treating of acute cardiogenic pulmonary edema: A pilot study.

Science.gov (United States)

Pagano, Antonio; Numis, Fabio G; Rosato, Valerio; Russo, Teresa; Porta, Giovanni; Bosso, Giorgio; Serra, Claudia; Masarone, Mario; Visone, Giuseppe; Paladino, Fiorella

2018-04-24

Non-invasive ventilation is usually adopted as a support to medical therapy in patients with acute pulmonary edema, but which modality between Pressure Support Ventilation (PSV) and Continuous Positive Airway Pressure (CPAP) has better favourable effects is not been yet well known. Aim of this observational study was to provide data on these different non-invasive ventilation modalities in the management of acute cardiogenic pulmonary edema. One-hundred-fifty-three patients consecutively admitted to the Emergency Room of two different Center were enrolled and randomly assigned to CPAP or PSV. Data relative to mortality, need of endotracheal intubation, sequential blood gas analysis were compared. Furthermore, there were no significant differences regarding mortality in the two groups, but patients treated with PSV had a significant lower rate of endotracheal intubation and a higher improvement of blood gas analyses parameters. In conclusion, our data support only a slight advantage in favour to PSV versus CPAP. Copyright © 2018 Elsevier B.V. All rights reserved.

Early predictors of success of non-invasive positive pressure ventilation in hypercapnic respiratory failure.

Science.gov (United States)

Bhattacharyya, D; Prasad, Bnbm; Tampi, P S; Ramprasad, R

2011-10-01

Non-invasive positive pressure ventilation (NIPPV) has emerged as a significant advancement in the management of acute hypercapnic respiratory failure. Patients with hypercapnic respiratory failure requiring ventilation therapy (respiratory rate [RR] of > 30 breaths per minutes, PaCO2 > 55 mmHg and arterial pH success group and these parameters continued to improve even after four and 24 hours of NIPPV treatment. Out of 24 (24%) patients who failed to respond, 13 (54%) needed endotracheal intubation within one hour. The failure group had higher baseline HR than the success group. Improvement in HR, RR, pH, and PCO2 one hour after putting the patient on NIPPV predicts success of non-invasive positive pressure ventilation in hypercapnic respiratory failure.

The Conceptual Design of High Pressure Reversible Axial Tunnel Ventilation Fans

Directory of Open Access Journals (Sweden)

A. G. Sheard

2012-01-01

Full Text Available Tunnel ventilation fans, classically, must have the ability to both supply and extract air from a tunnel system, with the operator's choice dependent on the tunnel ventilation system's operating mode most appropriate at any given point in time. Consequently, tunnel ventilation fans must incorporate a reversible aerodynamic design which limits the maximum fan pressure rise. This paper presents three high pressure reversible fan concepts. These comprise a two-stage counter rotating fan, a single-stage high speed fan, and a two-stage fan with a single motor and impeller on each end of the motor shaft. The authors consider the relative merits of each concept. The third concept offers the most compact fan, transform, silencer, and damper package size. The authors discuss the mechanical design challenges that occur with a two-stage fan with a single motor and impeller on each end of the motor shaft. They present and consider a selected motor bearing arrangement and casing design for maintainability. Finally, the authors present both prototype fan and full-scale package aerodynamic and acoustic performance, before discussing the challenges presented by high temperature certification in accordance with the requirements of EN 12101-3: 2012.

Flexible bronchoscopy and mechanical ventilation in managing Mounier-Kuhn syndrome: a case report

Directory of Open Access Journals (Sweden)

Aslihan Gürün Kaya

2017-04-01

Full Text Available ABSTRACT CONTEXT: Mounier-Kuhn syndrome is a rare congenital condition with distinct dilatation and diverticulation of the tracheal wall. The symptoms may vary and the treatment usually consists of support. CASE REPORT: The patient was a 60-year-old male with recurrent hospital admission. He was admitted in this case due to dyspnea, cough and sputum production. An arterial blood sample revealed decompensated respiratory acidosis with moderate hypoxemia. A chest computed tomography (CT scan showed dilatation of the trachea and bronchi, tracheal diverticula and bronchiectasis. Flexible bronchoscopy was performed, which revealed enlarged airways with expiratory collapse. Furthermore, orifices of tracheal diverticulosis were also detected. Non-invasive positive pressure ventilation (NPPV was added, along with long-term oxygen therapy. At control visits, the patient’s clinical and laboratory findings were found to have improved. CONCLUSION: Flexible bronchoscopy can be advocated for establishing the diagnosis and non-invasive mechanical ventilation can be used with a high success rate, for clinical wellbeing in Mounier-Kuhn syndrome.

Reducing pressure ulcers in patients with prolonged acute mechanical ventilation: a quasi-experimental study.

Science.gov (United States)

Loudet, Cecilia Inés; Marchena, María Cecilia; Maradeo, María Roxana; Fernández, Silvia Laura; Romero, María Victoria; Valenzuela, Graciela Esther; Herrera, Isabel Eustaquia; Ramírez, Martha Teresa; Palomino, Silvia Rojas; Teberobsky, Mariana Virginia; Tumino, Leandro Ismael; González, Ana Laura; Reina, Rosa; Estenssoro, Elisa

2017-01-01

To determine the effectiveness of a quality management program in reducing the incidence and severity of pressure ulcers in critical care patients. This was a quasi-experimental, before-and-after study that was conducted in a medical-surgical intensive care unit. Consecutive patients who had received mechanical ventilation for ≥ 96 hours were included. A "Process Improvement" team designed a multifaceted interventional process that consisted of an educational session, a pressure ulcer checklist, a smartphone application for lesion monitoring and decision-making, and a "family prevention bundle". Fifty-five patients were included in Pre-I group, and 69 were included in the Post-I group, and the incidence of pressure ulcers in these groups was 41 (75%) and 37 (54%), respectively. The median time for pressure ulcers to develop was 4.5 [4 - 5] days in the Pre-I group and 9 [6 - 20] days in the Post-I group after admission for each period. The incidence of advanced-grade pressure ulcers was 27 (49%) in the Pre-I group and 7 (10%) in the Post-I group, and finally, the presence of pressure ulcers at discharge was 38 (69%) and 18 (26%), respectively (p pressure ulcers. The duration of mechanical ventilation and the presence of organ failure were positively associated with the development of pressure ulcers, while the multifaceted intervention program acted as a protective factor. A quality program based on both a smartphone application and family participation can reduce the incidence and severity of pressure ulcers in patients on prolonged acute mechanical ventilation.

Changes in Cross-Sectional Area and Transverse Diameter of the Heart on Inspiratory and Expiratory Chest CT: Correlation with Changes in Lung Size and Influence on Cardiothoracic Ratio Measurement.

Directory of Open Access Journals (Sweden)

Hayato Tomita

Full Text Available The aim of this study was to investigate physiological changes in cardiac area and diameters between inspiratory and expiratory chest computed tomography (CT, and to assess their correlation with lung size change and influence on cardiothoracic ratio (CTR measurements.The institutional review board of our institution approved this study, and informed consent was waived. Forty-three subjects underwent inspiratory and expiratory chest CT as part of routine clinical care. On both inspiratory and expiratory scans, lung volumes and maximum lung diameters (transverse and vertical directions were measured. The maximum cardiac cross-sectional area (CSA and the maximum transverse cardiac diameter were measured on both scans, and the CT-based CTR was calculated. Changes in the lung and cardiac measurements were expressed as the expiratory/inspiratory (E/I ratios. Comparisons between inspiratory and expiratory measurements were made by the Wilcoxon signed-rank test. Correlations between the E/I ratios of lung and heart measurements were evaluated by Spearman's rank correlation analysis.Cardiac CSA and transverse cardiac diameter was significantly larger on expiratory than on inspiratory CT (p < 0.0001. Significant negative correlations were found between the E/I ratios of these cardiac measurements and the E/I ratios of lung volume and vertical lung diameter (p < 0.01. CT-based CTR was significantly larger on expiration than on inspiration (p < 0.0001.Heart size on chest CT depends on the phase of ventilation, and is correlated with changes in lung volume and craniocaudal lung diameter. The CTR is also significantly influenced by ventilation.

Effect of dynamic random leaks on the monitoring accuracy of home mechanical ventilators: a bench study.

Science.gov (United States)

Sogo, Ana; Montanyà, Jaume; Monsó, Eduard; Blanch, Lluís; Pomares, Xavier; Lujàn, Manel

2013-12-10

So far, the accuracy of tidal volume (VT) and leak measures provided by the built-in software of commercial home ventilators has only been tested using bench linear models with fixed calibrated and continuous leaks. The objective was to assess the reliability of the estimation of tidal volume (VT) and unintentional leaks in a single tubing bench model which introduces random dynamic leaks during inspiratory or expiratory phases. The built-in software of four commercial home ventilators and a fifth ventilator-independent ad hoc designed external software tool were tested with two levels of leaks and two different models with excess leaks (inspiration or expiration). The external software analyzed separately the inspiratory and expiratory unintentional leaks. In basal condition, all ventilators but one underestimated tidal volume with values ranging between -1.5 ± 3.3% to -8.7% ± 3.27%. In the model with excess of inspiratory leaks, VT was overestimated by all four commercial software tools, with values ranging from 18.27 ± 7.05% to 35.92 ± 17.7%, whereas the ventilator independent-software gave a smaller difference (3.03 ± 2.6%). Leaks were underestimated by two applications with values of -11.47 ± 6.32 and -5.9 ± 0.52 L/min. With expiratory leaks, VT was overestimated by the software of one ventilator and the ventilator-independent software and significantly underestimated by the other three, with deviations ranging from +10.94 ± 7.1 to -48 ± 23.08%. The four commercial tools tested overestimated unintentional leaks, with values between 2.19 ± 0.85 to 3.08 ± 0.43 L/min. In a bench model, the presence of unintentional random leaks may be a source of error in the measurement of VT and leaks provided by the software of home ventilators. Analyzing leaks during inspiration and expiration separately may reduce this source of error.

Mechanical ventilation strategies for intensive care unit patients without acute lung injury or acute respiratory distress syndrome: a systematic review and network meta-analysis.

Science.gov (United States)

Guo, Lei; Wang, Weiwei; Zhao, Nana; Guo, Libo; Chi, Chunjie; Hou, Wei; Wu, Anqi; Tong, Hongshuang; Wang, Yue; Wang, Changsong; Li, Enyou

2016-07-22

It has been shown that the application of a lung-protective mechanical ventilation strategy can improve the prognosis of patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). However, the optimal mechanical ventilation strategy for intensive care unit (ICU) patients without ALI or ARDS is uncertain. Therefore, we performed a network meta-analysis to identify the optimal mechanical ventilation strategy for these patients. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, EMBASE, MEDLINE, CINAHL, and Web of Science for studies published up to July 2015 in which pulmonary compliance or the partial pressure of arterial oxygen/fraction of inspired oxygen (PaO2/FIO2) ratio was assessed in ICU patients without ALI or ARDS, who received mechanical ventilation via different strategies. The data for study characteristics, methods, and outcomes were extracted. We assessed the studies for eligibility, extracted the data, pooled the data, and used a Bayesian fixed-effects model to combine direct comparisons with indirect evidence. Seventeen randomized controlled trials including a total of 575 patients who received one of six ventilation strategies were included for network meta-analysis. Among ICU patients without ALI or ARDS, strategy C (lower tidal volume (VT) + higher positive end-expiratory pressure (PEEP)) resulted in the highest PaO2/FIO2 ratio; strategy B (higher VT + lower PEEP) was associated with the highest pulmonary compliance; strategy A (lower VT + lower PEEP) was associated with a shorter length of ICU stay; and strategy D (lower VT + zero end-expiratory pressure (ZEEP)) was associated with the lowest PaO2/FiO2 ratio and pulmonary compliance. For ICU patients without ALI or ARDS, strategy C (lower VT + higher PEEP) was associated with the highest PaO2/FiO2 ratio. Strategy B (higher VT + lower PEEP) was superior to the other strategies in improving pulmonary

Mechanics of lung ventilation in a large aquatic salamander, siren lacertina

Science.gov (United States)

Brainerd; j

1998-06-01

Lung ventilation in Siren lacertina was studied using X-ray video, measurements of body cavity pressure and electromyography of hypaxial muscles. S. lacertina utilizes a two-stroke buccal pump in which mixing of expired and inspired gas is minimized by partial expansion of the buccal cavity during exhalation and then full expansion after exhalation is complete. Mixing is further reduced by the use of one or two accessory inspirations after the first, mixed-gas cycle. Exhalation occurs in two phases: a passive phase in which hydrostatic pressure and possibly lung elasticity force air out of the lungs, and an active phase in which contraction of the transverse abdominis (TA) muscle increases body cavity pressure and forces most of the remaining air out. In electromyograms of the lateral hypaxial musculature, the TA became active 200-400 ms before the rise in body cavity pressure, and activity ceased at peak pressure. The TA was not active during inspiration, and no consistent activity during breathing was noted in the external oblique, internal oblique and rectus abdominis muscles. The finding that the TA is the primary expiratory muscle in S. lacertina agrees with findings in a previous study of another salamander, Necturus maculosus. Together, these results indicate that the use of the TA for exhalation is a primitive character for salamanders and support the hypothesis that the breathing mechanism of salamanders represents an intermediate step in evolution between a buccal pump, in which only head muscles are used for ventilation, and an aspiration pump, in which axial muscles are used for both exhalation and inhalation.

Limiting volume with modern ventilators.

Science.gov (United States)

Wing, Thomas J; Haan, Lutana; Ashworth, Lonny J; Anderson, Jeff

2015-06-01

The acute respiratory distress syndrome (ARDS) network low tidal-volume study comparing tidal volumes of 12 ml/kg versus 6 ml/kg was published in 2000. The study was stopped early as data revealed a 22% relative reduction in mortality rate when using 6 ml/kg tidal volume. The current generation of critical care ventilators allows the tidal volume to be set during volume-targeted, assist/control (volume A/C); however, some ventilators include options that may prevent the tidal volume from being controlled. The purpose of this bench study was to evaluate the delivered tidal volume, when these options are active, in a spontaneously breathing lung model using an electronic breathing simulator. Four ventilators were evaluated: CareFusion AVEA (AVEA), Dräger Evita® XL (Evita XL), Covidien Puritan Bennett® 840(TM) (PB 840), and Maquet SERVO-i (SERVO-i). Each ventilator was connected to the Hans Rudolph Electronic Breathing Simulator at an amplitude of 0 cm H2O and then 10 cm H2O. All four ventilators were set to deliver volume A/C, tidal volume 400 ml, respiratory rate 20 bpm, positive end-expiratory pressure 5 cm H2O, peak flowrate 60 L/min. The displayed tidal volume was recorded for each ventilator at the above settings with additional options OFF and then ON. The AVEA has two options in volume A/C: demand breaths and V-sync. When activated, these options allow the patient to exceed the set tidal volume. When using the Evita XL, the option AutoFlow can be turned ON or OFF, and when this option is ON, the tidal volume may vary. The PB 840 does not have any additional options that affect volume delivery, and it maintains the set tidal volume regardless of patient effort. The SERVO-i's demand valve allows additional flow if the patient's inspiratory flowrate exceeds the set flowrate, increasing the delivered tidal volume; this option can be turned OFF with the latest software upgrade. Modern ventilators have an increasing number of optional settings. These settings may

Is increased positive end-expiratory pressure the culprit? Autoresuscitation in a 44-year-old man after prolonged cardiopulmonary resuscitation: a case report

OpenAIRE

Hagmann, Henning; Oelmann, Katrin; Stangl, Robert; Michels, Guido

2016-01-01

Background The phenomenon of autoresuscitation is rare, yet it is known to most emergency physicians. However, the pathophysiology of the delayed return of spontaneous circulation remains enigmatic. Among other causes hyperinflation of the lungs and excessively high positive end-expiratory pressure have been suggested, but reports including cardiopulmonary monitoring during cardiopulmonary resuscitation are scarce to support this hypothesis. Case presentation We report a case of autoresuscita...

Noninvasive positive pressure ventilation in acute asthmatic attack

Directory of Open Access Journals (Sweden)

A. Soroksky

2010-03-01

Full Text Available Asthma is characterised by reversible airway obstruction. In most patients, control of disease activity is easily achieved. However, in a small minority, asthma may be fatal. Between the two extremes lie patients with severe asthmatic attacks, refractory to standard treatment. These patients are at an increased risk of recurrent severe attacks, with respiratory failure, and mechanical ventilation. Invasive mechanical ventilation of the asthmatic patient is associated with a higher risk of complications and, therefore, is a measure of last resort. Noninvasive positive pressure ventilation (NPPV is another treatment modality that may be beneficial in patients with severe asthmatic attack who are at an increased risk of developing respiratory failure. These patients have the potential to benefit from early respiratory support in the form of NPPV. However, reports of NPPV in asthmatic patients are scarce, and its usage in asthmatic attacks is, therefore, still controversial. Only a few reports of NPPV in asthma have been published over the last decade. These studies mostly involve small numbers of patients and those who have problematic methodology. In this article we review the available evidence for NPPV in asthma and try to formulate our recommendations for NPPV application in asthma based on the available evidence and reports.

High positive end-expiratory pressure levels promote bacterial translocation in experimental pneumonia

NARCIS (Netherlands)

Lachmann, Robert A.; van Kaam, Anton H.; Haitsma, Jack J.; Lachmann, Burkhard

2007-01-01

A previous study in piglets with experimental pneumonia showed that reducing atelectasis by means of open lung ventilation attenuated bacterial translocation compared to conventional ventilation settings. This study examined the effect of open lung ventilation with higher than necessary positive

Anaesthesia ventilators

Directory of Open Access Journals (Sweden)

Rajnish K Jain

2013-01-01

Full Text Available Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV. PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

Anaesthesia ventilators.

Science.gov (United States)

Jain, Rajnish K; Swaminathan, Srinivasan

2013-09-01

Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

Anaesthesia ventilators

Science.gov (United States)

Jain, Rajnish K; Swaminathan, Srinivasan

2013-01-01

Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits. PMID:24249886

Effects of a preemptive alveolar recruitment strategy on arterial oxygenation during one-lung ventilation with different tidal volumes in patients with normal pulmonary function test.

Science.gov (United States)

Jung, Jong Dal; Kim, Sang Hun; Yu, Byung Sik; Kim, Hye Ji

2014-08-01

Hypoxemia during one-lung ventilation (OLV) remains a major concern. The present study compared the effect of alveolar recruitment strategy (ARS) on arterial oxygenation during OLV at varying tidal volumes (Vt) with or without positive end-expiratory pressure (PEEP). In total, 120 patients undergoing wedge resection by video assisted thoracostomy were randomized into four groups comprising 30 patients each: those administered a 10 ml/kg tidal volume with or without preemptive ARS (Group H and Group H-ARS, respectively) and those administered a 6 ml/kg tidal volume and a 8 cmH2O PEEP with or without preemptive ARS (Group L and Group L-ARS, respectively). ARS was performed using pressure-controlled ventilation with a 40 cmH2O plateau airway pressure and a 15 cmH2O PEEP for at least 10 breaths until OLV began. Preemptive ARS significantly improved the PaO2/FiO2 ratio compared to the groups that did not receive ARS (P volume combined with 8 cmH2O PEEP after preemptive ARS may reduce the risk of pulmonary injury caused by high tidal volume during one-lung ventilation in patients with normal pulmonary function.

Safety and effectiveness of the high-frequency chest wall oscillation vs intrapulmonary percussive ventilation in patients with severe COPD

Directory of Open Access Journals (Sweden)

Nicolini A

2018-02-01

pressure, maximal expiratory pressure and arterial blood gas values. However, in the group comparison analysis for the same variables between IPV group and HFCWO group, we observed a significant improvement in the IPV group maximal inspiratory pressure, maximal expiratory pressure, BCSS, and CAT. Similar results were observed in changes of sputum cytology with reduction of inflammatory cells (neutrophils and macrophages. Conclusion: The two techniques improved daily life activities and lung function in patients with severe COPD. IPV demonstrated a significantly greater effectiveness in improving some pulmonary function tests linked to the small bronchial airways obstruction and respiratory muscle strength and scores on health status assessment scales (BCSS and CAT as well as a reduction of sputum inflammatory cells compared with HFCWO. Keywords: severe COPD, intrapulmonary percussive ventilation, high-frequency chest wall oscillation, daily life activity

[Special artificial respiration procedures and intracranial pressure. Animal experiment studies, development and use of a new pressure measuring technic, clinical aspects].

Science.gov (United States)

Schedl, R

1985-01-01

-fluctuations were found to be markedly reduced at frequencies of 20/min and usually eliminated at 30/min. We found an exponential correlation between ICP-fluctuations and respiratory frequency and there was no correlation between tidal volume and ICP. Central venous pressure amplitudes were found to be in linear correlation with respiratory frequency and tidal volumes as well. The amplitude of respiratory ICP-fluctuations seems to be more dependent on duration of expiratory time. As our findings demonstrate, artificial ventilation without entilator-related fluctuations in ICP ("brain-protective" ventilation) may be performed by conventional volume-constant, time-cycled ventilators.(ABSTRACT TRUNCATED AT 400 WORDS)

Transdiaphragmatic pressure in quadriplegic individuals ventilated by diaphragmatic pacemaker.

Science.gov (United States)

Garrido-García, H.; Martín-Escribano, P.; Palomera-Frade, J.; Arroyo, O.; Alonso-Calderón, J. L.; Mazaira-Alvarez, J.

1996-01-01

BACKGROUND: Electrophrenic pacing can be used in the management of ventilatory failure in quadriplegic patients. A study was undertaken to determine the pattern of transdiaphragmatic pressure (PDI) during the conditioning phase of electrophrenic pacing to see if it had a possible role in optimising the process of conditioning. METHODS: The tidal volume (TV) and PDI were measured in a group of six quadriplegic patients commencing ventilation by low frequency pulse stimulation (7-10 Hz) and low respiratory rate stimulation (quadriplegia due to high spinal injury can be maintained with ventilation by continuous electrophrenic pacing. The control criteria used in this study for pacing were tidal volume and the patient's tolerance, and the PDI measurement did not contribute any additional information to help with managing the conditioning process. PMID:8733497

Measurement of regional ventilation under the condition of 'pursed lip breathing' (PLB) with newly designed PLB-model

Energy Technology Data Exchange (ETDEWEB)

Komatani, Akio; Yamaguchi, Koichi; Takahashi, Kazuei; Ikeda, Hideki; Takahashi, Keiji [Yamagata Univ. (Japan)

1982-12-01

A new device was designed to control the expiratory positive pressure from 0 to 100 mmH/sub 2/O as a simulation of the ''pursed lip breathing'' (PLB). Using this device, the effects of PLB to regional ventilation were evaluated. Each patient was examined twice, first in ordinary breathing and second, after 10 to 15 minutes break, in the condition of PLB with the PLB-model. The washin and washout curves of /sup 133/Xe gas were recorded by an Anger camera interfaced to the computer system (DEC PDP-11/34 GAMMA-11). Functional images of T1/2 and B1/2 (breath number) on the /sup 133/Xe washout curves were adopted as the indices of relative function of the regional ventilation. Histograms of the B1/2 distribution were also adopted to estimate the ventilation about the whole lung. Under the condition of PLB, the regional ventilation was improved in most cases of chronic pulmonary emphysema (CPE) and had a tendency to deteriorate in the case of CPE with asthma and the other lung diseases. This examination with the PLB-model might be available to evaluate the regional ventilation during PLB and follow-up of chronic obstructive lung disease.

Effect of mechanical pressure-controlled ventilation in patients with disturbed respiratory function during laparoscopic cholecystectomy

Directory of Open Access Journals (Sweden)

Šurbatović Maja

2013-01-01

Full Text Available Background/Aim: Laparoscopic cholecystectomy is considered to be the gold standard for laparoscopic surgical procedures. In ASA III patients with concomitant respiratory diseases, however, creation of pneumoperitoneum and the position of patients during surgery exert additional negative effect on intraoperative respiratory function, thus making a higher challenge for the anesthesiologist than for the surgeon. The aim of this study was to compare the effect of intermittent positive pressure ventilation (IPPV and pressure controlled ventilation (PCV during general anesthesia on respiratory function in ASA III patients submitted to laparoscopic cholecystectomy. Methods. The study included 60 patients randomized into two groups depending on the mode of ventilation: IPPV or PCV. Respiratory volume (VT, peak inspiratory pressure (PIP, compliance (C, end-tidal CO2 pressure (PETCO2, oxygen saturation (SpO2, partial pressures of O2, CO2 (PaO2 and PaCO2 and pH of arterial blood were recorded within four time intervals. Results. There were no statistically significant differences in VT, SpO2, PaO2, PaCO2 and pH values neither within nor between the two groups. In time interval t1 there were no statistically significant differences in PIP, C, PETCO2 values between the IPPV and the PCV group. But, in the next three time intervals there was a difference in PIP, C, and PETCO2 values between the two groups which ranged from statistically significant to highly significant; PIP was lower, C and PETCO2 were higher in the PCV group. Conclusion. Pressure controlled ventilation better maintains stability regarding intraoperative ventilatory parameters in ASA III patients with concomitant respiratory diseases during laparoscopic cholecystectomy.

Protective versus Conventional Ventilation for Surgery: A Systematic Review and Individual Patient Data Meta-analysis.

Science.gov (United States)

Serpa Neto, Ary; Hemmes, Sabrine N T; Barbas, Carmen S V; Beiderlinden, Martin; Biehl, Michelle; Binnekade, Jan M; Canet, Jaume; Fernandez-Bustamante, Ana; Futier, Emmanuel; Gajic, Ognjen; Hedenstierna, Göran; Hollmann, Markus W; Jaber, Samir; Kozian, Alf; Licker, Marc; Lin, Wen-Qian; Maslow, Andrew D; Memtsoudis, Stavros G; Reis Miranda, Dinis; Moine, Pierre; Ng, Thomas; Paparella, Domenico; Putensen, Christian; Ranieri, Marco; Scavonetto, Federica; Schilling, Thomas; Schmid, Werner; Selmo, Gabriele; Severgnini, Paolo; Sprung, Juraj; Sundar, Sugantha; Talmor, Daniel; Treschan, Tanja; Unzueta, Carmen; Weingarten, Toby N; Wolthuis, Esther K; Wrigge, Hermann; Gama de Abreu, Marcelo; Pelosi, Paolo; Schultz, Marcus J

2015-07-01

Recent studies show that intraoperative mechanical ventilation using low tidal volumes (VT) can prevent postoperative pulmonary complications (PPCs). The aim of this individual patient data meta-analysis is to evaluate the individual associations between VT size and positive end-expiratory pressure (PEEP) level and occurrence of PPC. Randomized controlled trials comparing protective ventilation (low VT with or without high levels of PEEP) and conventional ventilation (high VT with low PEEP) in patients undergoing general surgery. The primary outcome was development of PPC. Predefined prognostic factors were tested using multivariate logistic regression. Fifteen randomized controlled trials were included (2,127 patients). There were 97 cases of PPC in 1,118 patients (8.7%) assigned to protective ventilation and 148 cases in 1,009 patients (14.7%) assigned to conventional ventilation (adjusted relative risk, 0.64; 95% CI, 0.46 to 0.88; P ventilation with low VT and high PEEP levels and 63 cases in 525 patients (12%) assigned to ventilation with low VT and low PEEP levels (adjusted relative risk, 0.93; 95% CI, 0.64 to 1.37; P = 0.72). A dose-response relationship was found between the appearance of PPC and VT size (R2 = 0.39) but not between the appearance of PPC and PEEP level (R2 = 0.08). These data support the beneficial effects of ventilation with use of low VT in patients undergoing surgery. Further trials are necessary to define the role of intraoperative higher PEEP to prevent PPC during nonopen abdominal surgery.

Pressure Ulcer Incidence in Patients Wearing Nasal-Oral Versus Full-Face Noninvasive Ventilation Masks.

Science.gov (United States)

Schallom, Marilyn; Cracchiolo, Lisa; Falker, Antoinette; Foster, Jennifer; Hager, JoAnn; Morehouse, Tamara; Watts, Peggy; Weems, Linda; Kollef, Marin

2015-07-01

Device-related pressure ulcers from noninvasive ventilation masks alter skin integrity and cause patients discomfort. To examine the incidence, location, and stage of pressure ulcers and patients' comfort with a nasal-oral mask compared with a full-face mask. A before-after study of a convenience sample of patients with noninvasive ventilation orders in 5 intensive care units was conducted. Two groups of 100 patients each received either the nasal-oral mask or the full-face mask. Skin was assessed before the mask was applied and every 12 hours after that or upon mask removal. Comfort levels were assessed every 12 hours on a Likert scale of 1 to 5 (1, most comfortable). A pressure ulcer developed in 20% of patients in the nasal-oral mask group and 2% of patients in the full-face mask group (P face mask (mean [SD], 1.9 [1.1]) than with the nasal-oral mask (mean [SD], 2.7 [1.2], P face mask and 25 (SD, 20.7) and 92% for nasal-oral mask. No patients who had a pressure ulcer develop with the nasal-oral mask had a pressure ulcer develop with the full-face mask. The full-face mask resulted in significantly fewer pressure ulcers and was more comfortable for patients. The full-face mask is a reasonable alternative to traditional nasal-oral masks for patients receiving noninvasive ventilation. ©2015 American Association of Critical-Care Nurses.

Lung perfusion and ventilation scintigraphy in pre- and postoperative diagnostics

International Nuclear Information System (INIS)

Sandrock, D.; Munz, D.L.

1998-01-01

Lung perfusion (Tc-99m labeled albumin particles) and ventilation (Xe-133 gas) are used prior to thoracic surgery in order to evaluate changes in perfusion and ventilation due to the underlying diseases. Furthermore, perfusion scintigraphy allows combined with spirometry the prediction of the postinterventional vital capacity and the forced expiratory volume in 1 s. The correlation coefficient for this procedure compared with values measured postoperatively are in the range of 0.8. The method allows the assessment of operability in terms of postinterventional function. (orig.) [de

Assessing the influence of mechanical ventilation on blood gases and blood pressure in rattlesnakes

DEFF Research Database (Denmark)

Bertelsen, Mads Frost; Buchanan, Rasmus; Jensen, Heidi Meldgaard

2014-01-01

OBJECTIVE: To characterize the impact of mechanical positive pressure ventilation on heart rate (HR), arterial blood pressure, blood gases, lactate, glucose, sodium, potassium and calcium concentrations in rattlesnakes during anesthesia and the subsequent recovery period. STUDY DESIGN: Prospectiv...

Common-path Fourier domain optical coherence tomography of irradiated human skin and ventilated isolated rabbit lungs

Science.gov (United States)

Popp, A.; Wendel, M.; Knels, L.; Knuschke, P.; Mehner, M.; Koch, T.; Boller, D.; Koch, P.; Koch, E.

2005-08-01

A compact common path Fourier domain optical coherence tomography (FD-OCT) system based on a broadband superluminescence diode is used for biomedical imaging. The epidermal thickening of human skin after exposure to ultraviolet radiation is measured to proof the feasibility of FD-OCT for future substitution of invasive biopsies in a long term study on natural UV skin protection. The FD-OCT system is also used for imaging lung parenchyma. FD-OCT images of a formalin fixated lung show the same alveolar structure as scanning electron microscopy images. In the ventilated and blood-free perfused isolated rabbit lung FD-OCT is used for real-time cross-sectional image capture of alveolar mechanics throughout tidal ventilation. The alveolar mechanics changing from alternating recruitment-derecruitment at zero positive end-expiratory pressure (PEEP) to persistent recruitment after applying a PEEP of 5 cm H2O is observed in the OCT images.

A new positive pressure ventilation delivery system: its impact on lung ventilation studies that are technically inadequate or non diagnostic

International Nuclear Information System (INIS)

Bui, C.; Leiper, C.; Lee, K.; Saunders, C.; Dixson, H.; Elison, B.; Bennett, G.; Gibian, T.; Rutland, J.; Tse, V.; Elzein, H.; Babicheva, R.

2000-01-01

Full text: The objective of this study was to evaluate the efficacy and safety of an improved Positive Pressure Ventilation Delivery System (PVDS) in the investigation of Pulmonary Embolism (PE). The major component of PVDS is a commercially available, self-inflating 1.6L Hudson Resuscitator Bag, filled with either oxygen or air (if the patient has CO 2 retention), which is squeezed by the operator to push Technegas from the Technegas Generator Chamber to the patient via the Patient Administration Set synchronously with patient inspiration. 27 spontaneously breathing in-patients (12 males, 15 females, age range 64-89, 21 with chronic airflow limitation), whose conventional lung ventilation images were technically inadequate or non diagnostic, were re-scanned using PVDS within four days after the conventional ventilation study. Randomised blinded visual interpretation of conventional ventilation/perfusion scan vs. PVDS-assisted ventilation/perfusion scan was performed by consensus reading with two experienced observers. In conclusion PVDS was safe and well tolerated. PVDS improved the image quality of the lung ventilation scans in this cohort of patients. This technique has the potential to improve the accuracy of lung scanning in patients with severe lung disease. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

Role of bronchodilation and pattern of breathing in increasing tidal expiratory flow with progressive induced hypercapnia in chronic obstructive pulmonary disease.

Science.gov (United States)

Finucane, Kevin E; Singh, Bhajan

2018-01-01

Hypercapnia (HC) in vitro relaxes airway smooth muscle; in vivo, it increases respiratory effort, tidal expiratory flows (V̇ exp ), and, by decreasing inspiratory duration (Ti), increases elastic recoil pressure (Pel) via lung viscoelasticity; however, its effect on airway resistance is uncertain. We examined the contributions of bronchodilation, Ti, and expiratory effort to increasing V̇ exp with progressive HC in 10 subjects with chronic obstructive pulmonary disease (COPD): mean forced expiratory volume in 1 s (FEV 1 ) 53% predicted. Lung volumes (Vl), V̇ exp , esophageal pressure (Pes), Ti, and end-tidal Pco 2 ([Formula: see text]) were measured during six tidal breaths followed by an inspiratory capacity (IC), breathing air, and at three levels of HC. V̇ exp and V̇ with submaximal forced vital capacities breathing air (V̇ sFVC ) were compared. Pulmonary resistance ( Rl) was measured from the Pes-V̇ relationship. V̇ exp and Pes at end-expiratory lung volume (EELV) + 0.3 tidal volume [V̇ (0.3Vt) and Pes (0.3Vt) , respectively], Ti, and Rl correlated with [Formula: see text] ( P pulmonary disease (COPD), progressive HC increases tidal expiratory flows by inducing bronchodilation and via an increased rate of inspiration and lung viscoelasticity, a probable increase in lung elastic recoil pressure, both changes increasing expiratory flows, promoting lung emptying and a stable end-expiratory volume. Bronchodilation with HC occurred despite optimal standard bronchodilator therapy, suggesting that in COPD further bronchodilation is possible.

Open lung approach vs acute respiratory distress syndrome network ventilation in experimental acute lung injury.

Science.gov (United States)

Spieth, P M; Güldner, A; Carvalho, A R; Kasper, M; Pelosi, P; Uhlig, S; Koch, T; Gama de Abreu, M

2011-09-01

Setting and strategies of mechanical ventilation with positive end-expiratory pressure (PEEP) in acute lung injury (ALI) remains controversial. This study compares the effects between lung-protective mechanical ventilation according to the Acute Respiratory Distress Syndrome Network recommendations (ARDSnet) and the open lung approach (OLA) on pulmonary function and inflammatory response. Eighteen juvenile pigs were anaesthetized, mechanically ventilated, and instrumented. ALI was induced by surfactant washout. Animals were randomly assigned to mechanical ventilation according to the ARDSnet protocol or the OLA (n=9 per group). Gas exchange, haemodynamics, pulmonary blood flow (PBF) distribution, and respiratory mechanics were measured at intervals and the lungs were removed after 6 h of mechanical ventilation for further analysis. PEEP and mean airway pressure were higher in the OLA than in the ARDSnet group [15 cmH(2)O, range 14-18 cmH(2)O, compared with 12 cmH(2)O; 20.5 (sd 2.3) compared with 18 (1.4) cmH(2)O by the end of the experiment, respectively], and OLA was associated with improved oxygenation compared with the ARDSnet group after 6 h. OLA showed more alveolar overdistension, especially in gravitationally non-dependent regions, while the ARDSnet group was associated with more intra-alveolar haemorrhage. Inflammatory mediators and markers of lung parenchymal stress did not differ significantly between groups. The PBF shifted from ventral to dorsal during OLA compared with ARDSnet protocol [-0.02 (-0.09 to -0.01) compared with -0.08 (-0.12 to -0.06), dorsal-ventral gradients after 6 h, respectively]. According to the OLA, mechanical ventilation improved oxygenation and redistributed pulmonary perfusion when compared with the ARDSnet protocol, without differences in lung inflammatory response.

Flow-synchronized nasal intermittent positive pressure ventilation in the preterm infant: development of a project

Directory of Open Access Journals (Sweden)

Corrado Moretti

2013-06-01

Full Text Available This manuscript describes the experience of our team in developing a flow-triggered nasal respiratory support for the neonate and its related clinical applications. Although mechanical ventilation (MV via an endotracheal tube has undoubtedly led to improvement in neonatal survival in the last 40 years, the prolonged use of this technique may predispose the infant to the development of many possible complications, first of all, bronchopulmonary dysplasia (BPD. Avoiding mechanical ventilation is thought to be a critical goal, and different modes of non invasive respiratory support may reduce the intubation rate: nasal continuous positive airway pressure (NCPAP, nasal intermittent positive pressure ventilation (NIPPV and its more advantageous form, synchronized nasal intermittent positive pressure ventilation (SNIPPV. SNIPPV was initially performed by a capsule placed on the baby’s abdomen. To overcome the disadvantages of the abdominal capsule, our team decided to create a flow-sensor that could be interposed between the nasal prongs and the Y piece. Firstly we developed a hot-wire flow-sensor to trigger the ventilator and we showed that flow-SNIPPV can support the inspiratory effort in the post-extubation period more effectively than NCPAP. But, although accurate, the proper functioning of the hot-wire flow-sensor was easily compromised by secretions or moisture, and therefore we started to use as flow-sensor a simpler differential pressure transducer. In a following trial using the new device, we were able to demonstrate that flow-SNIPPV was more effective than conventional NCPAP in decreasing extubation failure in preterm infants who had been ventilated for respiratory distress syndrome (RDS. More recently we used flow-SNIPPV as the primary mode of ventilation, after surfactant replacement, reducing MV need and favorably affecting short-term morbidities of treated premature infants. We also successfully applied SNIPPV to treat apnea of

Postural lung recruitment assessed by lung ultrasound in mechanically ventilated children.

Science.gov (United States)

Tusman, Gerardo; Acosta, Cecilia M; Böhm, Stephan H; Waldmann, Andreas D; Ferrando, Carlos; Marquez, Manuel Perez; Sipmann, Fernando Suarez

2017-10-13

Atelectasis is a common finding in mechanically ventilated children with healthy lungs. This lung collapse cannot be overcome using standard levels of positive end-expiratory pressure (PEEP) and thus for only individualized lung recruitment maneuvers lead to satisfactory therapeutic results. In this short communication, we demonstrate by lung ultrasound images (LUS) the effect of a postural recruitment maneuver (P-RM, i.e., a ventilatory strategy aimed at reaerating atelectasis by changing body position under constant ventilation). Data was collected in the operating room of the Hospital Privado de Comunidad, Mar del Plata, Argentina. Three anesthetized children undergoing mechanical ventilation at constant settings were sequentially subjected to the following two maneuvers: (1) PEEP trial in the supine position PEEP was increased to 10 cmH 2 O for 3 min and then decreased to back to baseline. (2) P-RM patient position was changed from supine to the left and then to the right lateral position for 90 s each before returning to supine. The total P-RM procedure took approximately 3 min. LUS in the supine position showed similar atelectasis before and after the PEEP trial. Contrarily, atelectasis disappeared in the non-dependent lung when patients were placed in the lateral positions. Both lungs remained atelectasis free even after returning to the supine position. We provide LUS images that illustrate the concept and effects of postural recruitment in children. This maneuver has the advantage of achieving recruitment effects without the need to elevate airways pressures.

Effect of PEEP and inhaled nitric oxide on pulmonary gas exchange during gaseous and partial liquid ventilation with small volumes of perfluorocarbon.

Science.gov (United States)

Max, M; Kuhlen, R; Falter, F; Reyle-Hahn, M; Dembinski, R; Rossaint, R

2000-04-01

Partial liquid ventilation, positive end-expiratory pressure (PEEP) and inhaled nitric oxide (NO) can improve ventilation/perfusion mismatch in acute lung injury (ALI). The aim of the present study was to compare gas exchange and hemodynamics in experimental ALI during gaseous and partial liquid ventilation at two different levels of PEEP, with and without the inhalation of nitric oxide. Seven pigs (24+/-2 kg BW) were surfactant-depleted by repeated lung lavage with saline. Gas exchange and hemodynamic parameters were assessed in all animals during gaseous and subsequent partial liquid ventilation at two levels of PEEP (5 and 15 cmH2O) and intermittent inhalation of 10 ppm NO. Arterial oxygenation increased significantly with a simultaneous decrease in cardiac output when PEEP 15 cmH2O was applied during gaseous and partial liquid ventilation. All other hemodynamic parameters revealed no relevant changes. Inhalation of NO and instillation of perfluorocarbon had no additive effects on pulmonary gas exchange when compared to PEEP 15 cmH2O alone. In experimental lung injury, improvements in gas exchange are most distinct during mechanical ventilation with PEEP 15 cmH2O without significantly impairing hemodynamics. Partial liquid ventilation and inhaled NO did not cause an additive increase of PaO2.

Effects of nasal positive expiratory pressure on dynamic hyperinflation and 6-minute walk test in patients with COPD.

Science.gov (United States)

Wibmer, Thomas; Rüdiger, Stefan; Heitner, Claudia; Kropf-Sanchen, Cornelia; Blanta, Ioanna; Stoiber, Kathrin M; Rottbauer, Wolfgang; Schumann, Christian

2014-05-01

Dynamic hyperinflation is an important target in the treatment of COPD. There is increasing evidence that positive expiratory pressure (PEP) could reduce dynamic hyperinflation during exercise. PEP application through a nasal mask and a flow resistance device might have the potential to be used during daily physical activities as an auxiliary strategy of ventilatory assistance. The aim of this study was to determine the effects of nasal PEP on lung volumes during physical exercise in patients with COPD. Twenty subjects (mean ± SD age 69.4 ± 6.4 years) with stable mild-to-severe COPD were randomized to undergo physical exercise with nasal PEP breathing, followed by physical exercise with habitual breathing, or vice versa. Physical exercise was induced by a standard 6-min walk test (6 MWT) protocol. PEP was applied by means of a silicone nasal mask loaded with a fixed-orifice flow resistor. Body plethysmography was performed immediately pre-exercise and post-exercise. Differences in mean pre- to post-exercise changes in total lung capacity (-0.63 ± 0.80 L, P = .002), functional residual capacity (-0.48 ± 0.86 L, P = .021), residual volume (-0.56 ± 0.75 L, P = .004), S(pO2) (-1.7 ± 3.4%, P = .041), and 6 MWT distance (-30.8 ± 30.0 m, P = .001) were statistically significant between the experimental and the control interventions. The use of flow-dependent expiratory pressure, applied with a nasal mask and a PEP device, might promote significant reduction of dynamic hyperinflation during walking exercise. Further studies are warranted addressing improvements in endurance performance under regular application of nasal PEP during physical activities.

A prospective crossover comparison of neurally adjusted ventilatory assist and pressure-support ventilation in a pediatric and neonatal intensive care unit population.

LENUS (Irish Health Repository)

Breatnach, Cormac

2012-02-01

OBJECTIVE: To compare neurally adjusted ventilatory assist ventilation with pressure-support ventilation. DESIGN: Prospective, crossover comparison study. SETTING: Tertiary care pediatric and neonatal intensive care unit. PATIENTS: Sixteen ventilated infants and children: mean age = 9.7 months (range = 2 days-4 yrs) and mean weight = 6.2 kg (range = 2.4-13.7kg). INTERVENTIONS: A modified nasogastric tube was inserted and correct positioning was confirmed. Patients were ventilated in pressure-support mode with a pneumatic trigger for a 30-min period and then in neurally adjusted ventilatory assist mode for up to 4 hrs. MEASUREMENTS AND MAIN RESULTS: Data collected for comparison included activating trigger (neural vs. pneumatic), peak and mean airway pressures, expired minute and tidal volumes, heart rate, respiratory rate, pulse oximetry, end-tidal CO2 and arterial blood gases. Synchrony was improved in neurally adjusted ventilatory assist mode with 65% (+\\/-21%) of breaths triggered neurally vs. 35% pneumatically (p < .001) and 85% (+\\/-8%) of breaths cycled-off neurally vs. 15% pneumatically (p = .0001). The peak airway pressure in neurally adjusted ventilatory assist mode was significantly lower than in pressure-support mode with a 28% decrease in pressure after 30 mins (p = .003) and 32% decrease after 3 hrs (p < .001). Mean airway pressure was reduced by 11% at 30 mins (p = .13) and 9% at 3 hrs (p = .31) in neurally adjusted ventilatory assist mode although this did not reach statistical significance. Patient hemodynamics and gas exchange remained stable for the study period. No adverse patient events or device effects were noted. CONCLUSIONS: In a neonatal and pediatric intensive care unit population, ventilation in neurally adjusted ventilatory assist mode was associated with improved patient-ventilator synchrony and lower peak airway pressure when compared with pressure-support ventilation with a pneumatic trigger. Ventilating patients in this new mode

Validation of a protocol to evaluate maximal expiratory pressure using a pressure transducer and a signal conditioner

Directory of Open Access Journals (Sweden)

Viviane Soares

2011-09-01

Full Text Available The respiratory muscles can present fatigue and even chronic inability to generate force. So, reliable devices are necessary to their evaluation. The aim of this study is to evaluate the MEP (Maximal Expiratory Pressure values of individuals between 20 and 25 years old and to validate a protocol using a pressure transducer and a signal conditioner comparing it with the digital manometer. We evaluated the MEP of 10 participants. They remained seated and made six respiratory maneuvers from Total Lung Capacity (TLC to Residual Volume (RV. The results in the study showed no statistically significant differences when compared to values reported in the literature, and that the pressure transducer provides reliable values for MEP.Os músculos respiratórios podem apresentar fadiga e até mesmo a incapacidade crônica na geração de força, sendo necessários dispositivos confiáveis para sua avaliação. O objetivo deste estudo foi avaliar a pressão expiratória máxima (PeMáx de indivíduos entre 20 e 25 anos e validar um protocolo que utiliza um transdutor de pressão e um condicionador de sinais comparando-o com a manovacuometria. Foram avaliadas a PeMáx de 10 participantes. Estes permaneceram sentados e realizaram seis manobras respiratórias a partir da capacidade pulmonar total (CPT até o volume residual (VR. Os resultados do estudo não apresentaram diferenças estatisticamente significativas quando comparados com os valores de normalidade descritos na literatura e mostraram que o transdutor de pressão fornece valores confiáveis para Pe máx.

Nasal high-frequency oscillatory ventilation impairs heated humidification: A neonatal bench study.

Science.gov (United States)

Ullrich, Tim L; Czernik, Christoph; Bührer, Christoph; Schmalisch, Gerd; Fischer, Hendrik S

2017-11-01

Nasal high-frequency oscillatory ventilation (nHFOV) is a novel mode of non-invasive ventilation used in neonates. However, upper airway obstructions due to viscous secretions have been described as specific adverse effects. We hypothesized that high-frequency oscillations reduce air humidity in the oropharynx, resulting in upper airway desiccation. Therefore, we aimed to investigate the effects of nHFOV ventilatory settings on oropharyngeal gas conditions. NHFOV or nasal continuous positive airway pressure (nCPAP) was applied, along with heated humidification, to a previously established neonatal bench model that simulates oropharyngeal gas conditions during spontaneous breathing through an open mouth. A digital thermo-hygro sensor measured oropharyngeal temperature (T) and humidity at various nHFOV frequencies (7, 10, 13 Hz), amplitudes (10, 20, 30 cmH 2 O), and inspiratory-to-expiratory (I:E) ratios (25:75, 33:66, 50:50), and also during nCPAP. Relative humidity was always >99%, but nHFOV resulted in lower mean T and absolute humidity (AH) in comparison to nCPAP (P humidification during nHFOV. © 2017 Wiley Periodicals, Inc.

Multi-detector CT evaluation in patients suspected of tracheobronchomalacia: Comparison of end-expiratory with dynamic expiratory volumetric acquisitions

Energy Technology Data Exchange (ETDEWEB)

Ferretti, Gilbert R. [Department of Radiology (France)], E-mail: gferretti@chu-grenoble.fr; Jankowski, Adrien [Department of Radiology (France)], E-mail: ajankowski@chu-grenoble.fr; Perrin, Marie Amelie [Department of Radiology (France)], E-mail: maperrin@chu-grenoble.fr; Chouri, Nathalie [Department of Respiratory Diseases (France)], E-mail: nchouri@chu-grenoble.fr; Arnol, Nathalie [Sleep Laboratory and EFCR, University Hospital, Grenoble (France); HP2 Laboratory, INSERM ERI 0017 (Hypoxia: Pathophysiology), Joseph Fourier University, Grenoble (France)], E-mail: narnold@chu-grenoble.fr; Aubaud, Laurent [Department of Radiology (France)], E-mail: laubaud@chu-grenoble.fr; Pepin, Jean-Louis [Sleep Laboratory and EFCR, University Hospital, Grenoble (France); HP2 Laboratory, INSERM ERI 0017 (Hypoxia: Pathophysiology), Joseph Fourier University, Grenoble (France)], E-mail: jlpepin@chu-grenoble.fr

2008-11-15

Purpose: The aim of this study was to compare dynamic expiratory imaging and end-expiratory imaging using multi-detector CT (MDCT) of the central airways in patients suspected of tracheobronchomalacia (TBM). Methods: This study had local ethical committee approval. Seventy patients suspected of TBM were prospectively included. All patients underwent evaluation of central airways by three different low-dose MDCT acquisitions: end inspiration, end expiration, and dynamic expiration. Degree of airway collapse was measured by calculating the percentage change in the area and diameter of the airways between inspiratory and the two expiratory techniques at three levels of the trachea and in the sagittal diameter of the right and left main bronchi. Three threshold levels of percentage reduction in diameter or area (30%, 50%, and 70%) for defining TBM were evaluated. Results: In the entire population, the mean percentage of airway collapse was significantly greater with dynamic expiratory imaging than with the end-expiratory imaging at three different levels: lower thoracic trachea (26% vs. 16.6%, p < 0.009), right (25.2% vs. 14%, p < 0.01) and left main (24.7% vs. 13.3%, p < 0.01) bronchus. Whatever the threshold value for defining TBM, dynamic expiratory imaging always resulted in diagnosing TBM in more patients than end-expiratory imaging. Conclusions: Dynamic expiratory imaging shows a significantly greater degree and a significantly greater extent of airway collapse than standard end-expiratory imaging in patients suspected of TBM. Further evaluation of the clinical relevance of such findings is warranted.

Diffuse Ceiling Ventilation

DEFF Research Database (Denmark)

Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

with conventional ventilation systems (mixing or displacement ventilation), diffuse ceiling ventilation can significantly reduce or even eliminate draught risk in the occupied zone. Moreover, this ventilation system presents a promising opportunity for energy saving, because of the low pressure loss, extended free...

Use of positive pressure in preoperative and intraoperative of bariatric surgery and its effect on the time of extubation

Directory of Open Access Journals (Sweden)

Letícia Baltieri

2015-04-01

Full Text Available BACKGROUND AND OBJECTIVE: To investigate the influence of intraoperative and preoperative positive pressure in the time of extubation in patients undergoing bariatric surgery. METHOD: Randomized clinical trial, in which 40 individuals with a body mass index between 40 and 55 kg/m2, age between 25 and 55 years, nonsmokers, underwent bariatric surgery type Roux-en-Y gastric bypass by laparotomy and with normal preoperative pulmonary function were randomized into the following groups: G-pre (n = 10: individuals who received treatment with noninvasive positive pressure before surgery for 1 h; G-intra (n = 10: individuals who received positive end-expiratory pressure of 10 cm H2O throughout the surgical procedure; and G-control (n = 20: not received any preoperative or intraoperative intervention. Following were recorded: time between induction of anesthesia and extubation, between the end of anesthesia and extubation, duration of mechanical ventilation, and time between extubation and discharge from the post-anesthetic recovery. RESULTS: There was no statistical difference between groups. However, when applied to the Cohen coefficient, the use of positive end-expiratory pressure of 10 cm H2O during surgery showed a large effect on the time between the end of anesthesia and extubation. About this same time, the treatment performed preoperatively showed moderate effect. CONCLUSION: The use of positive end-expiratory pressure of 10 cm H2O in the intraoperative and positive pressure preoperatively, influenced the time of extubation of patients undergoing bariatric surgery.

Noninvasive positive pressure ventilation enhances the effects of aerobic training on cardiopulmonary function.

Directory of Open Access Journals (Sweden)

Takashi Moriki

Full Text Available The purpose of this study was to determine the effect of aerobic training under noninvasive positive pressure ventilation (NPPV on maximal oxygen uptake ([Formula: see text].Ten healthy young male volunteers participated in the study. Before the training, stroke volume (SV and cardiac output (CO were measured in all subjects under 0, 4, 8, and 12 cmH2O NPPV at rest. Then, the subjects exercised on a cycle ergometer at 60% of pre-training [Formula: see text] for 30 min daily for 5 consecutive days with/without NPPV. The 5-day exercise protocol was repeated after a three-week washout period without/with NPPV. The primary endpoint was changes in [Formula: see text]. The secondary endpoints were changes in SV, CO, maximum heart rate (HRmax, maximum respiratory rate (RRmax, maximum expiratory minute volume (VEmax and the percent change in plasma volume (PV.NPPV at 12 cmH2O significantly reduced SV and CO at rest. [Formula: see text] significantly increased after 5 days training with and without NPPV, but the magnitude of increase in [Formula: see text] after training under 12 cmH2O NPPV was significantly higher than after training without NPPV. VEmax significantly increased after training under NPPV, but not after training without NPPV. HRmax and RRmax did not change during training irrespective of NPPV. The percent change in PV was similar between training with and without NPPV. The 5-day training program with NPPV resulted in greater improvement in [Formula: see text] than without NPPV.Aerobic training under NPPV has add-on effects on [Formula: see text] and exercise-related health benefits in healthy young men.

Actual performance of mechanical ventilators in ICU: a multicentric quality control study

Directory of Open Access Journals (Sweden)

Govoni L

2012-12-01

Full Text Available Leonardo Govoni,1 Raffaele L Dellaca,1 Oscar Peñuelas,2,3 Giacomo Bellani,4,5 Antonio Artigas,3,6 Miquel Ferrer,3,7 Daniel Navajas,3,8,9 Antonio Pedotti,1 Ramon Farré3,81TBM-Lab, Dipartimento di Bioingegneria, Politecnico di Milano University, Milano, Italy; 2Hospital Universitario de Getafe – CIBERES, Madrid, Spain; 3CIBER de Enfermedades Respiratorias, Bunyola, Spain; 4Department of Experimental Medicine, University of Milan, Bicocca, Italy; 5Department of Perioperative Medicine and Intensive Care, San Gerardo Hospital, Monza (MI, Italy; 6Critical Care Center, Sabadell Hospital, Corporació Sanitaria Universitaria Parc Tauli, Universitat Autonoma de Barcelona, CIBERES, Spain; 7Department of Pneumology, Hospital Clinic, IDIBAPS, Barcelona, Spain; 8Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universidad de Barcelona-IDIBAPS, Barcelona, Spain; 9Institut de Bioenginyeria de Catalunya, Barcelona, SpainAbstract: Even if the performance of a given ventilator has been evaluated in the laboratory under very well controlled conditions, inappropriate maintenance and lack of long-term stability and accuracy of the ventilator sensors may lead to ventilation errors in actual clinical practice. The aim of this study was to evaluate the actual performances of ventilators during clinical routines. A resistance (7.69 cmH2O/L/s – elastance (100 mL/cmH2O test lung equipped with pressure, flow, and oxygen concentration sensors was connected to the Y-piece of all the mechanical ventilators available for patients in four intensive care units (ICUs; n = 66. Ventilators were set to volume-controlled ventilation with tidal volume = 600 mL, respiratory rate = 20 breaths/minute, positive end-expiratory pressure (PEEP = 8 cmH2O, and oxygen fraction = 0.5. The signals from the sensors were recorded to compute the ventilation parameters. The average ± standard deviation and range (min–max of the ventilatory parameters were the following: inspired

Continuous positive airway pressure and conventional mechanical ventilation in the treatment of meconium aspiration syndrome.

Science.gov (United States)

Goldsmith, J P

2008-12-01

Meconium aspiration syndrome (MAS) is a complex syndrome that ranges in severity from mild respiratory distress to severe respiratory failure, persistent pulmonary hypertension of the newborn and sometimes death. Understanding of the syndrome's complicated pathophysiology will help determine the appropriate treatment strategy, including the use of continuous positive airway pressure (CPAP), conventional mechanical ventilation (CMV) and other therapies. Approximately 30 to 50% of infants diagnosed with MAS will require CPAP or mechanical ventilation. The optimum modes of ventilation for MAS are not known. Very few studies have been conducted to determine 'best' ventilatory strategies. Despite the introduction, over the last two decades, of innovative ventilatory treatments for this disease (for example, surfactant, high-frequency ventilation, inhaled nitric oxide, extracorporeal membrane oxygenation), the majority of infants can be successfully managed with CPAP or mechanical ventilation alone.

Transfer factor, lung volumes, resistance and ventilation distribution in healthy adults.

Science.gov (United States)

Verbanck, Sylvia; Van Muylem, Alain; Schuermans, Daniel; Bautmans, Ivan; Thompson, Bruce; Vincken, Walter

2016-01-01

Monitoring of chronic lung disease requires reference values of lung function indices, including putative markers of small airway function, spanning a wide age range.We measured spirometry, transfer factor of the lung for carbon monoxide (TLCO), static lung volume, resistance and ventilation distribution in a healthy population, studying at least 20 subjects per sex and per decade between the ages of 20 and 80 years.With respect to the Global Lung Function Initiative reference data, our subjects had average z-scores for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC of -0.12, 0.04 and -0.32, respectively. Reference equations were obtained which could account for a potential dependence of index variability on age and height. This was done for (but not limited to) indices that are pertinent to asthma and chronic obstructive pulmonary disease studies: forced expired volume in 6 s, forced expiratory flow, TLCO, specific airway conductance, residual volume (RV)/total lung capacity (TLC), and ventilation heterogeneity in acinar and conductive lung zones.Deterioration in acinar ventilation heterogeneity and lung clearance index with age were more marked beyond 60 years, and conductive ventilation heterogeneity showed the greatest increase in variability with age. The most clinically relevant deviation from published reference values concerned RV/TLC values, which were considerably smaller than American Thoracic Society/European Respiratory Society-endorsed reference values. Copyright ©ERS 2016.

Effect of acute kidney injury on weaning from mechanical ventilation in critically ill patients.

Science.gov (United States)

Vieira, José M; Castro, Isac; Curvello-Neto, Américo; Demarzo, Sérgio; Caruso, Pedro; Pastore, Laerte; Imanishe, Marina H; Abdulkader, Regina C R M; Deheinzelin, Daniel

2007-01-01

Acute kidney injury (AKI) worsens outcome in various scenarios. We sought to investigate whether the occurrence of AKI has any effect on weaning from mechanical ventilation. Observational, retrospective study in a 23-bed medical/surgical intensive care unit (ICU) in a cancer hospital from January to December 2003. The inclusion criterion was invasive mechanical ventilation for > or =48 hrs. AKI was defined as at least one measurement of serum creatinine of > or =1.5 mg/dL during the ICU stay. Patients were then separated into AKI and non-AKI patients (control group). The criterion for weaning was the combination of positive end-expiratory pressure of or =85% increase in baseline serum creatinine (hazard rate, 2.30; 95% confidence interval, 1.30-4.08), oliguria (hazard rate, 2.51; 95% confidence interval, 1.24-5.08), and the number of antibiotics (hazard rate, 2.64; 95% confidence interval, 1.51-4.63) predicted longer duration of weaning. The length of ICU stay and ICU mortality rate were significantly greater in the AKI patients. After adjusting for Simplified Acute Physiology Score II, oliguria (odds ratio, 30.8; 95% confidence interval, 7.7-123.0) remained as a strong risk factor for mortality. This study shows that renal dysfunction has serious consequences in the duration of mechanical ventilation, weaning from mechanical ventilation, and mortality in critically ill cancer patients.

Peak Pressures and PaO2/FiO2 Ratios Are Associated With Adverse Outcomes in Patients on Mechanical Ventilators.

Science.gov (United States)

Whiting, Jeremy; Edriss, Hawa; Yang, Shengping; Nugent, Kenneth

2016-06-01

Patients requiring mechanical ventilation can have complications related to their underlying diseases and hospital-related events. It is possible that easily obtained information early in the course of mechanical ventilation can provide information about important outcomes. Medical records from 281 episodes of mechanical ventilation in the medical intensive care unit were reviewed to collect information on patient demographics, admitting diagnoses, laboratory tests, duration of mechanical ventilation, the development of ventilator-associated events and mortality. Ventilator pressures from day 2 were analyzed for this study. Most patients (72.7%) were ≥50 years, 53.8% were men and 66.3% had a body mass index (BMI) ≥ 25kg/m(2).The mean Acute Physiology and Chronic Healthy Evaluation II score was 13.6 ± 5.9. The median initial PaO2/FiO2 was 240 with interquartile range of 177-414. The median duration of ventilation was 4 days (interquartile range: 2-9 days). A PaO2/FiO2 ratio 500, and a BMI > 30kg/m(2) was associated with decreased mortality compared with normal BMIs. A PaO2/FiO2 ratio 30kg/m(2) were all associated with having a ventilator-associated event. There was a positive correlation between peak pressure (day 2) and the duration of ventilation (r = 0.263, P = 0.007). Easily available information collected on day 2 of mechanical ventilation can help identify patients at risk for poor outcomes, including the duration of mechanical ventilation, the development of ventilator-associated complications and mortality. Prospective studies measuring peak pressures are needed to evaluate the utility of this simple measurement in the management of patients requiring mechanical ventilation. Published by Elsevier Inc.

Time to Death after Terminal Withdrawal of Mechanical Ventilation: Specific Respiratory and Physiologic Parameters May Inform Physician Predictions.

Science.gov (United States)

Long, Ann C; Muni, Sarah; Treece, Patsy D; Engelberg, Ruth A; Nielsen, Elizabeth L; Fitzpatrick, Annette L; Curtis, J Randall

2015-12-01

Discussions about withdrawal of life-sustaining therapies often include family members of critically ill patients. These conversations should address essential components of the dying process, including expected time to death after withdrawal. The study objective was to aid physician communication about the dying process by identifying predictors of time to death after terminal withdrawal of mechanical ventilation. We conducted an observational analysis from a single-center, before-after evaluation of an intervention to improve palliative care. We studied 330 patients who died after terminal withdrawal of mechanical ventilation. Predictors included patient demographics, laboratory, respiratory, and physiologic variables, and medication use. The median time to death for the entire cohort was 0.58 hours (interquartile range (IQR) 0.22-2.25 hours) after withdrawal of mechanical ventilation. Using Cox regression, independent predictors of shorter time to death included higher positive end-expiratory pressure (per 1 cm H2O hazard ratio [HR], 1.07; 95% CI 1.04-1.11); higher static pressure (per 1 cm H2O HR, 1.03; 95% CI 1.01-1.04); extubation prior to death (HR, 1.41; 95% CI 1.06-1.86); and presence of diabetes (HR, 1.75; 95% CI 1.25-2.44). Higher noninvasive mean arterial pressure predicted longer time to death (per 1 mmHg HR, 0.98; 95% CI 0.97-0.99). Comorbid illness and key respiratory and physiologic parameters may inform physician predictions of time to death after withdrawal of mechanical ventilation. An understanding of the predictors of time to death may facilitate discussions with family members of dying patients and improve communication about end-of-life care.

Inspiratory time and tidal volume during intermittent positive pressure ventilation.

OpenAIRE

Field, D; Milner, A D; Hopkin, I E

1985-01-01

We measured the tidal volume achieved during intermittent positive pressure ventilation using various inspiratory times with a minimum of 0.2 seconds. Results indicate that tidal volume shows no reduction with inspiratory times down to 0.4 seconds. An inspiratory time of 0.3 seconds, however, is likely to reduce tidal volume by 8%, and at 0.2 seconds a 22% fall may be anticipated.

Chest physiotherapy with positive expiratory pressure breathing after abdominal and thoracic surgery: a systematic review.

Science.gov (United States)

Orman, J; Westerdahl, E

2010-03-01

A variety of chest physiotherapy techniques are used following abdominal and thoracic surgery to prevent or reduce post-operative complications. Breathing techniques with a positive expiratory pressure (PEP) are used to increase airway pressure and improve pulmonary function. No systematic review of the effects of PEP in surgery patients has been performed previously. The purpose of this systematic review was to determine the effect of PEP breathing after an open upper abdominal or thoracic surgery. A literature search of randomised-controlled trials (RCT) was performed in five databases. The trials included were systematically reviewed by two independent observers and critically assessed for methodological quality. We selected six RCT evaluating the PEP technique performed with a mechanical device in spontaneously breathing adult patients after abdominal or thoracic surgery via thoracotomy. The methodological quality score varied between 4 and 6 on the Physiotherapy Evidence Database score. The studies were published between 1979 and 1993. Only one of the included trials showed any positive effects of PEP compared to other breathing techniques. Today, there is scarce scientific evidence that PEP treatment is better than other physiotherapy breathing techniques in patients undergoing abdominal or thoracic surgery. There is a lack of studies investigating the effect of PEP over placebo or no physiotherapy treatment.

Hemodynamic and respiratory factors that influence the opening of patent foramen ovale in mechanically ventilated patients.

Science.gov (United States)

Vavlitou, A; Minas, G; Zannetos, S; Kyprianou, T; Tsagourias, M; Matamis, D

2016-01-01

Patent foramen ovale (PFO) is an anatomic variant that may lead to several pathological conditions, notably right to left shunt, paradoxical embolism, hypoxemia, and cerebral fat embolism. Mechanical positive pressure ventilation may increase the prevalence of PFO opening in Intensive Care Unit (ICU) patients; however, the respiratory and hemodynamic determinants of PFO opening have been poorly investigated. Contrast-enhanced transesophageal echocardiogram (ce-TEE) is considered the gold standard for PFO detection. We prospectively performed a multicenter study using ce-TEE in order to determine the respiratory and hemodynamic factors that may lead to PFO opening. One hundred and eight consecutive ICU adult patients under mechanical ventilation from three tertiary care hospitals, were included in the study. A standard multiplane ce-TEE was performed, and the dimensions and function of the right and left ventricle were studied. In each patient, the right ventricle (RV) end-diastolic area, RV end-systolic area, left ventricle (LV) end-diastolic area, and LV ejection fraction were measured using the modified Simpson's rule and the four-chamber view. At least three bubble tests were performed to detect PFO opening. Ventilatory parameters such as tidal volume, plateau pressure, static lung compliance, and positive end-expiratory pressure were recorded during the bubble test. Data for 81 men and 27 women were analyzed. PFO was detected in 27 % of the study population. Statistical significance was found between the presence of PFO and plateau pressure (odds ratio 3.421, 95 % CI: 1.2-9.4, p =0.017). Additionally, the presence of right ventricular dilatation (RV>LV) was strongly associated with PFO opening (odds ratio 3.163, 95 % CI: 1.2-8.075, p =0.018). In this group of mechanically ventilated, critically ill adult patients, right ventricular dilatation and plateau pressure above 26 mmHg were significantly associated with foramen ovale opening. Hippokratia 2016, 20

Face Masks for Noninvasive Ventilation: Fit, Excess Skin Hydration, and Pressure Ulcers.

Science.gov (United States)

Visscher, Marty O; White, Cynthia C; Jones, Jennifer M; Cahill, Thomas; Jones, Donna C; Pan, Brian S

2015-11-01

Pressure ulcers (stages III and IV) are serious safety events (ie, never events). Healthcare institutions are no longer reimbursed for costs to care for affected patients. Medical devices are the leading cause of pediatric pressure ulcers. Face masks for noninvasive ventilation were associated with a high percentage of pressure ulcers at our institution. A prospective cohort study investigated factors contributing to pressure ulcer development in 50 subjects using face masks for noninvasive ventilation. Color imaging, 3-dimensional surface imaging, and skin hydration measurements were used to identify early skin compromise and evaluate 3 interventions to reduce trauma: (1) a silicone foam dressing, (2) a water/polyethylene oxide hydrogel dressing, and (3) a flexible cloth mask. A novel mask fit technique was used to examine the impact of fit on the potential for skin compromise. Fifty subjects age 10.4 ± 9.1 y participated with color images for 22, hydration for 34, and mask fit analysis for 16. Of these, 69% had diagnoses associated with craniofacial anomalies. Stage I pressure ulcers were the most common injury. Skin hydration difference was 317 ± 29 for sites with erythema versus 75 ± 28 for sites without erythema (P skin erythema and pressure ulcers. This fit method is currently being utilized to select best-fit masks from available options, to identify the potential areas of increased tissue pressure, and to prevent skin injuries and their complications. Improvement of mask fit is an important priority for improving respiratory outcomes. Strategies to maintain normal skin hydration are important for protecting tissue integrity. Copyright © 2015 by Daedalus Enterprises.

"THE EVALUATION OF THE POSSIBLE EFFECT OF POSITIVE END EXPIRATORY PRESSURE (PEEP) ON PHARMACOKINETICS OF PHENYTOIN IN PATIENTS WITH ACUTE BRAIN INJURY UNDER MECHANICAL VENTILATION."

OpenAIRE

"Elham Hadidi; Mojtaba Mojtahedzadeh; Mohammad Reza Rouini; Behzad Eftekhar; Mohammad Abdollahi; Atabak Najafi; Mohammad R. Khajavi; Saeed Rezaee; Reza Ghaffari; Minoo Afshar"

2005-01-01

Positive ventilation has shown to have an influence on pharmacokinetic and disposition of some drugs.Beacause phenytoin with a narrow therapautic range, is the most commonly used drug for prophylaxis and treatment of early seizures after acute brain injuries, in the present study the effect of short term PEEP (5-10 cm H2O for at least 8 hours) on phenytoin serum concentration and pharmacokinetic parameters such as Vmax and clearance in brain injured patients under mechanical ventilation was e...

Backrest position in prevention of pressure ulcers and ventilator-associated pneumonia: Conflicting recommendations

OpenAIRE

Burk, Ruth Srednicki; Jo Grap, Mary

2012-01-01

Pressure ulcers and ventilator-associated pneumonia (VAP) are both common in acute and critical care settings and are considerable sources of morbidity, mortality, and health care costs. To prevent pressure ulcers, guidelines limit bed backrest elevation to less than 30 degrees, whereas recommendations to reduce VAP include use of backrest elevations of 30 degrees or more. Although a variety of risk factors beyond patient position have been identified for both pressure ulcers and VAP, this ar...

Response of Preterm Infants to 2 Noninvasive Ventilatory Support Systems: Nasal CPAP and Nasal Intermittent Positive-Pressure Ventilation.

Science.gov (United States)

Silveira, Carmen Salum Thomé; Leonardi, Kamila Maia; Melo, Ana Paula Carvalho Freire; Zaia, José Eduardo; Brunherotti, Marisa Afonso Andrade

2015-12-01

Noninvasive ventilation (NIV) in preterm infants is currently applied using intermittent positive pressure (2 positive-pressure levels) or in a conventional manner (one pressure level). However, there are no studies in the literature comparing the chances of failure of these NIV methods. The aim of this study was to evaluate the occurrence of failure of 2 noninvasive ventilatory support systems in preterm neonates over a period of 48 h. A randomized, prospective, clinical study was conducted on 80 newborns (gestational age CPAP and 40 infants with nasal intermittent positive-pressure ventilation (NIPPV). The occurrence of apnea, progression of respiratory distress, nose bleeding, and agitation was defined as ventilation failure. The need for intubation and re-intubation after failure was also observed. There were no significant differences in birth characteristics between groups. Ventilatory support failure was observed in 25 (62.5%) newborns treated with nasal CPAP and in 12 (30%) newborns treated with NIPPV, indicating an association between NIV failure and the absence of intermittent positive pressure (odds ratio [OR] 1.22, P CPAP failure. After failure, 25% (OR 0.33) of the newborns receiving nasal CPAP and 12.5% (OR 0.14) receiving NIPPV required invasive mechanical ventilation. Ventilatory support failure was significantly more frequent when nasal CPAP was used. Copyright © 2015 by Daedalus Enterprises.

New generation neonatal high frequency ventilators: effect of oscillatory frequency and working principles on performance.

Science.gov (United States)

Grazioli, Serge; Karam, Oliver; Rimensberger, Peter C

2015-03-01

Several new generation neonatal ventilators that incorporate conventional as well as high frequency ventilation (HFOV) have appeared on the market. Most of them offer the possibility to use HFOV in a volume-targeted mode, despite absence of any preclinical data. With a bench test, we evaluated the performances of 4 new neonatal HFOV devices and compared them to the SensorMedics HFOV device. Expiratory tidal volumes (V(T)) were measured for various ventilator settings and lung characteristics (ie, modifications of compliance and resistance of the system), to mimic several clinical conditions of pre-term and term infants. Increasing the frequency proportionally decreased the V(T) for all the ventilators, although the magnitude of the decrease was highly variable between ventilators. At 15 Hz and a pressure amplitude of 60 cm H2O, the delivered V(T) ranged from 3.5 to 5.9 mL between devices while simulating pre-term infant conditions and from 2.6 to 6.3 mL while simulating term infant conditions. Activating the volume-targeted mode in the 3 machines that offer this mode allowed the V(T) to remain constant over the range of frequencies and with changes of lung mechanical properties, for pre-term infant settings only while targeting a V(T) of 1 mL. These new generation neonatal ventilators were able to deliver adequate V(T) under pre-term infant, but not term infant respiratory system conditions. The clinical relevance of these findings will need to be determined by further studies. Copyright © 2015 by Daedalus Enterprises.

Influence of tidal volume on ventilation inhomogeneity assessed by electrical impedance tomography during controlled mechanical ventilation

International Nuclear Information System (INIS)

Becher, T; Kott, M; Schädler, D; Vogt, B; Meinel, T; Weiler, N; Frerichs, I

2015-01-01

The global inhomogeneity (GI) index is a parameter of ventilation inhomogeneity that can be calculated from images of tidal ventilation distribution obtained by electrical impedance tomography (EIT). It has been suggested that the GI index may be useful for individual adjustment of positive end-expiratory pressure (PEEP) and for guidance of ventilator therapy. The aim of the present work was to assess the influence of tidal volume (V_T) on the GI index values. EIT data from 9 patients with acute respiratory distress syndrome ventilated with a low and a high V_T of 5   ±   1 (mean  ±  SD) and 9   ±   1 ml kg"−"1 predicted body weight at a high and a low level of PEEP (PEEP_h_i_g_h, PEEP_l_o_w) were analyzed. PEEP_h_i_g_h and PEEP_l_o_w were set 2 cmH_2O above and 5 cmH_2O below the lower inflection point of a quasi-static pressure volume loop, respectively. The lower inflection point was identified at 8.1   ±   1.4 (mean  ±  SD) cmH_2O, resulting in a PEEP_h_i_g_h of 10.1   ±   1.4 and a PEEP_l_o_w of 3.1   ±   1.4 cmH_2O. At PEEP_h_i_g_h, we found no significant trend in GI index with low V_T when compared to high V_T (0.49   ±   0.15 versus 0.44   ±   0.09, p = 0.13). At PEEP_l_o_w, we found a significantly higher GI index with low V_T compared to high V_T (0.66   ±   0.19 versus 0.59   ±   0.17, p = 0.01). When comparing the PEEP levels, we found a significantly lower GI index at PEEP_h_i_g_h both for high and low V_T. We conclude that high V_T may lead to a lower GI index, especially at low PEEP settings. This should be taken into account when using the GI index for individual adjustment of ventilator settings. (paper)

In vitro evaluation of aerosol delivery by different nebulization modes in pediatric and adult mechanical ventilators.

Science.gov (United States)

Wan, Gwo-Hwa; Lin, Hui-Ling; Fink, James B; Chen, Yen-Hey; Wang, Wei-Jhen; Chiu, Yu-Chun; Kao, Yu-Yao; Liu, Chia-Jung

2014-10-01

Aerosol delivery through mechanical ventilation is influenced by the type of aerosol generator, pattern of nebulization, and a patient's breathing pattern. This study compares the efficiency of pneumatic nebulization modes provided by a ventilator with adult and pediatric in vitro lung models. Three pneumatic nebulization modes (inspiratory intermittent [IIM], continuous [CM], and expiratory intermittent [EIM]) provided by the Galileo Gold ventilator delivered medical aerosol to collection filters distal to an endotracheal tube with adult and pediatric test lungs. A unit dose of 5 mg/2.5 mL albuterol was diluted into 4 mL with distilled water and added to a jet nebulizer. The nebulizer was placed proximal to the ventilator, 15 cm from the inlet of the heated humidifier chamber with a T-piece and corrugated aerosol tubing and powered by gas from the ventilator in each of the 3 modes. Time for nebulization was recorded in minutes. Albuterol samples collected in the inhalation filter, nebulizer, T-piece, and corrugated tubing were eluted with distilled water and analyzed with a spectrophotometer. The inhaled drug, as a percentage of total dose in both lung models, was 5.1-7.5%, without statistical significance among the 3 modes. Median nebulization times for IIM, CM, and EIM were 38.9, 14.3, and 17.7 min, respectively, and nebulization time for the 3 modes significantly differed (P ventilator was not dependent on nebulization mode during simulated pediatric and adult conventional mechanical ventilation. Use of expiratory intermittent mode and continuous nebulization should be considered to reduce treatment time. Copyright © 2014 by Daedalus Enterprises.

The Clinical Utilisation of Respiratory Elastance Software (CURE Soft): a bedside software for real-time respiratory mechanics monitoring and mechanical ventilation management.

Science.gov (United States)

Szlavecz, Akos; Chiew, Yeong Shiong; Redmond, Daniel; Beatson, Alex; Glassenbury, Daniel; Corbett, Simon; Major, Vincent; Pretty, Christopher; Shaw, Geoffrey M; Benyo, Balazs; Desaive, Thomas; Chase, J Geoffrey

2014-09-30

Real-time patient respiratory mechanics estimation can be used to guide mechanical ventilation settings, particularly, positive end-expiratory pressure (PEEP). This work presents a software, Clinical Utilisation of Respiratory Elastance (CURE Soft), using a time-varying respiratory elastance model to offer this ability to aid in mechanical ventilation treatment. CURE Soft is a desktop application developed in JAVA. It has two modes of operation, 1) Online real-time monitoring decision support and, 2) Offline for user education purposes, auditing, or reviewing patient care. The CURE Soft has been tested in mechanically ventilated patients with respiratory failure. The clinical protocol, software testing and use of the data were approved by the New Zealand Southern Regional Ethics Committee. Using CURE Soft, patient's respiratory mechanics response to treatment and clinical protocol were monitored. Results showed that the patient's respiratory elastance (Stiffness) changed with the use of muscle relaxants, and responded differently to ventilator settings. This information can be used to guide mechanical ventilation therapy and titrate optimal ventilator PEEP. CURE Soft enables real-time calculation of model-based respiratory mechanics for mechanically ventilated patients. Results showed that the system is able to provide detailed, previously unavailable information on patient-specific respiratory mechanics and response to therapy in real-time. The additional insight available to clinicians provides the potential for improved decision-making, and thus improved patient care and outcomes.

Analytical and experimental analysis of a low-pressure heat exchanger suitable for passive ventilation

DEFF Research Database (Denmark)

Hviid, Christian Anker; Svendsen, Svend

2011-01-01

AbstractA core element in sustainable ventilation systems is the heat recovery system. Conventional heat recovery systems have a high pressure drop that acts as blockage to naturally driven airflow. The heat recovery system we propose here consists of two separated air-to-liquid heat exchangers...... interconnected by a liquid loop powered by a pump ideal as a component in a heat recovery system for passive ventilation systems. This paper describes the analytical framework and the experimental development of one exchanger in the liquid-loop. The exchanger was constructed from the 8mm plastic tubing...... that is commonly used in water-based floor-heating systems. The pressure loss and temperature exchange efficiency was measured. For a design airflow rate of 560L/s, the pressure loss was 0.37Pa and the efficiency was 75.6%. The experimental results agree well with the literature or numerical fluid calculations...

[Management of patients receiving home respiratory care with tracheostomy and positive-pressure ventilation].

Science.gov (United States)

Aoki, Masashi

2013-01-01

On March 11, 2011, the Great East Japan Earthquake occurred and a massive tsunami hit the northeastern coast of Japan. In Miyagi prefecture in Tokoku district, 49 patients with amyotrophic lateral sclerosis were supported by home respiratory care with tracheostomy and positive-pressure ventilation at that time. Among them, two patients were died in the tsunami and 25 patients were forced to evacuate to hospitals. We should hurry to submit a guideline for medical transportation for patients with neuromuscular diseases requiring artificial ventilation. We also should research the disaster medicine in the field of neurology.

Positive outcome of average volume-assured pressure support mode of a Respironics V60 Ventilator in acute exacerbation of chronic obstructive pulmonary disease: a case report

Directory of Open Access Journals (Sweden)

Okuda Miyuki

2012-09-01

Full Text Available Abstract Introduction We were able to treat a patient with acute exacerbation of chronic obstructive pulmonary disease who also suffered from sleep-disordered breathing by using the average volume-assured pressure support mode of a Respironics V60 Ventilator (Philips Respironics: United States. This allows a target tidal volume to be set based on automatic changes in inspiratory positive airway pressure. This removed the need to change the noninvasive positive pressure ventilation settings during the day and during sleep. The Respironics V60 Ventilator, in the average volume-assured pressure support mode, was attached to our patient and improved and stabilized his sleep-related hypoventilation by automatically adjusting force to within an acceptable range. Case presentation Our patient was a 74-year-old Japanese man who was hospitalized for treatment due to worsening of dyspnea and hypoxemia. He was diagnosed with acute exacerbation of chronic obstructive pulmonary disease and full-time biphasic positive airway pressure support ventilation was initiated. Our patient was temporarily provided with portable noninvasive positive pressure ventilation at night-time following an improvement in his condition, but his chronic obstructive pulmonary disease again worsened due to the recurrence of a respiratory infection. During the initial exacerbation, his tidal volume was significantly lower during sleep (378.9 ± 72.9mL than while awake (446.5 ± 63.3mL. A ventilator that allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range was attached in average volume-assured pressure support mode, improving his sleep-related hypoventilation, which is often associated with the use of the Respironics V60 Ventilator. Polysomnography performed while our patient was on noninvasive positive pressure ventilation revealed obstructive sleep apnea syndrome (apnea-hypopnea index = 14, suggesting that his chronic

Variability in usual care mechanical ventilation for pediatric acute lung injury: the potential benefit of a lung protective computer protocol.

Science.gov (United States)

Khemani, Robinder G; Sward, Katherine; Morris, Alan; Dean, J Michael; Newth, Christopher J L

2011-11-01

Although pediatric intensivists claim to embrace lung protective ventilation for acute lung injury (ALI), ventilator management is variable. We describe ventilator changes clinicians made for children with hypoxemic respiratory failure, and evaluate the potential acceptability of a pediatric ventilation protocol. This was a retrospective cohort study performed in a tertiary care pediatric intensive care unit (PICU). The study period was from January 2000 to July 2007. We included mechanically ventilated children with PaO(2)/FiO(2) (P/F) ratio less than 300. We assessed variability in ventilator management by evaluating actual changes to ventilator settings after an arterial blood gas (ABG). We evaluated the potential acceptability of a pediatric mechanical ventilation protocol we adapted from National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI) Acute Respiratory Distress Syndrome (ARDS) Network protocols by comparing actual practice changes in ventilator settings to changes that would have been recommended by the protocol. A total of 2,719 ABGs from 402 patients were associated with 6,017 ventilator settings. Clinicians infrequently decreased FiO(2), even when the PaO(2) was high (>68 mmHg). The protocol would have recommended more positive end expiratory pressure (PEEP) than was used in actual practice 42% of the time in the mid PaO(2) range (55-68 mmHg) and 67% of the time in the low PaO(2) range (ventilator rate (VR) when the protocol would have recommended a change, even when the pH was greater than 7.45 with PIP at least 35 cmH(2)O. There may be lost opportunities to minimize potentially injurious ventilator settings for children with ALI. A reproducible pediatric mechanical ventilation protocol could prompt clinicians to make ventilator changes that are consistent with lung protective ventilation.

[Domiciliary noninvasive positive pressure ventilation in chronic alveolar hypoventilation].

Science.gov (United States)

Casas, J P; Robles, A M; Pereyra, M A; Abbona, H L; López, A M

2000-01-01

Effectiveness of treatment with domiciliary nocturnal noninvasive positive pressure ventilation is analyzed in a group of patients with chronic alveolar hypoventilation of different etiologies. It was applied with two levels of pressure (BiPAP) via nasal mask. Criteria for evaluation were symptomatology and improvement in gas exchange. Data were analyzed by Student t tests. A total of 13 patients were included, mean age 55.7 range 20 to 76 years (5 male 8 female). Main diagnosis was tuberculosis in 6, four of them having had surgical procedure (thoracoplasty 2, frenicectomy 1 and neumonectomy 1), myopathy 3 (myasthenia gravis 1, muscular dystrophy 1 and diaphragmatic paralysis 1), obesity-hypoventilation syndrome 1, escoliosis 1, bronchiectasis 1 and cystic fibrosis 1. These last two patients were on waiting list for lung transplantation. At the moment of consultation, the symptoms were: dysnea 13/13 (100%), astenia 13/13 (100%), hypersomnolency 10/13 (77%), cephalea 9/13 (69%), leg edema 6/13 (46%), loss of memory 6/13 (46%). Regarding gas exchange, they showed hypoxemia and hypercapnia. Mean follow up was of 2.2 years (range 6 months to 4 years). Within the year, all 13 patients became less dyspneic. Astenia, hypersomnolency, cephalea, leg edema and memory loss disappeared. Improvement in gas exchange was: PaO2/FiO2 from 269 +/- 65.4 (basal) to 336.7 +/- 75.3 post-treatment (p = 0.0018). PaCO2 from 70.77 +/- 25.48 mmHg (basal) to 46.77 +/- 8.14 mmHg (p = 0.0013). Ventilatory support was discontinued en 5 patients: three because of pneumonia requiring intubation and conventional mechanical ventilation, two of them died and one is still with tracheostomy; One patient with bronchiectasis and one with cystic fibrosis were transplanted. The remaining eight patients are stable. In conclusion, chronic alveolar hypoventilation can be effectively treated with domiciliary nocturnal noninvasive ventilation. Long term improvement in symptomatology and arterial blood gases