scholarly journals Effects of Different Levels of Variability and Pressure Support Ventilation on Lung Function in Patients With Mild–Moderate Acute Respiratory Distress Syndrome

2021 ◽  
Vol 12 ◽  
Author(s):  
Lorenzo Ball ◽  
Yuda Sutherasan ◽  
Martina Fiorito ◽  
Antonella Dall'Orto ◽  
Lorenzo Maiello ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Pressure Support Ventilation ◽  
Pressure Support ◽  
Distress Syndrome ◽  
Respiratory Mechanics ◽  
Support Ventilation ◽  
Different Levels

Background: Variable pressure support ventilation (vPSV) is an assisted ventilation mode that varies the level of pressure support on a breath-by-breath basis to restore the physiological variability of breathing activity. We aimed to compare the effects of vPSV at different levels of variability and pressure support (ΔPS) in patients with acute respiratory distress syndrome (ARDS).Methods: This study was a crossover randomized clinical trial. We included patients with mild to moderate ARDS already ventilated in conventional pressure support ventilation (PSV). The study consisted of two blocks of interventions, and variability during vPSV was set as the coefficient of variation of the ΔPS level. In the first block, the effects of three levels of variability were tested at constant ΔPS: 0% (PSV0%, conventional PSV), 15% (vPSV15%), and 30% (vPSV30%). In the second block, two levels of variability (0% and variability set to achieve ±5 cmH2O variability) were tested at two ΔPS levels (baseline ΔPS and ΔPS reduced by 5 cmH2O from baseline). The following four ventilation strategies were tested in the second block: PSV with baseline ΔPS and 0% variability (PSVBL) or ±5 cmH2O variability (vPSVBL), PSV with ΔPS reduced by 5 cmH2O and 0% variability (PSV−5) or ±5 cmH2O variability (vPSV−5). Outcomes included gas exchange, respiratory mechanics, and patient-ventilator asynchronies.Results: The study enrolled 20 patients. In the first block of interventions, oxygenation and respiratory mechanics parameters did not differ between vPSV15% and vPSV30% compared with PSV0%. The variability of tidal volume (VT) was higher with vPSV15% and vPSV30% compared with PSV0%. The incidence of asynchronies and the variability of transpulmonary pressure (PL) were higher with vPSV30% compared with PSV0%. In the second block of interventions, different levels of pressure support with and without variability did not change oxygenation. The variability of VT and PL was higher with vPSV−5 compared with PSV−5, but not with vPSVBL compared with PSVBL.Conclusion: In patients with mild-moderate ARDS, the addition of variability did not improve oxygenation at different pressure support levels. Moreover, high variability levels were associated with worse patient-ventilator synchrony.Clinical Trial Registration:www.clinicaltrials.gov, identifier: NCT01683669.

Sigh Improves Gas Exchange and Lung Volume in Patients with Acute Respiratory Distress Syndrome Undergoing Pressure Support Ventilation

2002 ◽  
Vol 96 (4) ◽  
pp. 788-794 ◽  
Author(s):  
Nicoló Patroniti ◽  
Giuseppe Foti ◽  
Barbara Cortinovis ◽  
Elena Maggioni ◽  
Luca M. Bigatello ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Gas Exchange ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Lung Volume ◽  
Pressure Support Ventilation ◽  
Airway Pressure ◽  
Pressure Support ◽  
Distress Syndrome ◽  
Support Ventilation

Background The aim of our study was to assess the effect of periodic hyperinflations (sighs) during pressure support ventilation (PSV) on lung volume, gas exchange, and respiratory pattern in patients with early acute respiratory distress syndrome (ARDS). Methods Thirteen patients undergoing PSV were enrolled. The study comprised 3 steps: baseline 1, sigh, and baseline 2, of 1 h each. During baseline 1 and baseline 2, patients underwent PSV. Sighs were administered once per minute by adding to baseline PSV a 3- to 5-s continuous positive airway pressure (CPAP) period, set at a level 20% higher than the peak airway pressure of the PSV breaths or at least 35 cm H2O. Mean airway pressure was kept constant by reducing the positive end-expiratory pressure (PEEP) during the sigh period as required. At the end of each study period, arterial blood gas tensions, air flow and pressures traces, end-expiratory lung volume (EELV), compliance of respiratory system (Crs), and ventilatory parameters were recorded. Results Pao2 improved (P < 0.001) from baseline 1 (91.4 +/- 27.4 mmHg) to sigh (133 +/- 42.5 mmHg), without changes of Paco2. EELV increased (P < 0.01) from baseline 1 (1,242 +/- 507 ml) to sigh (1,377 +/- 484 ml). Crs improved (P < 0.01) from baseline 1 (40.2 +/- 12.5 ml/cm H2O) to sigh (45.1 +/- 15.3 ml/cm H2O). Tidal volume of pressure-supported breaths and the airway occlusion pressure (P0.1) decreased (P < 0.01) during the sigh period. There were no significant differences between baselines 1 and 2 for all parameters. Conclusions The addition of 1 sigh per minute during PSV in patients with early ARDS improved gas exchange and lung volume and decreased the respiratory drive.

Short-term Cardiorespiratory Effects of Proportional Assist and Pressure-support Ventilation in Patients with Acute Lung Injury/Acute Respiratory Distress Syndrome

2006 ◽  
Vol 105 (4) ◽  
pp. 703-708 ◽  
Author(s):  
Eumorfia Kondili ◽  
Nectaria Xirouchaki ◽  
Katerina Vaporidi ◽  
Maria Klimathianaki ◽  
Dimitris Georgopoulos
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Acute Lung Injury ◽  
Gas Exchange ◽  
Lung Injury ◽  
Respiratory Distress Syndrome ◽  
Pressure Support Ventilation ◽  
Pressure Support ◽  
Distress Syndrome ◽  
Short Term ◽  
Support Ventilation

Background Recent data indicate that assisted modes of mechanical ventilation improve pulmonary gas exchange in patients with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Proportional assist ventilation (PAV) is a new mode of support that amplifies the ventilatory output of the patient effort and improves patient-ventilator synchrony. It is not known whether this mode may be used in patients with ALI/ARDS. The aim of this study was to compare the effects of PAV and pressure-support ventilation on breathing pattern, hemodynamics, and gas exchange in a homogenous group of patients with ALI/ARDS due to sepsis. Methods Twelve mechanically ventilated patients with ALI/ARDS (mean ratio of partial pressure of arterial oxygen to fractional concentration of oxygen 190 +/- 49 mmHg) were prospectively studied. Patients received pressure-support ventilation and PAV in random order for 30 min while maintaining mean airway pressure constant. With both modes, the level of applied positive end-expiratory pressure (7.1 +/- 2.1 cm H2O) was kept unchanged throughout. At the end of each study period, cardiorespiratory data were obtained, and dead space to tidal volume ratio was measured. Results With both modes, none of the patients exhibited clinical signs of distress. With PAV, breathing frequency and cardiac index were slightly but significantly higher than the corresponding values with pressure-support ventilation (24.5 +/- 6.9 vs. 21.4 +/- 6.9 breaths/min and 4.4 +/- 1.6 vs. 4.1 +/- 1.3 l . min . m, respectively). None of the other parameters differ significantly between modes. Conclusions In patients with ALI/ARDS due to sepsis, PAV and pressure-support ventilation both have clinically comparable short-term effects on gas exchange and hemodynamics.

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