Abstract
IntroductionThis study aims at comparing the very short-term effects of conventional and noisy (variable) pressure support ventilation (PSV) in mechanically ventilated patients with acute hypoxemic respiratory failure.MethodsThirteen mechanically ventilated patients with acute hypoxemic respiratory failure were enrolled in this monocentric, randomized crossover study. Patients were mechanically ventilated with conventional and noisy PSV, for one hour each, in random sequence. Pressure support was titrated to reach tidal volumes approximately 8 mL/kg in both modes. The level of positive end-expiratory pressure and fraction of inspired oxygen were kept unchanged in both modes. The coefficient of variation of pressure support during noisy PSV was set at 30%. Gas exchange, hemodynamics, lung functional parameters, distribution of ventilation by electrical impedance tomography, breathing patterns and patient-ventilator synchrony were analyzed.ResultsNoisy PSV was not associated with any adverse event, and was well tolerated by all patients. Gas exchange, hemodynamics, respiratory mechanics and spatial distribution of ventilation did not differ significantly between conventional and noisy PSV. Noisy PSV increased the variability of tidal volume (24.4 ± 7.8% vs. 13.7 ± 9.1%, P <0.05) and was associated with a reduced number of asynchrony events compared to conventional PSV (5 (0 to 15)/30 min vs. 10 (1 to 37)/30 min, P <0.05).ConclusionsIn the very short term, noisy PSV proved safe and feasible in patients with acute hypoxemic respiratory failure. Compared to conventional PSV, noisy PSV increased the variability of tidal volumes, and was associated with improved patient-ventilator synchrony, at comparable levels of gas exchange.Trial registrationClinicialTrials.gov, NCT00786292
Highlights
This study aims at comparing the very short-term effects of conventional and noisy pressure support ventilation (PSV) in mechanically ventilated patients with acute hypoxemic respiratory failure
We could not identify any negative effects of noisy PSV on gas exchange, hemodynamics or respiratory variables associated with the application of variable pressure support levels
The main findings of the present study were that, in a mixed population of patients with acute hypoxemic respiratory failure: 1) noisy PSV was not associated with adverse events; 2) gas exchange, hemodynamics, mean respiratory variables and regional distribution of ventilation did not differ significantly between conventional and noisy PSV; 3) noisy PSV was associated with significantly higher tidal volume variability than conventional PSV; 4) noisy PSV was associated with improved patient-ventilator synchrony compared to conventional PSV
Summary
This study aims at comparing the very short-term effects of conventional and noisy (variable) pressure support ventilation (PSV) in mechanically ventilated patients with acute hypoxemic respiratory failure. It has been shown that early restitution of spontaneous breathing activity is associated with benefits regarding pulmonary function as well as decreased need for Pressure support ventilation (PSV) is one of the most common modes of assisted spontaneous breathing [3]. Decreased variability of tidal volumes has been shown to be associated with impaired lung function and increased lung damage [5,6,7]. Experimental studies have demonstrated that the combination of assisted spontaneous breathing and variable tidal volumes by means of variable pressure support levels (variable pressure support ventilation - noisy PSV) may improve lung function and reduce pulmonary inflammatory response [8,9,10]. The ‘optimal’ level of pressure support variability is very close to the respiratory variability seen in healthy subjects [11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
