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.
RCT Entities:
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.
Authors: Giuseppe Natalini; Cosetta Minelli; Antonio Rosano; Pierluigi Ferretti; Carmine R Militano; Carlo De Feo; Achille Bernardini Journal: Crit Care Date: 2013-07-23 Impact factor: 9.097
Authors: Sarah M McMullen; Maureen Meade; Louise Rose; Karen Burns; Sangeeta Mehta; Robert Doyle; Dietrich Henzler Journal: PLoS One Date: 2012-08-16 Impact factor: 3.240