Hyperinflation using pressure support ventilation improves secretion clearance and respiratory mechanics in ventilated patients with pulmonary infection: a randomised crossover trial.

QUESTION Is ventilator-induced hyperinflation in sidelying more effective than sidelying alone in removing secretions and improving respiratory mechanics in ventilated patients with pulmonary infection? DESIGN Randomised crossover trial with concealed allocation and intention-to-treat analysis. PARTICIPANTS 30 mechanically ventilated patients with pulmonary infection in an adult intensive care unit. INTERVENTION The experimental intervention was 30 minutes of ventilator-induced hyperinflation using pressure support ventilation in sidelying; the control intervention was 30 minutes of sidelying. Participants received both interventions on the same day, with a five-hour washout period between them. OUTCOME MEASURES Secretion clearance was measured as sputum volume retrieved during the intervention. Respiratory mechanics were measured as static compliance and total resistance of the respiratory system before and after the intervention. RESULTS The experimental intervention cleared 1.3 ml (95% CI 0.5 to 2.2) more secretions than the control. After ventilator-induced hyperinflation in sidelying, respiratory compliance had increased 4.7 ml/cmH(2)O (95% CI 2.6 to 6.8) more than in sidelying alone. There was no difference in total resistance of the respiratory system between the interventions (mean difference 0.3 cmH(2)O/l/s, 95% CI -0.8 to 1.3). CONCLUSION The application of hyperinflation using pressure support ventilation in mechanically ventilated patients with pulmonary infection improves secretion clearance and increases static compliance of the respiratory system.