Short-term effects of prone position in chronic obstructive pulmonary disease patients with severe acute hypoxemic and hypercapnic respiratory failure.

OBJECTIVE: To assess the short-term effects of prone positioning (PP) in chronic obstructive pulmonary disease (COPD) patients with severe hypoxemic and hypercapnic respiratory failure requiring invasive mechanical ventilation.

DESIGN AND SETTING: Prospective observational study in the general intensive care unit of a university-affiliated hospital.

PATIENTS: 11 consecutive COPD patients with persistent hypoxemia (PaO2/FIO2 < or = 200 mmHg with FIO2 > or = 0.6) and hypercapnia requiring invasive mechanical ventilation. Patients with adult respiratory distress syndrome or left ventricular failure were excluded. Mean age was 73+/-11 years, mean weight 86+/-31 kg, mean SAPS II 53+/-10, and ICU mortality 36%.

INTERVENTIONS: Patients were turned every 6 h.

MEASUREMENTS AND RESULTS: A response to PP (20% or greater PaO2/FIO2 increase) was noted in 9 (83%) patients. Blood gases were measured in the PP and supine (SP) positions 3 h after each turn, for 36 h, yielding six measurement sets (SP1, PP1, SP2, PP2, SP3, and PP3). PaO2/FIO2 was significantly better in PP: 190+/-26 vs. 113+/-9 mmHg for PP1/SP1, 175+/-22 vs. 135+/-16 mmHg for PP2/SP2, and 199+/-24 vs. 151+/-13 mmHg for PP3/SP3. After PP1 PaO2/FIO2 remained significantly improved, and the PaO2/FIO2 improvement from SP1 to SP2 was linearly related to PaO2/FIO2 during PP1 (r=0.8). The tracheal aspirate volume improved significantly from SP1 to PP1. PaCO2 was not significantly affected by position.

CONCLUSIONS: PP was effective in treating severe hypoxemia in COPD patients. The first turn in PP was associated with increased tracheal aspirate.