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

Abstract

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. Prospective observational study in the general intensive care unit of a university-affiliated hospital. 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%. Patients were turned every 6 h. 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. PP was effective in treating severe hypoxemia in COPD patients. The first turn in PP was associated with increased tracheal aspirate.