Prone positioning for acute respiratory distress syndrome in the surgical intensive care unit: Who, when, and how long?

Background. We evaluated the effects of prone positioning (PP) on surgery and trauma patients with acute respiratory distress syndrome (ARDS). Methods. Patients with ARDS were studied. Exclusion criteria were contraindications to PP. Patients were evaluated in the supine position and after being turned to the PP. After 6 hours, patients were returned to the supine position for 3 hours. One hour after each position change, arterial and mixed venous blood was drawn and analyzed for blood gases and pH, and hemodynamics were measured. Results. Over 20 months, 27 patients met the criteria, and 20 of the patients were entered into the study. On day 1, 18 of 20 patients (90 %) responded with an increase in PaO2 during PP. On day 2, 16 of 17 patients (94 %) responded; on clay 3, 15 of 16 patients responded (94 %); on day 4, 11 of 13 patients responded (85 %); on day 5, 8 of 8 patients responded (100 %); and on day 6, 4 of 5 patients responded (80 %). PaPO2/FIO2 and Qs/Qt were significantly improved (P <. 05) during PP. There were 91 periods of PP, lasting 10.3 +/- 1.2 hours. Of 91 changes to PP, 78 changes (86%) resulted in an improvement in PaO2/FIO2 of more than 20%. Conclusions. PP improves oxygenation in ARDS for 6 days with few complications.