Routine prone positioning in patients with severe ARDS: feasibility and impact on prognosis

Since 1997, we have routinely used prone positioning (PP) in patients who have a PaO(2)/FiO(2) below 100 mmHg after 24-48 h of mechanical ventilation and who are ventilated using a low stretch ventilation strategy. We report here the characteristics and prognosis of this subgroup of patients with severe lung injury to illustrate the feasibility, role, and impact of routine PP in acute respiratory distress syndrome (ARDS).

A total of 218 patients were admitted because of ARDS between 1997 and 2009. Of these patients, 57 (26%) were positioned prone because of a PaO(2)/FiO(2) below 100 mmHg after 24-48 h of mechanical ventilation. Age was 51 ± 16 years, PaO(2)/FiO(2) 74 ± 19, and PaCO(2) 54 ± 10 mmHg. The lung injury score was 3.13 ± 0.15. Tidal volume was 7 ± 2 mL/kg, PEEP 5.6 ± 1.2 cmH(2)O, and plateau pressure 27 ± 3 cmH(2)O. Prone sessions lasted 18 h/day and 3.4 ± 1.1 sessions were required to obtain an FiO(2) below 60%. The 60-day mortality was 19% and death occurred after 12 ± 5 days. The ratio between observed and predicted mortality was 0.43. In patients with a PaO(2)/FiO(2) below 60 mmHg, the 60-day mortality was 28%. Logistic regression analysis showed that among the 218 patients, PP appeared to be protective with an odds ratio of 0.35 [0.16-0.79].

We demonstrate the clinical feasibility of routine PP in patients with a PaO(2)/FiO(2) below 100 mmHg after 24-48 h and suggest that, when combined with a low stretch ventilation strategy, it is protective with a high survival rate.