• Adult respiratory distress syndrome;
  • prone position;
  • oxygenation

Background: The prone position is known to increase oxygen uptake in patients with Adult Respiratory Distress Syndrome (ARDS).

Methods: In this clinical study from 1995–96, 14 ARDS patients with severe respiratory failure were treated for at least 1 h in the prone position. Responders, defined as having more than 10% increase in PaO2/FiO2 ratio from baseline after 1 h, were treated at least 6 h in the prone position.

Results: 11 patients responded during the first period of the prone position (primary responders). Two of the 3 non-responders were turned prone a second time with increase in the PaO2FiO2 ratio (secondary responders). Mean PaO2FiO2 ratio (mean±SEM) in the supine position was 11.7±0.8 kPa, increasing to 16.6±1.8 kPa and 18.0±1.4 kPa after 1 and 6 h respectively (P=0.009). Mean time spent in the prone position was 69 h (range 3–256 h), and mean ventilatory time was 17 d (3–52 d). The mortality in this subgroup of our patients with ARDS was 42%, compared to 58% in 19 patients not turned prone in the same period.

Conclusions: The prone position together with PEEP appears to improve ventilation-perfusion matching. The prone position is simple, effective and readily available and could be used early in most patients with ARDS.