Effects of different positive end-expiratory pressure titration strategies during prone positioning in patients with acute respiratory distress syndrome: a prospective interventional study

Prone positioning in combination with the application of low tidal volume and adequate positive end-expiratory pressure (PEEP) improves survival in patients with moderate to severe acute respiratory distress syndrome (ARDS). However, the effects of PEEP on end-expiratory transpulmonary pressure (Ptp ) during prone positioning require clarification. For this purpose, the effects of three different PEEP titration strategies on Ptp , respiratory mechanics, mechanical power, gas exchange, and hemodynamics were evaluated comparing supine and prone positioning. In forty consecutive patients with moderate to severe ARDS protective ventilation with PEEP titrated according to three different titration strategies was evaluated during supine and prone positioning: (A) ARDS Network recommendations (PEEP ), (B) the lowest static elastance of the respiratory system (PEEP ), and (C) targeting a positive Ptp (PEEP ). The primary endpoint was to analyze whether Ptp differed significantly according to PEEP titration strategy during supine and prone positioning. Ptp increased progressively with prone positioning compared with supine positioning as well as with PEEP and PEEP compared with PEEP (positioning effect p