[Best positive end expiratory pressure settlement in acute respiratory discomfort syndrome and prone position].

BACKGROUND AND OBJECTIVES In acute respiratory discomfort syndrome (ARDS) patients, prone position improves oxygenation in more than 70% of the cases. It is well known that prone position promotes a lot of pulmonary changes, including pulmonary mechanics, so we hypothesized that there is the necessity to optimize the ventilatory parameters after the patient is placed in prone position, especially the positive end expiratory pressure (PEEP) values. The objective of this study valued the influence of the prone position at the calculation of the ideal PEEP, given a title by the best pulmonary complaisance and he compared the pulmonary alterations of mechanics, of oxygenation and of ventilation in the positions supine and prone. METHODS Prospective study, taken place in the Irmandade Santa Casa de Misericórdia de São Paulo Intensive Care Service. Three fases have been compared. Fase 1: in supine position, after the best PEEP calculation. Fase 2: two hours after the patient was placed in prone position and the best PEEP was calculated. The patient was kept for 6 hours in this position. Fase 3: after this time, patient was placed in supine again and after two hours, a new best PEEP calculation and arterial gas analysis was done. And then fase1 versus fase 2, fase 2 versus fase 3, fase 3 versus fase1 were compared. RESULTS There were no differences in the PEEP values found in all study fases: fase 1 = 14 ± 4.43; fase 2 = 14.73 ± 4.77 and fase 3 = 13.65 ± 4.92. CONCLUSIONS There were no differences in best PEEP values between prone and supine position. Therefore, there is no need to recalculate the PEEP value after each position change.