Abstract
BACKGROUND: Positive end-expiratory pressure (PEEP) improves oxygenation and can prevent ventilator- induced lung injury in patients with acute respiratory distress syndrome (ARDS). Nevertheless, PEEP can also induce detrimental effects by its influence on the cardiovascular system. The purpose of this study was to assess the effects of PEEP on gastric mucosal perfusion while applying a protective ventilatory strategy in patients with ARDS. MATERIALS AND METHODS: Thirty-two patients were included in the study. A pressure-volume curve was traced and ideal PEEP, defined as lower inflection point + 2cmH(2)O, was determined. Gastric tonometry was measured continuously (Tonocap). After baseline measurements, 10, 15 and 20cmH(2)O PEEP and ideal PEEP were applied for 30 min each. By the end of each period, hemodynamics, CO(2) gap (gastric minus arterial partial pressures), and ventilatory measurements were taken. RESULTS: PEEP had no effect on CO(2) gap (median [range], baseline: 18 [2-30] mmHg; PEEP 10: 18 [0-40] mmHg; PEEP 15: 17 [0-39] mmHg; PEEP 20: 16 [4-39] mmHg; ideal PEEP: 19 [9-39] mmHg; P = 0.19). Cardiac index also remained unchanged (baseline: 4.7 [2.6-6.2] l min(-1) m(-2) ; PEEP 10: 4.4 [2.5-7] l min(-1) m(-2) ; PEEP 15: 4.4 [2.2-6.8] l min(-1) m(-2) ; PEEP 20: 4.8 [2.4-6.3] l min(-1) m(-2) ; ideal PEEP: 4.9 [2.4-6.3] l min(-1) m(-2) ; P = 0.09). CONCLUSION: PEEP of 10-20 cmH(2)O does not affect splanchnic perfusion and is hemodynamically well tolerated in most patients with ARDS, including those receiving inotropic supports.