[Effects of positive end-expiratory pressure on lung recruited volume and oxygenation in patients with acute respiratory distress syndrome].

OBJECTIVE: To access alveolar recruitment with positive end-expiratory pressure (PEEP) and to correlate the recruited volume with arterial oxygenation in acute respiratory distress syndrome (ARDS).

METHODS: Eleven ventilated patients satisfying criteria of ARDS were included in the study group. Recruited volume of three different PEEP levels [5 cm H2O, 10 cm H2O, 15 cm H2O (1 cm H2O=0.098 kPa)] were measured by pressure-volume curve method. Effects of different PEEP levels on lung mechanics and gas exchange were compared.

RESULTS: Lung recruited volume elevated when PEEP increased from 5 cm H2O to 15 cm H2O[(40.2+/-15.3)ml vs. (123.8+/-43.1)ml vs. (178.9+/-43.5)ml, all P<0.05]. Arterial oxygenation index increased with PEEP and a positive correlation was found between recruited volume and changes in arterial oxygenation index (r=0.483, P<0.01). There was no significant difference during the static compliance at different PEEP levels at a fixed tidal volume (P>0.05). Recruited volume at PEEP 15 cm H2O in the patient group with lower inflection point (LIP) was larger than the group without LIP.

CONCLUSION: Recruited volume increases with PEEP, and the PEEP-induced increase in arterial oxygenation is significantly correlated to recruited volume.