[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.