Alveolar recruitment improves ventilation during thoracic surgery: a randomized controlled trial.

Background: This study was conducted to determine whether an alveolar recruitment strategy (ARS) applied during two-lung ventilation (TLV) just before starting one-lung ventilation (OLV) improves ventilatory efficiency.

Methods: Subjects were randomly allocated to two groups: (i) control group: ventilation with tidal volume (VT) of 8 or 6 ml kg(-1) for TLV and OLV, respectively, and (ii) ARS group: same ventilatory pattern with ARS consisting of 10 consecutive breaths at a plateau pressure of 40 and 20 cm H(2)O PEEP applied immediately before and after OLV. Volumetric capnography and arterial blood samples were recorded 5 min (baseline) and 20 min into TLV, at 20 and 40 min during OLV, and finally 10 min after re-establishing TLV.

Results: Twenty subjects were included in each group. In all subjects, the airway component of dead space remained constant during the study. Compared with baseline, the alveolar dead space ratio (VD(alv)/VT(alv)) increased throughout the protocol in the control but decreased in the ARS group. Differences in VD(alv)/VT(alv) between groups were significant (P<0.001). Except for baseline, all values in kPa (sd) were higher in the ARS than in the control group (P<0.001), respectively [70 (7) and 55 (9); 33 (9) and 24 (10); 33 (8) and 22 (10); 70 (7) and 55 (10)].

Conclusions: Recruitment of both lungs before instituting OLV not only decreased alveolar dead space but also improved arterial oxygenation and the efficiency of ventilation.