Restoration of pulmonary compliance after laparoscopic surgery using a simple alveolar recruitment maneuver

Abstract

Study objective: To test the hypothesis that a pulmonary maneuver designed to recruit additional alveoli (thereby decreasing atelectasis) applied before extubation can restore pulmonary compliance to baseline values.

Design: Cohort study.

Setting: Operating room of a university hospital.

Patients: 20 ASA physical status I and II patients scheduled to undergo laparoscopic radical nephrectomy.

Interventions: Participants received a balanced general anesthesia using intermittent positive pressure ventilation. A pulmonary recruitment maneuver was performed as a single manual inflation of the lungs to 40 cm H(2)O, maintained for 10 seconds after release of pneumoperitoneum.

Measurements: Respiratory mechanics including dynamic compliance were measured continuously using the VenTrak respiratory mechanics monitor (VenTrak; Novametrix, Wallingford, CT, USA). Respiratory measures were recorded together with arterial blood gases after induction (T1), with the patient placed in the lateral "jackknife" position (T2), 10 and 120 minutes after CO(2) insufflation (T3 and T4), immediately after desufflation in the lateral and supine positions (T5 and T6), and 10 minutes after a pulmonary recruitment maneuver at the conclusion of surgery (T7). Outcome data were analyzed using analysis of variance for repeated measures; P < 0.05 was defined as statistically significant.

Main results: On average, compliance decreased from an initial value of 63.5 to 52.6 mL/cm H(2)O when patients were turned from the supine to the lateral position (T1 vs. T2; P < 0.001), and decreased further to 31.07 mL/cm H(2)O after CO(2) insufflation (T2 vs. T3; P < 0.001). Compliance increased to 50.8 mL/cm H(2)O after desufflation and 54.4 mL/cm H(2)O after turning the patient to the supine position, but did not return to baseline levels until after performance of the pulmonary recruitment maneuver, 64.3 mL/cm H(2)O (T6 vs. T7; P < 0.001, and T1 vs. T7; P = 0.73).

Conclusions: Respiratory mechanics do not fully return to baseline levels after desufflation following laparoscopy; however, lung compliance can be fully restored using a simple alveolar recruitment maneuver.