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 H₂O, 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 CO₂ 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/cmH₂O when patients were turned from the supine to the lateral position (T1 vs. T2; P < 0.001), and decreased further to 31.07 mL/cmH₂O after CO₂ insufflation (T2 vs. T3; P < 0.001). Compliance increased to 50.8 mL/cmH₂O after desufflation and 54.4 mL/cmH₂O 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/cmH₂O (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.

Keywords: Atelectasis, Dynamic compliance, Laparoscopic surgery, Pneumoperitoneum, Pulmonary recruitment maneuver