Recruitment maneuvers and lung ultrasound-assessed aeration in laparoscopic cholecystectomy : A prospective randomized controlled trial.

Abstract

Background: General anesthesia and CO₂ pneumoperitoneum during laparoscopic cholecystectomy can cause regionally heterogeneous loss of lung aeration. We evaluated whether two scheduled alveolar recruitment maneuvers (RM), added to otherwise identical low tidal volume ventilation, altered perioperative aeration measured by lung ultrasound (LUS).

Methods: In this single-center, prospective, randomized controlled trial, 80 adults (American Society of Anesthesiologists (ASA) physical status I-III) scheduled for elective laparoscopic cholecystectomy were allocated 1:1 to an RM group (n = 40) or a no RM control group (n = 40). Both groups received tidal volumes of 6-8 mL/kg predicted body weight and positive end-expiratory pressure (PEEP) of 5 cmH2O₂O. In the RM group, a stepwise RM was performed immediately after establishment of pneumoperitoneum and repeated after pneumoperitoneum deflation, before emergence and extubation. An 8‑zone LUS protocol was applied at 5 predefined time points: before induction (T1), 5 min after induction (T2), after the first RM during pneumoperitoneum (T3), immediately after extubation and after the second RM (T4), and 30 min after extubation in the post-anesthesia care unit (PACU) (T5). The primary outcome was the composite LUS score trajectory analyzed using a linear mixed-effects model.

Results: Baseline LUS scores were comparable between groups (median [IQR], 5 [4-6] vs. 5 [4-7]; p = 0.840). After pneumoperitoneum and the first RM, the LUS scores were lower in the RM group than in the no RM control group (3 [2-4] vs. 7 [5-8.25]; p < 0.001). The difference persisted immediately after extubation (4 [3-5] vs. 6 [5-7]; p < 0.001) and at PACU assessment (3 [2-4] vs. 6 [4-7.25]; p < 0.001). The group × time interaction was significant (χ²(4) = 63.02; p < 0.001) and remained significant after adjustment for age, sex, ASA status, and body weight. No significant between-group differences were detected in SpO₂, mean arterial pressure, or heart rate at any assessment (all p ≥ 0.070). No recruitment maneuver required premature termination for excessive peak inspiratory pressure or hemodynamic instability, and no rescue interventions were needed.

Conclusion: Two scheduled RMs were associated with lower perioperative LUS scores through early PACU follow-up without detectable differences in the recorded oxygenation or hemodynamic variables. These findings demonstrate a physiological improvement in regional aeration but do not establish a reduction in postoperative pulmonary complications or other patient-centered outcomes.