Recruitment of lung volume during surgery neither affects the postoperative spirometry nor the risk of hypoxaemia after laparoscopic gastric bypass in morbidly obese patients: a randomized controlled study

Abstract

Intraoperative recruitment manoeuvres (RMs) combined with PEEP reverse the decrease in functional residual capacity (FRC) associated with anaesthesia and improve intraoperative oxygenation. Whether these benefits persist after operation remains unknown. We tested the hypothesis that intraoperative RMs associated with PEEP improve postoperative spirometry including FRC and reduce the incidence of postoperative hypoxaemia in morbidly obese (MO) patients undergoing laparoscopic gastric bypass. After IRB approval and informed consent, 50 MO patients undergoing laparoscopic gastric bypass under volume-controlled ventilation (tidal volume 6 ml kg(-1) of IBW) were randomly ventilated with either 10 cm H₂O PEEP or with 10 cm H₂O PEEP and one RM carried out after induction of pneumoperitoneum, and another after exsufflation. Anaesthesia and analgesia were standardized. Spirometry was assessed before operation and 24 h after surgery. Postoperative oxygenation and the apnoea-hypopnoea index (AHI) were recorded during the first postoperative night. Age, BMI, and STOP BANG score were similar in both groups. FRC decrease after surgery was minimal [0.15 (0.14) litre in control and 0.38 (0.19) litre in the RM group] and similar between the groups (P=0.35). FVC, FEV1, mean [Formula: see text], percentage of time spent with [Formula: see text] below 90%, and AHI did not differ significantly between the groups. This study demonstrates that when added to a protective mechanical ventilation combining low tidal volume and high PEEP, two RMs do not improve postoperative lung function including FRC, arterial oxygenation, and the incidence of obstructive apnoea in MO patients after laparoscopic upper abdominal surgery. EudraCT 2011-000999-33.