Background and Goal of the Study: In recent literature it is has been suggested that deep neuromuscular block (NMB) improves surgical conditions during laparoscopy. The effect of deep NMB on postoperative respiratory function was not investigated in laparoscopic bariatric surgery. We investigated the respiratory function after anaesthesia with deep NMB and moderate NMB. This study was funded by MSD.
Materials and methods: Eligible patients were >18 years of age and were obese (BMI>30kg/m2) or morbidly obese (BMI>40kg/m2) and scheduled to undergo laparoscopic gastric bypass surgery. Patients were stratified according to their BMI and evenly randomized over a deep NMB-group (rocuronium bolus and infusion maintaining a posttetanic count of 1-2, reversal with sugammadex 4mg/kg) and a moderate NMB-group (rocuronium bolus and top-ups maintaining a train-of-four count of 1-2, reversal with neostigmine 50µg/kg and glycopyrolate). Anaesthesia was induced and maintained with propofol and remifentanil. In both groups patients were extubated when the TOF-ratio was >0.9. The primary outcome measure was the postoperative pulmonary function assessed by peak expiratory flow (PEF), forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) and measured with an electronic portable peak flow meter. Data are presented as mean±SEM.
Results and discussion: After IRB approval and obtaining informed consent, 60 patients were included in the study. After surgery, all the pulmonary function tests were considerably impaired in both groups when compared to baseline (see Table 1). There was no statistically significant difference in the decrease in PEF, FEV1 and FVC (expressed as % change from baseline) between the deep and the moderate NMB-group (51.3±6.0% vs. 51.5±3.5%; P=0.97, 45.2±6.9% vs. 48.8±3.6%; P=0.64, 51.9±3.1% vs. 49.0±4.2%; P=0.29, respectively). In the deep NMB-group, 2 patients required postoperative non-invasive CPAP vs. 1 patient in the moderate NMB-group (P=0.6). No patient needed reintubation after surgery.

The effect of deep versus moderate neuromuscular block on postoperative respiratory function in bariatric laparoscopic surgery: a randomized, double blind clinical trial