The Effect of Deep Neuromuscular Block on Surgical Condition During Laparoscopic Colorectal Surgery (DEEPCOL)

Patients >18 years of age with an america society of anesthesiologist classification of I or II who were scheduled to undergo elective laparoscopic colorectal surgery were included. The exclusion criteria were a history of neuromuscular, renal, or hepatic disease, a history of low abdominal surgery; treatment with drugs known to interfere with neuromuscular function. Patients were randomised to either the moderate or deep neuromuscular blockade group using Random Allocation Software (version 1.0). Premedication with intravenous midazolam at 0.03 mg/kg was performed in the reception area. In the operating room, routine monitoring was performed, including electrocardiography, non-invasive arterial pressure measurements, and pulse oximetry. Additionally, acceleromyography was applied to monitor the response of the corrugator supercilii muscle. Neuromuscular management and monitoring were performed according to the Good Clinical Research Practice guidelines. After the induction of anaesthesia with propofol and remifentanil using target-controlled infusers and before rocuronium administration, the TOF-Watch-SX was calibrated and stabilised; a 50-Hz tetanic stimulation was applied for 5 s, the TOF-Watch-SX was calibrated, and a series of train-of-four (TOF) measurements were documented for >2 min until a stable baseline was obtained (<5% variation in the TOF ratios). Next, intravenous rocuronium at 0.6 mg/kg was administered, and tracheal intubation was performed after confirmation of relaxation. Anesthesia was maintained with desflurane and target-controlled infusion of remifentanil while monitoring the bispectral index. A continuous dose of intravenous rocuronium (10-60 mg/hr) was used to maintain moderate (TOF count of 1 or 2) or deep (post-tetanic count [PTC] of 1 or 2) neuromuscular blockade. The IAP alarm(IAP>15mmHg) rate were checked. Any movement during the operation as reported by the surgeon or anaesthesiologist was recorded. At the end of the operation, the surgeon rated the surgical condition on a 5-point scale. Patients in the moderate group were reversed with neostigmine at 50 µg/kg and glycopyrrolate at 10 µg/kg at a TOF count of 1 or 2, and patients in the deep group were reversed with intravenous sugammadex at 4 mg/kg at PTC of 1 or 2. The time from administration of the reversal agents to a TOF ratio of 0.9 was recorded. Postoperative pain and opioid consumption were evaluated at 24, 48h postoperatively. Postoperative nausea and/or vomiting, dry mouth, were also evaluated at the same time points.