RESUMEN
BACKGROUND: Laparoscopic cholecystectomy performed during low intraabdominal pressure (<12 mm Hg) is associated with significantly less postoperative pain than standard pressure (≥12 mm Hg). The impact on surgical space conditions and safety of operating at lower pressures has not been adequately described, but deep neuromuscular blockade may be beneficial. We investigated if deep muscle relaxation would be associated with a higher proportion of procedures with "optimal" surgical space conditions compared with moderate relaxation during low-pressure (8 mm Hg) laparoscopic cholecystectomy. METHODS: In this assessor-blinded study, 48 patients undergoing elective laparoscopic cholecystectomy were administered rocuronium for neuromuscular blockade and randomized to either deep neuromuscular blockade (rocuronium bolus plus infusion maintaining a posttetanic count 0-1) or moderate neuromuscular blockade (rocuronium repeat bolus only for inadequate surgical conditions with spontaneous recovery of neuromuscular function). Patients received anesthesia with propofol, remifentanil, and rocuronium. The primary outcome was the proportion of procedures with optimal surgical space conditions (assessed by the surgeon as 1 on a 4-point scale). Secondary outcomes included the proportion of procedures completed at pneumoperitoneum 8 mm Hg and surgical space conditions on dissection of the gallbladder (numeric rating scale 0-100; 0 = optimal surgical space conditions; 100 = unacceptable surgical space conditions). RESULTS: Optimal surgical space conditions during the entire procedure were observed in 7 of 25 patients allocated to deep neuromuscular blockade and in 1 of 23 patients allocated to moderate blockade (P = 0.05) with an absolute difference of 24% between the groups (95% confidence interval, 4%-43%). Laparoscopic cholecystectomy was completed at pneumoperitoneum 8 mm Hg in 15 of 25 and 8 of 23 patients in the deep and moderate group, respectively (95% confidence interval, -2% to 53%; P = 0.08). Surgical space conditions during dissection of the gallbladder assessed by use of the numeric rating scale were 20 (10-50) (median [25%-75% range]) in the deep neuromuscular blockade group and 30 (10-50) in the moderate group (P = 0.58; Wilcoxon-Mann-Whitney odds, 1.2; 95% confidence interval, 0.6-2.5). No operations were converted to laparotomy. CONCLUSIONS: Deep neuromuscular blockade was associated with surgical space conditions that were marginally better than with moderate muscle relaxation during low-pressure laparoscopic cholecystectomy.