Abstract
BACKGROUND: Myocardial injury after non-cardiac surgery (MINS) is a common and serious complication in older patients. This study investigates the impact of neuromuscular block on the MINS incidence and other cardiovascular complications in the early postoperative stage of older patients undergoing laparoscopic colorectal cancer resection. METHODS: 70 older patients who underwent laparoscopic colorectal cancer resection were separated into the deep neuromuscular block group and moderate neuromuscular block group for 35 cases in each group (n = 1:1). The deep neuromuscular block group maintained train of four (TOF) = 0, post-tetanic count (PTC) 1-2, and the moderate neuromuscular block group maintained TOF = 1-2 during the operation. Sugammadex sodium was used at 2 mg/kg or 4 mg/kg for muscle relaxation antagonism at the end of surgery. The MINS incidence was the primary outcome and compared with Fisher's exact test. About the secondary outcomes, the postoperative pain was analyzed with Man-Whitney U test, the postoperative nausea and vomiting (PONV) and the incidence of cardiovascular complications were analyzed with Chi-square test, intraoperative mean artery pressure (MAP) and cardiac output (CO) ratio to baseline, length of stay and dosage of anesthetics were compared by two independent samples t-test. RESULTS: MINS was not observed in both groups. The highest incidence of postoperative cardiovascular complications was lower limbs deep vein thrombosis (14.3% in deep neuromuscular block group and 8.6% in moderate neuromuscular group). The numeric rating scale (NRS) score in the deep neuromuscular block group was lower than the moderate neuromuscular block group 72 h after surgery (0(1,2) vs 0(1,2), P = 0.018). The operation time in the deep neuromuscular block group was longer (356.7(107.6) vs 294.8 (80.0), min, P = 0.008), the dosage of propofol and remifentanil was less (3.4 (0.7) vs 3.8 (1.0), mg·kg(-1)·h(-1), P = 0.043; 0.2 (0.06) vs 0.3 (0.07), μg·kg(-1)·min(-1), P < 0.001), and the length of hospital stay was shorter than the moderate neuromuscular block group (18.4 (4.9) vs 22.0 (8.3), day, P = 0.028). The differences of other outcomes were not statistically significant. CONCLUSIONS: Maintaining different degrees of the neuromuscular block under TOF guidance did not change the MINS incidence within 7 days after surgery in older patients who underwent laparoscopic colorectal cancer resection. TRIAL REGISTRATION: The present study was registered in the Chinese Clinical Trial Registry (10/02/2021, ChiCTR2100043323).