A novel stimulating electrode attachment method designed to maintain electromyography-based neuromuscular monitoring detectability during laparoscopic surgery: a single-center randomized, double-blind, controlled pilot study.

Purpose: We evaluated the electromyography (EMG)-based neuromuscular monitoring detectability of our novel stimulating electrode attachment method compared to the original Nihon-Kohden (Tokyo, Japan) attachment method.

Methods: This single-center randomized, double-blind, controlled pilot study enrolled 32 patients aged ≥ 18 years, undergoing scheduled laparoscopic surgery. The EMG electrode NM-345Y™ was attached to one forearm using the Nihon-Kohden method (Pattern N-K) and the other forearm using our novel method (Pattern Cross). The allocation to each attachment method was determined post-randomization. In Pattern Cross, the NM-345Y™ was attached such that the line connecting the anode and cathode crosses the ulnar nerve. Patients received 0.9 mg/kg rocuronium after calibration with the forearm in 90-degree supination. Following tracheal intubation, the forearm was positioned in 0-degree pronation. Intraoperatively, 0.2 mg/kg rocuronium was administered if the train-of-four (TOF) count one persisted for 1 min on either side. Post-surgery, the forearm position was returned to 90-degree supination, and rocuronium was antagonized with sugammadex. TOF and post-tetanic count (PTC) were simultaneously measured bilaterally every 15 s and 5 min, respectively, from post-calibration to tracheal extubation.

Results: The time to first PTC appearance was significantly shorter by 33 min in the Pattern Cross group than in the Pattern N-K group (95% Confidence interval: 1-66, p = 0.043). Following sugammadex administration, TOF ratios ≥ 0.9 were achieved in 72% of patients in the Pattern N-K group and 97% of those in the Pattern Cross group (p = 0.025).

Conclusions: Crossing the line connecting the anode and cathode with the ulnar nerve stabilizes EMG-based neuromuscular monitoring detectability.