Sugammadex-Induced Clenching During Neuromuscular Blockade Reversal

Study Objective: This study aims to evaluate the incidence, severity, and risk factors of sugammadex-induced mouth clenching during neuromuscular blockade (NMB) reversal in adult surgical patients. Study Design: This prospective, randomized, double-blind, controlled clinical trial enrolls adult patients (ASA physical status I-II, aged 19-70 years) undergoing elective surgery under general anesthesia with rocuronium. Patients will be randomized into four groups to receive either sugammadex at doses of 1 mg/kg, 2 mg/kg, or 4 mg/kg, or a combination of pyridostigmine and glycopyrrolate. Primary Outcome: The primary outcome is the incidence of clenching within 10 minutes after NMB reversal, assessed by clinical observation, masseter EMG, and airway pressure changes, using a novel five-grade severity scale. Secondary Outcomes: Secondary outcomes include the severity of clenching, time to TOF ratio ≥0.9, BIS values at clenching onset, complications, and identification of risk factors such as dose, sex, BIS, age, BMI, and rocuronium dose. Significance: This study seeks to improve perioperative safety by identifying modifiable risk factors and informing dose adjustments or alternative reversal strategies to prevent sugammadex-induced clenching, particularly in high-risk populations.

This prospective, randomized, double-blind clinical trial aims to investigate the incidence, risk factors, and clinical implications of sugammadex-induced clenching during neuromuscular blockade reversal under general anesthesia. Sugammadex, a selective relaxant binding agent, is widely used for the rapid reversal of rocuronium-induced neuromuscular blockade. However, reports of jaw clenching and masseter muscle contraction following sugammadex administration have raised safety concerns, particularly regarding airway management and patient discomfort during emergence from anesthesia. A total of 240 adult patients (ASA physical status I-II, aged 19 to 70 years) scheduled for elective surgery under general anesthesia with rocuronium will be enrolled. Participants will be randomly assigned to one of four groups in a 1:1:1:1 ratio: sugammadex 1 mg/kg (S1), 2 mg/kg (S2), 4 mg/kg (S4), or pyridostigmine 0.2 mg/kg with glycopyrrolate 0.01 mg/kg (PG) as the control. Clenching events will be assessed within 10 minutes of drug administration using three criteria: visible jaw clenching, increased masseter electromyographic (EMG) activity (\>50 μV for ≥2 seconds), and a rise in airway pressure (\>5 cm H₂O). Severity will be graded using a novel five-level classification system. Secondary outcomes include the severity and timing of clenching, time to train-of-four (TOF) ratio ≥0.9, bispectral index (BIS) value at the time of clenching onset, airway-related complications, and risk factor analysis based on dose, sex, BIS, age, BMI, and total rocuronium dose. This study hypothesizes a dose-dependent increase in clenching with higher doses of sugammadex, potentially with a higher incidence in female patients and those with higher BIS values at reversal."