A Prospective, Randomized, Double-Blind Study of the Incidence, Severity, and Risk Factors of Clenching Induced by Sugammadex During Neuromuscular Blockade Reversal

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."