Rocuronium is a non depolarizing muscle relaxant of rapid onset and of intermediate duration. It is useful for short operations and for rapid control of the airway in pediatric patients. However the intravenous injection of rocuronium cause pain and a withdrawal movement. The purpose of this study was to evaluate the effect of lidocaine pretreatment in pediatric patients receiving rocuronium (10 mg/ml) and diluted rocuronium (1 mg/ml) on withdrawal movement.

The study was approved by our institutional review board, and informed consent was obtained from all parents. One hundred and twenty five patients, aged from 4 months to 10 years, ASA physical status 1-2 undergoing general anesthesia for elective surgery were randomly enrolled in the study. Allergy history to a trial drug, pediatric patients on analgesics, difficult vein access and severely crying pediatric patients on arrival were excluded. All patients were non-premedicated and had a 22 G i.v. catheter inserted into the dorsum of hand before operation. On arrival in the operation room, routine non invasive monitors were placed and a free flow of i.v. fluid without edema, redness, hardness or pain was confirmed. After the administration of glycopyrrolate 0.004 mg/kg, inhalational induction was performed with 4-8 vol% sevoflurane by face mask fitting. One group received rocuronium 0.3 mg/kg (RS group) or vecuronium 0.05 mg/kg (VS group) was administered after 0.5 ml of 0.9% NaCl. A second group received rocuronium 0.3 mg/kg (RL group) or vecuronium 0.5 mg/kg (VL group) after lidocaine 1 mg/kg. A third group received rocuronium 1 mg/ml diluted with 0.9% NaCl (1:9) (RD group). Muscle relaxant-induced withdrawal movements were assessed by using a 4-grade scales (0-3). We also observed pulse rate alterations. Vein redness was evaluated just after administration and vein hardness five minutes after intubation by using a 4-grade scale (0-3).

Withdrawal movements were more intense in the rocuronium group (R group, 3.8 times, P < 0.01) than in the vecuronium group (V group). Lidocaine pretreatment (L group, 1.8 times, P < 0.01) or diluted rocuronium (RD group, 1.9 times, P < 0.01) decreased withdrawal movement incidence. Withdrawal movement incidence was positive correlated with a change in pulse rate (Spearman's rho = 0.36, P < 0.01).

Lidocaine pretreatment in patients receiving rocuronium (10 mg/ml) or diluted rocuronium (1 mg/ml) effectively reduces withdrawal movement during the administration of rocuronium.