It is well known that burn patients are resistant to the action of nondepolarizing muscle relaxants. Rocuronium, with a shorter onset time and freedom from electrolyte side effects, may be considered for rapid sequence induction in these circumstances. This randomized, double-blind study was conducted to assess the onset time, duration of action of neuromuscular blockades and the intubating conditions induced by rocuronium in major burn patients.

Adult patients, suffered from major burn injury, aged 18-59 years, ASA physical status I or II, more than 4 weeks and less than 6 months after the initial injury, were included. Propofol and fentanyl based intravenous anesthesia was conducted with nitrous-oxide and oxygen. Neuromuscular blockade was monitored by acceleromyography, TOF-Watch(R) (Organon Teknika B.V., Boseind, The Netherlands), using Train-of-Four (TOF) stimulation. Rocuronium (Esmeron, Organon Inc, USA), at ED95 x 3 (0.9 mg/kg) and ED95 x 4 (1.2 mg/kg) were given intravenously over 5 s in both groups of burn and nonburn patients, respectively. Onset time, duration of action, and intubating conditions were assessed and graded according to the Guidelines for Good Clinical Research Practice.

Average burn TBSA were between 30% and 40%, and the elapsed time after the initial injury was approximately a month. Demographic data revealed no significant differences between burn and nonburn groups. The average time to 95% neuromuscular block was significantly prolonged in the burn group compared to the non-burn group (115.0 ± 58.4 vs. 68.4 ± 15.8 sec at 0.9 mg/kg, 86.1 ± 19.7 vs. 56.9 ± 10.9 sec at 1.2 mg/kg, P < 0.05). Time to reappearance of T1 and duration TOF ratios 0.1, 0.25, 0.75 and 0.8 with respect to baseline were significantly shorter in the burn group. Intubating conditions ranged from good to excellent in the majority. When the different dosages were compared in the burn groups, all measured parameters improved as the dose was increased.

Rocuronium showed significant resistance in the neuromuscular blockade of burn patients, which appeared to improve as increasing the dosage.