Nitrous oxide for the prevention of rocuronium injection pain: A randomized, double-blind, controlled clinical trial

Abstract

Background: Pain on injection of rocuronium bromide is a common side-effect in anesthetic practice. This study has been carried out to assess the effect of nitrous oxide on the pain and withdrawal response caused by rocuronium injection. Materials and Methods: A prospective, randomized, double-blind, placebo-controlled study was carried out in the department of Anesthesiology, Regional Institute of Medical Sciences, Imphal to determine the effect of nitrous oxide (N 2 O) on the frequency and severity of pain and withdrawal reactions after injection of rocuronium. 80 (Eighty) ASA physical status I and II patients undergoing general anesthesia for elective surgery were enrolled. The patients were divided into group O and group N and randomized to receive 100% oxygen (O 2 ) or 50% N 2 O in O 2 for 2 minutes followed by a sub-paralyzing dose of rocuronium 0.06 mg/kg. After induction of anesthesia with thiopentone 5 mg/kg, an intubating dose of rocuronium 0.6 mg/kg was given. The patients were observed after injection of rocuronium 0.06 mg/kg, and asked to rate pain in the arm on a 4-point (0-3) verbal rating scale (none, mild, moderate or severe). After the intubating dose of rocuronium, withdrawal reactions were recorded. Results: Thirty-five patients (87.5%) in the group N and 20 patients (50%) in the group O reported no pain (P <0.001). The pain was mild in 5 (12.5%) and 20 (50%) patients in nitrous group and oxygen group, respectively, (P < 0.001). Withdrawal response after an intubating dose of rocuronium was observed in 4 (10%) and 11 (27.5%) patients in the N 2 O and O 2 groups, respectively, (P <0.05). No patients reported moderate or severe pain. Conclusion: Inhalation of 50% N 2 O in O 2 reduces the incidence and severity of pain and the withdrawal reactions associated with rocuronium injection.