Comparison of Succinylcholine, Rocuronium, and Rocuronium with Magnesium on Time of Onset of Paralysis in Adult Patients Undergoing Rapid Sequence Induction: A Double Blinded Randomised Control Trial.

Objective: We compared magnesium sulphate pre-treatment with rocuronium at a dose of 0.9 mg kg^-1 to the standard succinylcholine (1 mg kg^-1) in rapid sequence induction to see if this combination had an onset of paralysis comparable to succinylcholine.

Methods: This was a prospective, single-centre, double-blinded, parallel-arm, randomized controlled trial on patients aged 18-60 years, either sex, the American Society of Anesthesiologists I and II. Patients received a 100 mL normal saline infusion followed by either succinylcholine at 1 mg kg^-1 (Group S), or rocuronium 0.9 mg kg^-1 (Group R), or a 100 mL normal saline infusion containing magnesium sulphate 60 mg kg^-1, followed by rocuronium 0.9 mg kg^-1 (Group MgR). The primary outcome was the time of onset of paralysis evidenced by fading of train-of-four (TOF). Secondary outcomes were the intubation conditions, and the laryngoscopy response.

Results: Data from 135 patients showed TOF fading times differed significantly across the groups, with Group S showing a median (interquartile range-IQR) of 65 (61-70) seconds, Group R 102 (98-108) seconds, and Group MgR 82 (79-85) seconds (P < 0.001). The ease of laryngoscopy and response to cuff inflation showed no significant difference (P=1.000). Analysis of the position of the vocal cords suggested a significant difference (P < 0.001). Finally, the total intubating conditions indicated a significant difference among the groups (P < 0.001), favouring Group MgR for excellent intubating conditions.

Conclusion: The onset of action was significantly faster with succinylcholine than with magnesium sulphate-rocuronium. Nevertheless, it was significantly faster with magnesium sulphate-rocuronium than with rocuronium alone. However, the intubation conditions were better when magnesium was added to rocuronium.