Thiopental-Rocuronium Versus Ketamine-Rocuronium for Rapid-Sequence Intubation in Parturients Undergoing Cesarean Section

We investigated the neuromuscular effects and conditions of tracheal intubation after administration of rocuronium in 40 parturients undergoing elective cesarean section. After preoxygenation, anesthesia was induced in 20 patients by thiopental 4 mg/kg and, in the other 20 patients, by ketamine 1.5 mg/kg. Rocuronium 0.6 mg/kg was then administered, and neuromuscular transmission was assessed using electromyographic response to train-of-four stimulation of the ulnar nerve at the wrist every 10 s. The time to T1/control ratio of 50% neuromuscular block (NMB) as well as the time to maximum NMB (onset time) were compared in the two groups. The time to 50% block was 45 +/- 10 s in the thiopental group and 42 +/- 14 s in the ketamine group, while the onset time was 105 +/- 35 s in the thiopental group and 101 +/- 35 s in the ketamine group. Neither the time to 50% NMB nor the onset time were significantly different between the two groups. Tracheal intubation at 50% NMB was easily performed in all patients in the ketamine-rocuronium group but was difficult in 75% of the thiopental-rocuronium group. We concluded that ketamine 1.5 mg/kg followed by rocuronium 0.6 mg/kg may be suitable for rapid-sequence induction of anesthesia in parturients undergoing cesarean section.