Background : There are situations in anesthesia in which it may be desirable to achieve rapid tracheal intubation. Rapid tracheal intubation with rocuronium has been studied using a probability-based approach. But these studies used intravenous anesthetics for anesthetic induction. Therefore, we aimed to predict doses of rocuronium giving 90% and 95% probabilities of intubation within 60 seconds and to estimate their action durations using sevoflurane for anesthetic induction.
Methods : Anesthesia was induced in sixty patients with sevoflurane. Patients received randomly rocuronium, 0.0, 0.3, 0.6, 0.9 or 1.2 mg/kg (n = 12/dose). Laryngoscopy began 40 seconds later, aiming for intubation at 60 seconds, and conditions were graded as either perfect, acceptable of unacceptable, with the first two conditions being taken as
successful intubation. Duration of action was accepted as time until a twitch height recovery of 15%. The dose versus the fraction of patients showing successful intubation was analyzed by logistic regression. Doses giving 90% and 95% (D90 and D95) probabilities of successful intubation were calculated.
Results : Of the 12 patients in each group (0.0, 0.3, 0.6, 0.9 or 1.2 mg/kg), intubation was successful in 4, 10, 12, 12 and 12 patients, respectively. The D90 and D95 doses were determined to be 0.34 and 0.43 mg/kg, respectively.
Conclusions : After induction with sevoflurane, rocuronium at 0.43 mg/kg, gives a 95% probability of successful intubation at 60 seconds.ope
