Abstract
This randomized controlled study examined intubating conditions and haemodynamic changes following sevoflurane nitrous oxide induction in four groups: three different doses of alfentanil compared with low-dose alfentanil and suxamethonium. All patients received atropine 0.3 mg IV before induction of anaesthesia with vital capacity breaths of sevoflurane 8% (more than 7% in the inspiratory gas) in 60% nitrous oxide and oxygen. Patients were allocated randomly to four groups of intravenous supplements: group SA20, alfentanil 20 μg.kg -1 ; group SA25, alfentanil 25 μg.kg -1 ; group SA30, alfentanil 30 μg.kg -1 ; group SSA, alfentanil 10 μg.kg -1 and suxamethonium 1 mg.kg -1 . Orotracheal intubation and assessment of intubating conditions was performed by one of the investigators who was blinded to the subject's group. Intubating conditions were satisfactory or excellent in 83%, 80%, 92% and 96% of patients in groups SA20, SA25, SA30 and SSA respectively. These differences were not statistically significant. The increase in heart rate associated with laryngoscopy and tracheal intubation was effectively attenuated in all groups. Mean arterial pressure decreased significantly and similarly after induction in all groups. Two minutes after intubation the mean arterial pressure was increased significantly (P<0.05) compared to the post-induction value in group SSA. The intubating conditions obtained with sevoflurane plus alfentanil 30 μg.kg -1 were comparable to those provided by the sevoflurane, suxamethonium and alfentanil 10 μg.kg -1 combination.