Vecuronium or suxamethonium for rapid sequence intubation: which is better?

The effects of suxamethonium, and of vecuronium given after three subparalyzing (priming) doses, on the time of onset of neuromuscular blockade and on the resultant intubating conditions were compared. This study involved five groups of 10 patients (ASA class I or II) who were premedicated with flunitrazepam 0.015 mg kg-1 i.m. Anaesthesia was induced with thiopentone 6 mg kg-1 and fentanyl 0.003 mg kg-1. In groups 2, 3 and 4 the patients were given a priming dose of vecuronium 0.01, 0.015 and 0.02 mg kg-1, respectively. Three minutes later the intubating dose of vecuronium was given: 0.1 mg kg-1 (group 1), 0.09 mg kg-1 (group 2), 0.085 mg kg-1 (group 3), 0.08 mg kg-1 (group 4). When the electromyographic response was 95% of control, the trachea was intubated. In groups 2, 3 and 4, the onset time was significantly decreased compared with group 1. Increasing the priming dose from 0.01 mg kg-1 did not offer any advantage. The duration of blockade (time from the intubating dose to 15% recovery) was not significantly increased with any priming dose. In group 5, the trachea was intubated after suxamethonium 1.5 mg kg-1. Mean onset time, which was significantly shorter than in the other groups, was half that of the groups that received a priming dose. Intubation conditions were better in group 5 than in the other groups (P less than 0.01).