Succinylcholine is still the most frequently used muscle relaxant for rapid-sequence intubation despite its well-known side effects. Rocuronium has been reported to develop a rapid onset of action and may be suitable as a component of a rapid-sequence intubation. The purpose of this study was to compare tracheal intubating conditions by following different rocuronium doses and application techniques versus succinylcholine.

Fifty nine ASA physical status 1 and 2 adult patients scheduled for elective surgeries were anesthetized with thiopental sodium 5 mg/kg and muscle relaxant using a rapid-sequence technique. Group I (n = 12) received succinylcholine 1.0 mg/kg, group II (n = 15) received rocuronium 1.0 mg/kg, group III (n = 16) received rocuronium 0.6 mg/kg as a single bolus dose, and group IV (n = 16) received a priming dose of rocuronium 0.06 mg/kg followed three minutes later by rocuronium 0.54 mg/kg. Intubation was performed 60 seconds after the administration of muscle relaxant and intubating conditions were evaluated by clinical scoring (Table 1), and train-of-four (TOF) count of the adductor pollicis by accelerography.

TOF counts of group I were lower than those of groups III and IV, and those of group II were lower than group III (P < 0.0083). Group II had intubating conditions similar to group I. The intubating conditions of groups I and II were better than those of groups III and IV (P < 0.0083).

Rocuronium 1.0 mg/kg may be a suitable alternative for succinylcholine 1.0 mg/kg during rapid-sequence intubation. Priming principle does not produce faster or better intubating conditions than a single bolus injection.