The onset of pipecuronium following application of the priming principle

Pipecuronium bromide, a long acting non-depolarizing neuromuscular blocking agent was administered to four groups of 10 patients using the priming technique. The effects of the combination of two different priming doses (0.01 or 0.015 mg kg-1) given at two different time intervals (3 or 4 min) before the 'main' intubating dose (0.07 or 0.065 mg kg-1) were investigated. Onset times were recorded and the intubation conditions were scored and compared with a group of patients receiving the same total amount of pipecuronium (0.08 mg kg-1) in a single bolus injection. Intubating conditions at 90 s after administration of the intubating dose were found to be significantly improved in all primed groups but the onset times, evaluated using the response of the adductor pollicis muscle to a single twitch stimulation, were similar to that observed after the single bolus injection. The optimal priming combination is considered to be 0.01 mg kg-1 of pipecuronium followed 3 to 4 min later by 0.07 mg kg-1.