The priming technique, in which a small dose of nondepolarizing muscle relaxant is administered 3–6 minutes before giving the intubation dose, can speed up the onset of muscle relaxation in patients with paralysis during intubation. We investigated the priming technique and compared 2 different priming agents (rocuronium and cisatracurium) at a priming time of 3 minutes and its effect on decreasing the onset time of cisatracurium.
A total of 60 patients with ASA physical status I–II scheduled for elective surgery were enrolled. After induction with propofol and fentanyl, the patients were randomized into 1 of 3 groups. Group 1 received rocuronium 0.06 mg/kg as a priming dose. Group 2 received cisatracurium 0.01 mg/kg as a priming dose. Group 3 received normal saline and constituted the control group. After a 3-minute priming time, intubation doses of cisatracurium were given (Groups 1 and 2, 0.14 mg/kg; Group 3, 0.15 mg/kg). First twitch height percentage (T1/T0%; % of control) and train-of-four percentage (T4/T1%) were recorded every 10 seconds from baseline until T1/T0% reached 0.
Rocuronium (Group 1) and cisatracurium (Group 2) significantly accelerated the onset of cisatracurium (Group 1, 117.0 ± 29.0 seconds; Group 2, 151.0 ± 37.5 seconds; Group 3, 221.5 ± 36.6 seconds; all p < 0.001).
Priming with rocuronium or cisatracurium for 3 minutes significantly accelerated the onset of cisatracurium. Priming with rocuronium for 3 minutes improved the onset time of cisatracurium even more than priming with cisatracurium itself.