ABSTRACT
The neuromuscular blocking and cardiovascular effects of rocuronium (Roc) have been compared with succinylcholine (Scc), mivacurium (Miv) and vecuronium (Vec). Thirty six healthy adult patients were randomly assigned to receive Roc (0.6 mg/kg), Scc (1.0 mg/kg), Miv (0.16 mg/kg) and Vec (0.08 mg/kg) during induction with propofol and fentanyl. The 3M surface electtodes (Red Dot, Ag/AgC1) were applied over the ulnar nerve at the wrist and supramaximal transcutaneous stimulation from a peripheral nerve stimulator (Innervator, Fisher & Paykel, New Zealand) using a 0.2 ms square wave pulses in duration at 0.1 Hz were applied. The twitch response of the thumb adductor was measured mechanomyographically using 2 kg load cell strain gauge (Model No. 505H, RS Component, Ltd, U.K.) with a thumb piece modification. Recordings were made on a Gould TA 240 Easy Graf Thermal Array Recorder with a 6600 series transducer signal. The time from injection of muscle relaxant to complete depression of control twitch height (onset), the time from injection to 25% recovery of control twitch height (clinical duration, CD) and recovery indices (RI, time from 25% to 75% recovery of control twitch height) were measured, and the cardiovascular effects; heart rate (HR) and mean arterial pressure (MAP), were determined before and after injection of muscle relaxants. Onset times for patients, receiving Roc, Scc, Vec and Miv were 65.0+/-13.5 s, 54.0+/-5.2 s, 191.+/-58.0 s and 201.3+/-37.6 s. CDs were 33.6+/-6.6 min, 8.4+/-2.1 min, 21.6+/-4.8 min and 13.0+/-2.2 min. RIs were 12.9+/-4.3 min, 5.5+/-1.2 min, 10.9+/-3.8 min and 6.9+/-1.3 min. There were no significant changes of HR, however MAP were decreased significantly from 2 min after injection of Roc. Consequently, onset time of Roc were faster than that of Miv or Vec and slower than that of Scc but not significant. However, CD and RI of Roc were significantly longer than those of the others, with minimum cardiovascular effects.