Neuromuscular and Cardiovascular Effects of Pipecuronium Bromide

Hwang, Kyung Ho; Park, Wook; Kim, Sung Yell

Abstract

Pipecuronium bromide is a new biaquaternary steroid-type neuromuscular bloeking agent that is closely similar to pancuronium and vecuronium in chemical structure. The purpose of this study was to evaluate neuromuscular and cardiovascular effects of pipecuronium bromide in patients under enflurane anesthesia in comparison with those of pan- curonium and vecuronium bromide. 35 ASA class I or II adult patients were assigned to one of the following groups; pipecuro- nium 0.08mg/kg(n=15), vecuronium 0.08mg/kg(n=10), and pancuronium 0.1 mg/kg(n=10) as a bolus dose. To investigate cumulative effect of pipecuronium, an additional incremental doses (1 mg) of pipecuronium were given repeatedly to 5 patients in pipecuronium group at every 25% recovery of first twitch height(Ti) of train-of four(TOF) stimulation after administration of in- itial dose. Anesthesia was induced with iv thiopental 5-6 mg/kg and inhalation of 0 (21/min.)-NO(41/ min.)-enflurane(2%), and maintained with O(11/min.)-NA3(21/min.)-enflurane(1-2%). All pa- tients were intubated at 5 minutes after administration of one of these muscle relaxants fol- lowing T> of TOF was depressed more than 95% of control height. Neuromuscular blocking effect was assessed by electromyographic response of hypothenar muscles in response to TOF stimulation of ulnar nerve every 20 seconds at wrist throughout study. Heart rate, systolic and diastolic blood pressures, and mean arterial pressure were noninvasively measured for 20 minutes after adminisf,ration of muscle relaxant. The results obtained were as follows, 1) The onset times from administration of vecuronium, pipecuronium, and paneuronium to 95% depression of T, were 3.4k0.88, 3.8k0.21, and 4.3+/-0.86min. respectively. The onset time of pipecuronium was similar to that of vecuronium but significantly shorter than that of pancur- onium(p<0.05). 2) The duration of action from administration of pipecuronium to 25% reeovery of T was 92.9 +/-15.3min. which was significantly shorter than that of pancuronium(115.2 +/-17.04min., p< 0.05) and longer than that of vecuronium(27.5 +/-5.89 min., p<0.05). 3) Recovery index of pipecuronium was 39.5+7.53min. which was also shorter than that of pancuronium(46.2+/-3.52 min., p < 0.05) and longer than that of vecuronium(13.3+/-1.77 min., p < 0.05). 4) Durations from 10% to 25% recovery of T1 hy additional incremental doses of pipecuronium were not altered significantly by the repeated administration. 5) There were no significant changes on heart rate and blood pressure by 0.08 mg/kg of pipecuronium or vecuronium while heart rate was increased in 21% to 27% for 20 min. after administration of pancuronium. In conclusion, pipecuronium bromide appears to be a useful alternative to pancuronium or vecuronium in relatively long duration of muscular relaxation in patients in whom hemodynamic changes, especially tachycardia, must be avoided.