Effect of Oxytocin on the Succinylcholine Induced Neuromuscular Blockade / 대한마취과학회지

ABSTRACT

Oxytocin has a stimulant effect on the smooth muscle of the uterus and mammary gland. Infusion or bolus injection of oxytocin followed later by the administration of succinylcholine is a fairly frequent sequence of events in our practice of obstetrical anesthesia. There were few reports and conflicting results about the effect of oxytocin on the response to a muscle relaxant. To assess the effect of oxytocin on the response to succinylcholine, we studied pregnant women(20 cases) compared with non pregnant women(20 cases). All patients were free of hepatic, renal, endocrine or neuromuscular disease. The ulnar nerve was stimulated at elbow using surface electrodes with square wave, supramaximal stimuli of 0.2 ms duration at a frequency of 1 Hz(Emerson peripheral nerve stimulator, U.S.A). The isometric twitch tension of indirectly stimulated adductor muscle was recorded by biophysiograph(San Ei, Japan). The effect of single bolus injection of oxytocin 10 I.U at the 50% recovery of succinylcholine induced neuromuscular blockade was compared in the pregnant and non pregnant patients. The results were as follows: 1) In the pregnant patients group: Twitch height was unaffected in 50% of patients while 10% of the patients were observed with 100% twitch height depression. Mean maximal twitch height depression was 61.2+/-28.58% and the duration of twitch depression was 95.2+/-43.45 sec. The effect of oxytocin on serum potassium change was not significant statistically(p0.05).