بررسي مقايسه اي تاثير پيش درماني با پانكورو نيوم و آتراكوريوم بر طول اثر ساكسينيل كولين

EVALUATION OF EFFECT OF PRE-TREATMENT WITH PANCURONIUM AND ATRACURIUM ON D URATION OF EFFECT OF SUCCINYLCHOLINE

Introduction: Prevention of succinylcholine induced fasciculation by means of pre-treatment with nonparalizing doses of nondepolarizing neuromuscular blocking drugs can affect both the quality and duration of neuromuscular-blocking effect of succinylcholine. Shortening or prolongation of succinylcholine effect is important because paralizing doses of nondepolarizing muscle relaxant should not be administered until succinylcholine induced paralysis disappears. Review of Medline 2003 and proquest 2003 softwares showed that from among the studies performed on pretreatment and defasciculation in the last 15 years, only the survey of Ebeling has focused on alteration of duration of action of succinylcholine following pretreatment. Methods: In his study, Ebeling found that duration of action of succinylcholine was shortened following pre-treatment with atracurium while pre-treatment with pancuronium caused its prolongation. In this Randomized clinical trial study ,duration of action of succinylcholine following pre-treatment with atracurium and and pancuronium was determined in 98 patients aged 20-50 yrs with ASA physical status I and II scheduled for elective surgical procedure under general anesthesia. The patients were randomly divided into three groups: group A atracurium (33 cases) , group B pancuronium (33 cases) , and group C control (32 cases). Before injection of succinylcholine , atracurium 50 µglkg and pancuronium 10µg/kg was administered intravenously to group A and B , respectively . Patients in group C did not receive any drug as pre-treatment . Time between disappearance of first response wave toT.O.F stimulation of ulnar never at wrist to reappearance of it was defined as duration of action of succinylcholine and duly recorded. Results : Duration of action of succinylcholine after pre-treatment with atracurium (5.58 ± 0.24minutes) was shorter than control group (7.36 ± 0.26 minutes); while pancuronium (10.79± 0.29) pre-treatment prolonged it. Differences between the three groups were statistically significant (p<0.001). The prolonged duration of succinylcholine effect after pancuronium is probably due to known inhibition of pseudocholine-esterase by pancuronium by competitive antagonism of acetylcholine receptors. Conclusion: Atracurium increases the concentration of unbounded succinylcholine and therefore shortens the duration of effect of succinylcholine .