neuromuscular blocking effect of full and half equipotent doses of d-tubocurarine and vecuronium combinations versus d-tubocurarine alone

ABSTRACT

This study was carried out on 30 patients [17 males and 13 females] undergoing elective surgical procedures under general anaesthesia. No patient had neuromuscular [NM], renal, cardiovascular, respiratory or hepatic diseases. All patients were premedicated with 10 mg of diazepam orally and 1 mg of atropine intramuscular 1 hour pre-operatively. Anaesthesia was induced with thiopental 4-5 mg/kg, while the equipment for monitoring the neuromuscular function [The Myograph 2000-Biometer], being attached to the patient. Succinuyl-choline in a dose of 1 mg/Kg was used to facilitate tracheal intubation Anaesthesia was maintained with nitrous oxide [N2O] in oxygen [73 L/min] and 0.5% Halothane with increments of 20 mg pethidine given if needed. After stabilization of twitch response of train-of-four [TOF], the muscle relaxant under study was given and patients were classified into 3 groups. The first group received 0.3 mg/Kg of d-Tubocurarine [dtc], the second group received 0.03 mg/Kg of dtc plus 0.005 mg/Kg of vecuronium [Vecu.] The third group received 0.015 mg/Kg of dtc plus 0.0025 mg/Kg of vecu. At the end of the surgical procedure, spontaneous recovery was allowed to occur and the residual blockade was antagonized. The onset times and 5% to 25% recovery times were estimated. This study was carried out to evaluate the NM blocking effect of combinations of dtc and vecu. in full and half equipotent doses of each drug versus dtc alone. It was found that full equipotent doses of dtc plus vec. can produce 95% depression of NM function as dtc alone; while Half equipotent doses can not produce more than 60% depression of NM function and all patients received the combinations of the two drugs recovered significantly more quickly than patients received dtc alone