Evaluation of neuromuscular blockade with vecuronium during general anesthesia with oxygen, nitrous oxide, isoflurane versus oxygen, air, isoflurane: A randomized controlled study

Abstract

Background: The use of air oxygen mixture with isoflurane has become more common in the place of nitrous oxide, especially in laparoscopic and abdominal surgeries. With a varied mixture of gases and isoflurane used in general anesthesia, the exact dosing requirement and time duration of action have not been precisely studied with vecuronium when given as a bolus, as is given routinely. Purpose: This study was undertaken to evaluate and compare the neuromuscular effect of vecuronium during anesthesia with oxygen, nitrous oxide and isoflurane versus oxygen, air and isoflurane. Methodology: The study was a prospective, randomized controlled trial on 70 patients allocated into two groups as follows: Group N (nitrous oxide group) and Group A (medical air group). The primary objective was to measure and compare the posttetanic count (PTC 1 ) – train of four (TOF 1 ) interval, to evaluate the time taken for recovery from the intense blockade in both groups. The secondary objectives were to compare time duration for twitch height depression to be 30% of baseline after administering vecuronium, time duration from vecuronium administration to appearance of the first PTC 1 , PTC (n) at the reappearance of the 1 st twitch, time interval between TOF 1 and TOF 3 and time from vecuronium administration to appearance of TOF 3 in both the groups. Results: There is no significant difference between both the groups with reference to the block onset time using 30% depression of single twitch and recovery time from neuromuscular blockade using PTC, PTC 1 -TOF 1 and TOF 1 -TOF 3 time intervals. Conclusion: Measuring and comparing neuromuscular transmission monitoring parameters such as the onset time(ST depression to 30%), and recovery using PTC, PTC 1 -TOF 1 and TOF 1 -TOF 3 time intervals, it is concluded that the character of neuromuscular block with vecuronium is unaffected and not prolonged with or without nitrous oxide when used with isoflurane.