Assessment of Adequate Recovery from Vecuronium - Induced Neuromuscular Blockade

Jang, Jin Ho; Park, Jin Woo; Park, Joo Yeol

Abstract

Time to antagonism induced by pyridostigmine from different levels of neuromuscular blockade was evaluated in 45 patients anesthetized with nitrous oxide, fentanyl, and vecuronium. Neuromuscular blockade, as monitered by train-of-four count, was antagonized at varing degrees of spontaneous recovery. Train-of-four ratio was used as an index of the ability of the patients to maintain adequate spontaneous ventil'ation, and maximum inspiratory pressure as an index of the ability of the patients to protect their airways against aspiration or obstruction. We measured time from administration of pyridostigmine to train-of-four ratio of 70% indicating the recovery of the ability to maintain adquate spontaneous ventilation, and time to maximum inspiratory pressure of -45 cmH2O indicating the recovery of the ability to protect the patients airways against aspiration or obstruction. For a train-of-four count level of 0-1, reversal time to train-of-four ratio of 70% was 22.73+/-3.00 minutes and that to maximum inspiratory pressure of -45 cmH2O was 30.33+/-2.69 minutes. For a train-of-four count level of 2- 3, reversal time to train-of-four ratio of 70% was 17.33+/-3.18 minutes and that to maximum inspiratory pressure of -45cmH2O was 22.27+/-2.91 minutes. For a train-of-four count level of 4, reversal time to train-of-four ratio of 70% was 8.40+/-3.58 minutes and that to maximum inspiratory pressure of -45 cmH2O was 14.60+/-3.11 minutes. It is concluded that the more shallow is the neuromuscular blockade, the more rapid and the safer is the reversal of neuromuscular blockade, although the dose of reversal drug was determined according to the depth of neuromuscular blockade. Moreover, it should take more than 30 minutes to antagonixe profaund neuromuacular hlock- ade induced by vecuronium to such a degree that not only can the patients maintain adequate spontaneous ventilation, but they can maintain the airways and protect them against aspiration as well.