[The influence of sevoflurane and isoflurane on the recovery from cisatracurium-induced neuromuscular block.].

BACKGROUND AND OBJECTIVES

The effects of neuromuscular blockers on the neuromuscular junction are potentiated by volatile anesthetics. This study aimed at evaluating the influence of sevoflurane and isoflurane on the recovery of cisatracurium- induced neuromuscular block.

METHODS

Ninety ASA I and II patients undergoing elective surgeries under general anesthesia were included in this study. Patients were allocated in three groups: Group I (sevoflurane), Group II (isoflurane) and Group III (propofol). All patients were premedicated with intramuscular midazolam (0.1 mg.kg-1) 30 min before surgery. Anesthesia was induced with alfentanil (50 microg.kg-1), propofol (2.5 mg.kg-1) and cisatracurium (0.15 mg.kg-1). Patients were then ventilated under mask with 100% O2 until disappearance of all TOF responses when laryngoscopy and tracheal intubation were performed. Volatile agents for anesthetic maintenance were introduced immediately after tracheal intubation in 2% and 1% concentrations, respectively, for sevoflurane and isoflurane, as well as the propofol continuous infusion (7 to 10 mg.kg-1.h-1) for Group III. All patients received a 50% mixture of O2 and N2O. Neuromuscular function was monitored by adductor pollicis muscle acceleromyography with TOF stimulation at 15-second intervals. Clinical duration of neuromuscular block (T1(25%)) and recovery index (RI=T1(25-75%)) were evaluated.

RESULTS

Mean time and standard deviation for clinical duration (T1(25%)) and recovery index (RI=T1(25-75%)) were respectively: Group I (66.2 +/- 13.42 min and 23.6 +/- 5.02 min), Group II (54.4 +/- 6.58 min and 14.9 +/- 3.82 min) and Group III (47.2 +/- 7.43 min and 16.2 +/- 2.93 min). There were significant differences in clinical duration between Groups I and II, I and III and II and III. There was a significant difference in recovery index between Group I and the other groups.

CONCLUSIONS

The recovery from cisatracurium-induced neuromuscular block was longer during anesthesia with volatile agents as compared to propofol. The most pronounced effect was observed with sevoflurane.