Summary

Background and objective: Volatile anaesthetics inhibit nicotinic acetylcholine receptors at clinically relevant concentrations with higher affinity for the neuronal nicotinic receptor. The inhibitory effects of propofol on nicotinic receptors have only been documented at supraclinical concentrations. The aim of this study was to determine recovery properties and train-of-four (TOF) fade of mivacurium during sevoflurane and propofol anaesthesia, in order to examine any differences both in the enhancement of the neuromuscular block (postjunctional effects) and in TOF fade (prejunctional effects).

Methods: Twenty ASA I–II adult patients were randomly allocated to maintenance of anaesthesia with sevoflurane (end-tidal concentration 2%) or propofol. Neuromuscular block was assessed by acceleromyography and a single dose of mivacurium (0.15 mg kg−1) was administered (in the sevoflurane group after 30 min of exposure to sevoflurane). We measured time for recovery of the first twitch of the TOF (T1) from 25–75%, time from 25% recovery of T1 to achieving a TOF ratio (TOFR) of 0.8, TOFR at 50%, 75% and 90% recovery of T1, and height of T1 at TOFR of 0.7 and 0.9. Data were tested using t-test for independent samples.

Results: Recovery times (mean (95% confidence interval, CI)) of mivacurium in the sevoflurane group (T1 25–75%, 11.3 (8.1–14.5) min; T1 25%-TOFR0.8, 19.1 (15.7–22.5) min) were significantly longer (P < 0.05) than in the propofol group (T1 25–75%, 6.5 (5.2–7.7) min; T1 25%-TOFR0.8, 11.3 (7.8–10.3) min). No differences were found in the relations between TOFR and T1 or vice versa, between the groups.

Conclusions: Recovery times after a single dose of mivacurium were prolonged by sevoflurane compared with propofol but no differences in TOF fade were observed between the two anaesthetics.

Summary

Background and objective: To test the hypothesis that gabexate mesilate, a protease inihibitor, hastens recovery from neuromuscular blockade, we examined the effect of gabexate mesilate on the recovery of vecuronium-induced neuromuscular blockade in anaesthetized patients in a double-blind, randomized fashion.

Methods: Thirty adult patients were divided into two groups of 15. In the gabexate mesilate group, immediately after administration of vecuronium 0.1 mg kg−1, a continuous infusion of gabexate mesilate was started at a speed of 1.5 mg kg−1 h−1. In the control group, normal saline was administered instead of gabexate mesilate. Times to the return of T1, T2, T3 or T4 (first, second, third and fourth response of train-of-four (TOF)), times to the recovery of T1/control to 0.25 (T25) or 0.5 (T50), recovery of T1/control or TOF ratio (T4/T1) were compared between the two groups.

Results: Times to the returns of T1, T2, T3 and T4 in the gabexate mesilate group were significantly shorter than in the control group (19.4 ± 6.8 vs. 25.7 ± 7.2 min for T1; mean ± SD, P = 0.020). Times to T25 and T50 were significantly shorter in the gabexate mesilate group than in the control group (34.0 ± 9.9 vs. 51.3 ± 10.2 min for T25, P < 0.001). T1/control and TOF ratio in the gabexate mesilate group were significantly higher than in the control group 40–80 min and 40–120 min after administration of vecuronium, respectively (P < 0.05).

Conclusion: Gabexate mesilate hastens recovery from neuromuscular block in anaesthetized patients receiving vecuronium.