Pharmacodynamic Effects Of Rocuronium During Liver Transplantation

Background: Little is known about the neuromuscular effects of rocuronium during the phases of liver transplantation without veno-venous bypass. We investigated the pharmacodynamics of rocuronium in patient with different preoperative liver function during phases of liver transplantation surgery. We evaluated the correlation between neuromuscular paralysis induced by rocuronium during the neohepatic phase and early postoperative graft liver function.Methods: Twenty-one adult patients undergoing liver transplantation were divided into three groups according to the Child-Pugh classification, Group A (Child A n=7), group B (Child B n=7) and group C (Child C n=7). Another 10 patients with normal liver function undergoing selective surgery under general anesthesia were allocated in group D. Anesthesia was induced with midazolam, fentanyl and rocuronium (0.6mg/kg). The neuromuscular function was monitored by single twitch stimulation of the ulnar nerve using accelerography (TOF-Watch SX). Rocuronium was infused continuously with 2.0-0.5mg/kg/h as T₁ recovered to 75%, a bolus dose of rocuronium was given during paleohepatic period until T₁ back to 25%; but there was only same bolus dose in neohepatic period. Onset time, no-response period, clinical duration, T₁ 25%-50% recovery time and recovery index of the initialdose and the incremental doses were recorded. Serum aspartame aminotransferase, alanine aminotransferase, prothrombin time and bile output were observed for 3 days postoperatively. All data are presented as means ± SD, recovery time during the three periods of liver transplantation were compared using ANOVA and q test. Pearson test was used for verifying correlation between allograft function and duration of action, recover index of rocuronium in the neohepatic period. A p-value<0.05 was considered to be statistically significant.Results: Onset of the initial dose of rocuronium in group D (136.1 + 55.2s) and A (155.3±20.3s) occurred faster than that in group B (232.9 + 97.6s) and C (253.6 + 82.5s)(p<0.05). Furthermore, duration of action (56.00 + 20.16; 112.68 +21.19min), Ti25-50% recovery time(22.71+ 8.44;38.71 + 10.62min) and recovery index(44.50 + 21.56; 62.21 ± 19.78min) of the initial and incremental doses of rocuronium were significantly prolonged during paleohepatic period in group C (p<0.05). There was no significant difference in recovery time of rocuronium during anhepatic period in three liver transplantation groups (P>0.05). No-response period (73.64+21.88 vs. 47.14 + 15.97min) and clinical duration (129.18 + 33.96 vs. 76.27+ 18.64min) were prolonged significantly during neohepatic period comparing to paleohepatic period (p<0.05) in group A. The onset, no-response period, clinical duration and recovery index were without statistical difference (P>0.05) between paleohepatic period and neohepatic period in group C. None of patients occurred primary dysfunction, but there were not correlation between immediate allograft function and clinical duration of rocuronium in the early neohepatic period.Conclusions: Liver dysfunction influences on the pharmacodynamics of rocuronium in paleohepatic period, but not in anhepatic and neohepaticperiods. There was not correlation between immediate allograft function and clinical duration of rocuronium in the early neohepatic period.