Abstract:

Objective To explore the pharmacodynamics of continuous infusion of rocuronium during the liver transplantation for infants. Methods Fourteen patients who underwent transplantation of living donor liver were selected. Patients were 6 months to 2 years old. Their body weights were 5-10 kg. The scores of Child-Push were 7-10; the classifications of hepatic function were B or C; and their ASA were Ⅲ or Ⅳ. The responses of the adductor pollicis muscle to train-of-four (TOF) stimulation of ulnar nerve were monitored. Rocuronium of 0.6 mg/kg was given during induction. Tracheal intubation was performed when 100% blockade was attained and mechanical ventilation was instituted. When T1 recovered to 3%, rocuronium was infused at an initial infusion rate of 5 μg/kg/min. The infusion rate was adjusted to maintain T1 at 3%-10%. The administration of muscle relaxant was stopped after the suture of the peritoneum. The onset time, TOF no reaction period, the time for the recovery of T1 to 25%, recovery index, and average infusion rates of rocuronium at three stage were recorded. Results The onset time of rocuronium was (82.86±14.77) s; the TOF no reaction period was (45.80±16.88) min; the time for the recovery of T1 to 25% was (18.98±8.57) min; and the recovery time was (37.05±7.95) min. The muscle inhibition was maintained constant and the infusion rate was (2.80±0.96) μg/(kg/min) before the anhepatic phase, (1.81±0.34) μg/(kg/min) during the anhepatic phase, and (2.54±0.98)μg/(kg/min) after reperfusion. Compared to the requirement of rocuronium before the anhepatic phase, the requirement of rocuronium after the anhepatic phase decreased 35% (P<0.05) and the requirement of rocuronium during the anhepatic phase remained the same. Conclusion During the liver transplantation for infants, the average dose of rocuronium after the anhepatic phase is lower than that before the anhepatic phase and the average dose of rocuronium during the anhepatic phase is the same as that before the anhepatic phase. The pharmacodynamics characteristics of muscle relaxants during liver transplantation should be fully understood. When rocuronium is administrated to induce, tracheal intubation should be performed 1.5 min after the administration of rocuronium. The drug dosage should be appropriately reduced during the anhepatic stage to avoid prolonging the neuromuscular blockade.

Key words: pediatric liver transplantation, rocuronium, pharmacodynamics