Muscle relaxation effect and safety of mivacurium in patients with early hepatocirrhosis

Abstract

Objective To observe muscle relaxation effect and safety of mivacurium in hepatocirrhosis patients, and provide a guidance in its clinical application. Methods Candidates for elective laparoscopic surgery were divided into a hepatocirrhosis group(group C, n=32) and a non hepatocirrhosis group (group N, n=25). Muscular relaxation monitor was applied with a train of four stimulation(TOF). The intubation dosage was 0.2 mg/kg. Tracheal intubation was performed when train of four stimulation ratio(TOFr, T4∶T1) was 0, and pump infusion of mivacurium was started when muscle relaxation began to recover (TOFr>0) with a velocity of 0.6 mg·kg-1·h-1, which was switched to 0.3 mg·kg-1·h-1 and then stopped in 30 min and 20 min prior to end of suturing in group C and group N respectively. The key parameter included plasma cholinesterase(PchE) activity, histamine concentration, variation of MAP, HR, onset time of mivacurium, acting duration of the first dose, time of TOFr recovery, time from drug withdrawal to extubation, and recovery index. Results The PchE activity were(4 304±901) U/L and (6 227±1 289) U/L in two groups (P 0.05). The mean histamine concentrations of all patients were (0.196±0.020), (0.238±0.021), (0.278±0.024) μg/L prior to intravenous injection of mivacurium and in 5 min and 10 min post to injection, there were significant differences between the three times points(P 0.05). The duration of the first dose were(20±4) min and (16±3) min respectively, the recovery of TOFr to 75% were (35±10) min and (24±5) min, time from drug withdrawal to extubation were (35±9) min and (24±7) min, and there were significant differences between the two groups (P<0.05). Conclusions The plasma histamine concentration increase slightly without significant influence on MAP and HR, with satisfactory intubation conditions, good muscle relaxation and fast recovery from muscle relaxation when mivacurium was applied in patients with early hepatic cirrhosis. Compared with non hepatic cirrhosis patients, the time of muscle relaxation recovery induced by mivacurium was longer in hepatic cirrhosis patients, but compared with other muscle relaxant, it still had obvious advantages. Because mivacurium didn't directly depend on the liver to metabolize, so it could reduce the burden of liver on drug metabolism. It is recommended to be applied in patients with early hepatic cirrhosis. Key words: Cirrhosis of liver; Mivacurium chloride; Histamine; Cholinesterase; Monitoring of muscle relaxation