Pittet J F, Morel D R, Mentha G, Schopfer C, Belenger J, Benakis A, Tassonyi E
Department of Anesthesiology, University Hospital of Geneva, Switzerland.
Anesthesiology. 1994 Jul;81(1):168-75. doi: 10.1097/00000542-199407000-00023.
Rapid assessment of hepatic function early after reperfusion of the liver graft is of great importance, because it may allow for prompt detection of incipient hepatic graft failure. The current study was undertaken to determine whether the continuous recording of neuromuscular transmission could be used as an on-line assessment of hepatic function during liver transplantation when a muscle relaxant with high hepatic uptake is used.
We quantified and compared the effect of liver exclusion and graft reperfusion on the level of vecuronium-induced neuromuscular blockade in nine pigs studied twice within 3 days. During the 1st day (control session), an intravenous infusion of vecuronium was administered to maintain a constant 90-95% twitch depression during 180 min. The twitch response was then allowed to recover spontaneously to 75% of its prerelaxant value. Neuromuscular transmission was continuously measured on the right anterior leg using an acceleration transducer. During the same time period, the metabolic rate of 14C-labeled aminopyrine (a well-established quantitative test of the liver microsomal function) was determined by measuring the excretion of 14CO2 in expired air after administration of an intravenous bolus of 14C-labeled aminopyrine. Two days later, the pigs underwent a hepatic autotransplantation, during which vecuronium was administered to maintain a constant 90-95% twitch depression. After reperfusion of the liver graft, the vecuronium infusion rate was maintained at its anhepatic level, and the recovery index of the neuromuscular blockade (the time from 25% to 75% recovery of twitch height) was calculated. The aminopyrine breath test was performed during the last 30 min of the anhepatic phase, and during 3 h after reperfusion of the liver graft.
During control studies, the mean infusion rate of vecuronium was 1.30 +/- 0.33 mg.kg-1.h-1 and the recovery index was 3.4 +/- 0.5 min. During liver dissection, the infusion rate of vecuronium was similar to the control value (1.18 +/- 0.16 mg.kg-1.h-1), then considerably decreased to 0.05 +/- 0.03 mg.kg-1.h-1 during the anhepatic phase. After reperfusion of the liver graft, the recovery index was markedly prolonged to 35.5 +/- 15.8 min, indicating a prolongation of the recovery of neuromuscular blockade by a factor of 10.4. Excretion of 14CO2 was equal to zero during the anhepatic phase and then increased to 0.19 +/- 0.11% during the 1st h after reperfusion of the liver graft, an excretion rate corresponding to 11.2% of control conditions. The relationship between individual changes in the recovery index of the neuromuscular blockade and 14CO2 excretion in expired air after reperfusion of the liver graft showed a strong significant correlation (r2 = 0.71).
These results indicate that, compared with the control studies, there is a similar decrease in the recovery rate of vecuronium-induced neuromuscular blockade and in the metabolic rate of 14C-labeled aminopyrine during the progressive recovery of hepatic function immediately after unclamping of the liver vessels. Metabolism of 14C-labeled aminopyrine increased progressively during the reperfusion phase. Therefore, recording of neuromuscular transmission during liver transplantation could serve as a continuous and easy to perform assessment of liver graft function provided that a muscle relaxant with a high hepatic uptake is used for neuromuscular blockade.
肝移植肝再灌注后早期快速评估肝功能非常重要，因为这可能有助于及时发现早期肝移植失败。本研究旨在确定当使用肝摄取率高的肌肉松弛剂时，神经肌肉传递的连续记录是否可用于肝移植期间肝功能的在线评估。
我们在3天内对9头猪进行了两次研究，量化并比较了肝血流阻断和移植肝再灌注对维库溴铵诱导的神经肌肉阻滞水平的影响。在第1天（对照期），静脉输注维库溴铵以在180分钟内维持恒定的90 - 95%颤搐抑制。然后让颤搐反应自发恢复至其松弛前值的75%。使用加速度传感器连续测量右前肢的神经肌肉传递。在同一时间段内，通过静脉推注14C标记的氨基比林后测量呼出气体中14CO2的排泄量，来测定14C标记的氨基比林的代谢率（一种成熟的肝微粒体功能定量测试）。两天后，猪接受肝自体移植，在此期间给予维库溴铵以维持恒定的90 - 95%颤搐抑制。肝移植再灌注后，维库溴铵输注速率维持在无肝期水平，并计算神经肌肉阻滞的恢复指数（从颤搐高度恢复25%至75%的时间）。在无肝期的最后30分钟以及肝移植再灌注后的3小时内进行氨基比林呼气试验。
在对照研究期间，维库溴铵的平均输注速率为1.30±0.33mg·kg-1·h-1，恢复指数为3.4±0.5分钟。在肝脏解剖期间，维库溴铵的输注速率与对照值相似（1.18±0.16mg·kg-1·h-1），然后在无肝期显著降至0.05±0.03mg·kg-1·h-1。肝移植再灌注后，恢复指数显著延长至35.5±15.8分钟，表明神经肌肉阻滞的恢复延长了10.4倍。在无肝期，14CO2的排泄量等于零，然后在肝移植再灌注后的第1小时增加至0.19±0.11%，排泄率相当于对照条件下的11.2%。肝移植再灌注后神经肌肉阻滞恢复指数的个体变化与呼出气体中14CO2排泄量之间的关系显示出强烈的显著相关性（r2 = 0.71）。
这些结果表明，与对照研究相比，在肝脏血管夹闭后肝功能逐渐恢复期间，维库溴铵诱导的神经肌肉阻滞恢复率和14C标记的氨基比林代谢率有类似程度的下降。在再灌注阶段，14C标记的氨基比林的代谢逐渐增加。因此，只要使用肝摄取率高的肌肉松弛剂进行神经肌肉阻滞，肝移植期间神经肌肉传递的记录可作为一种连续且易于实施的肝移植功能评估方法。
