肝移植术后血氨和乳酸水平与肝性脑病的相关性

Correlation between blood ammonia, lactic acid levels and hepatic encephalopathy following liver transplantation

目的研究肝移植术后血氨和乳酸的动态监测结果与发生肝性脑病的相关性，分析乳酸清除率对受者术后存活率的影响。方法回顾性分析84例肝移植受者的临床资料，动态监测术前、术毕、术后12、24和48h的血氨和乳酸水平，并计算出术后12h的乳酸清除率。根据是否发生术后肝性脑病将受者分为肝性脑病组与非脑病组，计量资料采用t检验，计数资料采用，检验进行分析；另根据术后12h乳酸清除率的不同，将所有受者分为高乳酸清除率组和低乳酸清除率组，比较两组术后存活率。结果肝性脑病组术前血氨水平高于非脑病组，差异有统计学意义（P〈0．05），两组术前乳酸水平比较，差异无统计学意义（P〉0．05）；两组受者除术后48h血氨水平外，术后各阶段血氨和乳酸水平均高于术前，差异有统计学意义（P〈0．05）；肝性脑病组术毕至术后48h的血氨和乳酸水平均高于非脑病组，差异有统计学意义（P〈0．05）；肝性脑病组术后12h乳酸清除率明显低于非脑病组，差异有统计学意义（P〈0．01）；高乳酸清除率组受者术后1年存活率高于低乳酸清除率组，差异有统计学意义（P〈0．05）。结论肝移植术后血氨和乳酸水平与肝性脑病的发生密切相关。术后乳酸清除率高的受者预后较好。乳酸清除率可作为预后的评估指标。

Objective To investigate the correlation between blood ammonia and lactic acid levels and hepatic encephalopathy following liver transplantation and analyze the relationship between lactate clearance rate and the postoperative survival rate of the recipients. Methods The clinical data of 84 cases subject to liver transplantation were retrospectively analyzed. The levels of blood ammonia and lactic acid were dynamically monitored before operation, immediate after operation and 12, 24 and 48 h after operation. The lactate clearance rate was calculated 12 h after operation. The patients were divided into two groups： hepatic encephalopathy （experimental） group and non hepatic encephalopathy （control） group. The quantitative data were proceeded by t test, and qualitative data by X^2 test. The patients were divided into two groups according to 12 h lactate clearance rate （high lactate clearance rate group and low lactate clearance rate group） and the postoperative survival rate was compared between two groups. Results The blood ammonia levels in experimental group were higer than in control group before operation （P〈0. 05）, but there was no significant difference in lactic acid levels （P〉0. 05）. Except for blood ammonia levels at 48 h after operation, levels of blood ammonia and lactic acid at different time points after operation in two groups were higher than before operation （P〈0. 05）. Blood ammonia and lactic acid levels in experimental group from 0 to 48 h after operation were higher than in control group （P〈0. 01 ）. In experimental group, postoperative 12 h lactate clearance rate was significantly lower than in control group （P〈0. 01 ）. In high lactate clearance rate group, the postoperative 1-year survival rate was higher than in low lactate clearance rate group （P〈0. 05）. Conclusion Blood ammonia and lactic acid levels had a correlation with hepatic encephalopathy after liver transplantation. The recipients with a high lactate clearance rate after operation had a better prognosis. Lactate clearance rate can be used as an indicator to evaluate the prognosis.