肝移植术中连续温度稀释法监测心排血量的准确性

Accuracy of continuous thermodilut.ion cardiac output measurement during liver transplantation

目的评价肝移植术中连续温度稀释法监测心排血量（CO）的准确性。方法13例非静脉-静脉转流原位肝移植术病人，术中采用Abbott Opti—Q CCO／SvO2连续心排血量仪监测CO（CCO）；并于麻醉诱导后20、40、60、90、120min、下腔静脉阻断5、15、25、35、45min和下腔静脉开放5、15、25、60、90、120min时采用单次温度稀释法监测CO（BCO），连续测定3次，取其平均值；于BCO测定前后取两次CCO的平均值为该时点的CCO。计算各时点CCO与BCO间的相关系数，采用Bland—Altman法进行一致性检验。结果共收集196对CO数据，CCO范围为1．9～17．9L／min，BCO范围为2．1～18．3L／min。与其余时点比较，下腔静脉阻断5min和下腔静脉开放5min时CCO和BCO间的相关系数较低，偏离度较大，CCO监测存在明显的响应时间延迟现象；其他时点CCO和BCO间的偏离度为一0．18L／min，95％可信区间为-0．32～-0．03L／min，一致性界限为-2．09～1．73L／min，其下限的95％可信区间为-2．34～-1．84L／min，其上限的95％可信区间为1．48～1．99L／min。CCO和BCO的重复系数分别为0．36和0．86L／min。CCO与BCO的平均值与CCO的差值为（0．09±0．49）L／min，CCO的相对误差为4．6％±1．7％。结论肝移植术中血液动力学改变显著时，CCO存在明显的响应时间延迟现象；而在血液动力学相对稳定时，CCO和BCO之间缺乏良好的一致性，但CCO监测在临床上是可接受的。

Objective To evaluate the accuracy of continuous themlodilution cardiac output （CO） measurement during liver transplantation. Methods Thirteen patients undergoing orthotopic liver transplantation without veno-venous bypass were enrolled in this study. Continuous thermodilution cardiac output measurements （CCO） were performed using the Abbott Opti-Q CCO/SvO2 monitoring system. Bolus themlodilution cardiac output measurements （BCO） were obtained by three consecutive measurements at 20, 40, 60, 90 and 120 min after induction of anesthesia, at 5, 15, 25, 35 and 45 min after inferior caval vein clamping and at 5, 15, 25, 60, 90 and 120 min after unclamping. The mean value of the three BCO measurements was calculated. The mean value of the two CCO values before and after BCO measurements at one measured time point was calculated and defined as the CCO value at this time point. The correlation coefficients between CCO and BCO at corresponding time points were calculated and the agreement was assessed using Bland-Ahman analysis. Results Cardiac output measurements yielded 196 data pairs with a range of 1.9 to 17.9 L/min for CCO and 2.1 to 18.3 L/min for BCO. The correlation coefficients were significantly decreased, the biases were increased and delayed time response of continuous cardiac output monitoring was observed at 5 min after inferior caval vein clamping and unclamping than those at the other time points. The results of the analysis of agreement at the other time points revealed that the bias was - 0.18 L/min and 95% confidence interval was - 0.32- - 0.03 L/min; the limit of agreement was - 2.09- 1.73 L/min and 95% confidence interval for the lower and upper limits of agreement was - 2.34- - 1.84 L/min and 1.48 - 1.99 L/min respectively. The repeatability coefficient of CCO and BCO was 0.36 and 0.86 L/min respectively. The difference between the average value of CCO and BCO and CCO was （0.09 ± 0.49） L/min. The relative error of CCO measurements was 4.6 % ± 1.7 %. Conclusion The marked delayed time response of CCO monitoring exists when acute hemodynamic changes occurrs during liver transplantation. CCO measurements do not agree with BCO measurements under the relatively stable hemodynamics, but CCO measurements are clinically acceptable.