Schmidt Sven, Westhoff Timm, Schlattmann Peter, Zidek Walter, Compton Friederike
From the *Department of Nephrology, Charité University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany; †Department of Medicine I, Universitätsklinikum Marien Hospital Herne, Ruhr-Universität Bochum, Herne, Germany; and ‡Department of Medical Statistics, Informatics and Documentaton, Jena University Hospital, Jena, Germany.
Anesth Analg. 2016 May;122(5):1474-9. doi: 10.1213/ANE.0000000000001191.
Transpulmonary thermodilution (TPTD) is used frequently in the intensive care unit to determine cardiac index (CI), intrathoracic blood volume index (ITBVI), and extravascular lung volume index (EVLWI). Renal replacement therapy (RRT) influences TPTD results, but the underlying mechanisms are not completely understood. We hypothesized that RRT blood flow induces errors in TPTD measurements.
We analyzed TPTD data available from the PiCCO® plus hemodynamic measurement device on a personal computer using a proprietary Pulsion Medical Systems software. By using the dialysis catheter to inject the thermal indicator, 20 measurement series were performed in 12 intensive care unit patients determining CI, ITBVI, and EVLWI during RRT with the blood pump stopped, and at flows of 100 and 200 mL/min, respectively.
Data export was successful in 17 measurement series and showed a significant decrease in measured CI (6.5 ± 2.5 vs 5.4 ± 1.9 L/min/m, P < 0.001) and ITBVI (1358.8 ± 274.5 vs 1132.8 ± 218.3 mL/m, P < 0.001) with RRT and a significant increase in EVLWI (8.6 ± 4.4, 10.2 ± 4.5 mL/kg, P < 0.001). Blood temperature before and the temperature decrease after injection of the thermal indicator were unchanged by RRT. Mean transit time and downslope time of the thermodilution curve, however, were both increased with the RRT blood pump running (P ≤ 0.001).
Analysis of TPTD data shows that thermodilution curve forms are modified with RRT, resulting in an erroneous calculation of thermodilution-derived hemodynamic parameters.
经肺热稀释法（TPTD）在重症监护病房中常用于测定心脏指数（CI）、胸腔内血容量指数（ITBVI）和血管外肺水指数（EVLWI）。肾脏替代治疗（RRT）会影响TPTD结果，但其潜在机制尚未完全明确。我们推测RRT血流会导致TPTD测量出现误差。
我们使用专有的Pulsion Medical Systems软件在个人电脑上分析了PiCCO® plus血流动力学测量设备提供的TPTD数据。通过使用透析导管注入热指示剂，对12例重症监护病房患者进行了20次测量系列，分别在血泵停止时以及血泵流速为100和200 mL/min的RRT过程中测定CI、ITBVI和EVLWI。
17个测量系列的数据导出成功，结果显示RRT时测量的CI（6.5±2.5 vs 5.4±1.9 L/min/m，P<0.001）和ITBVI（1358.8±274.5 vs 1132.8±218.3 mL/m，P<0.001）显著降低，而EVLWI显著升高（8.6±4.4、10.2±4.5 mL/kg，P<0.001）。RRT对热指示剂注射前的血液温度以及注射后的温度下降没有影响。然而，热稀释曲线的平均通过时间和下降斜率时间在RRT血泵运行时均增加（P≤0.001）。
对TPTD数据的分析表明，RRT会改变热稀释曲线的形态，从而导致热稀释衍生的血流动力学参数计算错误。
