Wietasch G J, Mielck F, Scholz M, von Spiegel T, Stephan H, Hoeft A
Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Germany.
Anesthesiology. 2000 Feb;92(2):367-75. doi: 10.1097/00000542-200002000-00017.
Currently, quantitative measurement of global cerebral blood flow (CBF) at bedside is not widely performed. The aim of the present study was to evaluate a newly developed method for bedside measurement of CBF based on thermodilution in a clinical setting.
The investigation was performed in 14 anesthetized patients before coronary bypass surgery. CBF was altered by hypocapnia, normocapnia, and hypercapnia. CBF was measured simultaneously by the Kety-Schmidt inert-gas technique with argon and a newly developed transcerebral double-indicator dilution technique (TCID). For TCID, bolus injections of ice-cold indocyanine green were performed via a central venous line, and the resulting thermo-dye dilution curves were recorded simultaneously in the aorta and the jugular bulb using combined fiberoptic thermistor catheters. CBF was calculated from the mean transit times of the indicators through the brain.
Both methods of measurement of CBF indicate a decrease during hypocapnia and an increase during hypercapnia, whereas cerebral metabolic rate remained unchanged. Bias between CBF(TCID) and CBFargon was -7.1+/-2.2 (SEM) ml x min(-1) x 100 g(-1); precision (+/- 2 x SD of differences) between methods was 26.6 ml x min(-1) x 100 g(-1).
In the clinical setting, TCID was feasible and less time-consuming than alternative methods. The authors conclude that TCID is an alternative method to measure global CBF at bedside and offers a new opportunity to monitor cerebral perfusion of patients.
目前，床旁定量测量全脑血流量（CBF）尚未广泛开展。本研究的目的是在临床环境中评估一种基于热稀释法新开发的床旁测量CBF的方法。
对14例冠状动脉搭桥手术前的麻醉患者进行研究。通过低碳酸血症、正常碳酸血症和高碳酸血症改变CBF。采用凯蒂-施密特惰性气体技术（使用氩气）和新开发的经脑双指示剂稀释技术（TCID）同时测量CBF。对于TCID，通过中心静脉导管推注冰冷的吲哚菁绿，并使用组合光纤热敏电阻导管同时记录主动脉和颈静脉球部产生的热染料稀释曲线。根据指示剂通过大脑的平均传输时间计算CBF。
两种测量CBF的方法均显示低碳酸血症时CBF降低，高碳酸血症时CBF升高，而脑代谢率保持不变。CBF（TCID）与CBF氩气之间的偏差为-7.1±2.2（SEM）ml·min-1·100g-1；两种方法之间的精密度（±2×差异标准差）为26.6ml·min-1·100g-1。
在临床环境中，TCID是可行的，且比其他方法耗时更少。作者得出结论，TCID是一种在床旁测量全脑CBF的替代方法，为监测患者的脑灌注提供了新的机会。
