使用氙-133清除法与经颅多普勒超声检查法在心脏手术期间脑血流量的相对变化。

Relative changes in cerebral blood flow during cardiac operations using xenon-133 clearance versus transcranial Doppler sonography.

作者信息

Trivedi U H, Patel R L, Turtle M R, Venn G E, Chambers D J

机构信息

Department of Cardiac Surgical Research, Rayne Institute, St. Thomas' Hospital, London, United Kingdom.

出版信息

Ann Thorac Surg. 1997 Jan;63(1):167-74. doi: 10.1016/s0003-4975(96)01017-x.

DOI:10.1016/s0003-4975(96)01017-x

PMID:8993260

Abstract

BACKGROUND

Changes in cerebral blood flow (CBF) during cardiac operations have implications in terms of postoperative neurologic and neuropsychological dysfunction. Current techniques of CBF measurement are cumbersome and invasive. Transcranial Doppler sonography offers a noninvasive means of assessing changes in CBF. The aim of this study was validation of this technique with existing methods of CBF measurement during cardiac operations.

METHODS

We compared the changes in CBF using xenon-133 clearance with changes in middle cerebral artery velocity by transcranial Doppler sonography (VMCA) using pH-stat and alpha-stat acid-base management during cardiopulmonary bypass. Measurements were taken (1) before bypass, (2) at 28 degrees C on bypass, (3) at 37 degrees C on bypass, and (4) after bypass. Relative changes in CBF and VMCA, calculated as the percent change from the prebypass baseline value normalized to 100%, were used in this analysis.

RESULTS

During the hypothermic phase of cardiopulmonary bypass, CBF and VMCA increased by 45.9% and 51.8%, respectively (p < 0.001), during pH-stat acid-base management but decreased by only 26.4% and 22.4%, respectively (p < 0.0001), during alpha-stat acid-base management. Linear regression analysis of the absolute changes in CBF (mL . 100 g-1 . min-1) and VMCA (cm/s) showed a significant correlation (r = 0.60; r2 = 0.36; p < 0.0001), but a better correlation was obtained when relative changes in CBF and VMCA were compared (r = 0.89; r2 = 0.79; p < 0.0001).

CONCLUSIONS

Measurements of VMCA, expressed as relative changes of a pre-cardiopulmonary bypass level (using the noninvasive transcranial Doppler sonographic technique), can be used to examine CBF changes during cardiopulmonary bypass.

摘要

背景

心脏手术期间脑血流量（CBF）的变化对术后神经和神经心理功能障碍具有重要意义。目前的CBF测量技术既繁琐又具有侵入性。经颅多普勒超声检查提供了一种评估CBF变化的非侵入性方法。本研究的目的是在心脏手术期间用现有的CBF测量方法验证该技术。

方法

我们比较了在体外循环期间使用pH稳态和α稳态酸碱管理时，通过经颅多普勒超声检查（VMCA）测量的大脑中动脉速度变化与使用氙-133清除法测量的CBF变化。测量在以下时间点进行：（1）体外循环前；（2）体外循环期间体温为28℃时；（3）体外循环期间体温为37℃时；（4）体外循环后。本分析采用CBF和VMCA的相对变化，计算方法是以体外循环前基线值的百分比变化表示，并将其归一化为100%。

结果

在体外循环的低温阶段，在pH稳态酸碱管理期间，CBF和VMCA分别增加了45.9%和51.8%（p < 0.001），而在α稳态酸碱管理期间仅分别下降了26.4%和22.4%（p < 0.0001）。对CBF（mL·100g-1·min-1）和VMCA（cm/s）的绝对变化进行线性回归分析显示存在显著相关性（r = 0.60；r2 = 0.36；p < 0.0001），但比较CBF和VMCA的相对变化时相关性更好（r = 0.89；r2 = 0.79；p < 0.0001）。