Matta B F, Lam A M, Mayberg T S, Eng C C, Strebel S
Department of Anesthesiology, University of Washington School of Medicine, Harborview Medical Center, Seattle 98104, USA.
Br J Anaesth. 1995 Mar;74(3):296-300. doi: 10.1093/bja/74.3.296.
We have examined the cerebrovascular response to carbon dioxide during normotension, sodium nitroprusside (SNP)-induced hypotension and high dose isoflurane-induced hypotension in 10 patients who received a standardized general anaesthetic. Carbon dioxide reactivity was determined by varying PaCO2 between 3.0 and 8.0 kPa and recording simultaneously blood flow velocity from the middle cerebral artery (vmca). The paired vmca-PaCO2 data were analysed using linear regression to determine carbon dioxide reactivity. During hypotension, both high-dose isoflurane and SNP reduced significantly mean absolute (from 17.4 (SEM 2.3) to 13.0 (1.7) and 8.8 (1.3) cm s-1 kPa-1, respectively; P < 0.05) and relative (from 32.5 (3.8) to 23.6 (2.0) and 15.5 (1.3)% kPa-1, respectively; P < 0.05) cerebrovascular reactivity to carbon dioxide. This reduction was greater during SNP-induced hypotension (P < 0.05). We conclude that cerebrovascular reactivity to carbon dioxide was attenuated during isoflurane and SNP-induced hypotension, and that it was better preserved during isoflurane-induced hypotension.
我们在10例接受标准化全身麻醉的患者中，研究了在正常血压、硝普钠（SNP）诱导的低血压和高剂量异氟烷诱导的低血压期间脑血管对二氧化碳的反应。通过将动脉血二氧化碳分压（PaCO2）在3.0至8.0 kPa之间变化，并同时记录大脑中动脉的血流速度（vmca）来测定二氧化碳反应性。使用线性回归分析配对的vmca-PaCO2数据，以确定二氧化碳反应性。在低血压期间，高剂量异氟烷和SNP均显著降低了平均绝对（分别从17.4（标准误2.3）降至13.0（1.7）和8.8（1.3）cm·s-1·kPa-1；P<0.05）和相对（分别从32.5（3.8）降至23.6（2.0）和15.5（1.3）%·kPa-1；P<0.05）脑血管对二氧化碳的反应性。在SNP诱导的低血压期间，这种降低更大（P<0.05）。我们得出结论，在异氟烷和SNP诱导的低血压期间，脑血管对二氧化碳的反应性减弱，并且在异氟烷诱导的低血压期间其得到更好的保留。
