高碳酸血症会降低体外循环期间的脑氧耗量。

Hypercarbia depresses cerebral oxygen consumption during cardiopulmonary bypass.

作者信息

Prough D S, Rogers A T, Stump D A, Mills S A, Gravlee G P, Taylor C

机构信息

Department of Anesthesia, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, N.C. 27103.

出版信息

Stroke. 1990 Aug;21(8):1162-6. doi: 10.1161/01.str.21.8.1162.

DOI:10.1161/01.str.21.8.1162

PMID:2117784

Abstract

No human studies have systematically examined the relations among PaCO2, cerebral blood flow, and the cerebral metabolic rate for oxygen during hypothermic cardiopulmonary bypass. We varied PaCO2 during hypothermic (26-28 degrees C) cardiopulmonary bypass and estimated the cerebral metabolic rate for oxygen by multiplying cerebral blood flow (measured using xenon-133 clearance) by the cerebral arteriovenous difference in oxygen contents. Patients were randomly assigned to either of two methods of managing PaCO2 (uncorrected for body temperature). In group 1 (PACO2 32-48 mm Hg, n = 13) the mean +/- SD cerebral metabolic rate for oxygen was 0.40 +/- 0.11 ml O2 X 100 g-1 X min-1 at a mean +/- SD PaCO2 of 36 +/- 2.0 mm Hg and 0.40 +/- 0.14 ml O2 X 100 g-1 X min-1 at a mean +/- SD PaCO2 of 45 +/- 2 mm Hg. and 49-72 mm Hg, n = 12) the mean +/- SD cerebral metabolic rate for oxygen was 0.31 +/- 0.09 ml O2 X 100 g-1 X min-1 at a mean +/- SD PaCO2 of 55 +/- 3 mm Hg and 0.21 +/- 0.07 ml O2 X 100 g-1 X min-1 at a mean +/- SD PaCO2 of 68 +/- 2 mm Hg. Group 2 values differed significantly from those in Group 1 (p less than 0.05). In both groups, cerebral blood flow increased as PaCO2 increased. During cardiopulmonary bypass, increasing PaCO2 increases cerebral blood flow and decreases the cerebral metabolic rate for oxygen.

摘要

尚无人体研究系统地探究低温体外循环期间动脉血二氧化碳分压（PaCO₂）、脑血流量和脑氧代谢率之间的关系。我们在低温（26 - 28摄氏度）体外循环期间改变PaCO₂，并通过将脑血流量（使用氙-133清除法测量）乘以脑动静脉氧含量差值来估算脑氧代谢率。患者被随机分配至两种管理PaCO₂的方法之一（未校正体温）。在第1组（PaCO₂ 32 - 48 mmHg，n = 13）中，平均±标准差脑氧代谢率在平均±标准差PaCO₂为36 ± 2.0 mmHg时为0.40 ± 0.11 ml O₂×100 g⁻¹×min⁻¹，在平均±标准差PaCO₂为45 ± 2 mmHg时为0.40 ± 0.14 ml O₂×100 g⁻¹×min⁻¹。在第2组（PaCO₂ 49 - 72 mmHg，n = 12）中，平均±标准差脑氧代谢率在平均±标准差PaCO₂为55 ± 3 mmHg时为0.31 ± 0.09 ml O₂×100 g⁻¹×min⁻¹，在平均±标准差PaCO₂为68 ± 2 mmHg时为0.21 ± 0.07 ml O₂×100 g⁻¹×min⁻¹。第2组的值与第1组有显著差异（p < 0.05）。在两组中，脑血流量均随PaCO₂升高而增加。在体外循环期间，增加PaCO₂会增加脑血流量并降低脑氧代谢率。