清醒人类的临界氧输送低于7.3毫升氧气×千克⁻¹×分钟⁻¹。

Critical oxygen delivery in conscious humans is less than 7.3 ml O2 x kg(-1) x min(-1).

作者信息

Lieberman J A, Weiskopf R B, Kelley S D, Feiner J, Noorani M, Leung J, Toy P, Viele M

机构信息

Department of Anesthesia, The Cardiovascular Research Institute, University of California, San Francisco 94143-0648, USA.

出版信息

Anesthesiology. 2000 Feb;92(2):407-13. doi: 10.1097/00000542-200002000-00022.

DOI:10.1097/00000542-200002000-00022

PMID:10691227

Abstract

BACKGROUND

The "critical" level of oxygen delivery (DO2) is the value below which DO2 fails to satisfy the metabolic need for oxygen. No prospective data in healthy, conscious humans define this value. The authors reduced DO2 in healthy volunteers in an attempt to determine the critical DO2.

METHODS

With Institutional Review Board approval and informed consent, the authors studied eight healthy, conscious volunteers, aged 19-25 yr. Hemodynamic measurements were obtained at steady state before and after profound acute isovolemic hemodilution with 5% albumin and autologous plasma, and again at the reduced hemoglobin concentration after additional reduction of DO2 by an infusion of a beta-adrenergic antagonist, esmolol.

RESULTS

Reduction of hemoglobin from 12.5+/-0.8 g/dl to 4.8+/-0.2 g/dl (mean +/- SD) increased heart rate, stroke volume index, and cardiac index, and reduced DO2 (14.0+/-2.9 to 9.9+/-20 ml O2 x kg(-1) x min(-1); all P<0.001). Oxygen consumption (VO2; 3.0+/-0.5 to 3.4+/-0.6 ml O2 x kg(-1) x min(-1); P<0.05) and plasma lactate concentration (0.50+/-0.10 to 0.62+/-0.16 mM; P<0.05; n = 7) increased slightly. Esmolol decreased heart rate, stroke volume index, and cardiac index, and further decreased DO2 (to 7.3+/-1.4 ml O2 x kg(-1) x min(-1); all P<0.01 vs. before esmolol). VO2 (3.2+/-0.6 ml O2 x kg(-1) x min(-1); P>0.05) and plasma lactate (0.66+/-0.14 mM; P>0.05) did not change further. No value of plasma lactate exceeded the normal range.

CONCLUSIONS

A decrease in DO2 to 7.3+/-1.4 ml O2 x kg(-1) min(-1) in resting, healthy, conscious humans does not produce evidence of inadequate systemic oxygenation. The critical DO2 in healthy, resting, conscious humans appears to be less than this value.

摘要

背景

氧输送（DO2）的“临界”水平是指低于该值时，DO2无法满足机体对氧的代谢需求。目前尚无关于健康、清醒人类的前瞻性数据来确定这一数值。作者通过降低健康志愿者的DO2来试图确定临界DO2。

方法

在获得机构审查委员会批准并取得知情同意后，作者研究了8名年龄在19 - 25岁的健康、清醒志愿者。在使用5%白蛋白和自体血浆进行深度急性等容血液稀释前后的稳定状态下，以及在通过输注β - 肾上腺素能拮抗剂艾司洛尔进一步降低DO2后，血红蛋白浓度降低时，均进行了血流动力学测量。

结果

血红蛋白从12.5±0.8 g/dl降至4.8±0.2 g/dl（均值±标准差），使心率、每搏量指数和心脏指数增加，DO2降低（从14.0±2.9降至9.9±2.0 ml O2·kg⁻¹·min⁻¹；所有P<0.001）。氧耗量（VO2；从3.0±0.5增至3.4±0.6 ml O2·kg⁻¹·min⁻¹；P<0.05）和血浆乳酸浓度（从0.50±0.10增至0.62±0.16 mM；P<0.05；n = 7）略有增加。艾司洛尔降低了心率、每搏量指数和心脏指数，并进一步降低了DO2（降至7.3±1.4 ml O2·kg⁻¹·min⁻¹；与使用艾司洛尔前相比，所有P<0.01）。VO2（3.2±0.6 ml O2·kg⁻¹·min⁻¹；P>0.05）和血浆乳酸（0.66±0.14 mM；P>0.05）未进一步变化。血浆乳酸值均未超过正常范围。