Contribution of PO2, P-50, and Hb to changes in arteriovenous O-2 content during exercise in heart failure
Contribution of PO2, P-50, and Hb to changes in arteriovenous O-2 content during exercise in heart failure
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DOI：
10.1152/jappl.1996.80.2.623
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发表时间：
1996-02-01
影响因子：
3.3
通讯作者：
Agostoni, PG
中科院分区：
文献类型：
--
作者：
Perego, GB;Marenzi, GC;Agostoni, PG
正常受试者运动时动静脉O-2含量（a-vCO(2)）差异增加的机制包括PO2、血红蛋白（Hb） O-2半饱和时的O-2压力（P-50）和Hb浓度变化。本研究旨在评估心力衰竭患者运动后这些生化变化与a-vCO(2)差异的相关性。27例充血性心力衰竭患者[功能A级10例](运动峰值O-2摄取>20 ml。公斤(1)。min(-1))， B类9 （20-15 ml）。公斤(1)。min(-1))， C类8份（15-10毫升）。公斤(1)。min(-1))]进行心肺运动试验，每分钟一次同时从肺动脉和全身动脉采血，测定Hb、PO2、PCO2、pH、O-2含量（CO2）、Hb饱和度和乳酸（仅肺动脉），并计算P-50。在六个运动阶段进行数据分析：第一个是休息阶段，最后一个是高峰运动阶段，第二到第五个阶段是O-2消耗增加的1 / 5、2 / 5、3 / 5和4 / 5。峰值a-vCO(2)差。A、B、C类患者的运动强度分别为14.3 +/- 2.1、16.9 +/- 2.4和14.7 +/- 2.1 (SD) ml/dl。运动时Hb、P-50和PO2变化对a-vCO(2)差异增量的贡献分别为21%、17%和63%；唯一观察到的类间差异是P-50，它在a类a- vco(2)差异中起更大作用。Hb变化主要作用于动脉部位，而P-50和PO2作用于静脉部位。Hb的升高是恒定的，在无氧阈值以上，静脉P-50的升高更大，而静脉PO2的降低在运动开始时最为显著；C类患者在运动后半段未见静脉PO2变化。因此，a-vCO(2)差异在心力衰竭患者运动时明显增加，但与综合征的严重程度无关。Hb、P-50和PO2的变化最大程度地参与了a-vCO(2)差的增加。在C类患者中，在运动后半段PO2没有减少表明达到了“全身临界静脉PO2”。
Arteriovenous O-2 content (a-vCO(2)) differences increase during exercise in normal subjects through several mechanisms including PO2, O-2 pressure at which hemoglobin (Hb) is half saturated with O-2 (P-50), and Hb concentration changes. The present study was undertaken to evaluate how much these biochemical changes are relevant to a-vCO(2) difference through exercise in patients with heart failure. Twenty-seven patients with congestive heart failure [10 patients in functional class A (peak exercise O-2 uptake >20 ml . kg(-1). min(-1)), 9 in class B (20-15 ml . kg(-1). min(-1)), and 8 in class C (15-10 ml . kg(-1). min(-1))] underwent a cardiopulmonary exercise test with once-per-minute simultaneous blood sampling from the pulmonary and systemic arteries for determination of Hb, PO2, PCO2, pH, O-2 content (CO2), Hb saturation and lactic acid (pulmonary artery only), and calculation of P-50. Analysis of data was done at six exercise stages: the first at rest, the last at peak exercise, and the second to the fifth at one-, two-, three-, and four-fifths of O-2 consumption increase. a-vCO(2) difference at peak. exercise was 14.3 +/- 2.1, 16.9 +/- 2.4, and 14.7 +/- 2.1 (SD) ml/dl in class A, B, and C patients, respectively. The contribution of Hb, P-50, and PO2 changes to the increments of a-vCO(2) difference during exercise was 21, 17, and 63%, respectively; the only interclass difference observed was for P-50, which plays a greater role in a-vCO(2) difference in class A. Hb changes act mainly at the arterial site, whereas P-50 and PO2 act at the venous site. Hb increase was constant through the test, venous P-50 increase was greater above anaerobic threshold, and venous PO2 reduction was most remarkable at the onset of exercise; in class C patients, no venous PO2 change was recorded in the second half of exercise. Thus a-vCO(2) difference increase during exercise is notable in patients with heart failure but unrelated to the severity of the syndrome. Hb, P-50, and, to the greatest degree, PO2 changes participate in the increment of a-vCO(2) difference. In class C patients, the lack of PO2 reduction in the second half of exercise suggests the achievement of a ''whole body critical venous PO2.''