Quantitative assessment of changes in blood CO2 tension mediated by the Haldane effect

Abstract

Adequate assessment of circulatory and gas-exchange interactions may involve the quantification of the Haldane effect (HE) and of the changes in blood[Formula: see text] mediated by changes in Hb-O2 saturation and O2-linked CO2 binding. This is commonly prevented by the complexity of the involved calculations. To simplify the task, a large series of patient measurements has been processed by regression analysis, thus developing an accurate fit for this quantification[Formula: see text]( n= 247, r 2 = 0.99, P ≪ 0.001), where (v-a)Pco 2 HEis the reduction in venous [Formula: see text]([Formula: see text], Torr) allowed by the chemical binding of CO2 in blood due to the HE (Torr), (a-v)HbO2 is the arteriovenous difference in Hb-bound O2 (ml/dl), and Hct is hematocrit fraction. Values of (v-a)Pco 2 HEestimated by this expression compared well with the results of previously published experiments. This formula is useful in assessing the impact of HE on [Formula: see text] and venoarterial [Formula: see text] gradient and the survival advantage offered by HE in extreme conditions. Use may be extended to all investigative and clinical settings in which changes in blood O2 saturation and O2-linked CO2 binding must be converted into the corresponding changes in dissolved CO2 and[Formula: see text].