Subject index

Abstract

Alterations in the oxyhemoglobin dissociation curve might affect calculations of arteriovenous oxygen differences and might contribute to maintenance of myocardial oxygénation in patients with acute myocardial infarction. Accordingly, we analyzed oxyhemoglobin dissociation curves by the dynamic scanning technique as well as red cell diphosphoglycerate and adenosine triphosphate (ATP) determinations in peripheral venous and arterial blood samples from 43 patients with acute myocardial infarction. The oxyhemoglobin dissociation curve in these patients was shifted to the right, as reflected by an increase in p50 values beginning as early as 2 hours and as late as 10 days after the onset of infarction. The magnitude of the p50 shift did not correlate with initial or prevailing levels of systemic or pulmonary arterial PO2, red cell 2,3-diphosphoglycerate, ATP or cardiac index. The p50 values in venous and simultaneously obtained arterial samples correlated closely. Peak P50 was related to initial clinical class, size of infarct measured by serial serum creatine phosphokinase (CPK) analysis and acute mortality. Results obtained indicate that shifts in the oxyhemoglobin dissociation curve in. patients with acute infarction may facilitate oxygen availability to marginally perfused myocardium and must be taken into account when arteriovenous oxygen differences are calculated on the basis of PO2 or hemoglobin oximeter determinations, or both.