This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Willford, D. C Articles by Garden, R. M Search for Related Content PubMed Articles by Willford, D. C Articles by Garden, R. M Social Bookmarking                         What's this?

Changes in oxygen-haemoglobin affinity and myocardial function during extracorporeal perfusion in immature pigs

Department of Medicine, University of California

William Y Moores

Department of Surgery University of California

Richard M Garden

Department of Medicine, University of California at San Diego

An alteration in oxygen-haemoglobin affinity, as indicated by the partial pressure of oxygen at 50% haemoglobin saturation (P₅₀), may theoretically affect oxygen delivery to the myocardium and, thus, alter myocardial tissue PO₂ and possibly myocardial function. We studied the effect of changes in P₅₀ on heart function, metabolism, and coronary sinus PO₂ in 10 anaesthetized immature domestic pigs. To facilitate exchange transfusions and control of preload (left ventricular end diastolic pressure, LVEDP), afterload (mean arterial pressure), cardiac output, and heart rate, the animals were placed on right heart bypass. Stroke work (SW), myocardial oxygen consumption (MVO ₂), coronary blood flow (CBF), arterial-coronary sinus O₂ content difference (CaO₂ -CcsO₂), and P₅₀ were measured with a control blood prime and after an exchange transfusion with blood having either a low (Group I) or high (Group II) affinity for oxygen. Results (Mean ± SEM, Control versus Test): P₅₀ (mmHg) at 37°C and pH 7.4 increased in Group 1 (35.5 ± 0.7 versus 40.1 ± 1.2, p <0.01) and decreased in Group II (34.7 ± 1.3 versus 26.3 ± 0.5, P <0.001). At 8mmHg LVEDP, SW (gram·metres, g.m) remained constant in Group I (12.2 ± 1.1 versus 11.7 ± 0.8 g·m), but decreased (p <0.05) in Group II (11.7 ± 0.9 versus 8.6 ± 0.61 g.m). In addition, Starling curves relating SW to LVEDP between 4 and 18mmHg were uniformly depressed in Group II but not Group I. No significant change in MVO₂ occurred in either group. Group II demonstrated decreased CaO₂- CcsO₂ (9.3 ± 0.8 versus 6.0 ± 0.3ml O₂/dl, p <0.05) and increased CBF (121.6 ± 16.5 versus 188.9 ± 16.9ml/min/1 00gm, p <0.01). PcsO₂ increased significantly in Group I (26.6 ± 4.2 versus 36.1 ± 2.7, P <0.02) but not Group II. In conclusion, a decrease in P₅₀ appeared to decrease myocardial function despite a lack of change in PcsO₂ or MVO₂. A decrease in P₅₀ also led to an increase in CBF. An increase in P₅₀ did not alter function, but did increase coronary sinus and, presumably, tissue PO₂.

Perfusion, Vol. 7, No. 2, 89-101 (1992)
DOI: 10.1177/026765919200700203


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?