title: Effect of an increase in HbO2 affinity on the calculated capillary recruitment of an isolated rat heart.
abstract: The effect of an increase in hemoglobin O2 affinity on myocardial O2 delivery was studied in a blood perfused working rat heart preparation. In a first series of experiments P50 (PO2 for which saturation is 50%) was lowered by use of carbon monoxide. The heart was alternatively perfused with the blood sample of P50 = 32 mm Hg and the blood sample of P50 = 17 mm Hg. O2 capacity of both samples was kept the same by appropriate hemodilution. In a second serie of experiments change of P50 was obtained by the use of adult human erythrocytes containing hemoglobin creteil with a P50 of 13.6 mm Hg. As P50 decreased from 25 to 10 mm Hg, coronary sinus PO2 (PcsO2) diminished from 26 +/- 2 to 18 +/- 2 mm Hg (-29 +/- 2%), coronary sinus O2 content (CcsO2) increased by 15 +/- 3%, myocardial oxygen consumption did not change significantly. The percentage of increase of coronary flow was 23 +/- 4%. Analysis of these results with a simple mathematical model of O2 delivery suggest that increase in HbO2 affinity is corrected by a simultaneous increase in coronary flow and capillary recruitment.
mesh_terms: D000818:Animals; D002196:Capillaries / Q000502:physiology; D003326:Coronary Circulation; D006455:Hemoglobins, Abnormal / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D010108:Oxyhemoglobins / Q000378:metabolism*; D051381:Rats
chemical_list: D006455:Hemoglobins, Abnormal; D010108:Oxyhemoglobins