Circulation research
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Circulation research · Oct 1976
The response of canine coronary vascular resistance to local alterations in coronary arterial P CO2.
The effect of hypercapnia on coronary vascular resistance (CVR) was studied in seven open-chest dogs. Coronary blood flow was supplied to the cannulated left main coronary artery from the femoral artery by a precision pump. Coronary arterial PCO2 was locally controlled with a small membrane oxygenator in the coronary perfusion circuit. ⋯ When coronary flow was reduced to an ischemic level there was little response in CVR to hypocapnia. Thus the level of arterial PCO2 can have an important effect on CVR independent of changes in O2 consumption. Myocardial PCO2, derived from metabolically produced CO2 and contributed to by arterial CO2, may be a major factor in normal control of coronary flow.