Coronary perfusion and myocardial metabolism during open-heart surgery in man.

Myocardial oxygen consumption and extraction of lactate and free fatty acids (FFA) have been measured in six patients during cardiopulmonary bypass at two coronary flow rates differing by 25 per cent (109 and 148 ml. per minute). Significant differences were found between these flows and between natural and artificial coronary perfusion. This fact indicates the presence of anaerobic metabolism, especially at the lower coronary flow. These findings are discussed in relation to criteria for coronary flow and perfusion pressure during open-heart procedures.