Myocardial blood flow, oxygen uptake and carbon dioxide release of the human heart during hemodilution

Myocardial blood flow, oxygen consumption and carbon dioxide release were studied before and during hemodilution in man. Dextran 70 was used as the dilutional agent to reduce hematocrit values from 37 to 28% (mean). The decrease of oxygen content in arterial blood after hemodilution was compensated by an increase of cardiac output. The myocardial blood flow increased proportionally more than the cardiac output, resulting in a virtually unchanged oxygen tension in coronary sinus blood. The metabolism of the heart was not affected as the respiratory quotient remained unchanged. This investigation suggests that blood losses up to 20% of the total blood volume can be replaced by dextran solutions, without a significant decrease of myocardial oxygen supply.