Increased cardiac output and oxygen transport after intraoperative isovolemic hemodilution. A study in patients with...

The effects of isovolemic hemodilution on cardiac output and oxygen transport in 11 patients during elective vascular surgery were evaluated. Mean hemoglobin level was decreased from 12.5 +/- 0.6 to 10.2 +/- 0.5 g/dL by withdrawing blood and replacing it with an equal volume of colloid. Hemodilution increased cardiac output from 4.8 +/- 0.3 to 6.4 +/- 0.4 L/min, increased oxygen delivery from 830 +/- 75 to 900 +/- 95 mL/min and increased oxygen consumption from 190 +/- 20 to 240 +/- 40 mL/min. Systemic vascular resistance and mean arterial blood pressure decreased significantly, but cardiac filling pressure, pulmonary vascular resistance, heart rate, and intrapulmonary shunt did not change. In four of these patients who did not require all their blood during surgery, 1 unit of their withdrawn blood was reinfused after completion of surgery. In all four patients, cardiac output, oxygen delivery, and oxygen consumption decreased from the pretransfusion values. We conclude that, since intraoperative isovolemic hemodilution increased blood flow and systemic oxygen transport, it may be useful in the intraoperative management of patients with atherosclerotic vascular disease.