Response of some biophysical properties of blood to changes in the perfusion flow rate during cardiopulmonary bypass.
Cardiopulmonary bypass (CPB) is a safe support system during major cardiac operations because it allows the distribution of adequately oxygenated blood to the entire body. The optimal perfusion flow to be used during hypothermic CPB remains a controversial issue. In the present study, the effect of different flows and pressures on oxygen delivery, extraction and consumption was compared. Such an effect was evaluated for 40 patients undergoing open-heart surgery using CPB (membrane oxygenator) and systemic hypothermia. The patients were randomized into two groups (20 each) according to the flow and pressure (low flow, low pressure and high flow, high pressure). The electrical impedance from 50 Hz to 10 MHz for blood samples and erythrocytes for both groups was also measured at different time intervals (before-, during and post-CPB). No significant change for low flow group was recorded (p > 0.05) while the dielectric properties of the high-flow group were greatly affected by the time of operation. Hence, low flow can be safely used in young patients without any organ impairment or carotid artery disease, while high flow should be used for patients with any organ dysfunction, at the initiation of CPB and during rewarming to compensate for the increase in oxygen consumption and the need for better perfusion pressure.
Ali
Maha Anwar
MA
Department of Biophysics, Faculty of Science, Cairo University, Giza, Egypt.
D000328:Adult; D000465:Algorithms; D055592:Biophysical Phenomena; D001703:Biophysics; D001790:Blood Physiological Phenomena; D002315:Cardiopulmonary Bypass; D017097:Electric Impedance; D004566:Electrodes; D004594:Electrophysiology; D004907:Erythrocyte Deformability / Q000502:physiology; D004912:Erythrocytes / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007036:Hypothermia, Induced; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010477:Perfusion
D010100:Oxygen