Designing an extracorporeal deep-hypothermic heat exchanger and optimizing its operating conditions

A theoretical study altered the tube and fin dimensions of a commercial hypothermic heat exchanger (HE) used in cardiopulmonary bypass during open-heart surgery to obtain an optimized design (OHE). This OHE was then tested analytically by modeling the patient/HE system with a single-pool body assumption, modified to accommodate for body temperature gradients. Simultaneous solution of the body differential and system HE equations, showed that the OHE could provide the clinically desirable cool-down phase within 20 min, and the warm-up within 30 min for a wide range of patient types and cardiac outputs. precise holding phase temperatures also could be obtained, +or-0.05 degrees C, through optimal control of the HE's water inlet temperature.<>