Proceedings

Optimising Cardiopulmonary Bypass Utilizing Continuous Oxygen Saturation Monitoring

The Johns Hopkins Hospital Section of Perfusion Technology, Baltimore, MD

^* Direct communications to: Paul A. Page, B.S., CCP, PA., Blalock Room 614, 600 North Wolfe Street, Baltimore MD 21205

Abstract

Proper management of cardiopulmonary bypass requires the analysis of both arterial and venous blood gases at regular intervals, and is most critical during the rewarming phase. ^3,4 In some hospitals blood gas results are received as long as 15 to 30 minutes after the sample is drawn. More frequent blood gas analysis or ideally continuous measurement of oxygen saturation allows the perfusionist to make continuous adjustments as the patient’s oxygen requirements change. Two hundred patients were selected for study. One hundred were perfused using regular periodic blood analyses. A second group of one hundred patients were perfused utilizing an in-line saturation meter.

The blood flow rate was 6% lower during hypothermia and 5% lower while warm in the group utilizing the saturation meter. The total gas flow rate was reduced by 20% while cold and 16% while warm in the metered group. The CPB arterial and venous pO₂ RANGES were reduced with the use of the oxygen saturation meter. The same make of hybrid oxygenator was utilized on all patients in both study groups.

Based on the close correlation of the oxygen saturations afforded by the saturation meter and those measured by the blood gas laboratory, we found the Bentley Oxygen Saturation Meter reliable and accurate. It may help protect the patient from extremes in oxygenation and allows the perfusionist to regulate the oxygenator in the most precise and efficient operation.