Clinical Comparison of an Echocardiograph-Derived Versus Pulse Counter–Derived Cardiac Output Measurement in Abdominal Aortic Aneurysm Surgery

Abstract

To compare cardiac output (CO) measurements acquired using the Flotrac/Vigileo system (Edwards Lifesciences, Irvine, CA) and CO measured by transesophageal echocardiography using the product of the aortic valve area, the time integral of flow at the same site, and the heart rate during abdominal aortic aneurysm (AAA) surgery. A prospective clinical study. Cardiac surgery operating room of 1 heart center hospital. Twenty patients undergoing elective AAA surgery. CO was determined simultaneously using the Flotrac/Vigileo system (CO(AP)) and transesophageal echocardiography (CO(TEE)) as the reference method at 8 time points during AAA surgery. One hundred sixty simultaneous datasets were obtained. The authors observed a significant correlation between CO(AP) and CO(TEE) values (R = 0.56, p < 0.001). Bland-Altman analysis of CO(AP) and CO(TEE) showed a bias of 0.12 L/min and limits of agreement from -1.66 to 1.90 L/min, with a percentage error of 41%. Just after aortic clamping, CO(AP) significantly increased, but CO(TEE) decreased in comparison with previous measurements. There was a significant association among changes in CO(AP) and pulse pressure, heart rate, and central venous pressure (CVP). However, changes in CO(TEE) were only associated with variations in heart rate. CO(AP) values were not clinically acceptable for use in AAA surgery because of wide variations during aortic clamping and declamping. Changes in pulse pressure, heart rate, and CVP were associated with significant changes in CO(AP), whereas only changes in heart rate showed associated changes in CO(TEE).