Intraoperative measurement of Cardiac output during Cardiac Surgery: Which TEE method is best?

The measure of left ventricle performance, as reflected by stroke volume, is an important component of hemodynamic assessment during cardiac surgery. The most commonly used technique to measure cardiac output is thermodilution, via a pulmonary artery catheter (PAC), but its invasive nature and potential for serious complications led to the utilization of less invasive methods, such as those based on transesophageal echocardiogram (TEE). The primary purpose of this study, a collaboration with Dr. Massimiliano Meineri at the University of Toronto, is to compare cardiac output measurements between TEE and PAC thermodilution techniques.