Validation of the Cheetah NICOM by Comparison to TEE During Open Vascular Surgery - Pilot Study

The Cheetah NICOM is a non-invasive cardiac output monitor that has been validated in various clinical contexts but not during the occlusion of major arteries, as takes place in vascular surgery. The present study will evaluate the precision and validity of the measures taken by the device during open vascular surgery procedures. The measurements will be compared to the those calculated by transesophageal echocardiography at various key points during the surgeries. The validity of the cardiac output, stroke volume and stroke volume variation measurements will be evaluated, as well as the device's ability to track rapid changes in cardiac output.