Cardiac Output Measurement by TEE

The measurement of the LV performance, as reflected by measuring cardiac output (CO), is an important component of hemodynamic assessment during cardiac (and non-cardiac) surgery. It has become standard of care in guiding fluid management and inotropic therapy in both the operating room (OR) and the intensive care unit (ICU) in most centres, and is considered by far the most understood and commonly communicated parameter of cardiac performance, in addition to being consistently shown as a predictor of patients' outcome. Several methods have been used to measure CO. The most commonly used is via thermodilution (PAC), but its invasive nature and potential for serious complications led to the utilization of the non-invasive methods, such as those based on TEE. Since the establishment of the role of TEE in the setting of hemodynamic monitoring during cardiac surgery, various ways of quantifying LV function have been utilized. The method recommended by current guidelines is a volumetric calculation via the method of disks (modified Simpson's method, MOD). Recent advances in ultrasound technology and software development allow the utilization three-dimensional (3D) volumetric assessment and speckle tracking for cardiac deformation.