The operating principles and methods for the continuous determination of aortic blood flow (ABF) with the Dynemo 3000 system are described in detail. The system uses a novel transesophageal ultrasonic Echo-Doppler probe simultaneously to measure aortic diameter and blood flow velocity at the same anatomic level, in real-time. Non-invasive ABF measurement is combined with vital sign data from standard monitors to provide a composite hemodynamicprofile including volume, after load and contractility data used by the physician to optimize therapy. A review of the clinical validation and comparison to thermo dilution measurements showing a significant positive correlation over a wide range of clinical flow situations is also briefly presented.