A method of blood flow monitoring for a patient, the method comprising the steps of: a) receiving a first signal indicative of the real time cardiac output for the patient b) processing the continuous wave Doppler signal to provide an estimate of blood flow velocity as a function of time c) receiving a pressure measurement indicative of the blood flow resistance through the patient and d) calculating an Inotropy measure indicative of the potential and kinetic energy of the cardiac output of the patient.