LiDCOplus is a hemodynamic monitor, which is reliable method for beat-by-beat derivation of hemodynamic parameters from the existing arterial pressure catheter and waveform provides surgeons, and anesthesiologists a significantly improved hemodynamic monitoring option. The device is designed to improve patient management but it requires calibration with the absolute value obtained from a single point cardiac output measurement once every eight hours. The PulseCO software provides continuous assessment of a patient's hemodynamic status, by analyzing and processing the arterial pressure signal from the primary blood pressure monitor. The concept of using the blood pressure waveform to measure blood flow changes has been previously suggested by a number of investigators. These methods provide cardiac output trend data following calibration by an independent.