Patent ID: 6719705
Filing Date: 2004-04-13
Classification: A61B

Abstract:
A method for noninvasively determining a patient's cardiac output, comprising the steps of:providing a first tissue probe having a first radiation emitter and a first radiation detector, said first radiation emitter being adapted to emit first radiation having at least a first wavelength, said first radiation detector being adapted to receive said first radiation after absorbance through the patient's blood; providing a second tissue probe having a second radiation emitter and a second radiation detector, said second radiation emitter being adapted to emit second radiation having at least a second wavelength, said second radiation emitter being adapted to receive said second radiation after absorbance through the patient's blood, said first and second tissue probes being further adapted to measure the patient's blood pulse; placing said first tissue probe proximate a first extremity of the patient; placing said second tissue probe proximate a second, opposing extremity of the patient; substantially simultaneously and continuously measuring first extremity oxygen saturation at each blood pulse in said first extremity with said first tissue probe and second extremity oxygen saturation at each blood pulse in said second extremity with said second probe, said first extremity oxygen saturation measurement providing a plurality of first oxygen saturation values, said second extremity oxygen saturation measurement providing a plurality of second oxygen saturation values; measuring the patient's pulse rate; determining matching oxygen saturation using said first and second oxygen saturation values; determining the patient's blood volume: determining cardiac stroke volume using said blood volume and said pulse rate; and determining the patient's cardiac output using said cardiac stroke volume and said pulse rate.