The current invention is described using a preferred embodiment that usesindicator dilution, such as injecting a saline solution and sensing thepresence ofindicator and its concentration with an ultrasound sensor. Those of ordinaryskill in theart, once they understand the principles of the current invention will realizethat otherphysical properties of the blood can be changed and other types of sensors canbeused to obtain the dilution curves without departing from the spirit of theinvention.Among potential changes in blood properties possible are its opticalproperties,electrical proprieties (electrical impedance), thermal properties, or anyother appropriatephysical or chemical properties of the blood. Accordingly, optical sensors,electricalsensors, thermal sensors, or other appropriate physical or chemical sensorscan beused, maybe used depending on the change in the property of the blood made.Additionally, isotope tracers with appropriate sensors could be used. This isnot meantto be an exhaustive list. The equations can be modified to work with differentindicatorswhich will not depart from the spirit of the invention.
