A cardiac output measurement device volumetrically heating a predefined quantity of blood flowing through a heart by arbitrarily applying a containable energy field to the blood using a thermodilution catheter having an emitter that uniformly emits electromagnetic radiation. Blood temperature is measured...http://www.google.ca/patents/US5954659?utm_source=gb-gplus-sharePatent US5954659 - Method and apparatus for invasively measuring cardiac output by detecting temperature differences of blood heated by radiation
