Sensors located on a sensor carrier are placed adjacent one or more of a surgical patient's major thoracic blood-containing structures such as the aorta or pulmonary artery, and characteristics of blood in the blood-containing structures are determined noninvasively by measuring transmission or reflection...http://www.google.ca/patents/US7010337?utm_source=gb-gplus-sharePatent US7010337 - Method and apparatus for monitoring blood condition and cardiopulmonary function
