An endotracheal breathing tube for use in surgical operations is equipped with a light emitting device adjacent its distal end to reside within the patient's trachea during use and with a compatible photosensitive detector positionable outside the patient's body in contact with the neck to intercept...http://www.google.co.uk/patents/US5005573?utm_source=gb-gplus-sharePatent US5005573 - Endotracheal tube with oximetry means
