Techniques are provided for detecting the circadian state of a patient using an implantable medical device based on selected blood carbon dioxide (CO2) parameters. In one example, the implantable device tracks changes in end tidal CO2 (etCO2) levels and changes in maximum variations of pCO2 levels per...http://www.google.de/patents/US7207947?utm_source=gb-gplus-sharePatent US7207947 - System and method for detecting circadian states using an implantable medical device
