Methods and apparatus for determining the difference between a regional CO.sub.2 partial pressure of a selected body organ of a mammalian subject, such as the gut, and a systemic CO.sub.2 partial pressure of the subject. The regional CO.sub.2 partial pressure value is tonometrically obtained at body...http://www.google.com/patents/US6216023?utm_source=gb-gplus-sharePatent US6216023 - Method and apparatus for determining differences between regional CO2 and systemic CO2 measurements
