CONTINUOUS MEASUREMENT OF TISSUE OXYGEN AND CARBON-DIOXIDE GAS TENSIONS IN DOG LIVER IN ISCHEMIA-REPERFUSION

An experiment was conducted to determine whether the oxygen and carbon dioxide gas tensions in liver tissue (PtO2 and PtCO2, respectively) r eflect the state of microcirculation and/or metabolism in the ischemic liver. Subjects were divided into three groups: group 1, 30 min ische mia; group 2, 60 min ischemia; group 3, four times of intermittent 15 min ischemia after every 10 min of reperfusion. PtO2, PtCO2 and tissue blood flow (TBF) were measured by mass spectrometry, comparatively st udied with the serum GOT level as an indicator of liver tissue damage. Furthermore, the time point at which the PtCO2 increase for 1 min ini tially became less than 1/2 of the maximum value was located on the tr ansit curve of PtCO2, referred to as the critically anaerobic (CA) poi nt, with which new indices of critically anaerobic score (CAS) and tim e (CAT) (see details in text) were developed. The profiles of PtO2 and PtCO2 during ischemia and reperfusion were clearly demonstrated, and the CA point was observed 12.7 +/- 2.9 min after induction of ischemia . PtO2 was positively correlated with TBF and negatively with the seru m GOT level. Furthermore, not only CAS but also CAT were significantly correlated with PtO2, TBF, and the serum GOT level. It was concluded that PtCO2 reflects the state of anaerobic tissue metabolism during is chemia and PtO2 reflects the magnitude of microcirculatory disturbance and tissue injury caused by ischemia/reperfusion. Therefore, continuo us monitoring of not only PtO2 but also PtCO2 is beneficial for patien ts undergoing hepatic surgery with ischemia.