EFFECTS OF EXTRACORPOREAL-CIRCULATION ON BLOOD KETONE-BODY RATIO REFLECTING HEPATIC ENERGY-METABOLISM DURING CARDIAC OPERATION

To examine the effects of extracorporeal circulation using an artifici al heart and lung machine on hepatic energy metabolism in patients wit h cardiac operation using hypothermia, the arterial blood ketone body ratio (AKBR) reflecting the hepatic mitochondrial redox state was dete rmined in 12 patients who had undergone cardiac operation using extrac orporeal circulation from March to August 1991. Changes in AKBR were c ompared with those before and after extracorporeal circulation. AKBR d ecreased significantly after the beginning of extracorporeal circulati on (p<0.001) and remained at a lower level throughout extracorporeal c irculation. On termination of extracorporeal circulation, the initial level was immediately resumed. The extent of decrease in ketone body r atio at ten minutes before termination of extracorporeal circulation w as correlated with short term postoperative hepatic insufficiency. The patients whose ratio decreased below 0.4 showed increased levels in g lutamic-pyruvic transaminase at the end of the first and second week a fter operation. Changes in AKBR were significantly associated with tho se in blood pressure (r=0.433; p<0.005) and body temperature (r=0.472; p<0.005). It was concluded that blood pressure and body temperature i nfluence the blood ketone body ratio during extracorporeal circulation .