Arterial ketone body ratio during and after cardiopulmonary bypass

This study is the first to investigate the alteration in hepatic function during and after cardiopulmonary bypass in 30 patients by measuring the arterial ketone body ratio, an index of mitochondrial redox potential (oxidized nicotinamide-adenine dinucleotide/reduced nicotinamide-adenine dinucleotide). Although the preoperative arterial ketone body ratio was within normal limits (1.24 +/- 0.63), it decreased markedly 5 minutes after the start of cardiopulmonary bypass to 0.35 +/- 0.12 and remained at this low level throughout bypass. After bypass it continued to rise in a time-dependent fashion, returning to its preoperative level by the morning of the second postoperative day in normal convalescent patients. However, the ratio recovered more slowly in patients who required prolonged circulatory or respiratory support than in other patients. Thus we suggest that cardiopulmonary bypass had deleterious effects on the hepatic mitochondrial redox potential, which may contribute to homeostatic derangements and metabolic abnormalities.