Mitochondrial redox state in the critically ill.

Abnormal oxygen use and organ failure in the critically ill may result from 'poisoning' of mitochondrial function. Measurement of arterial ketone body ratio (AKBR) has been proposed to reflect mitochondrial redox state and may provide a useful marker to monitor mitochondrial function in the critically ill. We measured AKBR (acetoacetate to beta-hydroxybutyrate) and plasma lactate concentrations in 20 critically ill patients, on 3 consecutive days after admission to the intensive care unit. Nine (45%) patients died (five with sepsis) within the 30-day follow-up period. AKBR increased significantly over the 3 days of the study in patients who died (P = 0.034) and decreased in those who survived (P < 0.0001). In addition, there was a significant difference between survivors and non-survivors (P = 0.015). We conclude that serial AKBR measurement may be useful in the management of septic patients.