Changes in acid-base status, lactate concentration and purine metabolites during reconstructive aortic surgery.

Hypoxanthine has been proposed as a better indicator of hypoxic damage than acid-base status or lactate. Acid-base status, lactate and purine metabolites were therefore measured in 17 patients undergoing aortic surgery. Blood samples were taken systemically just before aortic clamping and after declamping, and from the femoral vein after declamping. The systemic hypoxanthine levels increased threefold after declamping, due to 20 times higher hypoxanthine concentration in the femoral vein. The percentage changes in concentration of hypoxanthine correlated well (r = 0.85) with the aorta-clamping time. The changes in acid-base status and lactate levels were erratic and showed no correlation with the duration of the ischemic period.