Effect of respiratory alkalosis on blood lactate and pyruvate in humans

Abstract

Arterial lactate and pyruvate were determined at various levels of hypocapnia and alkalemia in humans during active hyperventilation. Lactate and pyruvate increased in all subjects, and the increases showed an inverse relationship to the decrease in PCO2 a''d H+ concentration. However, even the maximum changes were relatively small, the mean lactate increasing less than 1 mmole/liter H2O at PcO2 = 20 mm Hg, pH = 7.61. Lactate uniformly rose more than pyruvate with consequent rise in lactate/pyruvate ratio. In subjects studied over a period of 2 hr, lactate and pyruvate rose to a peak at 45-75 min*and then declined. In no case was there progressive elevation of lactate or pyruvate nor was there progressive deficit of "true" bicarbonate, ft is concluded that respiratory alkalosis in humans leads neither to large increases in lactate and pyruvate nor to progressive shifts in the buffer curve of the blood. When such increases occur in association with hypocapnia and alkalemia it becomes necessary to invoke some metabolic or circulatory disturbance as a contributing factor,.