Changes in plasma and whole blood lactate in response to arterial occlusion.

The development of lactic acidaemia in the adult forearm in response to partial and total arterial occlusion is described in both plasma and whole blood. Under conditions of total occlusion of the brachial artery lactate levels in the plasma compartment rise at a significantly faster rate; mean difference in gradients -11.6 95% confidence limits -15.6 and -7.6. Thus in these conditions they provide a more sensitive index of tissue hypoxia. Under conditions of partial occlusion there is no significant difference; mean difference in gradients 1.0 95% confidence limits 9.4 and -7.3. Though plasma lactate levels are more sensitive to the ischaemic state in certain circumstances, whole blood measurements are equally applicable to the monitoring of trends in blood lactic acid.