Should we be measuring more often? Lactate levels are frequently elevated in critically ill patients and correlate well with disease severity. Elevated lactate levels are prognostic in prehospital, emergency department, and intensive care unit settings. A recent study found that in patients with hyperlactatemia on ICU admission, lactate-guided therapy significantly reduced hospital mortality when adjusting for predefined risk factors. As this was consistent with important secondary endpoints, this study suggests that initial lactate monitoring has clinical benefit. A review of the literature reported
that supported blood lactate monitoring as being useful for risk assessment in patients admitted acutely to hospital, and especially the trend, achieved by serial lactate sampling, is valuable in predicting in-hospital mortality.
All patients with a lactate at admission above 2.5 mM should be closely monitored for signs of deterioration, but patients with even lower lactate levels should be considered for serial lactate monitoring. The correlation between lactate levels in arterial and venous blood was found to be acceptable, and venous sampling should therefore be encouraged, as the risk and inconvenience for this procedure is minimal for the patient. Venous assays of lactate are readily available on many blood gas instruments, larger chemistry instruments and even in some POC instruments.