Effect of alcohol on the lactate/pyruvate ratio of recently injured adults.

Abstract

To compare the ability of plasma (lactate) and the plasma lactate/pyruvate (L/P) ratio to predict shock-related outcome after injury and also to examine the influence of plasma ethanol on any relationships found. Prospective observational study. Emergency departments in the UK and the Republic of South Africa. Blood samples were taken at presentation from 232 adult patients 1-23 hrs (median, 3.5 hrs) after sustaining an injury or injuries deemed sufficiently severe to require inpatient care. Plasma concentrations of lactate, pyruvate, and ethanol, anatomical severity of injury, development of multiple organ failure, and 30-day survival were determined. At 90% specificity for predicting subsequent mortality and/or multiple organ failure, plasma lactate >or=3.85 mmol/L was 23% (5% to 41%) more sensitive than an L/P ratio of >or=42.76. At 90% sensitivity for ruling out morbidity, plasma lactate <1.6 mmol/L is 6% (-1% to 13%) more specific than an L/P ratio of <14.08. High L/P ratios were noted to be associated with a detectable plasma alcohol level. A post hoc regression analysis showed that alcohol-positive/-negative status was a much stronger predictor of the L/P ratio than was anatomical severity of injury, shock, or time after injury. Plasma lactate alone is a better predictor than the L/P ratio of shock-related outcome after injury. The interpretation of L/P ratios after injury is confounded in the presence of elevated plasma ethanol.