Association of Blood Lactate Concentration and Outcome in Foals

Abstract

Lactate concentration in blood or plasma ([LAC]) and change in [LAC] are associated with survival in sick foals. [LAC] and change in [LAC] over time are associated with survival at 96 hours and discharge in neonatal foals. Furthermore [LAC] and change in [LAC] over time correlate with blood culture results and blood pressure at admission. Two hundred and twenty-five foals consecutively admitted to a Neonatal Intensive Care Unit. Retrospective case review. Foals <or=30 days of age with [LAC] from arterial (190) or umbilical (35) blood gas analysis ([LAC](BG)) at admission, 24, and 48 hours. [LAC](BG), blood pressure, blood culture status, and outcome (survival versus nonsurvival at 96 hours and discharge) were recorded. Change in [LAC](BG) over time ([LAC](BG)DeltaT) was calculated. [LAC](BG) was lower in survivors (96 hours and discharge) at all times. [LAC](BG)DeltaT was larger for survivors (96 hours). Odds of survival (96 hours and discharge) decreased 18, 39, 53 and 22, 38, and 47%, respectively, at each sample time for every 1 mmol/L increment in [LAC](BG) and increased 156% for each 1.0/day increment in [LAC](BG)DeltaT from admission to 24 hours at 96 hours. Blood pressure and [LAC](BG) were not correlated (P= .196) until removal of selected foals (mean arterial pressure <60 mmHg, admission [LAC](BG) <5.5 mmol/L) (P < .001). Bacteremia was not associated with [LAC](BG). Proposed admission [LAC](BG) cut-points for future studies were 6.5 mmol/L (96 hours) and 5.5 mmol/L (discharge). Prospective studies evaluating [LAC], [LAC](BG)DeltaT, and cut-points in sick foals are warranted.