Association of Blood Lactate Concentration and Outcome in Foals

Background: Lactate concentration in blood or plasma ([LAC]) and change in [LAC] are associated with survival in sick foals. Hypothesis: [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. Animals: Two hundred and twenty‐five foals consecutively admitted to a Neonatal Intensive Care Unit. Methods: Retrospective case review. Foals ≤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 ΔT) was calculated. Results: [LAC] BG was lower in survivors (96 hours and discharge) at all times. [LAC] BG ΔT 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 ΔT 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). Conclusions and Clinical Importance: Prospective studies evaluating [LAC], [LAC] BG ΔT, and cut‐points in sick foals are warranted.