Association of hyperlactatemia with age, diagnosis, and survival in equine neonates

Objective - To investigate the association between blood lactate concentration, measured at admission and following 12-36 hours of treatment, and age, diagnosis, and survival in neonatal foals. Design - Retrospective, observational study. Setting - Two equine referral hospitals. Animals - One hundred and twelve foals ≤96 hours of age were included. Interventions - Arterial or venous blood samples were obtained from all foals at admission and surviving foals at 12-36 hours. Measurements - The lactate concentration (LAC) was recorded at 2 time points: admission (LAC-Admission) and 12-36 hours following treatment (LAC-24 hours). Main Results - LAC decreased by 0.05 mmol/L for each increased hour of age at presentation. Premature/dysmature foals demonstrated increased odds of nonsurvival of 55% for each 1 mmol/L increase in LAC-Admission while foals with major diagnoses of neonatal encephalopathy (NE), enteritis and 'Other' had increased odds of nonsurvival of 52%, 113%, and 247%, respectively, for each 1.0 mmol/L increase in LAC. Blood-culture positive foals had significantly lower LAC than blood culture negative foals. LAC-Admission and LAC-24 hours were significantly larger in nonsurviving foals. LAC-Admission of >6.9 mmol/L and LAC-24 hours >3.2 mmol/L, respectively, correctly classified 85.6% and 94.1% of cases as survivors or nonsurvivors. No differences were found when the 24-hour change in LAC was investigated in terms of outcome, age at admission, or major diagnosis; however, LAC-24 hours remained significantly associated with survival. Conclusions - Admission or persistent hyperlactatemia is associated with a nonsurvival. Younger foals, premature/dysmature foals, and foals with neonatal encephalopathy had the largest LAC.