ANALYTICAL CLINICAL STUDIES
Sequential L-lactate concentration in hospitalised equine neonates: A prospective multicentre study
- Portions of these data were presented in abstract at the 2010 American College of Veterinary Internal Medicine Forum and the 2010 International Veterinary Emergency and Critical Care Symposium.
Reasons for performing study
Evaluation of serial blood lactate concentrations [LAC] are of prognostic value for morbidity and mortality in critically ill human patients and neonatal foals, but have not been prospectively evaluated in a large multicentre study of critically ill neonatal foals.
To prospectively evaluate the prognostic value of sequential [LAC] analysis in critically ill neonatal foals with risk of mortality.
Prospective, observational study.
Thirteen university and private equine referral hospitals enrolled 643 foals over the 2008 foaling season and [LAC] was measured at admission ([LAC]ADMIT) and 24 ([LAC]24), 48 ([LAC]48), 72 ([LAC]72), 96 ([LAC]96) and 120 h ([LAC]120) after admission. [LAC] changes over time ([LAC]Δ) were calculated between sampling points.
Nonsurvivors had significantly greater [LAC]ADMIT, [LAC]24 and [LAC]48 compared with surviving foals (P<0.001). In nonsurviving foals [LAC]Δ did not decrease over time while survivors showed significant positive [LAC]Δ between [LAC]ADM–24 and all other time periods (P<0.001). Logistic regression analysis showed that the odds of survival decreased for each 1 mmol/l [LAC] increase at all time points for all critically ill foals, independent of major final diagnoses as potential confounders. Septic foals had significantly greater [LAC] at all time points compared with nonseptic foals (P<0.001) and [LAC]Δ in septic foals was significantly more positive (suggesting better clearance of lactate from the blood) only at [LAC]ADM–24 and [LAC]72–96 (P<0.01), while in nonseptic foals [LAC]Δ was significantly positive between [LAC]ADM–24 compared with all other time periods (P<0.001).
Blood lactate concentration is a strong, independent biomarker used to predict mortality in critically ill foals. Lactate metabolism is impaired in nonsurviving and septic foals and [LAC]Δ can be utilised to identify patients at high risk for mortality.