Preliminary results from a prospective multicenter study of the association of lactate concentration with survival in sick neonatal foals

The concentration of lactate [LAC] in the blood of sick equine neonates at admission ([LAC]ADMIT) and other time points is associated with survival in several retrospective studies, with larger [LAC] associated with non-survival. We hypothesized that this association would remain when examined prospectively. Thirteen university and private equine referral hospitals on 3 continents enrolled 643 foals over the 2008 foaling season of both hemispheres. Signalment, historical, clinical and clincopathologic data were entered into a standardized spreadsheet by a single veterinarian at each institution. Spreadsheets were unified into a single data set for analysis. Not all data were available for all foals. Data were analyzed using Kruskal-Wallis and regression analysis, P _ 0.05. There were more colts (N 5 354) than fillies (N 5 277) enrolled; there was no difference in [LAC]ADMIT by sex. Neither gestational age nor age at admission were significantly different between survivors and non-survivors. Median [LAC]ADMIT was significantly larger in non-survivors (N 5 120, 5.79 mmol/L, P o 0.001) compared to survivors (N 5 466, 3.55 mmol/L). The difference in [LAC] between groups remained statistically significant through 120 hrs post-admission. [LAC]ADMIT was significantly greater in foals born following premature placental separation (P o 0.001) and those with a history of dystocia or Caesarian section delivery (Po0.001). Mean arterial pressure had a small (R2 5 19.1%) but significant (P o 0.001) association with [LAC]ADMIT. [LAC]ADMIT was not significantly different in blood culture positive vs negative foals. This large prospective study supports the findings of several smaller retrospective studies regarding the utility of initial and repeated [LAC] measurement in the management of sick foals.