Sequential L-lactate concentration in hospitalised equine neonates: A prospective multicentre study.

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. OBJECTIVES: To prospectively evaluate the prognostic value of sequential [LAC] analysis in critically ill neonatal foals with risk of mortality. STUDY DESIGN: Prospective, observational study. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Association of admission L-lactate concentration in hospitalised equine neonates with presenting complaint, periparturient events, clinical diagnosis and outcome: a prospective multicentre study.

REASONS FOR PERFORMING THE STUDY: Admission L-lactate concentration is a useful and commonly measured biomarker not previously prospectively evaluated in a large multicentre study of critically ill neonatal foals. OBJECTIVES: To evaluate overall outcome and the association of survival and L-lactate concentration at admission ([LAC]ADMIT) by periparturient history, presenting complaint and clinicians' major diagnosis for ill neonatal foals. METHODS: Thirteen university and private equine referral hospitals enrolled 643 foals over the 2008 foaling season. Case details, historical, clinical and clinicopathological data were entered into standardised spreadsheets then unified for analysis. RESULTS: Overall survival was 79% (505/643). Risk of nonsurvival increased with each 1 mmol/l increase in [LAC]ADMIT (odds ratio 1.14, P < 0.001). Mean arterial pressure had a small (r2 = 19.1) but significant (P < 0.001) association with [LAC]ADMIT. Foals experiencing known dystocia or premature placental separation had increased [LAC]ADMIT (P < 0.001). Single umbilical problems (excluding uroperitoneum), meconium impaction only and failure of passive transfer of immunity only had 100% survival. Six clinicians' major diagnoses had increased odds of nonsurvival for each 1 mmol/l increase in [LAC]ADMIT: 'sepsis'; 'unspecified enterocolitis'; 'unspecified colic'; 'unspecified trauma'; 'immune related (not failure of passive transfer of immunity)' and 'respiratory only'. CONCLUSIONS AND POTENTIAL RELEVANCE: Survival of critically ill foals is good but varies with peripartum history, presenting complaint and clinicians' major diagnosis. L-lactate concentration at admission proves its utility as a valuable prognostic biomarker in neonatal foals and its utility appears to vary with peripartum history and clinicians' major diagnosis.