Plasma endotoxin concentrations in clinically normal and potentially septic equine neonates

Plasma endotoxin concentrations were measured at 1 to 2 and 5 to 6 days of age in clinically normal foals and in potentially septic neonatal foals admitted to North Carolina State University's Veterinary Teaching Hospital for a variety of conditions. In 1 to 2 and 5 to 6 day old normal foals, median plasma endotoxin concentrations were 2.17 (range, 1.61-2.54; n = 6) and 2.89 (range, 2.61-3.50; n = 7) endotoxin units/mL (EU/mL), respectively. Median plasma endotoxin concentration in potentially septic foals with negative blood cultures or gram positive isolates (n = 8) was 2.73 (range, 0.59-4.04) EU/mL. In hospitalized foals with gram negative isolates (n = 6), median plasma endotoxin concentration was 78.06 (range, 0.76-2,696.41) EU/mL, but individual endotoxin values were only increased in foals that were extremely sick and died within hours of sampling. Plasma endotoxin concentrations were significantly greater in foals with sepsis scores > or = 11 compared with foals with sepsis scores < or = 10. Increased plasma endotoxin concentrations appear to predict an unfavorable outcome in septic foals, but normal endotoxin concentrations do not appear to have any predictive value.