2015 ACVIM Forum Research Abstract Program

Ninety-seven horses met the inclusion criteria. The median age was 2.5 years, and travel within 6 weeks of admission was the most common risk factor. Common historical complaints included fever (84% of cases), lethargy (78%) and inappetance (77%), while common physical examination findings at admission included tachycardia (75%), tachypnea (60%) and fever (43%). Hyperfibrinogenemia and hypoalbuminemia were present in 79% and 69% of cases, respectively. The most common bacteria isolated from tracheal aspirates and pleural fluid was Streptococcus equi subsp. zooepidemicus. Within individual animals, only 20% of tracheal aspirates and pleural fluid samples yielded the same results, with tracheal aspirate culture more sensitive than pleural fluid culture. Laminitis was diagnosed in 8% of horses. The survival rate to discharge from the hospital was 67%. A thoracotomy was performed in 11 horses (11%), and was positively associated with survival (P = 0.030). Azotemia was negatively associated with survival (P < 0.001) and return to work (P = 0.034). Horses with azotemia were 11 times more likely to die than horses without azotemia, with every 1 unit increase in creatinine increasing the risk of death 5-fold.