Evaluation of peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity for detection of septic peritonitis in horses

Objective-To determine whether peritoneal fluid pH, glucose concentration, and lactate dehydrogenase activity can be used to differentiate horses with septic peritonitis from those with nonseptic peritonitis, Design-Prospective study. Animals-46 horses, including 10 healthy horses, 15 horses with septic perit onitis, and 21 horses with nonseptic peritonitis. Procedure-Peritoneal fluid and blood samples were analyzed for pH, glucose concentration, and lactate dehydrogenase activity. Complete blood cell coun ts were performed, and peritoneal fluid samples were submitted for bacteria l culture. Results-Horses with septic peritonitis had significantly lower peritoneal f luid pH and glucose concentrations than horses with nonseptic peritonitis a nd healthy horses. Compared with other tests, serum-toperitoneal fluid gluc ose concentration differences > 50 mg/dl had the highest diagnostic use for detection of septic peritonitis. Peritoneal fluid pH < 7.3, glucose concen tration < 30 mg/dl, and fibrinogen concentration > 200 mg/dl were also high ly indicative of septic peritonitis. Clinical Implications-Peritoneal fluid pH and glucose concentration can be used to assist in the identification of horses with septic peritonitis. The se measurements can provide an early indication of sepsis, especially if cy tologic evaluation of periloneal fluid is unavailable or results are equivo cal and peritoneal fluid bacterial culture results are pending.