RESUMO
BACKGROUND: Serum N-terminal pro-C-natriuretic peptide (NT-proCNP) has shown promise as a diagnostic biomarker for sepsis. Its sensitivity to detect dogs with septic peritonitis (SP) is reportedly low, perhaps attributable to the compartmentalization of NT-proCNP in the abdominal cavity. OBJECTIVES: To evaluate the use of an ELISA for the measurement of NT-proCNP in canine abdominal fluid and to describe the peri-operative pattern of abdominal fluid and serum NT-proCNP concentrations in dogs with SP. ANIMALS: Five client-owned dogs with nonseptic abdominal effusion of varying etiologies and 12 client-owned dogs with SP undergoing abdominal surgery and placement of a closed-suction abdominal drain (CSAD). Six dogs were included upon hospital admission; 6 were included the day after surgery. METHODS: Prospective pilot study. A commercially available ELISA kit was analytically validated for use on canine abdominal fluid. The NT-proCNP concentrations were measured in the abdominal fluid of control dogs, and in serum and abdominal fluid of dogs with SP from admission for CSAD removal. RESULTS: In dogs with SP, admission abdominal fluid NT-proCNP concentrations were lower than the concurrent serum concentrations (P = 0.031), and lower than control canine abdominal fluid concentrations (P = 0.015). Postoperatively, abdominal fluid NT-proCNP concentrations remained lower than serum concentrations (P < 0.050), except on day 4. CONCLUSIONS AND CLINICAL IMPORTANCE: The ELISA kit was able to measure NT-proCNP in canine abdominal fluid. In dogs with SP, low serum NT-proCNP concentrations cannot be explained by abdominal compartmentalization.