Evaluation of postceliotomy peritoneal drain fluid volume, cytology, and blood-to-peritoneal fluid lactate and glucose differences in normal dogs.

Objective: To describe peritoneal drain fluid volume, fluid cytology, and blood-to-peritoneal fluid lactate and glucose concentration differences after exploratory celiotomy in normal dogs.

Study Design: Prospective study.

Animals: Healthy Beagle dogs (n=10).

Methods: After exploratory celiotomy, a peritoneal drain was placed, and peritoneal fluid was recorded every 6 hours for 7 days. Fluid was submitted for cytologic examination, and fluid and blood glucose and lactate concentrations were recorded every 12 hours. On day 7, drains were removed and drain tips submitted for aerobic bacterial culture.

Results: Mean peritoneal fluid volume decreased from 2.8 mL/kg/day (day 1) to 0.6 mL/kg/day (day 7). All dogs had degenerate neutrophils in peritoneal fluid throughout the 7 days. Four dogs developed contaminated drains. Blood-to-peritoneal glucose concentration differences > 20 mg/dL occurred after day 4. By day 7, 5 of 7 dogs with patent drains had blood-to-peritoneal lactate concentration differences < -2 mmol/L.

Conclusion: After day 4, blood-to-peritoneal glucose concentration differences were consistent with septic effusion based on previously reported values used to diagnose septic peritonitis in dogs. Blood-to-peritoneal lactate concentration differences varied but after day 4, >70% of dogs had differences consistent with septic peritonitis each day. Postoperative blood-to-peritoneal fluid glucose and lactate difference may not be reliable indicators of septic peritonitis when evaluating abdominal fluid collected with closed suction drains.