Analytical diagnostic peritoneal lavage in the diagnosis of intra-abdominal injury.

Diagnostic peritoneal lavage (DPL) was modified to detect dynamic changes occurring in lavage fluid in dogs following liver, spleen, or intestinal injury. In 33 animals lavage fluid was serially sampled over 75 minutes and analyzed for RBC and other variables. The spun sediment was Gram stained. In control groups, either saline or autologous blood was instilled into the peritoneal cavity at a known rate. In these experiments, the composition of lavage fluid did not significantly change over time. Blood infused at a constant rate into the abdominal cavity produced corresponding, continuing increases in the RBC count. In experimental groups, the liver, spleen, or intestine were injured before lavage. Only initial RBC counts greater than 1 million/mm3 or rising RBC counts in serial lavage samples were associated with life-threatening hemorrhage. Gram stains of samples were positive for bacteria in 43% of fasted dogs and in 80% of fed dogs with intestinal perforation.