A method of determining peritoneal penetration in gunshot wounds to the abdomen

It has previously been shown that 98% of gunshot wounds that penetrate the peritoneal cavity cause injuries that require surgical repair. Many gunshot wounds in the vicinity of the abdomen (GSWA) may actually be tangential and not penetrate the peritoneal cavity at all. Patients with such wounds may not require laparotomy. It is important to determine which patients with a potential tangential GSWA actually have penetration of the peritoneal cavity to minimize negative laparotomies. This study was undertaken to determine the sensitivity, specificity, and accuracy of diagnostic peritoneal lavage (DPL) in the determination of peritoneal penetration for patients who sustain GSWA.

DPL was performed for all patients who had sustained a GSWA in whom peritoneal penetration was unclear, i.e., patients whose GSWA appeared to be tangential, thoracoabdominal, or transpelvic and for whom a clear indication for laparotomy (shock, peritonitis, etc.) did not exist. Our threshold for a positive DPL was 10,000 red blood cells (RBC)/mm3. A prospective data base was kept with information on the location of the wound, DPL result, findings at laparotomy, and outcome.

During a 4-year period, 429 consecutive DPLs were performed for GSWA at our urban Level I trauma center. One hundred fifty DPLs were positive, with more than 10,000 RBC/mm3. Six of these patients were found to have no peritoneal penetration at laparotomy (false-positive). The remaining 144 patients with positive DPLs were found to have operative injuries (true-positive). Of the 279 patients with DPL counts less than 10,000 RBC/mm3, 2 developed indications for laparotomy and were found to have intraperitoneal injuries (false-negative). The remaining 277 patients had no peritoneal injuries (true-negative). This was demonstrated either by laparotomy done for another indication (n = 7) or by uneventful inpatient observation for 24 hours (n = 270). The sensitivity, specificity, and accuracy of DPL in determining peritoneal penetration in GSWA is therefore 99, 98, and 98%, respectively.

For patients who sustain GSWA for whom peritoneal penetration is unclear, DPL is a sensitive, specific, and accurate test to determine the need for laparotomy. It remains our test of choice when confronted with these patients.