Peritoneal lavage enzyme determinations following blunt and penetrating abdominal trauma

Diagnostic peritoneal lavage (DPL) provides a rapid and sensitive means of investigating the peritoneal cavity following blunt and penetrating trauma. However, its shortcomings include insensitivity in the early identification of isolated hollow viscus injuries. We have routinely assayed lavage amylase (LAM) and alkaline phosphatase (LAP) in acutely injured patients for more than 4 years to assess the contribution of lavage enzyme analysis to the overall accuracy of DPL. From 1,969 DPLs, LAM was analyzed in 1,881 (96%) and LAP in 1,734 (88%) of 1,536 blunt and 433 penetrating trauma cases. Of 28 patients with negative lavage by LRBC but LAM greater than or equal to 20 IU/L, 13 (46%) had clinically significant injury requiring laparotomy. Seventy-seven percent of these cases involved the small bowel. In this group, LAM greater than or equal to 20 IU/L had a sensitivity of 87%, specificity of 75%, and positive predictive value of 46% for significant intra-abdominal injury. Seven patients had LAM greater than or equal to 20 IU/L and LAP greater than or equal to 3 IU/L. These values had a sensitivity of 54%, specificity of 98%, and positive predictive value of 88% for significant abdominal injury. Elevations of LAM (greater than or equal to 20 IU/L) and LAP (greater than or equal to 3 IU/L) mandate laparotomy where the history is consistent with possible small bowel injury. Elevation of either enzyme alone should raise the suspicion of hollow visceral organ injury and warrant close observation.