Grossly positive peritoneal lavage and nontherapeutic laparotomy after abdominal stab wound

Diagnostic peritoneal lavage is often employed in the evaluation of stab wounds of the anterior abdomen and lower chest. This technique is perhaps too sensitive, however, in detecting self-limited solid visceral and abdominal wall injuries. We report five cases of nontherapeutic laparotomies in abdominal stab wound victims who had a grossly positive peritoneal lavage prior to surgery. Previous retrospective data indicate that such "false positive" lavages most commonly result from blood entering the abdominal cavity from the wound, although nonoperative injuries to solid viscera and iatrogenic trauma are sometimes implicated. We review these studies and suggest caution in relying too much on lavage results in determining the need for exploration after abdominal stab wounds. Rather, they must be considered alongside other findings in assessing each individual case.