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Objective: In critically ill patients with an equivocal abdominal examination, Computed Tomography (CT) is the standard of care for diagnosing or ruling out acute intra-abdominal pathology requiring emergent laparotomy. Despite its accuracy, CT can be falsely negative (very small area of necrotic bowel), falsely positive (non-specific pneumatosis), or cannot be performed (patient instability; contrast allergy, etc). The current study evaluates the accuracy of Diagnostic Peritoneal Lavage (DPL) in determining need for emergent laparotomy in critically ill patients with equivocal clinical+CT presentation.
Design: Prospective interventional study
Setting: Academic tertiary care hospital
Patients: Critically ill adult (>18 years) patients
Interventions: Diagnostic peritoneal lavage
Main Outcome Measures: Correlation of DPL cytology with need for emergent laparotomy
Results: During the 15 month study period ending February 2017, 6 critically ill patients with equivocal abdomen underwent DPL to determine the need for emergent laparotomy. DPL effluent fluid was examined for peritoneal leuko-sequestration with positive result defined as nucleated cells>500/mm³ and/or DPL fluid nucleated cell:red blood cell ratio>peripheral blood ratio. 3/6 (50%) patients had positive DPL prompting urgent laparotomy. 2/3 (66%) were true positives (small area of trans-mural necrosis of ascending colon: 1; and gangrenous cholecystitis: 1) and 1/3 (33%) false positive (colitis with no trans-mural necrosis). Remaining 3/6 (50%) were true negatives (benign clinical course: 1; and negative laparotomy/autopsy: 2). Sensitivity, specificity, positive and negative predictive values of DPL in predicting need for emergent laparotomy were 100%, 75%, 66%, and 100%, respectively.
Conclusions: In critically ill patients with possible intra-abdominal catastrophe requiring emergent surgery and with a CT scan that is either non diagnostic or cannot be performed, DPL is highly accurate in determining the need for emergent laparotomy.