Low-density Isolated Intraperitoneal Free Fluid in Pediatric Blunt Trauma Is Not Associated With Abdominal Injury

Objectives:  Isolated intraperitoneal free fluid (IIFF) is defined as intraperitoneal fluid seen on computed tomography (CT) without identifiable injury. In a hemodynamically stable patient, this finding creates a challenge for physicians regarding the next steps in management because the clinical significance of this fluid is not completely understood. We hypothesized that pediatric blunt trauma patients with a finding of simple IIFF on CT would not have clinically significant intraabdominal injury.

Methods:  A retrospective review (2009-2018) was conducted of all pediatric blunt trauma patients who underwent CT scan of the abdomen/pelvis at our institution. All patients with scans performed at our institution with the finding of IIFF were included. Scans were reviewed to measure the Hounsfield Units (HU) of the intraabdominal fluid. Groups were stratified into HU > 25 and HU ≤ 25, below accepted cutoffs for acute blood, and clinical outcomes were reviewed.

Results:  A total of 413 patients had free fluid on CT abdomen/pelvis with 279 (68%) having only the finding of IIFF. The HU was 25 or less in 236 (85%) patients. No patients in the HU ≤ 25 group required operative exploration or had examination findings to indicate they had intraabdominal injury. Four (9%) patients in the HU > 25 required laparotomy (P < 0.0001). No patients in the HU ≤ 25 group required further workup or hospital admission over concern for intraabdominal injury.

Conclusions:  Pediatric blunt trauma patients with HU of 25 or less IIFF and a nonperitonitic physical examination did not require operative exploration or further workup for intraabdominal injury. In the absence of other injuries, it is safe to discharge these patients without further workup.