Evaluation of focused assessment with sonography in trauma (FAST) scan in detecting free fluid and type of blunt intraabdominal injury: A multicenter retrospective study

Introduction: Blunt intra-abdominal injury (BAI) encompasses a significant portion of trauma cases in the emergency department (ED). Morison pouch is typically considered the most common area of positive free fluid (FF) in BAI on the focused assessment with sonography in trauma (FAST) scan; however, no studies to date have investigated the correlation of the abdominal quadrant for positive FF with the type of abdominal injury. Objectives: This study aims to determine the most common quadrant and sub-quadrants for detecting FF and their association with the type of injury in BAI patients. Methods: This retrospective multicentre study evaluated 86 BAI patients with positive FF; the findings were confirmed with CT abdomen or operative findings. All trauma patients who presented to the ED will receive a FAST scan as a routine examination as suggested by trauma life support guidelines. The FAST scan clips saved in the ultrasound machine were reviewed periodically, and clips with positive findings were extracted. The most common quadrant and sub-quadrant positive for FF were then determined. Positive quadrants and their association with the type of injury were also analysed. Areas studied were the right upper quadrant (RUQ), left upper quadrant (LUQ), and suprapubic area (SP). Sub-quadrant areas were RUQ 1–hepato-diaphragmatic; RUQ 2–Morison pouch; RUQ 3–caudal liver edge and superior para-colic gutter; LUQ 1–splenic-diaphragmatic; LUQ 2–spleno-renal; LUQ 3–around the inferior pole of the kidney; SP 1–bilateral to the bladder; SP 2–posterior to the bladder; and SP 3–posterior to uterus. Results: The most common quadrant was the RUQ, with positive FF results for 82 (95.3%) patients. In sub-quadrant analysis, RUQ 3 was the most common (78 patients, 90.75%), followed by RUQ 2 (73 patients, 84.9%) and LUQ 2 (51 patients, 59.3%). A significant association was observed between the LUQ region positive for FF and the presence of splenic injury (p = 0.006). Conclusion: In patients with BAI, the RUQ is the most common quadrant, and RUQ 3 is the most common sub-quadrant for detecting FF. A positive LUQ suggests the presence of splenic injury in BAI.