Blunt Abdominal Trauma Patients Are at Very Low Risk for Intra-abdominal Injury After Emergency Department Observation

Introduction: Patients are commonly admitted to the hospital for observation following blunt abdominal trauma (BAT), despite initially negative emergency department (ED) evaluations. With the current use of screening technology, such as computed tomography (CT) of the abdomen and pelvis, ultrasound, and laboratory evaluations, it is unclear which patients require observation. The objective of this study was to determine the prevalence of intra-abdominal injury (IAI) and death in hemodynamically normal and stable BAT patients with initially negative ED evaluations admitted to an ED observation unit and to define a low-risk subgroup of patients and assess whether they may be discharged without abdominal/pelvic CT or observation.

Methods: This was a retrospective cohort study performed at an urban level 1 trauma center and included all BAT patients admitted to an ED observation unit as part of a BAT key clinical pathway. All were observed for at least 8 hours as part of the key clinical pathway, and only minors and pregnant women were excluded. Outcomes included the presence of IAI or death during a 40-month follow-up period. Prior to data collection, low-risk criteria were defined as no intoxication, no hypotension or tachycardia, no abdominal pain or tenderness, no hematuria, and no distracting injury. To be considered low risk, patients needed to meet all low-risk criteria.

Results: Of the 1,169 patients included over the 2-year study period, 29% received a CT of the abdomen and pelvis, 6% were admitted to the hospital from the observation unit for further management, 0.4% (95% confidence interval [CI], 0.1%-1%) were diagnosed with IAI, and 0% (95% CI, 0%-0.3%) died. Patients had a median combined ED and observation length of stay of 9.5 hours. Of the 237 (20%) patients who met low-risk criteria, 7% had a CT of the abdomen and pelvis and 0% (95% CI, 0%-1.5%) were diagnosed with IAI or died.

Conclusion: Most BAT patients who have initially negative ED evaluations are at low risk for IAI but still require some combination of observation and CT. A subgroup of BAT patients may be safely discharged without CT or observation after the initial evaluation.