Context: Blunt abdominal trauma often presents a substantial diagnostic challenge. Well-informed clinical examination can identify patients who require further diagnostic evaluation for intra-abdominal injuries after blunt abdominal trauma.
Objective: To systematically assess the precision and accuracy of symptoms, signs, laboratory tests, and bedside imaging studies to identify intra-abdominal injuries in patients with blunt abdominal trauma.
Data sources: We conducted a structured search of MEDLINE (1950-January 2012) and EMBASE (1980-January 2012) to identify English-language studies examining the identification of intra-abdominal injuries. A separate, structured search was conducted for studies evaluating bedside ultrasonography.
Study selection: We included studies of diagnostic accuracy for intra-abdominal injury that compared at least 1 finding with a reference standard of abdominal computed tomography, diagnostic peritoneal lavage, laparotomy, autopsy, and/or clinical course for intra-abdominal injury. Twelve studies on clinical findings and 22 studies on bedside ultrasonography met inclusion criteria for data extraction.
Data extraction: Critical appraisal and data extraction were independently performed by 2 authors.
Data synthesis: The prevalence of intra-abdominal injury in adult emergency department patients with blunt abdominal trauma among all evidence level 1 and 2 studies was 13% (95% CI, 10%-17%), with 4.7% (95% CI, 2.5%-8.6%) requiring therapeutic surgery or angiographic embolization of injuries. The presence of a seat belt sign (likelihood ratio [LR] range, 5.6-9.9), rebound tenderness (LR, 6.5; 95% CI, 1.8-24), hypotension (LR, 5.2; 95% CI, 3.5-7.5), abdominal distention (LR, 3.8; 95% CI, 1.9-7.6), or guarding (LR, 3.7; 95% CI, 2.3-5.9) suggest an intra-abdominal injury. The absence of abdominal tenderness to palpation does not rule out an intra-abdominal injury (summary LR, 0.61; 95% CI, 0.46-0.80). The presence of intraperitoneal fluid or organ injury on bedside ultrasound assessment is more accurate than any history and physical examination findings (adjusted summary LR, 30; 95% CI, 20-46); conversely, a normal ultrasound result decreases the chance of injury detection (adjusted summary LR, 0.26; 95% CI, 0.19-0.34). Test results increasing the likelihood of intra-abdominal injury include a base deficit less than -6 mEq/L (LR, 18; 95% CI, 11-30), elevated liver transaminases (LR range, 2.5-5.2), hematuria (LR range, 3.7-4.1), anemia (LR range, 2.2-3.3), and abnormal chest radiograph (LR range, 2.5-3.8). Symptoms and signs may be most useful in combination, particularly in identification of patients who do not need further diagnostic workup.
Conclusions: Bedside ultrasonography has the highest accuracy of all individual findings, but a normal result does not rule out an intra-abdominal injury. Combinations of clinical findings may be most useful to determine which patients do not require further evaluation, but the ideal combination of variables for identifying patients without intra-abdominal injury requires further study.