When Should Abdominal Computed Tomography Be Considered in Patients with Lower Rib Fractures?

Predictive parameters for early detection of clinically relevant abdominal trauma in multiple-injury or polytraumatised patients: a retrospective analysis

Diagnosis of relevant organ injury after blunt abdominal injury (AI) in multiple-injury/polytraumatised patients is challenging. AI can be distinguished between injuries of parenchymatous organs (POI) of the upper abdomen (liver, spleen) and bowel and mesenteric injuries (BMI). Still, such injuries may be associated with delays in diagnosis and treatment. The present study aimed to verify laboratory parameters, imaging diagnostics, physical examination and related injuries to predict intraabdominal injuries. This retrospective, single-centre study includes data from multiple-injury/polytraumatised patients between 2005 and 2017. Two main groups were defined with relevant abdominal injury (AI+) and without abdominal injury (AI-). The AI+ group was divided into three subgroups: BMI+, BMI+/POI+, and POI+. Groups were compared in a univariate analysis for significant differences. Logistic regression analysis was used to determine predictors for AI+, BMI+ and POI+. 26.3% (271 of 1032) of the included patients had an abdominal injury. Subgroups were composed of 4.7% (49 of 1032) BMI+, 4.7% (48 of 1032) BMI+/POI+ and 16.8% (174 of 1032) POI+. Pathological abdominal signs had a sensitivity of 48.7% and a specificity of 92.4% for AI+. Transaminases were significantly higher in cases of AI+. Pathological computed tomography (CT) (free fluid, parenchymal damage, Bowel Injury Prediction Score (BIPS), CT Grade > 4) was summarised and had a sensitivity of 94.8%, a specificity of 98%, positive predictive value (PPV) of 94.5% and, negative predictive value (NPV) of 98.2% for AI+. The detected predictors for AI+ were pathological abdominal findings (odds ratio (OR) 3.93), pathological multi-slice computed tomography (MSCT) (OR 668.9), alanine (ALAT) ≥ 1.23 µmol/ls (OR 2.35) and associated long bone fractures (OR 3.82). Pathological abdominal signs, pathological MSCT and lactate (LAC) levels ≥ 1.94 mmol/l could be calculated as significant risk factors for BMI+. For POI+ pathological abdominal MSCT, ASAT ≥ 1.73 µmol/ls and concomitant thoracic injuries had significant relevance. The study presents reliable risk factors for abdominal injury and its sub-entities. The predictors can be explained by the anatomy of the trunk and existing studies. Elevated transaminases predicted abdominal injury (AI+) and, specifically, the POI+. The pathological MSCT was the most reliable predictive parameter. However, it was essential to include further relevant parameters.

Characteristics of rib fracture patients who require chest computed tomography in the emergency department

BACKGROUND

The disadvantages and complications of computed tomography (CT) can be minimized if CT is performed in rib fracture patients with high probability of intra-thoracic and intra-abdominal injuries and CT is omitted in rib fracture patients with low probability of intra-thoracic and intra-abdominal injuries. This study aimed to evaluate the factors that can identify patients with rib fractures with intra-thoracic and intra-abdominal injuries in the emergency department among patients with rib fracture.

METHODS

This retrospective observational study included adult patients (age ≥ 18 years) diagnosed with rib fracture on chest radiography prior to chest CT due to blunt chest trauma in the emergency department who underwent chest CT from January 2016 to February 2021. The primary outcomes were intra-thoracic and intra-abdominal injuries that could be identified on a chest CT. Multivariate logistic regression analysis was performed.

RESULTS

Among the characteristics of rib fractures, the number of rib fractures was greater (5.0 [3.0-7.0] vs. 2.0 [1.0-3.0], p < 0.001), bilateral rib fractures were frequent (56 [20.1%] vs. 12 [9.8%], p = 0.018), and lateral and posterior rib fracture was more frequent (lateral rib fracture: 160 [57.3%] vs. 25 [20.5%], p < 0.001; posterior rib fracture: 129 [46.2%] vs. 21 [17.2%], p < 0.001), and displacement was more frequent (99 [35.5%] vs. 6 [6.6%], p < 0.001) in the group with intra-thoracic and intra-abdominal injuries than in the group with no injury. The number of rib fractures (adjusted odds ratio [aOR], 1.44; 95% confidence interval [CI], 1.16-1.78; p = 0.001), lateral rib fracture (aOR, 2.80; 95% CI, 1.32-5.95; p = 0.008), and posterior rib fracture (aOR, 3.18; 95% CI, 1.45-6.94; p = 0.004) were independently associated with intra-thoracic and intra-abdominal injuries. The optimal cut-off for the number of rib fractures on the outcome was three. The number of rib fractures ≥ 3 (aOR, 3.01; 95% CI, 1.35-6.71; p = 0.007) was independently associated with intra-thoracic and intra-abdominal injuries.

CONCLUSION

In patients with rib fractures due to blunt trauma, those with lateral or posterior rib fractures, those with ≥ 3 rib fractures, and those requiring O₂ supplementation require chest CT to identify significant intra-thoracic and intra-abdominal injuries in the emergency department.