METHODS: Single-centre, registry-based retrospective cohort study, screening all consecutive trauma patients admitted to Lausanne University Hospital Trauma Centre from 2008 to 2015 after a road traffic accident. All patients with reliable information about the presence or absence of sBBMI who underwent abdominal CT and for whom calculation of the BIPS was possible were included for analysis. The incidence of delayed (>24h after admission) diagnosis in the patient group with sBBMI was determined and the diagnostic performance of the BIPS for sBBMI was assessed.
RESULTS: For analysis, 766 patients with reliable information about the presence or absence of sBBMI were included. The prevalence of sBBMI was 3.1% (24/766). In 24% (5/21) of stable trauma patients undergoing CT, a diagnostic delay of more than 24h occurred. Abdominal tenderness (p<0.0001) and CT grade ≥4 (p<0.0001) were associated with sBBMI, whereas CT grade 4 alone (p=0.93) and WBC count ≥17G/l (p=0.30) were not. A BIPS ≥2 had a sensitivity of 89% (95% CI, 67-99), specificity of 89% (95% CI, 86-91), positive likelihood ratio of 8 (95% CI, 6.1-10), negative likelihood ratio of 0.12 (95% CI, 0.03-0.44), positive predictive value (PPV) of 19% (95% CI, 15-24) and negative predictive value (NPV) of 99.7% (95% CI, 98.7-99.9). CT alone identified 79% (15/19) and the BIPS 89% (17/19) of patients with sBBMI (p=0.66).
CONCLUSIONS: Diagnostic delays in patients with sBBMI are common (24%), despite the routine use of abdominal CT. Application of the BIPS on the present cohort would have led to a high number of non-therapeutic abdominal explorations without identifying significantly more sBBMI early than CT alone.