A nomogram predicting the need for abdominal and pelvic computed tomography in blunt trauma patients: A retrospective cohort study

Background Abdominal and pelvic computed tomography (APCT) has become the preferred means for the initial evaluation of blunt trauma patients. However, computed tomography examination has some disadvantages, such as radiation exposure, the requirement for intravenous iodinated contrast medium, high cost, and time. We aimed to develop a nomogram to predict the need for APCT scanning after the primary survey of blunt trauma patients. Materials and methods We conducted a retrospective observational cohort study at a single-center and reviewed medical records of 972 trauma patients admitted between January 2013 and June 2016. We enrolled 786 blunt trauma patients who had undergone APCT and were 16 years of age or older. A multivariate logistic regression model was used to determine independent predictors for trauma-related findings on APCT scans. A nomogram was constructed to predict injury on APCT scans based on each predictive factor. Results Of 786 patients, 355 (45%) patients had at least 1 injury on APCT scans. Results of multivariate logistic regression analysis showed that independent predictive factors of injuries on APCT scans were as follows: falls (≥3 m high); pain (abdominal, back, flank, or pelvic); positive peritoneal signs; abnormal findings on chest radiographs; abnormal findings on pelvic radiographs; and positive findings on focused assessment with ultrasonography for trauma. The nomogram was developed using these parameters. The area under a receiver operating characteristic curve of the multivariate model for discrimination was 0.865 (95% confidence interval, 0.840–0.892). The calibration plot showed good agreement between predicted and observed outcomes. The maximal Youden index was 0.59, corresponding to a cutoff value > 59 points, which was considered the optimal cutoff value for the probability that the injury would be detected on APCT scans. Conclusion The nomogram, based on initial clinical findings in blunt trauma patients, will help clinicians be more selective in their use of APCT evaluations.