A new quantitative assessment method for predicting pneumonia caused by chest wall injury

The severity of rib fractures has been previously evaluated by combining categorical data, but these methods have only low predictive capability for respiratory complications and mortality. This study aimed to establish a more accurate method for predicting the development of pneumonia, a frequent complication in chest injuries, using anatomical relationships.

We analyzed three-dimensional reconstructed images of 644 consecutive trauma patients who underwent whole-body computed tomography (CT) in our institution within a 36-month study period from April 2017. The anatomical relationship between the right and left thoracic volumes of non-rib fracture patients was used to estimate thoracic volume changes on the injured side in unilateral rib fracture patients. The predictive capability of changes in thoracic volume for the development of pneumonia was evaluated according to the area under the receiver operating characteristic curve and compared with that of previous chest wall severity evaluation methods.

Of the 644 patients, 133 and 478 patients had unilateral rib fractures and non-rib fractures, respectively. The amount of change in thoracic volume due to unilateral rib fractures was significantly greater in pneumonia patients (400 mL vs. 160 mL, p < 0.01). The area under the receiver operating characteristic curve for the development of pneumonia was 0.83, which tended to be higher than that of the previous severity scoring methods.

The amount of change in chest volume, which can be estimated using CT images, has better predictive capability for pneumonia than previous severity assessment methods based on categorical data. The amount of change in chest volume measured using whole-body CT can be used to rapidly determine the optimal treatment for severe chest wall injuries.

Prognostic study, level IV.