Anatomical locations of air for rapid diagnosis of pneumothorax in blunt trauma patients.

Background: Bedside diagnostic ultrasound for traumatic pneumothorax is easy and reliable. However, the thoracic anatomical locations to be examined are debateable. We aimed to study the anatomical locations of blunt traumatic pneumothoraces as defined by chest CT scan to identify the areas that should be scanned while performing bedside diagnostic ultrasound. Methods: This is a retrospective analysis of a data collected for a previous study in blunt trauma patients at our hospital during a 4-year-period with CT confirmed pneumothoraces. The anatomical distribution of the pneumothoraces and their volume were analyzed. Advanced statistical analysis was performed using repeated measures logistic regression models. Results: Seven hundred three patients had a CT scan of the chest. Seventy-four patients (10.5%) were confirmed to have a pneumothorax. Only 64 were included in the study as they did not have a chest tube inserted before the CT scan. Twelve (18.8%) patients had bilateral pneumothorax. Seventy-six pneumothoraces were identified for which 41 patients had a right-sided pneumothorax and 35 patients had a left-sided pneumothorax. 95.1 % of the pneumothoraces detected on the right side were in the whole parasternal area with 75.6% seen in the lower parasternal region only. Similarly, 97.1 % of the pneumothoraces on the left side were seen in the whole parasternal area with 80% seen in the lower parasternal region only. Conclusions: The current study showed that air pockets of blunt traumatic pneumothoraces are mainly located at the parasternal regions especially in pneumothorax with small volume. We recommend a quick ultrasound scanning of the parasternal regions on both sides of the chest from proximal to distal as the appropriate technique for the detection of pneumothoraces in blunt trauma setting.