Comparing Sensitivity and Specificity of Ultrasonography With Chest Radiography in Detecting Pneumothorax and Hemothorax in Chest Trauma Patients: A Cross-Sectional Diagnostic Study

Abstract

Background Thoracic trauma accounts for 20-25% of all traumas and is the third most frequent cause of death, after abdominal injury and head trauma. In the Emergency Department (ED), shifting an unstable patient to the X-ray room for detecting pneumothorax and hemothorax is always risky and bedside X-ray causes radiation exposure not only to the particular patient but also to the surrounding patients in a congested and busy ED. This can be avoided by using bedside ultrasonography (USG) as the initial imaging modality in chest trauma patients. Objective To compare the sensitivity and specificity of ultrasonography and chest radiography in detecting pneumothorax and hemothorax in chest trauma patients. Methods This cross-sectional diagnostic study was conducted for a period of one year at Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India, a tertiary care centre. All consecutive patients (n=255) with a suspected history of chest trauma were included in the study. The patients were evaluated bedside using USG by point of care ultrasonography trained emergency medicine physician and subsequently underwent chest radiography for documentation of pneumothorax and hemothorax. Sensitivity and specificity were calculated for ultrasonography and chest X-ray (CXR) compared with the composite gold standard (chest radiography and computed tomography thorax). Results Of the 255 patients, 89% were males. The mean age of the patients was 43.46 (standard deviation 16.3). Road traffic accident (RTA) was the most common mode of injury (81%). The median (interquartile range) time interval between injury and arrival at the hospital was four hours (2.5-7). About 16.1% of the patients had subcutaneous emphysema. About 88.2% of the patients were hemodynamically stable and 78% of the patients had associated other system injuries. The sensitivity and specificity of USG in detecting pneumothorax were 85.7% and 95.3% respectively and that of CXR were 71.4% and 100% respectively. Our study found that the sensitivity and specificity of USG in detecting hemothorax were 79% and 97.9% respectively and that of CXR were 62.9% and 100% respectively. Even in the subset of patients in whom a computed tomography scan was done, the sensitivity of USG was higher than that of CXR in detecting pneumothorax and hemothorax. The specificity of USG in detecting pneumothorax was the same as that of CXR and the specificity of USG in detecting hemothorax was higher than that of CXR in that subset of patients. Conclusion The sensitivities of USG in detecting pneumothorax and hemothorax were higher than that of CXR. The specificities of USG in detecting pneumothorax and hemothorax were comparable to that of CXR. Hence bedside USG performed by emergency physician during resuscitation helps in rapid diagnosis and early management of chest trauma patients.

Thoracic Ultrasound Utility in Pulmonary Pathologies Following Blunt Chest Trauma: A Cross-Sectional Study From Barcelona, Venezuela

“…For hemothorax detection, ultrasound showed a sensitivity/specificity of 75.9%/95.9% compared to CXR with 58.6%/95.1% [29]. Other studies have also demonstrated the superiority of ultrasound over CXR in these patients [30]. The superiority of ultrasound is due to its high sensitivity in detecting fluids and gases, making it effective in identifying the presence of fluid (such as blood in the case of hemothorax) or air (as in the case of pneumothorax) in the thoracic cavity.…”

Current evidence on the use of pocus in the diagnosis of pneumothorax in emergency rooms: a systematic review

“…The diagnosis and management of respiratory diseases were limited, until recently, by the presence of air in the respiratory tract and solid structures in the rib cage, which prevented the passage of ultrasound waves and thus created image artifacts, characterizing a variety of pathologies of clinical interest [1][2][3]. Such artifacts are generated by the pleura, due to a difference in acoustic impedance between the air in the lung and the superficial tissues [4][5][6].…”