screening performance of ultrasonographic b-lines in detection of lung contusion following blunt trauma; a diagnostic accuracy study

Introduction: chest ultrasonography is routinely used in evaluation of chest trauma for diagnosis of pulmonary injury. this study aimed to evaluate the accuracy of b-lines for diagnosing lung contusion in patients with blunt trauma of the chest. methods: trauma patients who met the inclusion criteria were enrolled in the study and underwent ultrasonography by trained emergency medicine residents. ultrasound results were recorded in terms of number of b-lines and the existence of peripheral parenchymal lesion (ppl). after ultrasound, the patient underwent chest x-ray and chest ct scan (as reference test) and screening performance of b-lines and ppl were evaluated. results: 147 patients underwent chest ultrasound. the mean age of the patients was 40.74 ± 18.6 (78.9% male). b-lines>3 had 94.0% (95% ci: 83.45-98.75) sensitivity and 57.7% (95% ci: 47.3-67.7) specificity, b-lines>6 had 90.0% (95% ci: 78.2-96.7) sensitivity and 93.81%(95%ci: 87.0-97.7) specificity, and ppl had 34.0% (95% ci: 21.2-48.8) sensitivity and 100% (95% ci: 96.3-100.0) specificity. composite findings of b-lines>6 + ppl had 92.0% (95% ci: 80.8-97. 8) sensitivity and 93.8% (95% ci: 87.0-97.7) specificity in the diagnosis of lung contusion. conclusion: ppl and b-lines>6 had the highest accuracy in detecting lung contusion. b-line>6 had high sensitivity and specificity and was easy to perform; thus, it seems that b-line>6 could be considered as an alternative screening tool in detection of lung contusion.