Diagnostic Accuracy of Point-of-Care Ultrasound Versus Chest X-Ray for Pneumothorax Detection in Supine Blunt Trauma Patients

Abstract

Background: Traumatic pneumothorax requires rapid recognition during blunt-trauma resuscitation, yet portable supine chest radiography (CXR) has limited sensitivity because intrapleural air may accumulate anteriorly and remain radiographically occult. Point-of-care ultrasound (POCUS) provides rapid bedside assessment without ionizing radiation, but its comparative diagnostic performance in supine blunt-trauma patients requires focused synthesis. Objective: To systematically review and meta-analyze the diagnostic accuracy of bedside POCUS compared with portable supine CXR for detecting traumatic pneumothorax, using thoracic computed tomography as the principal reference standard. Methods: PubMed/MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library were systematically searched for diagnostic studies evaluating POCUS and supine CXR in blunt-trauma populations. Eligible studies provided diagnostic accuracy data against an appropriate reference standard. Study selection and data extraction were performed independently by two reviewers. Methodological quality was assessed using diagnostic-accuracy risk-of-bias principles based on QUADAS-2. Sensitivity and specificity were synthesized using a bivariate random-effects diagnostic meta-analysis, with heterogeneity and clinically relevant subgroup differences evaluated where data permitted. Results: Eleven studies comprising 2,839 participants were included. POCUS demonstrated pooled sensitivity of 87.3% (95% CI 84.2–90.0%; I²=41.2%), compared with 48.2% (95% CI 44.1–52.3%; I²=28.4%) for supine CXR. Pooled specificity was 98.2% (95% CI 97.3–98.9%) for POCUS and 99.0% (95% CI 98.3–99.5%) for CXR. POCUS detected 79.4% (95% CI 72.8–84.8%) of CT-confirmed radiographically occult pneumothoraxes. Conclusion: POCUS provides substantially greater sensitivity than supine CXR for detecting traumatic pneumothorax while maintaining similarly high specificity. Thoracic POCUS is therefore a valuable early bedside diagnostic modality, although confirmatory imaging remains appropriate when findings are negative, indeterminate, or clinically discordant