Accuracy of lung ultrasound in the diagnosis of acute respiratory distress syndrome: a systematic review and meta-analysis.

PURPOSE: Diagnosing acute respiratory distress syndrome (ARDS) traditionally relies upon chest radiography or computed tomography for radiologic criteria. Recent recommendations have proposed lung ultrasonography (LUS) as an alternative modality; however, the evidence supporting its utility remains uncertain. We sought to conduct a systematic review to evaluate the diagnostic accuracy of LUS for ARDS. METHODS: We searched MEDLINE, CINAHL, Embase®, and the Web of Science™ from inception through 16 May 2025, for original studies comparing the diagnostic accuracy of LUS to computed tomography or chest x-ray for ARDS diagnosis. We performed a diagnostic meta-analysis assessing lung ultrasound for ARDS, assessed the risk of bias of included studies using the QUADAS-2 tool, and rated the certainty of evidence using GRADE methodology. RESULTS: Our systematic review included 22 studies comparing LUS with a reference test using different scanning protocols and diagnostic thresholds, with variable interrater reliability. We included 13 studies in the meta-analysis (n = 1,999 patients, of which 618 [30.9%] had ARDS). The sensitivity of lung ultrasonography for ARDS was 0.69 (95% confidence interval [CI], 0.54 to 0.81; I2 = 82.9%) based on low certainty of evidence. The specificity of lung ultrasonography for ARDS was 0.95 (95% CI, 0.85 to 0.98; I2 = 88%) based on moderate certainty of evidence. CONCLUSIONS: Lung ultrasound is a better tool for diagnosing ARDS (higher specificity) than for ruling it out (moderate sensitivity). There was important between-study heterogeneity, including differences in scanning protocols and diagnostic thresholds, which was incorporated into the certainty of evidence assessments. These findings highlight the potential utility of lung ultrasound in ARDS diagnosis. STUDY REGISTRATION: PROSPERO ( CRD42023468933 ); first submitted 5 October 2023.