Diagnostic Accuracy of Chest Radiograph, and When Concomitantly Studied Lung Ultrasound, in Critically Ill Patients With Respiratory Symptoms: A Systematic Review and Meta-Analysis

Chest radiograph is considered the first-line diagnostic imaging modality for patients presenting with pulmonary symptoms in the ICU. In this meta-analysis, we aim to evaluate the diagnostic accuracy of chest radiograph, and when concomitantly studied lung ultrasound, in comparison with the gold-standard CT for adult critically ill patients with respiratory symptoms.PubMed, EMBASE, and Gray literature.Studies comparing chest radiograph, and if performed lung ultrasound, with CT for adult ICU patients with respiratory symptoms.Quality was scored with Quality Assessment of Diagnostic Accuracy Studies-2, and study setting, test characteristics, and study design were extracted.In the meta-analysis, we included 10 full-text studies, including 543 patients, and found that chest radiograph has an overall sensitivity of 49% (95% CI, 40-58%) and specificity of 92% (86-95%). In seven studies, where also lung ultrasound was studied, lung ultrasound had an overall sensitivity of 95% (92-96%) and specificity of 94% (90-97%). Substantial heterogeneity was found. A planned subgroup analysis for individual pathologies was performed. The results of four abstract-only studies, included in the systematic review, were considered unlikely to significantly influence results of our meta-analysis. Study limitations were that most studies were of low power combined with methodological limitations.This meta-analysis demonstrates that chest radiograph has a low sensitivity and reasonable specificity compared with CT for detecting lung pathology in critically ill patients. The studies also investigating lung ultrasound, showed lung ultrasound to be clearly superior to chest radiograph in terms of sensitivity with similar specificity, thereby opting to be the first-line diagnostic tool in these patients.