Lung ultrasound in a tertiary intensive care unit population: a diagnostic accuracy study.

BACKGROUND: Evidence from previous studies comparing lung ultrasound to thoracic computed tomography (CT) in intensive care unit (ICU) patients is limited due to multiple methodologic weaknesses. While addressing methodologic weaknesses of previous studies, the primary aim of this study is to investigate the diagnostic accuracy of lung ultrasound in a tertiary ICU population. METHODS: This is a single-center, prospective diagnostic accuracy study conducted at a tertiary ICU in the Netherlands. Critically ill patients undergoing thoracic CT for any clinical indication were included. Patients were excluded if time between the index and reference test was over eight hours. Index test and reference test consisted of 6-zone lung ultrasound and thoracic CT, respectively. Hemithoraces were classified by the index and reference test as follows: consolidation, interstitial syndrome, pneumothorax and pleural effusion. Sensitivity, specificity, positive and negative likelihood ratio were estimated. RESULTS: In total, 87 patients were included of which eight exceeded the time limit and were subsequently excluded. In total, there were 147 respiratory conditions in 79 patients. The estimated sensitivity and specificity to detect consolidation were 0.76 (95%CI: 0.68 to 0.82) and 0.92 (0.87 to 0.96), respectively. For interstitial syndrome they were 0.60 (95%CI: 0.48 to 0.71) and 0.69 (95%CI: 0.58 to 0.79). For pneumothorax they were 0.59 (95%CI: 0.33 to 0.82) and 0.97 (95%CI: 0.93 to 0.99). For pleural effusion they were 0.85 (95%CI: 0.77 to 0.91) and 0.77 (95%CI: 0.62 to 0.88). CONCLUSIONS: In conclusion, lung ultrasound is an adequate diagnostic modality in a tertiary ICU population to detect consolidations, interstitial syndrome, pneumothorax and pleural effusion. Moreover, one should be careful not to interpret lung ultrasound results in deterministic fashion as multiple respiratory conditions can be present in one patient. Trial registration This study was retrospectively registered at Netherlands Trial Register on March 17, 2021, with registration number NL9344.

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

OBJECTIVES: 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. DATA SOURCES: PubMed, EMBASE, and Gray literature. STUDY SELECTION: Studies comparing chest radiograph, and if performed lung ultrasound, with CT for adult ICU patients with respiratory symptoms. DATA EXTRACTION: Quality was scored with Quality Assessment of Diagnostic Accuracy Studies-2, and study setting, test characteristics, and study design were extracted. DATA SYNTHESIS: 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. CONCLUSIONS: 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.