Chest
Volume 142, Issue 4, October 2012, Pages 965-972
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Original Research
Chest Infections
Lung Ultrasound in the Diagnosis and Follow-up of Community-Acquired Pneumonia: A Prospective, Multicenter, Diagnostic Accuracy Study

https://doi.org/10.1378/chest.12-0364Get rights and content

Background

The aim of this prospective, multicenter study was to define the accuracy of lung ultrasound (LUS) in the diagnosis of community-acquired pneumonia (CAP).

Methods

Three hundred sixty-two patients with suspected CAP were enrolled in 14 European centers. At baseline, history, clinical examination, laboratory testing, and LUS were performed as well as the reference test, which was a radiograph in two planes or a low-dose CT scan in case of inconclusive or negative radiographic but positive LUS findings. In patients with CAP, follow-up between days 5 and 8 and 13 and 16 was scheduled.

Results

CAP was confirmed in 229 patients (63.3%). LUS revealed a sensitivity of 93.4% (95% CI, 89.2%-96.3%), specificity of 97.7% (95% CI, 93.4%-99.6%), and likelihood ratios (LRs) of 40.5 (95% CI, 13.2-123.9) for positive and 0.07 (95% CI, 0.04-0.11) for negative results. A combination of auscultation and LUS increased the positive LR to 42.9 (95% CI, 10.8-170.0) and decreased the negative LR to 0.04 (95% CI, 0.02-0.09). We found 97.6% (205 of 211) of patients with CAP showed breath-dependent motion of infiltrates, 86.7% (183 of 211) an air bronchogram, 76.5% (156 of 204) blurred margins, and 54.4% (105 of 193) a basal pleural effusion. During follow-up, median C-reactive protein levels decreased from 137 mg/dL to 6.3 mg/dL at days 13 to 16 as did signs of CAP; median area of lesions decreased from 15.3 cm2 to 0.2 cm2 and pleural effusion from 50 mL to 0 mL.

Conclusions

LUS is a noninvasive, usually available tool used for high-accuracy diagnosis of CAP. This is especially important if radiography is not available or applicable. About 8% of pneumonic lesions are not detectable by LUS; therefore, an inconspicuous LUS does not exclude pneumonia.

Trial registry

ClinicalTrials.gov; No.: NCT00808457; URL: www.clinicaltrials.gov

Section snippets

Materials and Methods

This was an international, multicenter, prospective, observational study in patients with suspected CAP in 14 European centers (two university hospitals, seven hospitals of internal medicine, one hospital of pulmonary medicine, two practices, and two EDs). The institutional review board approved the study protocol (number 2055-06/07), and patients provided written, informed consent before enrollment. This study is reported according to the Standards for the Reporting of Diagnostic Accuracy

Results

Between November 2007 and February 2011, 14 European centers recruited 397 patients. Thirty-five patients were excluded because of violations of inclusion criteria (n = 3) or an equivocal reference test (n = 32) (Fig 1). The remaining 362 patients underwent LUS and radiographic examinations. Sixty-three patients (17.4%) had low-dose CT scans; of them, 46 were according to the study protocol. In the remaining 17 patients, radiographic findings were confirmed by a spiral CT scan, which was

Discussion

To our knowledge, this is the first prospective multicenter study dealing with the use of LUS in the diagnosis and follow-up of CAP. These results show an excellent sensitivity of 94% and specificity of 98%, comparable with chest radiograph in two planes. LR > 10 and < 0.01 are considered to rule in or rule out diagnosis in most circumstances.12 Combining typical auscultation and positive LUS findings was about 43 times more likely in patients with CAP and provides strong evidence to rule in

Conclusions

To our knowledge, this is the first multicenter feasibility study to demonstrate that CAP may be diagnosed and followed up with LUS. The results show an excellent sensitivity and specificity at least comparable with chest radiograph in two planes. In cases with sonographic evidence of pneumonia, the diagnosis can be established. A radiograph or CT scan of the chest is necessary in cases with negative ultrasound results (in about 8% of the patients), if other differential diagnoses are taken

Acknowledgments

Author contributions: Dr Reissig had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Dr Reissig: contributed to the study conception and design, analysis and interpretation of the data, drafting of the manuscript and critical revision for important intellectual content, and approval of the final manuscript to be published.

Dr Copetti: contributed to the study conception and design, analysis and

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Funding/Support: The authors have reported to CHEST that no funding was received for this study.

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