Lung ultrasound in the diagnosis and follow-up of community-acquired pneumonia. A prospective multicentre diagnostic accuracy study

Abstract BACKGROUND:The aim of this prospective multicentre study was to define accuracy of lung ultrasound (LUS) in diagnosing community-acquired pneumonia (CAP). METHODS:362 patients with suspected CAP were enrolled in 14 European centres. At baseline, history, clinical examination, laboratory testing and LUS were performed as well as the reference test: X-ray in two planes or low-dose CT in case of inconclusive/negative X-ray but positive LUS. In patients with CAP, follow-up between day 5-8 and 13-16 was scheduled. RESULTS:CAP was confirmed in 229 patients (63.3%). LUS revealed a sensitivity of 93.4% with 95% confidence interval of [89.2%,96.3%], a specificity of 97.7% [93.4%,99.6%], and likelihood ratios (LR) of 40.5 [13.2,123.9] for positive and 0.07 [0.04,0.11] for negative results. A combination of auscultation and LUS increased positive LR ratio to 42.9 [10.8,170.0] and decreased negative LR to 0.04 [0.02,0.09].97.6% (205/210) of patients with CAP showed breath-dependant motion of infiltrates, 86.7% (183/211) an air bronchogram, 76.5% (156/204) blurred margins, 54.4% (105/193) a basal pleural effusion. During follow-up, median C-reactive protein decreased from 137 to 6.3 mg/dl at day 13-16 as well as signs of CAP: median area of lesions decreased from 15.3 to 0.2 cm(2), pleural effusion from 50 to 0 ml. CONCLUSIONS:LUS is a non-invasive, usually available tool for diagnosing CAP with high accuracy. This is especially important if X-ray is not available or not applicable. About 8% of pneumonic lesions are not detectable by LUS. Therefore, an inconspicuous LUS does not exclude pneumonia. ClinicalTrials.gov Identifier: NCT00808457