ABSTRACT
Background: The pandemic surge of Coronavirus disease 2019 (COVID-19) is posing the unprecedent challenge of rapidly identifying and isolating probable cases and diagnosing the main respiratory complications. We aimed to describe the application of a lung ultrasound (LUS)-based diagnostic approach, combining the LUS likelihood of COVID-19 pneumonia with patient’s symptoms and clinical history.Methods: This is an international multicenter prospective observational study on patients suspected for COVID-19, presenting to 22 different US and European hospitals. Patients underwent LUS and reverse transcription-polymerase chain reaction (RT-PCR) swab test. We identified 3 different clinical phenotypes based on pre-existing chronic cardiac or respiratory diseases (mixed phenotype), and on the presence (severe phenotype) or absence (mild phenotype) of signs and/or symptoms of respiratory failure at presentation. We defined the LUS likelihood of COVID-19 pneumonia according to 4 different patterns, characterized by the presence and distribution of typical and atypical LUS signs: high (HPLUS), intermediate (IPLUS), alternative (APLUS) and low (LPLUS) probability patterns. The association between the combination of patterns and phenotypes with RT-PCR results was described and analyzed.Findings: We studied 1462 patients, classified in mild (n=400), severe (n=727) and mixed (n=335) phenotypes. In the overall population, the HPLUS corresponded to a positive RT-PCR in 92.6% of cases, with similarly high percentages in all clinical phenotypes ranging from 87.5% (mild) to 90.3% (mixed) and 96.5% (severe). The IPLUS yielded a lower match with positive RT-PCR (65.7%). In patients with respiratory failure, the LPLUS predicted a negative RT-PCR in 100% of cases. In the overall population, the APLUS indicated an alternative pulmonary condition in 81.1% of patients. At multivariate analysis the HPLUS strongly predicted RT-PCR positivity (odds ratio 4.173, interquartile range 2.595-6.712, p<0.0001), independently from age, low oxygen saturation and dyspnea.Interpretation: Combining LUS patterns of probability for interstitial pneumonia with clinical phenotypes at presentation could facilitate the early diagnosis of COVID-19 or suggest an alternative pulmonary condition. This approach may be useful to rapidly guide and support patient’s allocation for a wiser use of hospital resources during a pandemic surge.Funding: None.Conflict of Interest: The authors declare no conflicts of interest. Ethical Approval: The local Ethical Committee Boards of each center approved the study, and the study was conducted following the ethical standards of the 1964 Helsinki declaration and its later amendments and with local guidelines for good clinical practice.