LUNG ULTRASOUND IN OUTPATIENTS WITH COVID-19 INFECTION ASSOCIATED PNEUMONIA

OBJECTIVES: The method of lung ultrasound (LUS) has been known for more than 20 years, but attracted attention during the epidemic of COVID-19 infection. LUS safe and low cost method assisting in the diagnosis of some acute respiratory diseases. The aim of the study is to evaluate the possibility of detecting LUS features using a 12-zone protocol in outpatients with pneumonia associated with COVID-19 infection. MATERIALS: We examined 39 outpatients with diagnostic criteria for COVID-19 infection (17 men and 22 women) aged 31-75 years (median 49 years). The SARS-CoV-2 reverse transcriptase polymerase chain reaction obtained from the oropharynx or nasopharynx according to WHO standards was performed in all patients. All patients underwent LUS immediately after computer tomography (CT) scan by a blinded specialist. LUS score was calculated according to presence and severity of abnormalities for 12 zones (maximum 36 points). Correlation analysis of the results of quantitative assessment was performed. We also calculated the diagnostic accuracy for LUS using CT as a reference for diagnosing interstitial abnormalities in COVID-19 pneumonia. RESULTS: CT diagnosis of pneumonia was found in 25 patients (64%; 95% CI 47-79). Ultrasounds abnormalities were detected in 31 patients, the most common were focal areas of nonconfluent B-lines, diffuse confluent B-lines, subpleural microconsolidations and in one case large parenchymal consolidations with air bronchograms. LUS false positive results were found in nonviral interstitial lung diseases and in one due chronic heart failure (in all cases LUS score=2). When evaluating the LUS, the optimal sensitivity/specificity cut-off was ≥2 points, the area under the curve (AUC) = 0.970 (95% CI 0.858-0.999; p <0.0001). The score of lung ultrasound significantly correlated with the quantitative assessment on CT scan (r = 0.928, p <0.001). CONCLUSIONS: LUS has excellent diagnostic accuracy for interstitial abnormalities in COVID-19 pneumonia in outpatients with disease mild and moderate grade. The results obtained are probably due to the typical localization of interstitial abnormalities in the lungs in COVID-19. LUS could represent a valid diagnostic aid in setting of a significant number of admitting patients.