Appropriateness of lung ultrasound for the diagnosis of COVID‐19 pneumonia

Abstract

Background Chest radiography (CXR) and computerized tomography (CT) are the standard methods for lung imaging in diagnosing COVID‐19 pneumonia in the intensive care unit (ICU), despite their limitations. This study aimed to assess the performance of bedside lung ultrasound examination by a critical care physician for the diagnosis of COVID‐19 pneumonia during acute admission to the ICU. Method This was an observational, prospective, single‐center study conducted in the intensive care unit of Adan General Hospital from April 10, 2020, to May 26, 2020. The study included adults with suspicion of COVID‐19 Infection who were transferred to the ICU. Patients were admitted to the ICU directly from the ED after reverse transcriptase‐polymerase chain reaction (RT‐PCR) swabs were sent to the central virology laboratory in Kuwait, and the results were released 16 to 24 hours after the time of admission. A certified intensivist in critical care ultrasound performed the lung ultrasound within 12 hours of the patient's admission to the ICU. The treating physician confirmed the diagnosis of COVID‐19 pneumonia based on a set of clinical features, inflammatory markers, biochemical profile studies, RT‐PCR test results, and CXR. Results Of 77 patients with suspected COVID‐19 pneumonia, 65 (84.4%) were confirmed. The median age of the patients was 48 (31‐68) years, and 51 (71%) were men. In the group of patients with confirmed COVID‐19 pneumonia, LUS revealed four signs suggestive of COVID‐19 pneumonia in 63 patients (96.9%) (sensitivity 96.9%, CI 85%‐99.5%). Two patients presented with unilateral lobar pneumonia without other ultrasonic signs of COVID‐19 pneumonia but with positive RT‐PCR results. Among patients in the group without COVID‐19 pneumonia who had negative RT‐PCR results, 11 (91.7%) were LUS negative for COVID‐19 pneumonia (specificity 91.7%, 95% CI 58.72%‐99.77%). Conclusions During the COVID‐19 outbreak, LUS allows the identification of early signs of interstitial pneumonia. LUS patterns that show a combination of the four major signs offer high sensitivity and specificity compared to nasopharyngeal RT‐PCR.