Lung Ultrasonography for COVID-19 Patients in Out of Hospital Settings

Abstract

Purpose: The portability of a hand-held ultrasound allows the health care worker to conduct lung ultrasound in out-of-hospital setting. It is used as a tool to conduct staging and triaging for COVID-19 patients. This study evaluated the utilization of lung ultrasound in an out-of-hospital setting versus chest x-rays in detecting and staging of COVID-19 patients with pneumonia. Methods: The study was conducted among COVID-19 subjects at an out-of-hospital setting whereby lung ultrasound was done and subsequently chest x-rays were taken after being admitted to the health care facilities. Lung ultrasound findings were reviewed by emergency physicians, while the chest x-rays were reviewed by radiologists. Radiologists were blinded by the patients’ lung ultrasound findings and clinical conditions. The analysis of the agreement between the lung ultrasound findings and chest x-rays was conducted. Results: A total of 261 subjects were recruited. LUS detected pulmonary infiltrative changes in more stage 3 COVID-19 subjects in comparison to chest x-rays. Multiple B-lines were the predominant findings at the right lower anterior, posterior and lateral zones. Interstitial consolidations and ground glass opacities were the predominant descriptive findings in chest x-rays. However, there was no agreement between lung ultrasound and chest x-ray findings in detecting COVID-19 pneumonia as the Cohen’s Kappa coefficient was 0.08 (95% CI 0.06–0.22, p = 0.16). Conclusion: The diagnostic imaging and staging of COVID-19 patients using lung ultrasound in out-of-hospital settings showed LUS detected lung pleural disease more often than CXR for stage 3 COVID-19 patients.