Evolution of Lung Abnormalities on Lung Ultrasound in Recovery From COVID-19 Disease—A Prospective, Longitudinal Observational Cohort Study

Objectives: SARS-CoV-2 can cause respiratory diseases with various manifestations. However, little is known about its potential for lung recovery. Lung ultrasound has shown characteristic changes during COVID-19 and has proven to be useful for triage, diagnosis, and therapy. This study investigated how the recovery process from COVID-19 respiratory disease can be monitored using 12-zone lung ultrasound. Methods: This prospective observational cohort study was conducted in a busy urban emergency department in London, United Kingdom, over a 20-week period between April and October 2020. We followed 24 patients recovering from COVID-19 with varying disease severity using 12-zone lung ultrasound at 2-week intervals and monitored the changes in the prevalence of lung abnormalities previously described in COVID-19 infection (irregular pleura, subpleural consolidation, B-lines, and small localized effusions). Results: Lung ultrasound showed that the lung recovers significantly over 20 weeks postdisease. Individual lung abnormalities also resolved at different rates. The entire rib space occupied by confluent B-lines wane after the acute phase, whereas irregular pleura and subpleural consolidations resolved more gradually. Separate wide B-lines moving with the pleura during respiration may represent more stable features, indicating residual fibrotic changes. Small, localized effusions appear transiently after the initial acute phase of the disease, peaking at approximately 10 weeks after infection. The measured lung abnormalities were strong predictors of perceived shortness of breath during ambulation. Conclusion: Lung ultrasound can be a useful tool for long-term monitoring of COVID-19 lung disease, avoiding repeated exposure to ionizing radiation, and may distinguish between acute and past infections.