Thoracic Ultrasound in COVID-19: Use of Lung and Diaphragm Ultrasound in Evaluating Dyspnea in Survivors of Acute Respiratory Distress Syndrome from COVID-19 Pneumonia in a Post-ICU Clinic

Abstract

Introduction: Dyspnea is a common symptom in survivors of severe COVID-19 pneumonia. While frequently employed in hospital settings, the use of point-of-care ultrasound in ambulatory clinics for dyspnea evaluation has rarely been explored. We aimed to determine how lung ultrasound score (LUS) and inspiratory diaphragm excursion (DE) correlate with patient-reported dyspnea during a 6-min walk test (6MWT) in survivors of COVID-19 acute respiratory distress syndrome (ARDS). We hypothesize higher LUS and lower DE will correlate with dyspnea severity.

Study design and methods: Single-center cross-sectional study of survivors of critically ill COVID-19 pneumonia (requiring high-flow nasal cannula, invasive, or non-invasive mechanical ventilation) seen in our Post-ICU clinic. All patients underwent standardized scanning protocols to compute LUS and DE. Pearson correlations were performed to detect an association between LUS and DE with dyspnea at rest and exertion during 6MWT.

Results: We enrolled 45 patients. Average age was 61.5 years (57.7% male), with average BMI of 32.3 Higher LUS correlated significantly with dyspnea, at rest (r = + 0.41, p = < 0.01) and at exertion (r = + 0.40, p = < 0.01). Higher LUS correlated significantly with lower oxygen saturation during 6MWT (r = -0.55, p = < 0.01) and lower 6MWT distance (r = -0.44, p = < 0.01). DE correlated significantly with 6MWT distance but did not correlate with dyspnea at rest or exertion.

Conclusion: Higher LUS correlated significantly with patient-reported dyspnea at rest and exertion. Higher LUS significantly correlated with more exertional oxygen desaturation during 6MWT and lower 6MWT distance. DE did not correlate with dyspnea.

Keywords: COVID-19; Diaphragm Excursion; Dyspnea; Lung Ultrasound Score; Post-ICU clinic; Thoracic Lung Ultrasound.