ABSTRACT
INTRODUCTION: Clinical phenotypes of acute hypoxic respiratory failure (AHRF) in COVID-19 have been proposed- Gattinoni type ?L? with less interstitial edema/ lung weight and greater compliance vs type ?H? with a more classic acute respiratory distress syndrome (ARDS) pattern of interstitial edema, higher lung weight and lower compliance. Lung ultrasound (LUS) is a sensitive tool for the detection of interstitial pulmonary edema. Our objective was to describe lung US profiles in COVID-19 induced AHRF, in association with markers of severity and outcomes. METHODS: Retrospective observational study. Consecutive critically-ill adult COVID-19 patients with AHRF and P/F ratio <300mmHg who underwent LUS performed by a single provider in March-April 2020 were included. Patients with an established alternate etiology of AHRF, or chronic lung parenchymal pathology, were excluded. LUS was performed in the anterior and lateral zones. LUS phenotypes were: A (<3 B-lines per intercostal space (ICS) permitted), B (at least 3 B-lines in any ICS) and C (consolidation >1cm thickness). B and C profiles could overlap. The A-profile was compared to all others in the analyses of statistical significance. Outcomes included the need for and duration of mechanical ventilation, need for tracheostomy and mortality. RESULTS: Ten patients met eligibility criteria. 3 demonstrated A-profile, 6 B-profile and 1 C-profile. Median days (interquartile range) from symptom onset to LUS was: A- 6 (6-14, p=0.20), B- 18 (8-30), C- 6. Median P/F ratio at the time of LUS was: A- 152 (103-269, p=0.31), B- 131 (112- 146), C-98. Median C-reactive protein (mg/dL): A- 8 (5-10, p=0.3), B- 18 (6-31), C- 12. Median Lactate Dehydrogenase (IU/L) was: A- 528 (287-594, p=0.36), B- 622 (528-787), C- 258. Median D-Dimer (mg/L FEU) was: A- 0.88 (0.64- 3.12, p=0.57), B- 2.50 (1.74-35.00), C- 0.35. Mechanical ventilation was required in: A- 1 (33%, p=0.067), 6 (100%), C- 1 (100%). Median days of mechanical ventilation was: A- 0 (0-20, p=0.03), B- 36 (32-52), C- 88. Median static compliance (mL/cmH2O) was: A- 18, B- 27 (25-28), C- 37. Tracheostomy was performed in: A- 0 (0%, p=0.008), B- 6 (100%), C- 1 (100%). Mortality was: A- 0, B- 1 (17%), C- 0. CONCLUSIONS: An A-profile on LUS appeared to be associated with less severe respiratory illness in COVID-19 AHRF with P/F< 300mmHg.