Detection of Pulmonary Shunts by Transcranial Doppler in Hospitalized Non-mechanically Ventilated Coronavirus Disease-19 Patients
Dr. Jaime L. I. Salazar-Orellana 1, Dr. Miguel García-Grimshaw 1, Dr. Sergio I. Valdés-Ferrer 1,2, Dr. Sergio M. Alday-Ramírez 3, Dr. Eduardo Ríos-Argaiz 3, Dra. Zuilma Y. Vásquez-Ortiz 4, Dr. Eduardo Rivero-Sigarroa 5, Dr. Amado Jiménez-Ruiz 6, Dr. Erwin Chiquete 1, Dr. Carlos Cantú-Brito 1, and Dr. Fernando D. Flores-Silva 1*..
1 Department of Neurology and Psychiatry, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMyNSZ), México City, México
2 Center for Biomedical Science, Feinstein Institute for Medical Research, Manhasset, New York, USA; Departments of
3 Internal Medicine
5 Intensive Care, INCMyNSZ, México City, México
6 Stroke, Dementia & Heart Disease Laboratory, Western University, London, Ontario, Canada
Originally Published / december 7, 2020 / DOI: 10.24875/RIC.20000569
In severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated disease coronavirus disease 2019 (COVID-19), hypoxemia mechanisms differ from those observed in acute respiratory distress syndrome. Hypoxemia and respiratory failure in COVID-19 are attributed to pulmonary angiopathy, increasing physiological pulmonary shunting1-3. Contrast-enhanced transcranial Doppler (TCD) with agitated saline of middle cerebral arteries (MCA) isa non-invasive method with a higher sensitivity for detecting right-to-left shunts than contrast-enhanced echocardiography4. TCD has been used to detect intrapulmonary shunts in COVID-19 patients undergoing invasive mechanical ventilation (IMV)5.
We studied the relationship between intrapulmonary shunting, disease severity, and in-hospital outcome in COVID-19 patients not undergoing IMV (nonIMV).
We conducted a prospective observational study at Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán from September 7, 2020, to October 14, 2020, including consecutive hospitalized, nonIMV adult (≥18 years) patients presenting during the first 10 days from symptom onset, with a positive SARS-CoV-2 real-time polymerase chain reaction test from nasal swab samples, and a COVID-19 compatible chest computed tomography (CT) scan. We excluded patients transferred to other hospitals.
We studied 31 patients (87.5% men, and mean age: 44.4 ± 11.02 years). Eight patients had a positive HITS test; one patient was diagnosed with a patent foramen ovale, and 7 (22.5%) with pulmonary shunts. The median interval from symptom onset to admission was 7 days. There were no differences in demographics, comorbidities, ABG analysis, and chest CT findings between patients with and those without pulmonary shunts (Table 1). Patients with a positive HITS test had higher D-dimer and lower C-reactive protein levels. The median number of HITS was 5 (IQR: 3-11). There was no relationship between the number of HITS, PaCO2 levels, PaO2/FiO2 ratio, or interval from symptom onset to admission (Fig. 1). At admission, all patients received intravenous dexa- methasone (6 mg/day for 5-10 days) and thrombo prophylaxis with either unfractionated heparin or enoxaparin before TCD was performed. None of the patients were receiving vasopressors or had a diagnosis of pulmonary bacterial coinfection when the TCD was performed. Five patients required IMV after TCD was performed (none with a positive HITS test). The number of days of in-hospital stay and outcome was similar between groups.