ABSTRACT
Objective: To describe the autonomic and SNC manifestations of patients with coronavirus disease 2019 (COVID-19) and happy hypoxemia. Background: Happy hypoxemia is the absence of dyspnea despite low oxygen saturation. Several hypotheses for its occurrence include potential viral neuroinvasion, autonomic dysfunction, and cortical ischemic damage. Design/Methods: We studied prospectively nine patients with COVID-19 who arrived at the ER with very low oxygen saturation (50-79%) and no dyspnea complaints. Patients were invited to participate and underwent a full clinical history, brain MRI with gadolinium, and 24H-Holter with spectroscopy while hospitalized and bed-ridden. We used Pearson's coefficient correlation for the correlation analysis. Results: Two patients were excluded from the study because they no longer wished to participate and one because he had FA. we analyzed six patients (66% women) with a mean age of 59 years old (47-83). Two patients had high blood pressure, one patient had a history of tuberculosis, and one had Down Syndrome. Upon arrival at the ER, the mean oxygen saturation was 67% and PaO2 59.3 (47-83). One patient (14%) complain of headache and none of anosmia or ageusia. Four patients underwent a brain MRI that showed gadolinium enhancement of the olfactory bulbs and white matter lesions. One patient also had a left insular lesion. Three patients had abnormal SDNN<100 (83ms, 30-146), and one had RMSSD <15. Vagally mediated changes reflected in HRv were significantly lower in patients with lower blood O2 saturation (SDDN p=0.002, r=.95, HF p=0.009, r=.92, LF/HF ns, -0.42). Conclusions: Patients with happy hypoxemia had decreased heart rate variability that correlated with the degree of hypoxemia, suggesting altered modulation of vagal tone and autonomic dysregulation. All the patients had olfactory bulb enhancement. In our patients, hyposmia /anosmia did not correlate with olfactory bulb hyperintensities or happy hypoxemia.