Introduction: Silent or “happy” hypoxia is an unexplained clinical condition of COVID-19. Patients experiencing silent hypoxia are unaware of the drop in their oxygen levels, and do not compensate for the decrease in oxygen levels by increasing ventilation. It is likely that the oxygen sensing mechanisms of the body are compromised by COVID-19. COVID-19 patients have elevated levels of coagulation products and inflammation, contributing to incidences of strokes and pneumonia.

Mechanisms: A common factor between these responses are neutrophils and neutrophil extracellular trap (NET) formation. Neutrophils are the first responders to infection and are involved with various physiological mechanisms, including hypoxia. The interdependent relationship between hypoxia and inflammation, mediated by neutrophils, is potentially a key factor of COVID-19 pathology and its poor prognosis. Hypoxic and inflammatory responses can also disrupt oxygen sensor chemoreception by altering ion channel conductance and contributing to the formation of microthrombi in carotid and neuroepithelial bodies.

Conclusion: Current treatments, such as the anti-coagulant heparin, has shown some success, but may only have short-term effectiveness. Therefore, elucidating COVID-19 pathology to distinguish the sources of clinical symptoms is critical in discovering long-term therapeutic options.