Silent hypoxia is a disease where oxygen levels in the body are fatally low which can damage vital organs if not addressed early enough. Little has been known about how the novel COVID-19 virus causes silent hypoxia until recently. Thus, biomedical engineers at Boston University and University of Vermont have used computer models and simulations to learn more about the correlation between COVID-19 and hypoxia, and have outlined three major mechanisms as to how COVID-19 can cause the lungs to stop delivering oxygen to the bloodstream.
In a healthy set of lungs, the blood oxygen saturation is between 95% to 100%, so when blood oxygen concentration in patients dip below 92% it is a major cause of concern and is an indicator for hypoxia. Normally, when this dip in oxygen saturation occurs, the blood vessels in the lungs constrict, allowing for blood to flow through the vessels in the lung tissue oxygenated and properly circulated through the rest of the body. However, in COVID-19 patients, preliminary clinical data showed that blood vessels in already damaged lung tissue actually expanded. In fact, researchers from BU used computational models to demonstrate this, revealing that blood flow is much higher than normal in areas of the lung that can no longer gather oxygen, leading to overall lower levels of oxygen throughout the body. This finding suggests that COVID-19 induced damaged lungs causes oxygen saturation levels to be overall lower than a healthy set of lungs, and in some severe instances, leads to silent hypoxia.