Yusuff Moshood
A new study by biomedical engineers from Boston University and the University of Vermont has revealed that silent hypoxia in COVID-19 patients may be caused by a combination of biological mechanisms that occur in the lungs.
The study, which was published in open access journal, Nature Communications, looked at how COVID-19 impacts the lungs’ ability to regulate where blood is directed.
This is even as a Nigerian public health physician, Dr. Daniel Ayira, stressed that clinicians must always intervene to arrest and reverse hypoxia to prevent death.
Hypoxia is a condition in which the supply of oxygen in the blood is insufficient for normal life functions.
There are a variety of causes and potential causes of any type of hypoxia and its symptoms include shortness of breath, rapid breathing and a fast heart rate.
Severe symptoms, however, include the inability to communicate, confusion, coma or death.
Scientists in the study tried to unravel why many patients infected with severe cases of COVID-19 experience dangerously low levels of oxygen, despite sometimes not showing symptoms of breathing difficulty.
It is known that coronavirus damages the lungs of patients and makes it incapable of functioning properly.
The lung tissues stop working causing silent hypoxia but how that occurs has not been clear.
To crack the mystery, the researchers use computer modelling to investigate low blood oxygen in COVID-19 patients.
They used computer modelling to test out three different scenarios that help explain how and why the lungs stop providing oxygen to the bloodstream.
According to biomedical engineer, Jacob Herrmann, the lead author of the new study, the first step was to look at how COVID-19 impacts the lungs’ ability to regulate where blood is directed.
Herrmann who is a research postdoctoral associate disclosed that preliminary clinical data have indicated that the lungs of some COVID-19 patients lose the ability to restrict blood flow to already damaged tissue, and in contrast, open up the blood vessels even more.
This, Herrmann said, is hard to see or measure on computerised tomography (CT) scan.
However, using a computational lung model, Herrmann and the other researchers tested that theory and discovered that for blood oxygen levels to drop to the levels observed in COVID-19 patients, blood flow would indeed have to be much higher than normal in areas of the lungs that can no longer gather oxygen.
This, they said, was contributing to low levels of oxygen throughout the entire body.
They also looked at how blood clotting may impact blood flow in different regions of the lung, especially when the lining of blood vessels get inflamed from COVID-19 infection.
Through using computer modelling of the lungs, the researchers found that while this could incite silent hypoxia, it may not be the only reason for oxygen levels to drop as low as the levels seen in COVID-19 patients.
The scientists then used their computer model to find out if COVID-19 interferes with the normal ratio of air-to-blood flow that the lungs need to function normally and if it can be a contributor to the severe, silent hypoxia that has been observed in COVID-19 patients.
Herrmann said their findings indicated that a combination of all three factors may be responsible for the severe cases of low oxygen in some COVID-19 patients.
He also noted that by having a better understanding of these underlying mechanisms, and how the combinations could vary from patient to patient, physicians can make better and informed decisions while treating COVID-19 patients using measures like ventilation and supplemental oxygen.
Bela Suki, a Boston University College of Engineering professor of biomedical engineering and one of the authors of the study said, “Different people respond to this virus so differently”.
Suki noted that physicians must understand all the possible reasons why a patients’ blood oxygen is low, noting that it would help them to decide on the proper treatment as well as the right medications to conscript blood vessels, bust blood clots or correct a mismatched air-to- blood flow ratio.
Speaking with PUNCH HealthWise, Dr. Ayira said the study has further emphasised how dangerous hypoxia is.
Ayira who is a medical officer at Faith City Hospital Lagos, said anything that damage the lung will lead to hypoxia, noting that when not quickly arrested hypoxia often lead to death.
The coronavirus, he said, is mostly transmitted by air, adding that when the virus enters the body, it is often recognised as a foreign object by the human system.
“It often attacks the lungs and damages it. It also triggers the body’s immune system prompting it to release cytokines which induce massive inflammatory reaction similar to that seen in asthmatic attacks.
“That usually leads to complications and deaths in COVID-19 patients,” he said.
The physician explained that the inability of air to enter the lungs is what usually induces severe hypoxia in COVID-19 patients making them struggle to breathe.
“That is why one of the treatments for COVID-19 patient is steroid as it helps to reduce the inflammatory response and allow the lungs to open up”.
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