Hello world! I have returned! I will try to revert back to my weekly Wednesday posts, but I figured this one was long overdue already. This post will not be the last time you see this topic on my blog because I feel that it should be talked about more. I, myself, am not too educated about it, so I wanted to educate myself and you guys about it.
Upon going to the doctor recently, I noticed a new medical device used on me alongside the typical sphygmomanometer and stethoscope. It was a pulse oximeter (below is a picture of it).
A pulse oximeter is a device that is typically clipped onto your finger to measure your oxygen saturation level. It can rapidly detect small changes in how efficiently oxygen is being carried to the extremities furthest from the heart like the legs and the arms. It uses infrared light refraction to measure how well oxygen is binding to your red blood cells. The device shines two wavelengths of light through the skin of the finger to detect the color of blood.
One of the main diagnostic criteria for COVID-19 is shortness of breath and low oxygen levels. COVID-19 enters the body through the respiratory system which causes direct injury to a person’s lungs via inflammation and pneumonia which leads to a decrease in the person’s oxygen saturation levels. Pulse oximeters are also helpful for detecting people who have “happy hypoxia” which is when the person with COVID-19 appears well but has dangerously low oxygen levels.
Because of the nature of how pulse oximeters obtain readings, they can be faulty if a person has circulatory issues with poor blood flow to the extremities (cold hands, intrinsic vascular disease or Raynaud’s phenomenon). In addition, dark colored nail polish can distort the readings. Also, the color of your skin also distorts readings. Researchers found that the device was three times more likely to give black patients false readings. Melanin which is “a dark brown to black pigment occurring in the hair, skin, and iris of the eye in people” absorbs lights in those wavelengths which causes errors within the readings.
Inaccurate oxygen level readings can also be the difference between going on necessary supplemental oxygen or not. Medicare requires you to have maximum of 88% of oxygen saturation and the test saying so or they will not cover the supplemental oxygen. So, people of color who are not getting an accurate reading because of the error of the device may not be put on lifesaving oxygen and could suffer brain cell damage due to the lower oxygen levels in their blood.
While researching, I stumbled upon some stories told by others about how the pulse oximeters had given them drastically inaccurate results. On Instagram, user @/nadirahyas said that she “literally had liquid in my diaphragm and couldn’t take a full breath, but according to the machine mhy oxygen levels were at 98%.” A normal reading is between 95-100.
Though there have been improvements to the device, there is always still work ahead. The majority of study subjects that were used were typically light skinned and that caused a skew in the data. If you are wanting to test out a new device, medically or not, remember to take into account a wide variety of people.
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