Let’s be honest, minds in the medical field are always looking at the different things happening around them. Doctors note something unexplainable, they simply research the phenomenon. One such object of interest for the past few decades has been the pulse oximeter

Why everyone is so worried about the Pulse Oximeter Readings? 

A pulse oximeter detects the levels of oxygenated versus deoxygenated haemoglobin in a patient or a user’s blood. The device performs this function by passing the infrared and red light. The difference between the two lights is detected on one end of the finger prong. 

Pulse oximeters are a crucial and regular part of the emergency room triage, intensive care units, critical care units and operation room. Pulse oximeters tell the healthcare professional the oxygen level of a patient. This ensures that a patient with hypoxia gets immediate access to an oxygen concentrator or an oxygen tank. The lowering of oxygen level can often indicate something progressively worsening and so a doctor or a nurse needs to know the correct information. 

What is Happening with the Pulse Oximeters?

An important thing that the developers of this device forgot to emphasize and focus upon was the physics behind the basic function. The pulse oximeter was initially developed for use of oxygen detection in people living at high altitudes. For some reason, all of these individuals were light or fair skinned. The issue in this instance arises with the physics at play in this scenario. The infrared and red light passed by the pulse oximeter easily pass through the layers of a person with lighter skin, the accuracy in these patients is perfect or close to it. 

On the other hand we have patients with darker skin tone. It has been noted that the light absorption is higher in case of darker colors. This can mean that the results in a pulse oximeter reading can be different and higher in patients with dark skin. Tests have shown a difference of up to 8% in the number of patients that were hypoxic and the pulse oximeter noted their blood oxygen as normal when compared to people of Caucasian descend. 

Where Does the Fault Lie in the Pulse Oximeter Bias Fiasco?

Another thing to remember is that the pulse oximetry is generally not used on body parts with thicker skin. This is done to ensure that the light can properly pass from one end to another. If so much case has been taken to ensure that proper readings than why has no one noticed that something was awry with pulse oximeter readings in people with dark skins? 

Hewlett Packard and NASA Worked on the Pulse Oximeters

The answer lies in the fact that someone did notice and they were working on a solution. Hewlett Packard was working with close to 8 lights to ensure that proper results are noted. However, the company suddenly stopped working on the device once it started working on computer devices in the 1980s. This made room for other people to bring forth their products.

It is worth remembering that engineers at NASA were testing the device on African Americans in order to ensure that the blood oxygen levels are correctly noted across the skin color spectrum. 

Now the responsibility on correct pulse oximeter development lay with the person now manufacturing the device. Takuo Aoyagi’s technology with its two lights was next introduced to the market. The device was low priced and tested on the local Japanese populace of light skinned people.  

Were the New Pulse Oximeters Under Any Scrutiny? 

 The new pulse oximeters were under observation from many concerned researchers. After the mixed results were noted, there was study from University of California, San Francisco’s Hypoxia Research Laboratory. By 2005, a study results were published to notify that there was a difference in oxygen levels noted by the pulse oximeter devices. In the year 2007, there was another study on this subject and once again it was confirmed that skin pigmentation had an effect on the accuracy of the pulse oximeter readings. 

What was Happening with the Research Data?

Normally the research results are posted in credible medical journals and from that point it get gets attention from many others till many people learn about it. However for some reason, the popularity of this study was not that great. Even the people from the African American descend missed it. 

Pulse oximetry study about the impact of skin pigmentation didn’t get its well-deserved attention till COVID-19 hit and doctors started seeing a difference in the oxygen levels. The blood oxygen levels of dark skinned individuals were reportedly lower than what the pulse oximeter device noted. 

Did You Know that Big Data Helped in Pulse Oximeter Fault Detection? 

Sjoding and his team started noticing this pattern of reduced arterial blood oxygen in patients with dark skin. They were absolutely horrified at this realization because it implied that they might have mistakenly sent someone with hypoxia and dangerous COVID-19 home.