Should brown and Black people worry about oximeter readings?

The onslaught of the Covid-19 pandemic has exposed well-entrenched disparities in how the rich and the poor receive medical treatments. 

One example is that millions of people living on the African continent and other low-income countries are waiting for their first vaccine jab while the United States and Europe are already on their way to administering booster shots.  

Then there’s the matter of medical devices, which are designed primarily to work on white people and give distorted readings when used on people of colour, putting at risk the lives of those who belong to ethnic minorities. 

Last month, British Health Secretary Sajid Javid, whose parents migrated to England from Pakistan, announced a review of medical devices to check how effective they are for a broader demographic. 

The pulse oximeter, a device that measures oxygen saturation level in our blood, is at the center of the debate. Covid-19 patients' oxygen saturation can drop to dangerous levels, and timely detection is essential to saving e lives. 

“These oximeters are being used in every country and they have the same problem, and the reason is that a lot of these medical devices, some of the drugs, the textbooks, the procedures, most of them are put together in majority-white countries and I think there is a systemic issue," Javid told BBC.

Oximeters, simply called pulse ox by doctors, became a must-have device both in homes and hospitals during the pandemic. Doctors routinely encourage people to buy them to monitor their oxygen levels at home. 

These devices, which cost a few dollars, can easily be clipped to a finger to get oxygen saturation reading as a percentage. 

Oximeters work by beaming two lights through the skin and tissue. But dark skins absorb more sunlight and exaggerate the oxygen level in the blood. 

Oxygen saturation at 90 or below is concerning, as the brain, heart, and lungs can be damaged at this level. Therefore, patients with low oxygen saturation need to be hooked on to an oxygen cylinder. 

But doctors generally won't recommend immediate intervention if the reading is above that threshold - say 92 or 93. And that’s where the big problem lies. 

An oximeter reading off the mark by even a few percentage points can become a matter of life and death for people with dark skin pigmentation. 

Dr Habib Naqvi, who oversees the UK government's efforts to tackle ethnic inequalities in the health system, said in an interview that there’s “a huge possibility” that some Covid-19 deaths in India were a result of false oximeter readings. 

Dark-skinned people often run into trouble with tech that depends on a combination of sensors and light. Black people have complained in the past about how no-touch soap dispensers and faucets won’t work for them in malls and airports. 

They knew it all along

Health experts had known about the racial bias in oximeter readings for 15 years. 

A 2005 study by researchers at the University of California, San Francisco (UCSF), found that most oximeters have been calibrated to work on light-skinned people. 

The world’s largest oximeter makers, including Masimo, Medtronic, Koninklijke Philips and Smiths Medical, are all based in the US and Europe. 

But the problem with the pulse oximeters, which are based on technology developed 30-40 years ago, was largely ignored and no one bothered to do anything about it. 

It was not until Amy Moran-Thomas, an Associate Professor of Anthropology at MIT, investigated the concerns related to the device and reported it in the Boston Review last year that the matter got some notice. 

After coming across Amy’s article, Dr Michael Sjoding of the University of Michigan Medical School carried out a systematic study, looking into thousands of blood oxygen measurements from Black and white patients to see if oximeter readings were biased. 

He found the pulse oximeters were three times more likely to miss low oxygen levels in black patients than white ones. 

Such a disparity in the reading of medical devices can have a lasting impact on the health of people belonging to minorities. For instance, information collected from oximeters in the US is fed into the hospital algorithms that decide which patient needs hospitalisation.  

Health authorities have asked doctors and nurses to run multiple tests on patients using oximeters to circumvent the problem of wrong readings. 

Experts in the field of bioethics have long argued that bias in medical devices and procedures is because most of the high-tech research takes place in developed countries and caters to the needs of their own people. 

Take for example the matter of xenotransplantation, the procedure by which an animal organ is transplanted into a human. 

Pig has become a preferred choice for research in the field even though hundreds of millions of Muslims don’t approve its use. 

“That’s because we haven’t invested in the research to meet our needs,” Dr Aasim Padela, an internationally-recognised expert on Muslim health disparities, told TRT World in a recent interview.