EXAKT Study – Exploring the role of pulse oximeters on the health outcomes of racially minoritised communities

Authors: Natalie Creary, Whelan Barzey and Caira Henry

The Covid-19 pandemic touched all our lives, but it soon became clear that we were not all impacted in the same way. Racially minoritised groups and communities from the Global South bore a disproportionate burden. As we grappled with the aftermath of the pandemic, the trauma of George Floyd’s murder and with increased hope with the traction gained through the Black Lives Matter movement, our society found itself in a crucial conversation about racism, and in particular how this shows up in the medical system. Amidst this, a burning question lingered: Did the pulse oximeters we relied on contribute to the disparities in outcomes for different racial groups?

We spoke to Dan Martin, Professor of Intensive Care Medicine at the University of Plymouth and Derriford Hospital in Devon who is also the Principal Investigator for the EXAKT study. He explains:

“During the COVID-19 pandemic I saw the studies and news articles which suggested pulse oximeters may not be as accurate as we thought they were in people with darker skin tones.” While the reason for this remains unclear, “it was only really during the COVID-19 pandemic, when hospitals were overwhelmed with patients with low oxygen levels that healthcare professionals really started to notice the effect of this.” He goes on to share how studies have found that pulse oximeters would often over-estimate the amount of oxygen in the blood for Black patients, which is “potentially dangerous as this underestimates their severity of illness. Additionally, pulse oximeters became more inaccurate with lower blood oxygen levels. This was a real worry for me.”

Curiosity led us to Tasnin, who pointed out a historical issue which may have real world consequences. Tasnin explained that:

“Historically, these devices were only tested on Caucasian and light-skinned individuals during the manufacturing process” and as these devices are often ‘mass produced and distributed all over the world. This means pulse oximeters could be being used in countries where not a single person can benefit from them, which is simply not good enough”.

The research that is available is not conclusive and a limitation of these studies has been that they have used ethnicity as a marker for skin tone when people’s complexions may vary within an ethnic group.  This gap in evidence is another example of how communities of the Global majority have been excluded with potentially fatal consequences. The EXAKT study aims to begin to fill this gap and to help us to understand if pulse oximeters work differently across skin tones. Prof Martin mentions that they use “a special device to measure skin tone called a spectrophotometer which is a bit like a camera but produces a series of numbers according to the colour it sees” this will help us to understand the connection between pulse oximeter readings and specific skin tones.

The story takes a poignant turn as Tasnin, the trial manager, shares a personal experience of losing someone to COVID-19:

‘During the pandemic I lost someone close to me due to COVID-19. Prior to their hospital admission, I remember that they would regularly use a pulse oximeter at home to take readings. At times I think to myself, was there a chance that the readings were inaccurate? Would the outcome have been different if they could have gotten to the hospital sooner? Unfortunately, this is a scenario that is all too familiar to people from marginalised communities. I think this study will help answer a lot of questions for us all.’

Sadly, this scenario resonates with many from marginalised communities. Not knowing,  places a great weight on the families who have lost loved ones as well as the practitioners who are treating patients. Tasnin believes the EXAKT study holds the key to answering these questions:

“I think that first and foremost it comes back to that theme of clarity and provide a comprehensive answer to the question, are pulse oximeters accurate or not? If the answer is yes, then the findings will provide closure for a lot of people. However, if the answer is no, then the next steps will be to get that information to the public, and particularly policymakers and manufacturers to start the process of changing things.”

Prof Martin also informs us how the findings from the EXAKT study could have a wider impact on the care people receive and potentially reduce health inequalities:

“Whilst outside the remit of our study, we hope that the data we produce will be used by other teams to find a solution to this problem. We will not be able to solve this problem ourselves, but the data can be used by other teams and manufacturers to design pulse oximeters that will be accurate for everyone.”

As we navigate the complex terrain of healthcare disparities, the EXAKT study stands as a beacon of hope. They are not only taking a different approach to answer the question of the accuracy of pulse oximeters they have also taken a new approach to involving communities in shaping how they do research. This blog is the first in a series which shares how Liberating Knowledge, their partners and communities have worked together to shape the course of this vital research to unveil the pulse oximeter mystery.

Date published: 12 April 2024