14 April 2021

Pulse Oximeter Bias Highlighted in Rapid Review

The accuracy of Pulse Oximeter readings from Black and minority ethnic people could be seriously misleading, particularly during the Covid-19 pandemic, and need further assessment.

The independent NHS Race and Health Observatory is today calling for further action and research alongside publication of a new rapid review that includes a series of recommendations for national healthcare, regulatory and research bodies.

Pulse Oximeters test the level of oxygen in a person’s blood by attaching a clip-like device to a person’s finger, toe, or earlobe, sending a beam of light through the body to measure and diagnose lower than normal blood oxygen levels.

The research review dating back to 1990, highlights inaccurate and ambiguous readings when factoring those with darker pigmentation and skin tones from a comprehensive stock-take of available research.

In addressing concerns for Black and minority ethnic patients at greater risk from COVID-19 who self-administer tests at home, the Observatory points to disparities and limitations.

The majority of oximeters have been developed based on studies measuring oxygen levels in Caucasian and light-skinned individuals.

Analysis from a recent 2020 Michigan University study found pulse oximeter readings of blood oxygen levels were three times more likely to be inaccurate among African-American patients, there has been limited widescale trials in the UK.

Treatment could also be delayed by individuals over-relying on physical descriptions within the product guidance of pulse oximeters. General terms such as ‘pale’, ‘blotchy skin’ or skin or lips ‘going ‘blue’, will not typically apply to Black and darker-skinned minority ethnic people.

Dr Huzaifa Adamali, Respiratory Consultant at North Bristol NHS Trust said:

“This review is needed and timely. Oxygen is probably the commonest drug used in the care of patients who present with medical emergencies. Oxygen saturation should be checked in all breathless and acutely ill patients.  Healthcare professionals are increasingly reliant on the pulse oximeter to detect early deterioration and inform clinical decision-making including commencement of oxygen therapy.

“Although a valuable clinical tool, we are becoming increasingly aware of its potential limitations and errors of interpretation.  Skin pigmentation may influence the accuracy of pulse oximetry readings.”

One key recommendation calls for an urgent review of suitable pulse oximetry products for ethnic minority people in England including those products used in medical settings.

Dr Habib Naqvi, Director of the NHS Race and Health Observatory, said:

“At this pivotal time, we cannot afford to overlook this rapid review and the recommendations for action which can prevent late hospital admissions and help improve the health of Black and minority ethnic people at risk or recovering from Covid-19.

“This review has stressed the need to ensure healthcare equipment and devices are culturally competent and sensitive, whilst  not contributing to the array of current and historic health inequalities.”

Royal Pharmaceutical Society Director for England, Ravi Sharma, said:

“The ever-growing evidence from vast reputable studies highlighting the inconsistencies of pulse oximeters cannot be ignored during a pandemic significantly impacting Black and minority ethnic people.

“This review exposes an area of health inequality where one treatment may yield more effective results for one group of patients over another, this is not acceptable and needs to be urgently addressed. Pharmacists and other healthcare professionals who use pulse oximeters in their practice or provide them to the public should take ethnicity into account when considering their effectiveness in users”

The review, carried out on behalf of the Observatory, was led by Olamide Dada from Cardiff University School of Medicine. In 2017, Olamide also founded the charity, Melanin Medics, which seeks to promote diversity in medicine.

Olamide Dada said:

“As this review clearly shows, more evidence is needed to examine the effectiveness of pulse oximeters for all patients. It is essential that clinicians and carers have full knowledge of diverse clinical signs when observing ethnic minority patients at risk of Covid-19, and particularly those using home devices.

“More detailed analysis is needed to help determine the reliance on, and future development of, pulse oximetry devices going forward.”

Background

  • The rapid review will be shared with a number of national healthcare regulatory bodies including NHS England and Improvement, Medicines and Healthcare products Regulatory Agency, Health Education England, General Medical Council, Medical Schools Council, Royal Colleges, British Medical Association and the National Institute for Health Research.
  • Pulse Oximeter devices are also used to detect low blood oxygen in conditions for pneumonia, anaemia, lung cancer, asthma and chronic obstructive pulmonary disease.
  • The NHS Race and Health Observatory, an independent body hosted by the NHS Confederation and supported by NHS England and NHS Improvement, will provide evidenced recommendations with regard to long-standing health inequalities affecting ethnic minority patients and communities, including maternity and neonatal outcomes, mental health, data and digital access to healthcare – as well as the immediate challenges of the impact of the pandemic.