Sickle Cell and Pulse Oximeter Accuracy: What the new FDA warning means for individuals living with sickle cell disease
By Dr. Stephen Boateng, Director of Research – Sickle Cell 101

Image courtesy of ScienceDirect.com

If you have ever been to a clinic for a regular check up or even had to go to the emergency room, you probably had a pulse oximeter clipped on your finger. It is a non-invasive pain-free way of measuring the oxygen in a person’s blood. For most individuals living with sickle cell disease, the pulse oximeter is a device they have to use daily because sickle cell is primarily an oxygen related condition.

Quick Refresher: In sickle cell disease, the red blood cells are sickle or crescent shaped and can block blood vessels and prevent proper blood flow. This ultimately leads to inadequate oxygen being delivered to tissues and vital organs and often results in multiple complications like pain, infection, stroke and many others.

In the News: In late February this year, the Food and Drugs Administration (FDA) issued a warning about the accuracy and limitations of the pulse oximeter, a device often relied on by individuals living with sickle cell disease. In the safety communication, the FDA informed patients and health care providers (HCPs) that “although pulse oximetry is useful for estimating blood oxygen levels, pulse oximeters have limitations and a risk of inaccuracy under certain circumstances that should be considered”. This announcement follows a research published in the New England Journal of Medicine (NEJM) in December suggesting that pulse oximeters may be less accurate when used in people with dark skin pigmentation. In that study, researchers found that compared with white patients, black patients had nearly three times greater frequency of occult hypoxemia that was not detected by pulse oximetry.

Looking Ahead: This safety communication from the FDA along with the findings from the NEJM study is extremely important for the sickle cell community especially for those who frequently use a pulse oximeter to monitor their blood oxygen levels. Below are some important tips and recommendations to remember when using your pulse oximeter at home.

• Do not solely rely on a pulse oximeter to assess your health condition or oxygen level.
• Follow your HCPs recommendation on when and how often to check your oxygen levels.
• To get the best reading from a pulse oximeter follow the manufacturer’s instructions.
• Be aware that multiple factors can affect the accuracy of a pulse oximeter reading, such as poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use, and the use of fingernail polish.
• When placing the oximeter on your finger, make sure your hand is warm, relaxed, and held below the level of the heart. Remove any fingernail polish on that finger.
• Sit still and do not move the part of your body where the pulse oximeter is located. Wait a few seconds until the reading stops changing and displays one steady number.
• Write down your oxygen levels with the date and time of the reading so you can easily track changes and report these to your health care provider. Changes or trends in measurements may be more meaningful than one single measurement.
• Pay attention to other signs or symptoms of low oxygen levels, such as:
  • Bluish coloring in the face, lips, or nails
  • Shortness of breath, difficulty breathing, or a cough that gets worse
  • Restlessness and discomfort
  • Chest pain or tightness
  • Fast or racing pulse rate
  • Be aware that some patients with low oxygen levels may not show any or all of these symptoms. Only a health care provider can diagnose a medical condition such as hypoxia (low oxygen levels).
• If you are concerned about the pulse oximeter reading, or if your symptoms are serious or getting worse, contact a healthcare provider.
• If you think you have a problem with a pulse oximeter, the FDA encourages you to report the problem through the MedWatch Voluntary Reporting Form

To learn more about the FDA report and recommendations on pulse oximeters, visit: https://www.fda.gov/medical-devices/safety-communications/pulse-oximeter-accuracy-and-limitations-fda-safety-communication