A pulse oximeter is a device that painlessly measures your oxygen saturation level, or how much oxygen your blood is carrying. Whether you purchase one on your own or under the direction of your doctor, an oximeter can be a useful tool if you have a health condition that impacts your breathing, and/or you use supplemental oxygen.

Why is Pulse Oximetry Important?

People with lung disease often develop hypoxemia, or low levels of oxygen in the blood. Low blood oxygen puts a strain on every organ in the body, especially the brain and heart. If your oxygen level is low, your doctor may prescribe supplemental oxygen to help keep your cells and organs functioning properly. A pulse oximeter will help you understand how much oxygen you need and when you may need it.

Adjusting Your Oxygen Flow Rate

If you use supplemental oxygen, ask your doctor what oxygen saturation level she wants you to maintain. Your doctor may then instruct you when to increase or decrease your oxygen flow rate according to your oxygen saturation reading. Be sure to ask your doctor at which point you should contact her if your reading is too low.

Best Times to Use a Pulse Oximeter

Although your doctor will clarify when and how often you should monitor your oxygen saturation, the American Thoracic Society (ATS) suggests that an oximeter reading may be helpful in the following situations:

  • When you’re first prescribed oxygen therapy – certain activities may impact your oxygen saturation level, for example, climbing stairs or walking further than normal. A pulse oximeter helps your doctor understand how normal, everyday activities affect your oxygen saturation. Keeping a record of these changes when you’re first prescribed oxygen therapy will help your doctor dose your oxygen flow rate accordingly.
  • During or after exercise – because your body needs more oxygen when you exercise, your oxygen saturation level may drop during periods of physical exertion. Your doctor may want you to check your oxygen status during or after exercise to determine if your oxygen needs increase during these times and if a higher oxygen flow rate is temporarily warranted.
  • During in-flight travel or travel to high-altitude locations – your oxygen needs may increase during travel to high altitudes and/or in-flight travel. If you’re planning a trip to a high-altitude location, be sure to discuss your oxygen needs in advance with your doctor and how often you should monitor your oxygen saturation at higher elevations.

Getting the Most Out of Your Pulse Oximeter

The following tips are recommended by the ATS to assist you in getting the most out of your oximeter:

  • Poor circulation – cold hands – smoking – artificial nails or nail polish – pulse oximetry readings may be inaccurate under certain conditions. Ask your doctor to demonstrate how to use your pulse oximeter to get the most accurate reading.
  • Is it possible to overdo it when it comes to pulse oximetry? You bet it is. A pulse oximeter can wind up driving you crazy to the point of making adjustments to your oxygen flow rate that you don’t really need. For best results, ask your doctor when and how often you should check your oxygen saturation levels.
  • Physical activity may or may not impact your oxygen saturation level. Ask your doctor when to increase or decrease your oxygen flow rate and when you should call to report a low reading.
  • Don’t smoke. Because smoking worsens lung disease and affects the oxygen level in your blood, quitting smoking is the single most important aspect of any treatment plan.

Please note: a pulse oximeter should be used as a general tool to monitor your oxygen status. Oximetry is not meant to replace arterial blood gas (ABG) studies or the advice of your doctor.

Bonnie Fahy RN, MN, Suzanne Lareau RN, MS. Marianna Sockrider, MD, DrPH. “Pulse Oximetry”. American Thoracic Society. Accessed April 5, 2015.