Pulse Oximetry

Posted September 30, 2022 by Anusha ‐ 2 min read

Pulse oximetry, or pulse ox, is a quick, inexpensive, and needle-free test that measures the amount of oxygen in your blood. It shows whether your heart and lungs supply enough oxygen to meet your body's needs.

Why Would I Need This Test?

Your doctor will use pulse oximetry whenever they think that your blood-oxygen levels could be too low. The device can help:

  • Diagnose symptoms like shortness of breath

  • Track your blood oxygen level during surgery

  • Test oxygen levels when you use supplemental oxygen

  • Show if you need extra oxygen when you exercise

Procedure for Pulse Oximetry

  • You may get this test during a doctor visit or hospital stay.

  • Your nurse will put a small, clip-like device called a pulse oximeter on your finger, toe, or ear.

  • Or they’ll put a sticky disposable probe on your finger, nose, toe, or forehead.

  • The pulse oximeter uses a special type of light to see how much oxygen is in the red blood cells traveling through the blood vessels under your skin.

  • The test is painless and quick.

  • In just a few seconds, the device will show your heart rate and oxygen saturation level the percentage of your red blood cells carrying oxygen.

  • It also measures your heart rate.

  • Your nurse will take the clip off if it’s just a one-time check.

  • During surgery or a sleep study, it may stay in place to track your blood oxygen.

  • You should be able to go home after pulse oximetry, unless you need to stay in the hospital for a procedure or more monitoring.

  • Your doctor will let you know what happens next and what to do after the test.

What Do the Results Mean?

  • A blood oxygen level lower than 89% means you may not have enough oxygen in your blood to meet your body’s needs.

  • This could be because there’s a problem with your heart or lungs.

  • If your levels are low, you may need to breathe in extra oxygen through a tube.

  • But a pulse oximeter reading is simply an estimate.

  • For example, a reading of 90% oxygen saturation on an FDA-approved prescription machine could mean anything from 86% to 94%.

In addition, a number of other things can affect the accuracy of the reading, including:

  • Bad circulation

  • Fingernail polish

  • Long or dirty fingernails

  • Tobacco use

  • Different pulse oximeter sensors (finger clip vs. adhesive)

  • Skin thickness

  • Skin temperature

Risks of Pulse Oximetry

Pulse oximetry is a safe test. There are no real risks. But:

  • Sometimes the sticky material on the probe might irritate your skin.

  • If you or your nurse don’t put the sensor on the right way, you may not get an accurate result.

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