An overnight pulse oximetry test is a commonly used screening test that evaluates blood oxygen levels.
Your healthcare provider may recommend one if you are suspected of having asleep disorderlike obstructive sleep apnea.
This test is also used to qualify for home oxygen use.
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What Is Overnight Pulse Oximetry?
Overnight oximetry is a simple test that can easily be done at home.
The test typically involves applying a plastic clip called an oximeter over the end of your finger.
Imagine a large clothespin or plastic sleeve that encloses your fingertip.
It is usually connected via a cable to a small box that records the data overnight.
Newer devices may adhere directly to the skin and provide similar measurements.
Within the overnight oximeter sensor is a red light.
This red light shines through your finger or the surface of your skin.
Highly oxygenated blood is redder, while blood that is poor in oxygen is bluer.
This changes the frequency of the light wavelength that is reflected back to the sensor.
This may happen recurrently in sleep apnea.
It is also possible for the oxygen levels to be sustained at lower levels.
This is especially true if there is underlying lung disease likechronic obstructive pulmonary disease (COPD)oremphysema.
Oxygen desaturations may be associated with increases in your heart rate.
These events may suggest the presence of sleep apnea.
Generally, desaturations to less than 80% are considered severe.
These drops in blood oxygen levels may require treatment.
If the underlying cause is sleep apnea, then CPAP or bilevel therapy may be effective.
However, in the absence of sleep apnea, supplemental oxygen may be needed to fix the abnormality.
This means you may need oxygen delivered via tubing to anasal cannulafrom an oxygen concentrator or oxygen tank.
Overnight Oximetry Pros and Cons
Overnight oximeter devices are becoming more widely available to consumers.
They can be purchased online or even at pharmacies.
Overnight oximetry is easy and inexpensive, but it is not perfect.
Oximeters only provide a limited amount of information.
In addition, there are subtleties involved in sleep disorders that may not be detectable.
Can Overnight Oximetry Monitors Diagnose Sleep Apnea?
Nevertheless, overnight oximetry may be useful in identifying some people who warrant further testing.
The test can suggest certain sleep disorders like sleep apnea or more serious lung conditions like emphysema.
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