The Deal with Pulse Oximeters

November 9th, 2011 | Author: COPD Coach

Dear COPD Coach,

Some friends of mine have told me that it is a good idea for a COPD patient to have a pulse oximeter. Is it worth spending money on and what should I look for in buying one? I have seen several on the internet but some are very inexpensive and some and very expensive.

Confused

Dear Confused,

Having a pulse oximeter can be a useful tool for any COPD patient, and if used properly, can indicate when you might be experiencing a problem (and hopefully catch it early). A pulse oximeter measures the percentage of oxygen in your blood along with your pulse rate (hence the name pulse oximeter). While useful, the unit is often not accurate enough for medical diagnostics and is not always as accurate as the kind your doctor may use.

Let’s start by detailing what a pulse oximeter does: It measures the percentage of oxygen in your blood (saturation or SpO2) along with your pulse rate. If your percentages are lower than what they normally are it could mean that you are in the beginning stages of an exacerbation.

A pulse oximeter, from alphamedicalsupplies.com

Or, if you are using supplemental oxygen a low “Sat” could indicate a problem with your oxygen source. Used during exercise, it can tell you when you have reached your tolerance, or need to increase your liter flow.What a pulse oximeter doesn’t tell you is if you are retaining carbon dioxide, (CO2, common to  some COPD patients) or have carbon monoxide, (CO), in your blood. In the case of either one, you saturations may read as normal but the presence of CO2 or CO in any significant amount will impact your breathing.

Remember, there are two elements of breathing: the first one is taking in oxygen into your body and the second part is getting carbon dioxide out of the body. It possible for someone to be getting enough oxygen into their body but not getting rid of enough carbon dioxide. And for some people, keeping these gases at safe levels can be a delicate balance!

Your oxygen is carried only on the red blood cells – the hemoglobin. So if you are anemic it will not be shown on the pulse oximeter, because as you remember, the pulse oximeter  measures the saturation in your hemoglobin. In other words, you could show up as being 100 percent saturated (which sounds great) but you might actually be low on oxygen if you have a low  hemoglobin. The only way to determine if you are anemic is with a blood test.

It is important to remember that pulse oximetry measures only oxygen saturation and pulse rate, not ventilation. In other words, it gives just a snapshot of your lung function. If your doctor wants to know more, he or she may order an ABG (arterial blood gas). ABG’s provide a full picture of the way your lungs are functioning in relation to your kidneys and other body systems.

Some things that will cause a pulse oximeter to give false readings are nail polish, fake fingernails, calloused skin or if your fingers are cold. Movement while taking your saturations will either cause the unit to give false results or take longer to display results.

You should monitor your pulse rate along with your SpO2 because they are predictors of health problems. If you have abnormal readings even for a short period of time, see a doctor. If for example your oxygen saturation appears normal but your pulse rate is high, it may indicate that your heart is working harder to keep your saturations high.

As for what units are best, in most cases, cheaper is not better. There are any number of inexpensive units out there, but in a majority of cases they are either inaccurate, difficult to use, or don’t last. I tried 5 different units and never once got a reading. I would recommend buying a meter from a local pharmacy where you can easily return it if it proved to be defective or unsatisfactory. If you purchase from an internet supplier, read the reviews and make sure they have a good return policy. It is never a bad idea to bring your unit to your doctor appointment or to pulmonary rehab class and check your readings against his unit. Make sure whatever unit you purchase takes regular batteries not special medical batteries, which are very expensive to replace. Bottom line is purchase the best unit you can afford and you will get far better results!

As with any device that uses technology, you must know how to use it, and interpret results properly. Once you get your meter, take your readings over several days at different times during the day. This will give you a base line to determine what is normal for you. In many cases your normal saturations will be lower at some times and higher at other times.

Word of caution: Don’t become obsessed with it! Some people feel the need to check their saturations every few minutes. If you get a low reading, don’t panic or over react. Wait a few minutes and take it again as you may have gotten a false reading the first time, which is not uncommon. If your readings continue to be abnormal, consult with your doctor. If your readings remain very low, get medical help!

Happy Breathing,

The COPD Coach

Ask the Expert is aimed at providing information for individuals with COPD to take to your doctor, and is not in any way intended to be medical advice.

If you would like to submit a question to the Coaches Corner email us at coachescorner@copdfoundation.org. We would love to hear your questions and comments. You can address your emails to any of the following: COPD Coach, Caregiver Coach, COPD Doctor or COPD RT.

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