You may hear the terms “pulse ox” or “oximeter”,
or questions on our lists and message boards regarding “what are your
stats” or “my o2 stats have been running”, etc. and wonder what these
terms or phrases mean.
There are two common methods that your physician and/or respiratory
therapist use to measure the amount of o2 (oxygen) concentration present
in your blood. The first is a bit more invasive and is called an ABG or
arterial blood gas. This requires getting a specimen of blood by way of
a needle-stick directly into an artery, not a vein, and usually obtained
from the wrist area. The second method is to use an oximeter (aka
What is a pulse oximeter?
A pulse oximeter is an ingenious tool
used to obtain oxygen (o2) saturation levels and pulse rates in a
non-invasive fashion. If you have ever been to the doctor or hospital
and have had a small device clipped onto your finger, much like a small,
fat cloths pin, this was most likely an oximeter. They come in many
shapes and sizes and serve a variety of uses, however, all with the same
end result -- to monitor oxygen saturation rates.
They are routinely used in operating
rooms by anesthesiologists as part of their continuous vital-sign
monitoring. They are used during the 6-minute walk tests done by our
physicians or pulmonary rehab teams to determine possible supplemental
oxygen needs, as well as used to evaluate our response to our current
oxygen-use settings. They are used as a tool, as well, in overnight
oximetry tests and in sleep labs to determine nocturnal (nighttime)
drops in oxygen levels (hypoxemia) that may require supplemental
oxygen-use and or other types of non-invasive breathing aids, such as
Bi-PAPs or C-PAPs.
How does pulse oximetry work?
This is indeed a complex and interesting
process. A pulse oximeter uses a beam of light transmitted through an
area of the body, most generally a finger, however, toes and earlobes
can be used as well under some circumstances, as in circulatory
disorders or the presence of thick artificial nails or deep dark nail
polish. The beam of light uses the color of our blood to determine the
oxygenation of it. The color of our blood changes somewhat, depending on
whether or not our red blood cells are adequately oxygenated.
Well-oxygenated blood is generally bright
red in color, and will absorb most of the light being transmitted
through the oximeter. Poorly oxygenated blood is more dark red-to-purple
in color, and will not absorb the beam of light as well. Another
fascinating aspect of the pulse oximeter is its ability to distinguish
between venous blood levels and arterial blood levels. The mechanics of
this magnificent technology allows it to distinguish between the
pulsating venous blood and the constant flow of arterial blood.
The measurements of oxygen levels
obtained by way of pulse oximetry are extremely close to those obtained
by the more invasive ABG. Regardless of the unit used -- the big,
table-top units used in hospitals with running tapes or the smaller
finger-tip, battery-operated units many COPDers have purchased -- the
technology is the same.
Please understand that the explanation
here is in lay terms from information taken from pages of technical
information from an oximeter manual, and in no way is meant to indicate
that they are simple mechanical devices, as nothing is farther from the
truth. The ability to put such complex technology in such a small piece
of equipment is nothing short of amazing.
Do I need one?
That is a question that only you can
answer. Many of us on supplemental oxygen have decided to purchase our
own personal pulse oximeter. We find comfort and security in being able
to monitor ourselves and our oxygen needs. We use them when we get very
short of breath to help guide us in determining what may be happening.
We use them while exerting ourselves or
exercising to make sure we are maintaining adequate oxygen levels. If we
notice severe drops or changes we are concerned about, we can then
contact our physicians to decide how best to manage your individual
Remember, oxygen is a medication! We
should never adjust our oxygen flow from the prescribed level with out
first consulting our physician. Some physicians are happy that their
patients have an oximeter and are being pro-active in their own care,
while some other physicians are strongly against their patients having
one. The concern, frequently, is that a patient will become obsessed
with checking and become overly alarmed at even minimal drops. This is
often not the case; however, it can and does happen. Only you can truly
decide if the out-of-pocket expense and extra security is worth it to
Will insurance cover the cost?
This is also an excellent question, as
the units are not inexpensive. We have found in our experiences that
generally most insurance companies do not cover the cost of an oximeter. Some
select insurance companies will cover the rental or purchase of one,
although that is rare. Please check with your own insurance company
before deciding and making a purchase
There are many sources for purchasing a
pulse oximeter on the Internet. Search until you find the best price
possible, as they change often. Some places require a physician’s
prescription, where others do not. If you are considering such a
purchase, make inquiries on our e-mail lists or message boards. Most
people will be happy to share their experiences and information as to
the best prices and or sources they have found. COPD-International does
not recommend or endorse one specific supplier over another.