Pulse oximeters are essentially medical devices which can monitor the levels of oxygen in your blood. The pulse oximeters for personal use are usually lightweight, pocket sized devices which obtain readings through your finger pulse. Larger pulse oximeter machines are found in hospitals for patient use. The use of a pulse oximeter is particularly important for those recovering from brain injuries, those with special needs and athletes, as monitoring blood oxygen levels is an important requirement for these three key groups. It is important to note that readings can be interrupted or produce inaccurate results on occasions, usually due to some common interferences.
1. Nail Polish/ Nail Art
Nail polish, gel nails and press on nails may interfere with your reading. It is important to remove any nail art before a pulse oximeter testing to ensure accurate results. The nail color can absorb light absorbed by the oximeter, therefore affecting the result.
2. Pigmentation of the Skin
Dark skin areas may also interfere with pulse oximeter readings by giving off increased Sp02 readings. Try to test your reading on a lighter area of skin t gain a more accurate reading.
3. Movement/Change in Heartbeat
Your movements at the time of the reading may affect the results. Some movements may cause irregular heartbeat patterns which can cause issues with achieveing an accurate reading. If a person is suffering from shock, their heartbeat levels and movements would make achieving an accurate reading very difficult. The SPO2 waveform, a common feature on home pulse oximeters, may be able to indicate such an interference.
4. Hemoglobin Levels
If a person is anaemic i.e. suffering from low hemoglobin levels (less than 11 g/dl), they may not be able to achieve an accurate reading from a pulse oximeter. On the flip side, if the person has high levels of a form of hemoglobin known as methemoglobin, this can also affect accuracy.
5. Bright Light
When trying to achieve a reading, try to shy away from bright external lights. At least attempt to shield the sensors of the device from the bright light.
6. Carbon Monoxide
Even the smallest amounts of carbon monoxide can prevent an accurate reading. The device cannot tell the difference between oxygen molecules and oxygen molecules which can lead to inflated readings. For this reason, a pulse oximeter should not be used to determine blood oxygen levels of chain smokers, or pateints who have suffered from severe smoke inhalation or carbon monoxide poisoning.
7. Blood Flow
Health conditions such as hypothermia and hypertension can lead to a reduction in blood flow. This reduction can lead to a pulse oximeter being unable to pick up a reading or indeed, displaying an inaccurate reading. It can be difficult to obtain an accurate reading from someone with cold hands as their blood flow has been interrupted. It is therefore important that a reading not be attempted in a cold environment.
8. Attempting Simultaneous Readings
You should not attempt any other readings, such as blood pressure readings, on the same arm at the same time as you are testing blood oxygen levels with a pulse oximeter. Your readings will be irregular and inaccurate.
by Elijah Litscher
Quest Products Inc