Finger pulse oximeters have become a staple in vital sign monitors. Their main purpose is to determine the oxygen content in blood, and typically non invasively, by measuring through the tip of the finger.
We will go over the basic physics and chemistry of finger pulse oximeters, or SpO2 sensors, and quickly describe what they measure, what conditions they are useful for, what they don't measure, and why they should be used in conjunction with the other vital signs monitors to ascertain respiratory sufficiency, or sufficient oxygen flow to the cells through bloodstream.
Basic physics and chemistry of finger oximeters - how dos pulse oximetry work?
The physics of a fingertip pulse oximeter or SpO2 filter is quite simple: by shining pulsed light through the finger, and measuring the absorption of light, it is possible to determine how much of the hemoglobin (oxygen carrier in human blood) is actually oxygenated, that is, carrying oxygen. The 100% is the ideal number, but values over 90% are okay.
What conditions are finger oximeters used for
Measuring the oxygen content in the blood with oxygen saturation monitors, or finger oximeters, is useful for quickly determining the state of the patient as far as oxygen content of the artheries. A digital pulse oxymenter will provide the measured result in a few seconds. The oxygen deficiency can only mean two things, either insufficient oxygen delivery to the cells and organs, or over-the-top consumption of oxygen by the cells. The second option usually applies for athletes at high levels of sports activity. On the other hand, insufficient oxygen supply can be detected with finger oximeters used by high altitude pilots who fly in open-air planes. The low reading on the oximeter will prompt them to start using oxygen masks at high altitudes. Measuring insufficient oxygen supply is useful in diseases that deal with lungs, or the cardiovascular system, such as COPD, sleep disorders, especially apneas (breathing stoppage).
What other measuring devices to use to determine respiratory sufficiency?
Since the pulsed light in the oximeter only determines the oxygen content of the arterial blood, that is insufficient for establishing the "respiratory sufficiency". To be sure that the cells in the patient's body are actually receiving sufficient oxygen, not only must the oxygen content be high, as determined by finger pulse oximeter, but also must the heart produce significant enough blood flow so that the oxygen in the blood actually flows into the cells. Thus, simultaneous oxygen content, heart pulse, and blood pressure measurements are essential to make sure there is sufficient air flow into the cells of the patient's body.
Where to find finger pulse oximeters online?
The prices of finger pulse oximeters have come down significantly, and there are dozens of worldwide manufacturers. A great selection of finger pulse oximeters, both for home use, athletic use, and hospital use, can be found online through this page: patient medical monitors reviews.