A pulse oximeter is a compact, non-invasive device that estimates the oxygen saturation level in the blood (SpO2) and measures pulse rate. This small clip-like tool typically attaches to a fingertip, shining light through the skin to assess how much oxygen is being carried by red blood cells. By providing these two key metrics, a pulse oximeter offers a quick way to monitor a person’s respiratory and circulatory health.
How to Use a Pulse Oximeter
Before taking a reading, ensure your hands are clean and warm. It is beneficial to rest quietly for at least five minutes beforehand, allowing your body to settle. Prepare the device by confirming it is clean and functioning correctly.
Insert your index or middle finger into the pulse oximeter, ensuring the nail faces upwards and the fingertip is pressed against the end of the device. Turn the pulse oximeter on, and keep your hand relaxed and still throughout the process. Movement can significantly interfere with the reading, leading to inaccurate results.
The device will display readings within a few seconds, but wait until the numbers stabilize. This usually takes at least one minute, or longer if the readings continue to fluctuate. Once a steady reading is obtained, you can record the stable reading, then remove the device.
Interpreting Your Readings
A pulse oximeter displays two numbers: oxygen saturation (SpO2) and pulse rate. Oxygen saturation indicates the amount of oxygen-carrying hemoglobin in your blood relative to the maximum it could carry. For a healthy adult at sea level, a normal SpO2 reading falls between 95% and 100%.
The pulse rate, measured in beats per minute (BPM), reflects how fast your heart is beating. A normal resting heart rate for adults ranges from 60 to 100 beats per minute. It is important to note that certain factors, such as age and fitness level, can influence an individual’s normal pulse rate. For example, well-trained athletes may have a lower resting heart rate.
Factors Influencing Accuracy
Cold hands, for instance, reduce blood flow to the fingers, which can lead to lower and less consistent readings. Poor circulation in the extremities can also impair the device’s ability to detect a strong signal, impacting reliability.
Nail polish, particularly dark colors like black, blue, or green, can interfere with the light transmission. Artificial nails can similarly obstruct the light path, leading to inaccurate results. Additionally, excessive movement during a reading can create signal interference, resulting in erroneous numbers. Strong ambient light can also interfere with the device’s light detector, contributing to inaccuracies.
When to Seek Medical Attention
While a pulse oximeter is a useful monitoring tool, it is not a diagnostic device. If your oxygen saturation consistently reads below 95%, it is considered low and may indicate an issue. A reading of 93% to 94% warrants contacting a healthcare provider.
If your SpO2 level drops to 92% or lower, immediate medical attention is needed. For readings of 90% or below, immediate medical care is recommended. These numerical thresholds should always be considered in conjunction with any symptoms you may be experiencing, such as shortness of breath, dizziness, confusion, or chest pain. Persistent low readings or a worsening of symptoms necessitates professional medical advice.