What is an Oximeter?
An oximeter is a compact medical device designed to non-invasively measure the oxygen saturation level in a person’s blood and their pulse rate. This device offers a quick and pain-free way to assess how effectively oxygen is being transported throughout the body.
How an Oximeter Works
A pulse oximeter operates on the principle of light absorption by hemoglobin, the protein in red blood cells that carries oxygen. The device uses two light-emitting diodes (LEDs) that shine red and infrared light through a body part, such as a fingertip or earlobe. Oxygenated hemoglobin absorbs more infrared light, while deoxygenated hemoglobin absorbs more red light.
A photodetector measures the amount of light that passes through. The oximeter then calculates the percentage of hemoglobin saturated with oxygen (SpO2) based on the ratio of absorbed red and infrared light. This process also determines the pulse rate by accounting for the pulsatile flow of arterial blood.
Interpreting Your Readings
Oximeters display two main readings: SpO2 and pulse rate. SpO2, or peripheral oxygen saturation, represents the percentage of oxygen-carrying hemoglobin in your blood.
For a healthy adult, a normal SpO2 reading ranges from 95% to 100%. A reading below 95% may be abnormal, and values under 90% are low, indicating hypoxemia (reduced blood oxygen levels).
The pulse rate indicates heart beats per minute (bpm). For most healthy adults, a normal resting heart rate falls between 60 and 100 bpm. Factors like age, fitness level, and medications can influence this range. Individual normal ranges can vary, especially for those with existing health conditions.
Common Uses for Oximeters
Pulse oximeters are used in various settings to monitor oxygenation and heart rate. They are utilized for individuals with chronic respiratory conditions, such as chronic obstructive pulmonary disease (COPD) or asthma, to track oxygen levels at home. The devices also monitor during sleep, particularly for conditions like sleep apnea, where oxygen saturation can drop.
Beyond medical conditions, oximeters are used for general wellness monitoring, especially during or after physical activity. They are also common in recovery from illnesses, like COVID-19, where monitoring oxygen levels is important. Healthcare providers use them during physical examinations and medical procedures.
Getting Accurate Results and When to Seek Help
To ensure accurate oximeter readings, place the device on a clean, warm finger and remain still during the measurement. Factors such as nail polish, artificial nails, poor circulation, or excessive movement can interfere with light transmission and lead to inaccurate results. Skin pigmentation can also affect accuracy.
Oximeters are monitoring tools, not a substitute for professional medical advice. Contact a healthcare provider if your SpO2 reading consistently drops below 95%. Seek immediate medical attention if your oxygen saturation level falls to 92% or lower, especially if accompanied by symptoms like shortness of breath, confusion, or a rapid heart rate.