Pulse Oximetry (2024)

FAQs

Pulse Oximetry? ›

Basically, pulse oximetry is a painless, noninvasive method of measuring the saturation of oxygen in a person's blood. Oxygen saturation is a crucial measure of how well the lungs are working.

For most people, a normal pulse oximeter reading for your oxygen saturation level is between 95% and 100%. If you have a lung disease such as COPD or pneumonia, your normal oxygen saturation level may be lower.

Is 92% a good oxygen level? In most people, a healthy blood oxygen level is 95–100%. Anything below 95% is considered low and may put you at risk of hypoxemia. That said, people with certain conditions, such as COPD, may need to maintain their blood oxygen at a different level.

The pulse oximeter uses a cold light source that shines a light through the fingertip, making the tip appear to be red. By analyzing the light from the light source that passes through the finger, the device is able to determine the percentage of oxygen in the red blood cell.

Principles of pulse oximetry

Currently available oximeters use two light-emitting diodes (LEDs) that emit light at the 660 nm (red) and the 940 nm (infrared) wavelengths. These two wavelengths are used because O₂Hb and Hb have differentabsorption spectra at these particular wavelengths.

The normal perfusion index (PI) ranges from 0.02% to 20%. If the perfusion index is at or below 0.4% showing weak pulse strength, then the oximeter reading can be unreliable. Peripheral artery diseases, diabetes, obesity, blood clots, etc.

Which finger to use in a pulse oximeter? As per the studies, your right hand's middle finger shows the best results. Make sure to take off any nail polish and avoid using on cold fingers as the readings may not show correctly.

90% or less This oxygen level is very concerning and may indicate a severe medical problem. Call 911 or go to the nearest emergency room immediately. You may need an urgent X-ray or heart test. 91% to 94% This oxygen level is concerning and may indicate a medical problem.

People should contact a health care provider if their oxygen saturation readings drop below 92%, as it may be a sign of hypoxia, a condition in which not enough oxygen reaches the body's tissues. If blood oxygen saturation levels fall to 88% or lower, seek immediate medical attention, says Dr. Lutchmansingh.

Oxygen saturation levels (SpO2) between 95 to 100 percent are considered normal for both adults and children (below 95% is considered abnormal). People over 70 years of age may have oxygen levels closer to 95%. Normal oxygen saturation levels (SpO2) are between 95 to 100 percent for both adults and children.

How accurate are pulse oximeters? ›

Prescription oximeters typically have an accuracy rate that's around 4% above or below a reading. So an oxygen level of 92% could actually be as low as 88% or as high as 96%. Pulse oximeter readings also tend to be most accurate at levels higher than 90%.

2 Hypoxemia occurs with lower levels of oxygen in the blood and can lead to complications or even death at dangerously low levels below 90%.

Place the oximeter on the fingertip of either your index (pointer) finger or your middle finger. It should feel snug but comfortable. Keep still for at least a minute. If the numbers keep fluctuating, you may need to be still for longer.

British Thoracic Society Guideline for oxygen use in adults in healthcare and emergency settings recommended target oxygen saturation of 94% to 98% for AHF patients. This target should be reduced to 88% to 92% if the patient is at risk of hypercapnic respiratory failure.

Oxygen saturation values of 95% to 100% are generally considered normal. Values under 90% could quickly lead to a serious deterioration in status, and values under 70% are life-threatening.

Inflammation in the lungs and respiratory tract can reduce the flow of oxygenated blood throughout the body, causing a patient to gasp for air. Normal oxygen saturation levels range between 94%-99%. When SPo2 levels fall below 93% it is a sign that oxygen therapy is required.

Blood oxygen readings are displayed in a percentage of SpO2 (peripheral oxygen saturation) and heart rates are displayed simply as BPM (beats per minute). According to the British Lung Foundation, your blood oxygen level should be around 95% to 100%. A healthy heart rate is 50 to 90 BPM.

90% or less This oxygen level is very concerning and may indicate a severe medical problem. Call 911 or go to the nearest emergency room immediately. You may need an urgent X-ray or heart test. 91% to 94% This oxygen level is concerning and may indicate a medical problem.