Pulse oximeters: For health care providers

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Pulse oximetry limitations

Arterial blood gas (ABG) testing is considered the gold standard in measuring blood oxygenation. Pulse oximeters offer convenience because they do not require a blood sample and can be easily measured at the bedside. However, pulse oximeter measurements are an estimate and are less accurate than ABG measurements.

This means there is always a risk that a pulse oximeter reading may be different from the actual blood oxygenation level. This difference may be clinically significant.

Recent reports have identified that pulse oximeter readings can be less accurate in people with dark skin. These reports describe a bias toward occult hypoxemia. Occult hypoxemia is when the estimated blood gas value measured by a pulse oximeter reads higher than the arterial blood gas measurement of oxygen saturation.

Reports have also indicated that pulse oximeter readings may be less accurate as true oxygen saturation decreases.

Regulated pulse oximeters typically give readings within 2% to 4% of ABG but can be less accurate due to many real-world factors, such as:

What we recommend

Even with these limitations, pulse oximeters are useful clinically. To support decision-making, consider taking measurements at different locations or finding a trend to assess oxygenation with a pulse oximeter more accurately.

When there are conflicting signs of hypoxia or doubt in the pulse oximeter reading:

Review the device labelling for information on:

It’s important to be aware of the limitations with using pulse oximeters so you can take action before an adverse event happens.

You should contact the manufacturer if:

Check that your device is licensed in Canada:

Report adverse events:

Report a medical device problem:

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