Understanding Factors That Can Impact Pulse Oximeter Accuracy

Pulse oximetry is a non-invasive measurement of oxygen saturation in the blood most often used in hospitals and emergency rooms. Although interpreting data from a pulse oximeter is an art as well as a science, it is useful for monitoring patients.

Probe Application

• The LED sections of the probe must face each other with skin between them; the cable should be flat against the skin to prevent damaging the wires inside.

Light

• Certain types of room lighting can cause a pulse oximeter to give false readings; cover the probe site to improve accuracy.

Motion

• If the patient is a child or is in a confused state, physical activity may be a factor. Position the probe as carefully as possible, covering and securing it completely.

Perfusion

• If the patient's blood pressure is dangerously low or their circulation is impaired, the pulse oximetry reading may be inaccurate or absent; place the probe closer to the heart by using a finger instead of a toe.

Skin Condition

• If the patient is a newborn, vernix, the waxy, white substance covering the skin, can interfere with pulse oximeter readings; lotions or oils have the same effect, so clean the skin before placing the probe.

In the Air

• Wireless devices and electronic equipment can interfere with pulse oximetry readings; the solution is to turn the monitor, or wait a moment.