How to read a pulse oximeter

Pulse oximeters are devices used to indirectly measure the amount of oxygen in the blood. Save Press image by JASON WINTER from Fotolia.com

Pulse oximeters are devices used to indirectly measure the amount of oxygen in the blood, measuring a quantity known as oxygen saturation or SpO2. SpO2 is a measure of the percentage of hemoglobin molecules bound to oxygen. Hemoglobin is the main protein that carries oxygen in the blood, and changes color when it binds oxygen. Therefore, by using sensors that detect color changes in the blood due to movement of bound oxygen hemoglobin, pulse oximeters can determine the amount of oxygen in the blood, which is useful for measuring respiratory function a patient.

Locate SpO2 reading. This reading can be found on the digital readout of the pulse oximeter and given as a percentage, often between 90 and 100%. The exact location can vary depending on the type oximeter in use, as indicated in user manuals for the pulse oximeter FP300C and R Series Zoll oximeters. Some oximeters will also have a bar indicating the signal strength, which is a measure of signal strength that is generating the sensor; high signal strength is less prone to errors. Typically, patients will SpO2 levels between 96 and 99%, according to Konica Minolta Sensory Incorporated. Levels below 90% are indicative of acute respiratory failure. However, the normal range may vary from patient to patient, and patients may have a SpO2 level below 90% and not suffer from respiratory problems.

Identifies the pulse. Pulse oximeters typically measure the pulse rate of the patient. This is shown as a number of two or three digits. Often shown with a heart shape or BPM letters, stands for "beats per minute" (Beats per minute).

Looking for any other measurement on the screen. Some pulse oximeters, such as the R series Zoll, also show the ECG and plethysmograph a patient. The ECG, which measures the electrical activity generated by the heart as it beats, can be used to monitor cardiac function and identify arrhythmias. A plethysmogram, on the other hand, shows changes in the amount of oxygen in the blood that occur with each heartbeat.