Pulse Oximetry

Pulse oximetry is an non invasive measurement of haemoglobin oxygen saturation. It also, in the process, reads pulse rate. It is based on differing infrared absorptions of saturated and unsaturated haemoglobin within the circulation. A probe is used which has both the transmitter and receiver of infrared light within it. It is commonly placed on the tongue but other sites include ear, toe and vulva/prepuce. It is important that the probe is not placed on a pigmented region.

• During anaesthesia, oxygen saturation should be kept above 90%.
• Poor peripheral perfusion can cause falsely low readings.
• If the pulse oximeter is reading low/no reading/error, then try re-adjusting the placement of the probe.
• If the reading is consistantly low, a Blood Gas Analysis is recommended if available.