oa Pulse Oximetry: A Useful Tool

The principal advantage of optical sensors for medical applications is their intrinsic safety since there is no electrical contact between the patient and the equipment. Pulse oximetry is a simple, continuous, non-invasive method of monitoring the percentage of haemoglobin (Hb) which is saturated with oxygen. Oxygen saturation (Sa02) is defined as the ratio of oxygen content of hemoglobin over oxygen carrying capacity. A pulse oximeter consists of two light-emitting diodes, a photocell detector and a microprocessor with a visual display unit. The unit displays the percentage of Hb saturated with oxygen together with a signal that is audible for each pulse beat, a calculated heart rate and in some models, a graphical representation of the blood flow past the probe. An oximeter gives early warning of hypoxic events.