Understanding Pulse Oximetry

What is pulse oximetry ?
 Methods of Measuring the efficiency of gas exchange in the lungs using optical sensor. How well the arterial blood is oxygenated (as opposed to whether or not air is going in and out of the lungs). This technique is well established in the medical field. As this is very safe as there are no electrical contact between the patient and the equipment.
The pulse oximeter extracts the pulsating arterial blood signal from an in vivo measurement, and therefore needs only 2 wavelengths to measure oxygen saturation.

Principle of operation :
The Pulse Oximeter is a non-invasive arterial oxygen saturation monitor. Continuous pulse and oxygen saturation readings are obtained by ear, finger, or soft probes. The oximeter determines a patient's arterial oxygen saturation and pulse rate by measuring the absorption of selected wavelengths of light passed through a living tissue. The Pulse Oximeter SaO2 calculation is based on the assumption that hemoglobin exists as oxyhemoglobin (HbO2) and reduced hemoglobin (Hb).

Resoruce Site  :
 Oximetry.org is a reference site where clinicians around the globe can access independent and objective clinical publications as well as other clinically relevant information on topics of oxygen transport and measurement ... (more information)