Manual - EDAN USA

H100B Pulse Oximeter User Manual7.1 Pulse Oximetry MeasurementThe oximeter uses oximetry to measure functionaloxygen saturation in the blood. Pulse oximetry works byapplying the sensor to a pulsating arteriolar vascular bed,such as a finger or a toe. The sensor contains a dual lightsource and a photonic detector.Bone, tissue, pigmentation, and venous vessels normallyabsorb a constant amount of light over time. Thearteriolar bed normally pulsates and absorbs variableamounts of light during the pulsations. The ratio of lightabsorbed is translated into a measurement of functionaloxygen saturation (SpO 2 ). Because a measurement ofSpO 2 is dependent upon light from the sensor, excessiveambient light can interfere with this measurement.Pulse oximetry is based on two principles: Oxyhemoglobin and deoxyhemoglobin differin their absorption of red and infrared light(spectrophotometry). The volume of arterial blood in tissue (hencelight absorption by the blood) changes duringthe pulse (plethysmography).- 67 -