INSTRUMENT FOR MEASURING SATURATION DEGREE OF OXYGEN

• Main Author: KONO HIROMASA
• Format: Patent
• Language: English
• Published: 28.01.1991
• Subjects: DIAGNOSIS; HUMAN NECESSITIES; HYGIENE; IDENTIFICATION; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEDICAL OR VETERINARY SCIENCE; PHYSICS; SURGERY; TESTING

PURPOSE:To exactly obtain the saturation degree of oxygen without being affected by hematocrit even in a region where the saturation degree of oxygen is low by determining the ratios of the reflected light intensity to the respective wavelengths which are logarithmically converted by a converting device and calculating the saturation degree of oxygen. CONSTITUTION:A measurement is started by a measurement start instruction from an operation section 23 and plural reflected light intensities to the light corresponding to 660nm and 800nm wavelengths of LEDs 141 and 142 to which signal transmission is executed by an optical fiber 105 and signal reception by an optical fiber 106 are inputted. This inputting is executed by inputting the digital signal from an A/D converter 22 in synchronization with the timing signal for inputting of the timing signals 33 and 34 outputted form a pulse timing circuit 12 when these timing signals are inputted. The plural reflected light intensities to the respective wavelengths are inputted in this way and are stored in a RAM 25. The average value of the reflected light intensities thereof is then determined. The ratio of the values of the two wavelengths of the calculated intensities of the reflected light is obtd. and normalized and is further logarithmically converted. The saturation degree of oxygen is calculated and displayed 27.