GB1282919A - Apparatus for examining properties of blood - Google Patents

Abstract

1282919 Examining blood photo-electrically PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 26 Aug 1969 [29 Aug 1968] 42472/69 Heading G1A In an apparatus for examining blood, light is fed to a blood sample through a light guide and the radiation (light or infrared) returned to a further light to guide, adjacent the first light guide at the sample end, is fed via a filter to a detector. As shown the apparatus comprises a block 1 having a cavity through which blood is caused to flow in turbulent fashion via ducts 3 and 4. The cavity is closed by a fibre optic plate 5 and silicon rubber seal 7. The block is releasably secured to the remainder of the apparatus by a bayonet fitting 24. Light from a source 15 and mirror 29 is periodically interrupted by a rotating disc 30 having apertures 31 and passes down a first light guide 8 (comprising a glass rod coated with a different glass) and passes into the sample via the window 5. Radiation returning through the window is picked up by further light guides 9, 10 and 11 positioned with their ends adject the window in a straight line and adjacent each other. The guides are of 1mm square cross-section and extend through an opaque resin block 13 to photo-cells or photo-sensitive semi-conductors 19 to 21 covered by filters 16 to 18. The filters 16 and 18 pass a frequency 805 Ám which is in the infrared range and is the isobestic wavelength (i.e. a wavelength at which the absorbtions of oxidized and reduced haemoglobin are equal, and the filter 17 passes a frequency of 650Ám (red light). The spacing between the guides 8 and 9 is such that the intensity of the radiation passed by filter 16 is independent of the haemoglobin concentration. The spacing between the guides 8 and 10 is equal to that between guides 8 and 9 and the ratio of the outputs gives the oxygen saturation percentage. The output from the detector 19 giving a measure of the hemolysis and/or deformation of the corpuscles. The distance between the guides 8 and 11 is greater than that between 8 and 9 and the output of the detector gives a measure of the overall haemoglobin concentration. The outputs of the detectors 19 and 21 are of logarithmic form and are linearized by logarithmic amplifiers. All outputs are displayed.