Non-invasive method for in vivo determination of the arterial blood oxygen saturation rate and device therefor

摘要

The device comprises three laser diodes (11, 12, 13) emitting at 660, 750 and 940 nm respectively and cyclically excited at the rate of a clock (17). The light emitted is channelled by three optical fibres, (14, 15, 16) in order to pass through a well-vascularised tissue region (1) of a subject over three substantially merged optical paths, and to end up on an optoelectronic sensor (10) which delivers interlaced signals representing the molecular absorption. The pulsation of the arterial blood in the region (1) induces variable components which are a function solely of the molecular absorptions due to oxyhaemoglobin, deoxyhaemoglobin and carboxyhaemoglobin. The signals are directed by gates (21, 22, 23) onto three channels where the variable components are extracted and digitised, which components are then processed in the microprocessor (30) in order to give the oxygen saturation (SaO2) and the fixation of carbon monoxide on the haemoglobin. IMAGE