Fibre-Optic Sensor for Monitoring Splanchnic Perfusion

M. Hickey and P.A. Kyriacou (UK)


Splanchnic perfusion, reflectance pulse oximetry, reflectance, photoplethysmography


There is a need for reliable monitoring of abdominal organ oxygen saturation (SpO2). Preliminary pilot studies using an electro-optical sensor have shown that good quality photoplethysmographic (PPG) signals can be detected from various human abdominal organs during open labarotomy. In an attempt to develop a splanchnic perfusion sensor that can be used pre-operatively, operatively and post-operatively, a new fibre optic sensor and processing system utilising the principle of reflectance pulse oximetry has been developed. To determine the optimal configuration (source/detector separation) of the optical fibres, an experimental procedure was carried out to examine the effect of separation distance on the acquired PPG signals, and to ultimately select a source-detector separation distance for the final design of the fibre-optic probe. PPG signals were obtained from the finger for all separation distances. The optimum range for source-detector separation was found to be between 3mm and 6mm. At closer separation, PPG signals were too erratic and unstable, while at larger separation the amplitudes of PPG signals were very small. The development of the fibre-optic probe as well as the experimental set-up and the results of the investigations are presented.

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