An oesophageal pulse oximetry system utilising a fibre-optic probe

A dual-wavelength fibre-optic pulse oximetry system is described for the purposes of estimating oxygen saturation (SPO2) from the oesophagus. A probe containing miniature right-angled glass prisms was used to record photoplethysmographic (PPG) signals from the oesophageal wall. Signals were recorded successfully in 19 of 20 patients, demonstrating that PPG signals could be reliably obtained from an internal vascularised tissue site such as the oesophageal epithelium. The value of the mean oxygen saturation recorded from the oesophagus was 94.0 +/- 4.0%. These results demonstrate that SPO2 may be estimated in the oesophagus using a fibre-optic probe.