Monitoring of brain tissue haemoglobin concentration and oxygen saturation using a three wavelength spectrophotometric method.

The authors report a new method of monitoring tissue oxygen saturation and haemoglobin concentration simultaneously and continuously using a three-wavelength spectrophotometry. Light emitting diodes were used as light source which made the recording probe small and flexible enough to be placed on the brain surface tightly. Stable and reliable recording of the tissue oxygen saturation and haemoglobin concentration was ascertained in the experimental studies using middle cerebral artery occlusion model of rabbit. In the clinical studies, monitoring during bypass surgery detected rapid changes of local oxygen metabolism and haemoglobin concentration in ischaemic brain. Simultaneous and continuous monitoring of tissue oxygen saturation and haemoglobin concentration enables more practical analysis of brain circulation and oxygen metabolism in experimental and clinical situations.