Near-infrared spectrophotometric monitoring of haemoglobin and cytochrome a, a3 in situ.

In the near-infrared region, two chromophores of biological interest, haemoglobin and cytochrome a,a3, have specific absorption bands, which respond to the oxygenation state of living tissues. Several authors have applied near-infrared spectroscopy to their analysis in situ(e.g. Jobsis, 1977; Gianni et al., 1982; Kariman and Burkhart, 1985a), but quantitative analyses in tissue have encountered difficulties from the overlap of changes in the amount and oxygenation state of haemoglobin and the redox state of cytochrome a,a3.