[IEEE 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Vol.20 Biomedical Engineering Towards the Year 2000 and Beyond - Hong Kong, China (29 Oct.-1 Nov. 1998)] Proceedings of the 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Vol.20 Biomedical Engineering Towards the Year 2000 and Beyond (Cat. No.98CH36286) - Can the blood content of the tissues be determined optically during pulse oximetry without knowledge of the oxygen saturation? -an in-vitro investigation