Chapter 4
Reflective Arterial Pulse Oximetry
for New Measuring Sites and Long-Term
Assessment of Dermal Perfusion
Boudewijn Venema
Abstract Until 2010, photoplethysmography (PPG) was almost exclusively used
commercially as a measurement method for vital signs in medical diagnostics.
Most of the conventional sensing systems were placed on the finger, for the noninvasive recording of cardiologically synchronous blood volume fluctuations and
arterial oxygen saturation. However, as the new decade entered, a clear trend became
apparent. New applications of PPG were developed and marketed for the first time
in medical diagnostics as well as in other areas of life. In addition to medical diagnostics, the basic technology of PPG can now be found in health care, life science
and other areas. It is clear that vital signs will become an integral part of the information age and that PPG, as a non-invasive technology, will always play a key role
in data collection. The research activities presented in this chapter on the topic of
new application sites of the PPG, conducted by the Chair of Medical Information
Technology at RWTH Aachen University, are in the context of this evolutionary
process. The described in-ear PPG system not only brings significant physiological
advantages, but also opens up new possibilities outside of clinical routine. The validation through various studies carried out on the dynamics of skin perfusion and
arterial oxygen saturation in the external auditory canal show fundamental findings
and principles with regard to the in-ear PPG. The chapter thus places the PPG in the
context of new fields of application: the research and development activities began
with an initial vision and, in retrospect, are a piece of the puzzle in the evolution of
photoplethysmography as it exists today. In addition, due to the general validity of
the study results, this chapter can be an inspiration and basis for future developments
and trends of PPG.
B. Venema (B)
Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH
Aachen University, Aachen, Germany
e-mail: perfusion.group@hia.rwth-aachen.de
© Springer Nature Singapore Pte Ltd. 2021
V. Blazek et al. (eds.), Studies in Skin Perfusion Dynamics,
Biological and Medical Physics, Biomedical Engineering,
https://doi.org/10.1007/978-981-15-5449-0_4
79
Reflective Arterial Pulse Oximetry
for New Measuring Sites and Long-Term
Assessment of Dermal Perfusion
Boudewijn Venema
Abstract Until 2010, photoplethysmography (PPG) was almost exclusively used
commercially as a measurement method for vital signs in medical diagnostics.
Most of the conventional sensing systems were placed on the finger, for the noninvasive recording of cardiologically synchronous blood volume fluctuations and
arterial oxygen saturation. However, as the new decade entered, a clear trend became
apparent. New applications of PPG were developed and marketed for the first time
in medical diagnostics as well as in other areas of life. In addition to medical diagnostics, the basic technology of PPG can now be found in health care, life science
and other areas. It is clear that vital signs will become an integral part of the information age and that PPG, as a non-invasive technology, will always play a key role
in data collection. The research activities presented in this chapter on the topic of
new application sites of the PPG, conducted by the Chair of Medical Information
Technology at RWTH Aachen University, are in the context of this evolutionary
process. The described in-ear PPG system not only brings significant physiological
advantages, but also opens up new possibilities outside of clinical routine. The validation through various studies carried out on the dynamics of skin perfusion and
arterial oxygen saturation in the external auditory canal show fundamental findings
and principles with regard to the in-ear PPG. The chapter thus places the PPG in the
context of new fields of application: the research and development activities began
with an initial vision and, in retrospect, are a piece of the puzzle in the evolution of
photoplethysmography as it exists today. In addition, due to the general validity of
the study results, this chapter can be an inspiration and basis for future developments
and trends of PPG.
B. Venema (B)
Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH
Aachen University, Aachen, Germany
e-mail: perfusion.group@hia.rwth-aachen.de
© Springer Nature Singapore Pte Ltd. 2021
V. Blazek et al. (eds.), Studies in Skin Perfusion Dynamics,
Biological and Medical Physics, Biomedical Engineering,
https://doi.org/10.1007/978-981-15-5449-0_4
79