90
B. Venema
4.4 Perspectives
This work presents results from human studies with a remission in-ear PPG sensor
with the aim of continuous cardiovascular monitoring. Due to proximity to the brain,
the system is expected to be independent of centralization and provide valid and
reliable monitoring of vital parameters in clinical life-threatening situations.
The hypoxia studies performed with 10 healthy volunteers show the feasibility of
simultaneous measurement of heart rate and SpO 2 with the ear sensor. According to
heart rate, a very good measurement accuracy was achieved with a standard deviation
of 1.2 bpm. In combination with a single-point calibration routine, the SpO 2 measurement of our in-ear pulse oximeter meets the requirements specified for pulse oximetry
[11]. Therefore, in-ear PPG seems to have good potential for SpO 2 measurement.
Even at this early stage of development, SpO 2 can be derived with acceptable accuracy and with minimal variation. Despite the need for a single-point calibration, the
physiological advantages of the new measuring position (the inner ear as ‘keyhole’
to the heart) seem to surpass the disadvantages [10].
References
1. B. Venema, J. Schiefer, V. Blazek, N. Blanik, S. Leonhardt, Evaluating innovative in-ear pulse
oximetry for unobtrusive cardiovascular and pulmonary monitoring during sleep. IEEE J. Trans.
Eng. Health Med. 1(8) (2013). https://doi.org/10.1109/JTEHM.2013.2277870
2. B. Venema, M.S. Wolke, V. Blazek, S. Leonhardt, A power consumption optimized reflective
in-ear pulse oximeter for mobile health monitoring, in Proc. Biomed. Wirel. Technol. Networks
Sens. Syst. IEEE Topical Conference IEEE, pp. 34–36 (2014)
3. J. Kreuzer, Alltagstauglich sensorik: kontinuierliches monitoring von körperkerntemperatur
und sauerstoffsättigung. Ph.D Thesis (Technische Universität München, Germany, 2009)
4. K. Budidha, P. Kyriacou, The human ear canal: investigation of its suitability for monitoring
photoplethysmographs and arterial oxygen saturation. Physiol. Meas. 35(2), 111 (2014)
5. K. Budidha, P. Kyriacou, Development of an optical probe to investigate the suitability of
measuring photoplethysmographs and blood oxygen saturation from the human auditory canal,
in Proc. Eng. Med. Biol. Soc. (EMBC), 35th Annual International Conference of the IEEE 2013,
pp. 1736–1739 (2013)
6. M. El-Khoury, J. Sola, V. Neuman, J. Krauss, Portable SpO 2 monitor: a fast response approach,
in Proc. IEEE Int. Conf. Portable Infor. Devices, pp. 1–5 (2007)
7. J. Patterson, G. Douglas, G. Yang, A flexible, low noise reflective PPG sensor platform for
ear-worn heart rate monitoring, in Proc. Wearable and Implantable Body Sensor Networks
BSN 2009, Berkeley, CA, pp. 286–291 (2009)
8. J.G. Webster, Design of pulse oximeters. CRC Press (2002)
9. R. Klinke, H.C. Pape, A. Kurtz, S. Silbernagl, Physiologie. Georg Thieme Verlag (2009)
10. B. Venema, J. Schiefer, V. Blazek, N. Blanik, S. Leonhardt, Advances in reflective oxygen
saturation monitoring with a novel in-ear sensor system: results of a human hypoxia study.
IEEE Trans. Biomed. Eng. 59(7), 2003–2010 (2012)
11. B. Venema, H. Gehring, I. Michelsen, N. Blanik, V. Blazek, S. Leonhardt, Robustness, specificity, and reliability of an in-ear pulse oximetric sensor in surgical patients. IEEE Biomed.
Health Inform. J. 18(4), 1178–1185 (2014)
B. Venema
4.4 Perspectives
This work presents results from human studies with a remission in-ear PPG sensor
with the aim of continuous cardiovascular monitoring. Due to proximity to the brain,
the system is expected to be independent of centralization and provide valid and
reliable monitoring of vital parameters in clinical life-threatening situations.
The hypoxia studies performed with 10 healthy volunteers show the feasibility of
simultaneous measurement of heart rate and SpO 2 with the ear sensor. According to
heart rate, a very good measurement accuracy was achieved with a standard deviation
of 1.2 bpm. In combination with a single-point calibration routine, the SpO 2 measurement of our in-ear pulse oximeter meets the requirements specified for pulse oximetry
[11]. Therefore, in-ear PPG seems to have good potential for SpO 2 measurement.
Even at this early stage of development, SpO 2 can be derived with acceptable accuracy and with minimal variation. Despite the need for a single-point calibration, the
physiological advantages of the new measuring position (the inner ear as ‘keyhole’
to the heart) seem to surpass the disadvantages [10].
References
1. B. Venema, J. Schiefer, V. Blazek, N. Blanik, S. Leonhardt, Evaluating innovative in-ear pulse
oximetry for unobtrusive cardiovascular and pulmonary monitoring during sleep. IEEE J. Trans.
Eng. Health Med. 1(8) (2013). https://doi.org/10.1109/JTEHM.2013.2277870
2. B. Venema, M.S. Wolke, V. Blazek, S. Leonhardt, A power consumption optimized reflective
in-ear pulse oximeter for mobile health monitoring, in Proc. Biomed. Wirel. Technol. Networks
Sens. Syst. IEEE Topical Conference IEEE, pp. 34–36 (2014)
3. J. Kreuzer, Alltagstauglich sensorik: kontinuierliches monitoring von körperkerntemperatur
und sauerstoffsättigung. Ph.D Thesis (Technische Universität München, Germany, 2009)
4. K. Budidha, P. Kyriacou, The human ear canal: investigation of its suitability for monitoring
photoplethysmographs and arterial oxygen saturation. Physiol. Meas. 35(2), 111 (2014)
5. K. Budidha, P. Kyriacou, Development of an optical probe to investigate the suitability of
measuring photoplethysmographs and blood oxygen saturation from the human auditory canal,
in Proc. Eng. Med. Biol. Soc. (EMBC), 35th Annual International Conference of the IEEE 2013,
pp. 1736–1739 (2013)
6. M. El-Khoury, J. Sola, V. Neuman, J. Krauss, Portable SpO 2 monitor: a fast response approach,
in Proc. IEEE Int. Conf. Portable Infor. Devices, pp. 1–5 (2007)
7. J. Patterson, G. Douglas, G. Yang, A flexible, low noise reflective PPG sensor platform for
ear-worn heart rate monitoring, in Proc. Wearable and Implantable Body Sensor Networks
BSN 2009, Berkeley, CA, pp. 286–291 (2009)
8. J.G. Webster, Design of pulse oximeters. CRC Press (2002)
9. R. Klinke, H.C. Pape, A. Kurtz, S. Silbernagl, Physiologie. Georg Thieme Verlag (2009)
10. B. Venema, J. Schiefer, V. Blazek, N. Blanik, S. Leonhardt, Advances in reflective oxygen
saturation monitoring with a novel in-ear sensor system: results of a human hypoxia study.
IEEE Trans. Biomed. Eng. 59(7), 2003–2010 (2012)
11. B. Venema, H. Gehring, I. Michelsen, N. Blanik, V. Blazek, S. Leonhardt, Robustness, specificity, and reliability of an in-ear pulse oximetric sensor in surgical patients. IEEE Biomed.
Health Inform. J. 18(4), 1178–1185 (2014)