Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia

Barry Dixon,1 David B MacLeod2 1Cyban Pty Ltd, Melbourne, VIC, Australia; 2Human Pharmacology and Physiology Laboratory, Department of Anesthesiology and School of Nursing, Duke University, Durham, NC, USACorrespondence: Barry Dixon Tel +61 0439618815Email barry.dixon@cyban.com.auIntroduction: Resea...

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Autores principales:	Dixon B, MacLeod DB
Formato:	article
Lenguaje:	EN
Publicado:	Dove Medical Press 2020
Materias:	oximetry brain injury brain volunteer hypoxia monitor. Medical technology R855-855.5
Acceso en línea:	https://doaj.org/article/58fd499223094e588622f325b1062aa8
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spelling	oai:doaj.org-article:58fd499223094e588622f325b1062aa82021-12-02T09:54:56ZAssessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia1179-1470https://doaj.org/article/58fd499223094e588622f325b1062aa82020-06-01T00:00:00Zhttps://www.dovepress.com/assessment-of-a-non-invasive-brain-oximeter-in-volunteers-undergoing-a-peer-reviewed-article-MDERhttps://doaj.org/toc/1179-1470Barry Dixon,1 David B MacLeod2 1Cyban Pty Ltd, Melbourne, VIC, Australia; 2Human Pharmacology and Physiology Laboratory, Department of Anesthesiology and School of Nursing, Duke University, Durham, NC, USACorrespondence: Barry Dixon Tel +61 0439618815Email barry.dixon@cyban.com.auIntroduction: Research in traumatic brain injury suggests better patient outcomes when invasive oxygen monitoring is used to detect and correct episodes of brain hypoxia. Invasive brain oxygen monitoring is, however, not routinely used due to the risks, costs and technical challengers. We are developing a non-invasive brain oximeter to address these limitations. The monitor uses the principles of pulse oximetry to record a brain photoplethysmographic waveform and oxygen saturations. We undertook a study in volunteers to assess the new monitor.Patients and Methods: We compared the temporal changes in the brain and skin oxygen saturations in six volunteers undergoing progressive hypoxia to reach arterial saturations of 70%. This approach provides a method to discriminate potential contamination of the brain signal by skin oxygen levels, as the responses in brain and skin oxygen saturations are distinct due to the auto-regulation of cerebral blood flow to compensate for hypoxia. Conventional pulse oximetry was used to assess skin oxygen levels. Blood was also collected from the internal jugular vein and correlated with the brain oximeter oxygen levels.Results: At baseline, a photoplethysmographic waveform consistent with that expected from the brain was obtained in five subjects. The signal was adequate to assess oxygen saturations in three subjects. During hypoxia, the brain’s oximeter oxygen saturation fell to 74%, while skin saturation fell to 50% (P< 0.0001). The brain photoplethysmographic waveform developed a high-frequency oscillation of &sim; 7 Hz, which was not present in the skin during hypoxia. A weak correlation between the brain oximeter and proximal internal jugular vein oxygen levels was demonstrated, R2=0.24, P=0.01.Conclusion: Brain oximeter oxygen saturations were relatively well preserved compared to the skin during hypoxia. These findings are consistent with the expected physiological responses and suggest skin oxygen levels did not markedly contaminate the brain oximeter signal.Keywords: oximetry, brain injury, brain, volunteer, hypoxia, monitorDixon BMacLeod DBDove Medical Pressarticleoximetrybrain injurybrainvolunteerhypoxiamonitor.Medical technologyR855-855.5ENMedical Devices: Evidence and Research, Vol Volume 13, Pp 183-194 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	oximetry brain injury brain volunteer hypoxia monitor. Medical technology R855-855.5
spellingShingle	oximetry brain injury brain volunteer hypoxia monitor. Medical technology R855-855.5 Dixon B MacLeod DB Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia
description	Barry Dixon,1 David B MacLeod2 1Cyban Pty Ltd, Melbourne, VIC, Australia; 2Human Pharmacology and Physiology Laboratory, Department of Anesthesiology and School of Nursing, Duke University, Durham, NC, USACorrespondence: Barry Dixon Tel +61 0439618815Email barry.dixon@cyban.com.auIntroduction: Research in traumatic brain injury suggests better patient outcomes when invasive oxygen monitoring is used to detect and correct episodes of brain hypoxia. Invasive brain oxygen monitoring is, however, not routinely used due to the risks, costs and technical challengers. We are developing a non-invasive brain oximeter to address these limitations. The monitor uses the principles of pulse oximetry to record a brain photoplethysmographic waveform and oxygen saturations. We undertook a study in volunteers to assess the new monitor.Patients and Methods: We compared the temporal changes in the brain and skin oxygen saturations in six volunteers undergoing progressive hypoxia to reach arterial saturations of 70%. This approach provides a method to discriminate potential contamination of the brain signal by skin oxygen levels, as the responses in brain and skin oxygen saturations are distinct due to the auto-regulation of cerebral blood flow to compensate for hypoxia. Conventional pulse oximetry was used to assess skin oxygen levels. Blood was also collected from the internal jugular vein and correlated with the brain oximeter oxygen levels.Results: At baseline, a photoplethysmographic waveform consistent with that expected from the brain was obtained in five subjects. The signal was adequate to assess oxygen saturations in three subjects. During hypoxia, the brain’s oximeter oxygen saturation fell to 74%, while skin saturation fell to 50% (P< 0.0001). The brain photoplethysmographic waveform developed a high-frequency oscillation of &sim; 7 Hz, which was not present in the skin during hypoxia. A weak correlation between the brain oximeter and proximal internal jugular vein oxygen levels was demonstrated, R2=0.24, P=0.01.Conclusion: Brain oximeter oxygen saturations were relatively well preserved compared to the skin during hypoxia. These findings are consistent with the expected physiological responses and suggest skin oxygen levels did not markedly contaminate the brain oximeter signal.Keywords: oximetry, brain injury, brain, volunteer, hypoxia, monitor
format	article
author	Dixon B MacLeod DB
author_facet	Dixon B MacLeod DB
author_sort	Dixon B
title	Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia
title_short	Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia
title_full	Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia
title_fullStr	Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia
title_full_unstemmed	Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia
title_sort	assessment of a non invasive brain oximeter in volunteers undergoing acute hypoxia
publisher	Dove Medical Press
publishDate	2020
url	https://doaj.org/article/58fd499223094e588622f325b1062aa8
work_keys_str_mv	AT dixonb assessmentofanoninvasivebrainoximeterinvolunteersundergoingacutehypoxia AT macleoddb assessmentofanoninvasivebrainoximeterinvolunteersundergoingacutehypoxia
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Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia

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