Relationship between retinal blood flow and arterial oxygen

Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia), but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modeled in the retina in particular the v...

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Main Authors:	Cheng, Richard W, Yusof, Firdaus, Tsui, Edmund, Jong, Monica, Duffin , James, Flanagan, John G, Fisher, Joseph A, Hudson, Christopher
Format:	Article
Language:	English English English
Published:	Wiley-Blackwell 2016
Subjects:	QP Physiology RE Ophthalmology
Online Access:	http://irep.iium.edu.my/47493/ http://irep.iium.edu.my/47493/ http://irep.iium.edu.my/47493/ http://irep.iium.edu.my/47493/1/firdaus_Yusof_Journal_of_Physiology.pdf http://irep.iium.edu.my/47493/3/47463_.pdf http://irep.iium.edu.my/47493/6/47493_WOS_Scopus.pdf

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spelling	iium-474932016-12-22T07:58:13Z http://irep.iium.edu.my/47493/ Relationship between retinal blood flow and arterial oxygen Cheng, Richard W Yusof, Firdaus Tsui, Edmund Jong, Monica Duffin , James Flanagan, John G Fisher, Joseph A Hudson, Christopher QP Physiology RE Ophthalmology Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia), but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modeled in the retina in particular the vascular reserve and resting tonus of the vessels. The objective of this study was to determine the limitations of the retinal vasculature by modeling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for 8 different blood gas conditions, with the end-tidal partial pressure of oxygen (PET O2 ) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon Laser Blood Flowmeter (CLBF) during the first visit, and using Doppler Spectral Domain Optical Coherence Tomography (Doppler SD-OCT, RTVue) during the second visit. We determined that the relationship between RBF and PaO2 can be modeled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content for all stages of hypoxia used in this study, but can no longer compensate below a PET O2 of 32-37 mmHg. These vessels have a great vascular range of adjustment, increasing diameter (8.5% arteriolar and 21% total venous area) with hypoxia (40 mmHg PET O2 ; p<0.001) and decreasing diameter (6.9% arteriolar and 23% total venous area) with hyperoxia (500 mmHg PET O2 ; p<0.001) to the same extent; indicating that the resting tonus is near the midpoint of the adjustment ranges at resting PaO2 where sensitivity is maximum. Wiley-Blackwell 2016-02-01 Article PeerReviewed application/pdf en http://irep.iium.edu.my/47493/1/firdaus_Yusof_Journal_of_Physiology.pdf application/pdf en http://irep.iium.edu.my/47493/3/47463_.pdf application/pdf en http://irep.iium.edu.my/47493/6/47493_WOS_Scopus.pdf Cheng, Richard W and Yusof, Firdaus and Tsui, Edmund and Jong, Monica and Duffin , James and Flanagan, John G and Fisher, Joseph A and Hudson, Christopher (2016) Relationship between retinal blood flow and arterial oxygen. The Journal of Physiology , 594 (3). pp. 625-640. ISSN 0022-3751 E-ISSN 1469-7793 http://onlinelibrary.wiley.com/doi/10.1113/JP271182/full 10.1113/JP271182
repository_type	Digital Repository
institution_category	Local University
institution	International Islamic University Malaysia
building	IIUM Repository
collection	Online Access
language	English English English
topic	QP Physiology RE Ophthalmology
spellingShingle	QP Physiology RE Ophthalmology Cheng, Richard W Yusof, Firdaus Tsui, Edmund Jong, Monica Duffin , James Flanagan, John G Fisher, Joseph A Hudson, Christopher Relationship between retinal blood flow and arterial oxygen
description	Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia), but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modeled in the retina in particular the vascular reserve and resting tonus of the vessels. The objective of this study was to determine the limitations of the retinal vasculature by modeling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for 8 different blood gas conditions, with the end-tidal partial pressure of oxygen (PET O2 ) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon Laser Blood Flowmeter (CLBF) during the first visit, and using Doppler Spectral Domain Optical Coherence Tomography (Doppler SD-OCT, RTVue) during the second visit. We determined that the relationship between RBF and PaO2 can be modeled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content for all stages of hypoxia used in this study, but can no longer compensate below a PET O2 of 32-37 mmHg. These vessels have a great vascular range of adjustment, increasing diameter (8.5% arteriolar and 21% total venous area) with hypoxia (40 mmHg PET O2 ; p<0.001) and decreasing diameter (6.9% arteriolar and 23% total venous area) with hyperoxia (500 mmHg PET O2 ; p<0.001) to the same extent; indicating that the resting tonus is near the midpoint of the adjustment ranges at resting PaO2 where sensitivity is maximum.
format	Article
author	Cheng, Richard W Yusof, Firdaus Tsui, Edmund Jong, Monica Duffin , James Flanagan, John G Fisher, Joseph A Hudson, Christopher
author_facet	Cheng, Richard W Yusof, Firdaus Tsui, Edmund Jong, Monica Duffin , James Flanagan, John G Fisher, Joseph A Hudson, Christopher
author_sort	Cheng, Richard W
title	Relationship between retinal blood flow and arterial oxygen
title_short	Relationship between retinal blood flow and arterial oxygen
title_full	Relationship between retinal blood flow and arterial oxygen
title_fullStr	Relationship between retinal blood flow and arterial oxygen
title_full_unstemmed	Relationship between retinal blood flow and arterial oxygen
title_sort	relationship between retinal blood flow and arterial oxygen
publisher	Wiley-Blackwell
publishDate	2016
url	http://irep.iium.edu.my/47493/ http://irep.iium.edu.my/47493/ http://irep.iium.edu.my/47493/ http://irep.iium.edu.my/47493/1/firdaus_Yusof_Journal_of_Physiology.pdf http://irep.iium.edu.my/47493/3/47463_.pdf http://irep.iium.edu.my/47493/6/47493_WOS_Scopus.pdf
first_indexed	2023-09-18T21:07:35Z
last_indexed	2023-09-18T21:07:35Z
_version_	1777411036310142976

Relationship between retinal blood flow and arterial oxygen

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