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Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects

CONTEXT: Retinal perfusion variability impacts ocular disease and physiology. AIM: To evaluate the response of central retinal artery (CRA) blood flow to temperature alterations in 20 healthy volunteers. SETTING AND DESIGN: Non-interventional experimental human study. MATERIALS AND METHODS: Baseline...

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Autores principales: Shamshad, M A, Amitava, A K, Ahmad, I, Wahab, S
Formato: Texto
Lenguaje:English
Publicado: Medknow Publications 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886247/
https://www.ncbi.nlm.nih.gov/pubmed/20413919
http://dx.doi.org/10.4103/0301-4738.62641
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author Shamshad, M A
Amitava, A K
Ahmad, I
Wahab, S
author_facet Shamshad, M A
Amitava, A K
Ahmad, I
Wahab, S
author_sort Shamshad, M A
collection PubMed
description CONTEXT: Retinal perfusion variability impacts ocular disease and physiology. AIM: To evaluate the response of central retinal artery (CRA) blood flow to temperature alterations in 20 healthy volunteers. SETTING AND DESIGN: Non-interventional experimental human study. MATERIALS AND METHODS: Baseline data recorded: Ocular surface temperature (OST) in °C (thermo-anemometer), CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) in cm/s using Color Doppler. Ocular laterality and temperature alteration (warming by electric lamp/cooling by ice-gel pack) were randomly assigned. Primary outcomes recorded were: OST and intraocular pressure (IOP) immediately after warming or cooling and ten minutes later; CRA-PSV and EDV at three, six and nine minutes warming or cooling. STATISTICAL ANALYSIS: Repeated measures ANOVA. RESULTS: (n = 20; μ ± SD): Pre-warming values were; OST: 34.5 ± 1.02°C, CRA-PSV: 9.3 ± 2.33 cm/s, CRA-EDV: 4.6 ± 1.27 cm/s. OST significantly increased by 1.96°C (95% CI: 1.54 to 2.37) after warming, but returned to baseline ten minutes later. Only at three minutes, the PSV significantly rose by 1.21 cm/s (95% CI: 0.51to1.91). Pre-cooling values were: OST: 34.5 ± 0.96°C, CRA-PSV: 9.7 ± 2.45 cm/s, CRA-EDV: 4.7 ± 1.12 cm/s. OST significantly decreased by 2.81°C (95% CI: −2.30 to −3.37) after cooling, and returned to baseline at ten minutes. There was a significant drop in CRA-PSV by 1.10cm/s (95% CI: −2.05 to −0.15) and CRA-EDV by 0.81 (95% CI: −1.47 to −0.14) at three minutes. At six minutes both PSV (95% CI: −1.38 to −0.03) and EDV (95% CI: −1.26 to −0.02) were significantly lower. All values at ten minutes were comparable to baseline. The IOP showed insignificant alteration on warming (95% CI of difference: −0.17 to 1.57mmHg), but was significantly lower after cooling (95% CI: −2.95 to −4.30mmHg). After ten minutes, IOP had returned to baseline. CONCLUSION: This study confirms that CRA flow significantly increases on warming and decreases on cooling, the latter despite a significant lowering of IOP.
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spelling pubmed-28862472010-07-02 Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects Shamshad, M A Amitava, A K Ahmad, I Wahab, S Indian J Ophthalmol Original Article CONTEXT: Retinal perfusion variability impacts ocular disease and physiology. AIM: To evaluate the response of central retinal artery (CRA) blood flow to temperature alterations in 20 healthy volunteers. SETTING AND DESIGN: Non-interventional experimental human study. MATERIALS AND METHODS: Baseline data recorded: Ocular surface temperature (OST) in °C (thermo-anemometer), CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) in cm/s using Color Doppler. Ocular laterality and temperature alteration (warming by electric lamp/cooling by ice-gel pack) were randomly assigned. Primary outcomes recorded were: OST and intraocular pressure (IOP) immediately after warming or cooling and ten minutes later; CRA-PSV and EDV at three, six and nine minutes warming or cooling. STATISTICAL ANALYSIS: Repeated measures ANOVA. RESULTS: (n = 20; μ ± SD): Pre-warming values were; OST: 34.5 ± 1.02°C, CRA-PSV: 9.3 ± 2.33 cm/s, CRA-EDV: 4.6 ± 1.27 cm/s. OST significantly increased by 1.96°C (95% CI: 1.54 to 2.37) after warming, but returned to baseline ten minutes later. Only at three minutes, the PSV significantly rose by 1.21 cm/s (95% CI: 0.51to1.91). Pre-cooling values were: OST: 34.5 ± 0.96°C, CRA-PSV: 9.7 ± 2.45 cm/s, CRA-EDV: 4.7 ± 1.12 cm/s. OST significantly decreased by 2.81°C (95% CI: −2.30 to −3.37) after cooling, and returned to baseline at ten minutes. There was a significant drop in CRA-PSV by 1.10cm/s (95% CI: −2.05 to −0.15) and CRA-EDV by 0.81 (95% CI: −1.47 to −0.14) at three minutes. At six minutes both PSV (95% CI: −1.38 to −0.03) and EDV (95% CI: −1.26 to −0.02) were significantly lower. All values at ten minutes were comparable to baseline. The IOP showed insignificant alteration on warming (95% CI of difference: −0.17 to 1.57mmHg), but was significantly lower after cooling (95% CI: −2.95 to −4.30mmHg). After ten minutes, IOP had returned to baseline. CONCLUSION: This study confirms that CRA flow significantly increases on warming and decreases on cooling, the latter despite a significant lowering of IOP. Medknow Publications 2010 /pmc/articles/PMC2886247/ /pubmed/20413919 http://dx.doi.org/10.4103/0301-4738.62641 Text en © Indian Journal of Ophthalmology http://creativecommons.org/licenses/by/2.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Article
Shamshad, M A
Amitava, A K
Ahmad, I
Wahab, S
Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
title Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
title_full Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
title_fullStr Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
title_full_unstemmed Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
title_short Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
title_sort changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886247/
https://www.ncbi.nlm.nih.gov/pubmed/20413919
http://dx.doi.org/10.4103/0301-4738.62641
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