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Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure
Steady-state cerebral blood flow (CBF) and dynamic cerebral autoregulation are reportedly maintained during −10° head-down tilt (HDT) despite slight increases in intracranial pressure (ICP). However, the higher ICP during −30° HDT may alter steady-state CBF and dynamic cerebral autoregulation. The p...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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American Physiological Society
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8993530/ https://www.ncbi.nlm.nih.gov/pubmed/35201934 http://dx.doi.org/10.1152/japplphysiol.00283.2021 |
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author | Kato, Tomokazu Kurazumi, Takuya Konishi, Toru Takko, Chiharu Ogawa, Yojiro Iwasaki, Ken-ichi |
author_facet | Kato, Tomokazu Kurazumi, Takuya Konishi, Toru Takko, Chiharu Ogawa, Yojiro Iwasaki, Ken-ichi |
author_sort | Kato, Tomokazu |
collection | PubMed |
description | Steady-state cerebral blood flow (CBF) and dynamic cerebral autoregulation are reportedly maintained during −10° head-down tilt (HDT) despite slight increases in intracranial pressure (ICP). However, the higher ICP during −30° HDT may alter steady-state CBF and dynamic cerebral autoregulation. The present study hypothesized that steady-state CBF and dynamic cerebral autoregulation would be altered by higher ICP during −30° HDT than during 0° and −10° HDT. Seventeen healthy participants were positioned horizontal (0°) and in −10° HDT and −30° HDT for 10 min in random order on separate days. The arterial blood pressure waveform was obtained using a finger blood pressure device and the cerebral blood velocity waveform in the middle cerebral artery was obtained using transcranial Doppler sonography (TCD) for the last 6 min in each position. ICP was estimated using noninvasive ICP (nICP) based on TCD. Dynamic cerebral autoregulation was evaluated by spectral and transfer function analysis. Although nICP was significantly higher during −30° HDT (12.4 mmHg) than during −10° HDT (8.9 mmHg), no significant differences in steady-state mean cerebral blood velocity or transfer function gain in any frequency ranges were seen among all angles of HDT. Counter to our hypothesis, the present results suggest that steady-state CBF and dynamic cerebral autoregulation may be preserved during short-term −30° HDT despite the higher ICP compared with that during −10° HDT. NEW & NOTEWORTHY This appears to be the first study to evaluate steady-state cerebral blood flow (CBF), dynamic cerebral autoregulation, and intracranial pressure (ICP) during −30° head-down tilt (HDT) compared with those during −10° HDT using noninvasive measurements. The results suggest that steady-state CBF and dynamic cerebral autoregulation are preserved despite the higher ICP during short-term −30° HDT compared with −10° HDT. |
format | Online Article Text |
id | pubmed-8993530 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Physiological Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-89935302022-04-19 Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure Kato, Tomokazu Kurazumi, Takuya Konishi, Toru Takko, Chiharu Ogawa, Yojiro Iwasaki, Ken-ichi J Appl Physiol (1985) Research Article Steady-state cerebral blood flow (CBF) and dynamic cerebral autoregulation are reportedly maintained during −10° head-down tilt (HDT) despite slight increases in intracranial pressure (ICP). However, the higher ICP during −30° HDT may alter steady-state CBF and dynamic cerebral autoregulation. The present study hypothesized that steady-state CBF and dynamic cerebral autoregulation would be altered by higher ICP during −30° HDT than during 0° and −10° HDT. Seventeen healthy participants were positioned horizontal (0°) and in −10° HDT and −30° HDT for 10 min in random order on separate days. The arterial blood pressure waveform was obtained using a finger blood pressure device and the cerebral blood velocity waveform in the middle cerebral artery was obtained using transcranial Doppler sonography (TCD) for the last 6 min in each position. ICP was estimated using noninvasive ICP (nICP) based on TCD. Dynamic cerebral autoregulation was evaluated by spectral and transfer function analysis. Although nICP was significantly higher during −30° HDT (12.4 mmHg) than during −10° HDT (8.9 mmHg), no significant differences in steady-state mean cerebral blood velocity or transfer function gain in any frequency ranges were seen among all angles of HDT. Counter to our hypothesis, the present results suggest that steady-state CBF and dynamic cerebral autoregulation may be preserved during short-term −30° HDT despite the higher ICP compared with that during −10° HDT. NEW & NOTEWORTHY This appears to be the first study to evaluate steady-state cerebral blood flow (CBF), dynamic cerebral autoregulation, and intracranial pressure (ICP) during −30° head-down tilt (HDT) compared with those during −10° HDT using noninvasive measurements. The results suggest that steady-state CBF and dynamic cerebral autoregulation are preserved despite the higher ICP during short-term −30° HDT compared with −10° HDT. American Physiological Society 2022-04-01 2022-02-24 /pmc/articles/PMC8993530/ /pubmed/35201934 http://dx.doi.org/10.1152/japplphysiol.00283.2021 Text en Copyright © 2022 The Authors https://creativecommons.org/licenses/by/4.0/Licensed under Creative Commons Attribution CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/) . Published by the American Physiological Society. |
spellingShingle | Research Article Kato, Tomokazu Kurazumi, Takuya Konishi, Toru Takko, Chiharu Ogawa, Yojiro Iwasaki, Ken-ichi Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure |
title | Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure |
title_full | Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure |
title_fullStr | Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure |
title_full_unstemmed | Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure |
title_short | Effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure |
title_sort | effects of −10° and −30° head-down tilt on cerebral blood velocity, dynamic cerebral autoregulation, and noninvasively estimated intracranial pressure |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8993530/ https://www.ncbi.nlm.nih.gov/pubmed/35201934 http://dx.doi.org/10.1152/japplphysiol.00283.2021 |
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