Cerebral hemodynamics during graded Valsalva manoeuvres
The Valsalva maneuver (VM) produces large and abrupt changes in mean arterial pressure (MAP) that challenge cerebral blood flow and oxygenation. We examined the effect of VM intensity on middle cerebral artery blood velocity (MCAv) and cortical oxygenation responses during (phase I, II, III) and fol...
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2014-09-01
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doaj-fedc71991afa4b51af867ba4db6ff9ec2020-11-24T22:53:45ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2014-09-01510.3389/fphys.2014.00349107979Cerebral hemodynamics during graded Valsalva manoeuvresBlake Graeme Perry0James David Cotter1Gaizka eMejuto2Toby eMundel3Samuel J.E. Lucas4Samuel J.E. Lucas5Massey UniversityUniversity of OtagoUniversity of the Basque CountryMassey UniversityUniversity Of BirminghamUniversity of OtagoThe Valsalva maneuver (VM) produces large and abrupt changes in mean arterial pressure (MAP) that challenge cerebral blood flow and oxygenation. We examined the effect of VM intensity on middle cerebral artery blood velocity (MCAv) and cortical oxygenation responses during (phase I, II, III) and following (phase IV) a VM. Healthy participants (n=20 mean ± SD: 27±7 y) completed 30 and 90% of their maximal VM mouth pressure for 10 s (order randomised) whilst standing. Beat-to-beat MCAv, cerebral oxygenation (NIRS) and MAP across the different phases of the VM are reported as the difference from standing baseline. There were significant interaction (phase * intensity) effects for MCAv, total oxygenation index (TOI) and MAP (all P<0.01). MCAv decreased during phases II and III (P<0.01), with the greatest decrease during phase III (-5 ± 8 and -19 ± 15 cm•s-1 for 30 and 90% VM, respectively). This pattern was also evident in TOI (phase III: -1±1 and -5±4%, both P<0.05). Phase IV increased MCAv (22±15 and 34±23 cm•s-1), MAP (15±14 and 24±17 mm Hg) and TOI (5±6 and 7±5 %) relative to baseline (all P<0.05). Cerebral autoregulation, indexed, as the %MCAv/%MAP ratio, showed a phase effect only (P <0.001), with the least regulation during phase IV (2.4±3.0 and 3.2±2.9). These data illustrate that an intense VM profoundly affects cerebral hemodynamics, with a reactive hyperemia occurring during phase IV following modest ischemia during phases II and III.http://journal.frontiersin.org/Journal/10.3389/fphys.2014.00349/fullSyncopeoxygenationcerebral blood flowhyperaemiaValsalva maneuver. |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Blake Graeme Perry James David Cotter Gaizka eMejuto Toby eMundel Samuel J.E. Lucas Samuel J.E. Lucas |
spellingShingle |
Blake Graeme Perry James David Cotter Gaizka eMejuto Toby eMundel Samuel J.E. Lucas Samuel J.E. Lucas Cerebral hemodynamics during graded Valsalva manoeuvres Frontiers in Physiology Syncope oxygenation cerebral blood flow hyperaemia Valsalva maneuver. |
author_facet |
Blake Graeme Perry James David Cotter Gaizka eMejuto Toby eMundel Samuel J.E. Lucas Samuel J.E. Lucas |
author_sort |
Blake Graeme Perry |
title |
Cerebral hemodynamics during graded Valsalva manoeuvres |
title_short |
Cerebral hemodynamics during graded Valsalva manoeuvres |
title_full |
Cerebral hemodynamics during graded Valsalva manoeuvres |
title_fullStr |
Cerebral hemodynamics during graded Valsalva manoeuvres |
title_full_unstemmed |
Cerebral hemodynamics during graded Valsalva manoeuvres |
title_sort |
cerebral hemodynamics during graded valsalva manoeuvres |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Physiology |
issn |
1664-042X |
publishDate |
2014-09-01 |
description |
The Valsalva maneuver (VM) produces large and abrupt changes in mean arterial pressure (MAP) that challenge cerebral blood flow and oxygenation. We examined the effect of VM intensity on middle cerebral artery blood velocity (MCAv) and cortical oxygenation responses during (phase I, II, III) and following (phase IV) a VM. Healthy participants (n=20 mean ± SD: 27±7 y) completed 30 and 90% of their maximal VM mouth pressure for 10 s (order randomised) whilst standing. Beat-to-beat MCAv, cerebral oxygenation (NIRS) and MAP across the different phases of the VM are reported as the difference from standing baseline. There were significant interaction (phase * intensity) effects for MCAv, total oxygenation index (TOI) and MAP (all P<0.01). MCAv decreased during phases II and III (P<0.01), with the greatest decrease during phase III (-5 ± 8 and -19 ± 15 cm•s-1 for 30 and 90% VM, respectively). This pattern was also evident in TOI (phase III: -1±1 and -5±4%, both P<0.05). Phase IV increased MCAv (22±15 and 34±23 cm•s-1), MAP (15±14 and 24±17 mm Hg) and TOI (5±6 and 7±5 %) relative to baseline (all P<0.05). Cerebral autoregulation, indexed, as the %MCAv/%MAP ratio, showed a phase effect only (P <0.001), with the least regulation during phase IV (2.4±3.0 and 3.2±2.9). These data illustrate that an intense VM profoundly affects cerebral hemodynamics, with a reactive hyperemia occurring during phase IV following modest ischemia during phases II and III. |
topic |
Syncope oxygenation cerebral blood flow hyperaemia Valsalva maneuver. |
url |
http://journal.frontiersin.org/Journal/10.3389/fphys.2014.00349/full |
work_keys_str_mv |
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