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Revisiting the frequency domain: the multiple and partial coherence of cerebral blood flow velocity in the assessment of dynamic cerebral autoregulation

Revisiting the frequency domain: the multiple and partial coherence of cerebral blood flow velocity in the assessment of dynamic cerebral autoregulation
Revisiting the frequency domain: the multiple and partial coherence of cerebral blood flow velocity in the assessment of dynamic cerebral autoregulation
Despite advances in modelling dynamic autoregulation, only part of the variability of cerebral blood flow velocity (CBFV) in the low frequency range has been explained. We investigate whether a multivariate representation can be used for this purpose. Pseudorandom sequences were used to inflate thigh cuffs and to administer 5% CO2. Multiple and partial coherence were estimated, using arterial blood pressure (ABP), end-tidal CO2 (EtCO2) and resistance area product as input and CBFV as output variables. The inclusion of second and third input variables increased the amount of CBFV variability that can be accounted for (p < 10?4 in both cases). Partial coherence estimates in the low frequency range (<0.07 Hz) were not influenced by the use of thigh cuffs, but CO2 administration had a statistically significant effect (p < 10?4 in all cases). We conclude that the inclusion of additional inputs of a priori known physiological significance can help account for a greater amount of CBFV variability and may represent a viable alternative to more conventional non-linear modelling. The results of partial coherence analysis suggest that dynamic autoregulation and CO2 reactivity are likely to be the result of different physiological mechanisms.
advances, modelling, dynamic, auto, regulation, variability, cerebral, blood, flow, velocity, frequency, pseudorandom, sequences, inflate, thigh, cuffs, coherence, arterial, pressure, statistics, physiological, non-linear, mechanisms
0967-3334
1056-1073
Katsogridakis, Emmanuel
863d80d0-d656-453d-98fe-70f2c16aaaf9
Simpson, David M.
53674880-f381-4cc9-8505-6a97eeac3c2a
Bush, Glen
cfea4e31-c324-480d-8308-72356a501af1
Fan, Lingke
f5684ccc-f5ef-4613-89bb-1b61ec6f74b6
Birch, Anthony A.
0a31c6be-d058-4ca4-a332-8dcff4a470ab
Allen, Robert
956a918f-278c-48ef-8e19-65aa463f199a
Potter, John F.
b49c726b-7954-429e-bc1c-37639a39e428
Panerai, Ronney B.
7acaf714-a17c-4df2-a1f3-b148c1445517
Katsogridakis, Emmanuel
863d80d0-d656-453d-98fe-70f2c16aaaf9
Simpson, David M.
53674880-f381-4cc9-8505-6a97eeac3c2a
Bush, Glen
cfea4e31-c324-480d-8308-72356a501af1
Fan, Lingke
f5684ccc-f5ef-4613-89bb-1b61ec6f74b6
Birch, Anthony A.
0a31c6be-d058-4ca4-a332-8dcff4a470ab
Allen, Robert
956a918f-278c-48ef-8e19-65aa463f199a
Potter, John F.
b49c726b-7954-429e-bc1c-37639a39e428
Panerai, Ronney B.
7acaf714-a17c-4df2-a1f3-b148c1445517

Katsogridakis, Emmanuel, Simpson, David M., Bush, Glen, Fan, Lingke, Birch, Anthony A., Allen, Robert, Potter, John F. and Panerai, Ronney B. (2016) Revisiting the frequency domain: the multiple and partial coherence of cerebral blood flow velocity in the assessment of dynamic cerebral autoregulation. Physiological Measurement, 37 (7), 1056-1073. (doi:10.1088/0967-3334/37/7/1056).

Record type: Article

Abstract

Despite advances in modelling dynamic autoregulation, only part of the variability of cerebral blood flow velocity (CBFV) in the low frequency range has been explained. We investigate whether a multivariate representation can be used for this purpose. Pseudorandom sequences were used to inflate thigh cuffs and to administer 5% CO2. Multiple and partial coherence were estimated, using arterial blood pressure (ABP), end-tidal CO2 (EtCO2) and resistance area product as input and CBFV as output variables. The inclusion of second and third input variables increased the amount of CBFV variability that can be accounted for (p < 10?4 in both cases). Partial coherence estimates in the low frequency range (<0.07 Hz) were not influenced by the use of thigh cuffs, but CO2 administration had a statistically significant effect (p < 10?4 in all cases). We conclude that the inclusion of additional inputs of a priori known physiological significance can help account for a greater amount of CBFV variability and may represent a viable alternative to more conventional non-linear modelling. The results of partial coherence analysis suggest that dynamic autoregulation and CO2 reactivity are likely to be the result of different physiological mechanisms.

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Katsogridakis - final submission Dec 2015.pdf - Accepted Manuscript
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Accepted/In Press date: 25 April 2016
e-pub ahead of print date: 31 May 2016
Keywords: advances, modelling, dynamic, auto, regulation, variability, cerebral, blood, flow, velocity, frequency, pseudorandom, sequences, inflate, thigh, cuffs, coherence, arterial, pressure, statistics, physiological, non-linear, mechanisms
Organisations: Inst. Sound & Vibration Research

Identifiers

Local EPrints ID: 398103
URI: http://eprints.soton.ac.uk/id/eprint/398103
ISSN: 0967-3334
PURE UUID: cce587a1-2a43-4d86-9a26-11104a2606c1

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Date deposited: 19 Jul 2016 08:54
Last modified: 07 Oct 2020 05:15

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Contributors

Author: Emmanuel Katsogridakis
Author: Glen Bush
Author: Lingke Fan
Author: Anthony A. Birch
Author: Robert Allen
Author: John F. Potter
Author: Ronney B. Panerai

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