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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.

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journal contribution
posted on 08.05.2019, 11:43 by E Katsogridakis, DM Simpson, G Bush, L Fan, AA Birch, R Allen, JF Potter, RB Panerai
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.

Funding

This study was supported by the UK EPSRC, grant nos EP/G008787/1 and EP/G010420/1.

History

Citation

Physiological Measurement, 2016, 37 (7), pp. 1056-1073

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Cardiovascular Sciences

Version

AM (Accepted Manuscript)

Published in

Physiological Measurement

Publisher

IOP Publishing

eissn

1361-6579

Copyright date

2016

Available date

08/05/2019

Publisher version

https://iopscience.iop.org/article/10.1088/0967-3334/37/7/1056/meta

Language

en