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The repeatability of cerebral autoregulation assessment using sinusoidal lower body negative pressure

The repeatability of cerebral autoregulation assessment using sinusoidal lower body negative pressure
The repeatability of cerebral autoregulation assessment using sinusoidal lower body negative pressure

A forced periodic variation in blood pressure produces a similar variation in cerebral blood velocity. The amplitudes and phases of the pressure and velocity waveforms are indicative of the dynamic response of the cerebral autoregulation. The phase of the velocity leads the pressure; the greater the phase difference the faster the autoregulation response. Various techniques have been employed to oscillate arterial blood pressure but measurement reproducibility has been poor. The purpose of this study was to assess the reproducibility of phase measurements when sinusoidal lower body negative pressure is used to vary blood pressure. Five healthy volunteers were assessed at two vacuum levels on each of eight visits. For each measurement a 12 s sinusoidal cycle was maintained for 5 min. The Fourier components of blood pressure and the middle cerebral artery velocity were determined at the oscillation frequency. The phase of velocity consistently led the pressure. The mean phase difference was 42+/-13 degrees for the stronger vacuum and 36+/-42 degrees for the weaker vacuum. The variation given is the within-subjects standard deviation estimated from a one-way analysis of variance. Sinusoidal lower body negative pressure is a useful stimulus for investigating autoregulation; it has advantages over other methods. High vacuums show good reproducibility but are too uncomfortable for patient use.

Adult, Blood Pressure, Blood Pressure Determination, Carbon Dioxide, Cerebrovascular Circulation, Female, Heart Rate, Homeostasis, Humans, Laser-Doppler Flowmetry, Lower Body Negative Pressure, Male, Middle Aged, Reference Values, Reproducibility of Results, Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't
0967-3334
73-83
Birch, A.A.
755f2236-4c0c-49b5-9884-de4021acd42d
Neil-Dwyer, G.
19520fec-ecd3-436f-9420-b7bd776751c3
Murrills, A.J.
4874f921-548f-4ac4-9195-34326e37e6cd
Birch, A.A.
755f2236-4c0c-49b5-9884-de4021acd42d
Neil-Dwyer, G.
19520fec-ecd3-436f-9420-b7bd776751c3
Murrills, A.J.
4874f921-548f-4ac4-9195-34326e37e6cd

Birch, A.A., Neil-Dwyer, G. and Murrills, A.J. (2001) The repeatability of cerebral autoregulation assessment using sinusoidal lower body negative pressure. Physiological Measurement, 23 (1), 73-83. (doi:10.1088/0967-3334/23/1/307).

Record type: Article

Abstract

A forced periodic variation in blood pressure produces a similar variation in cerebral blood velocity. The amplitudes and phases of the pressure and velocity waveforms are indicative of the dynamic response of the cerebral autoregulation. The phase of the velocity leads the pressure; the greater the phase difference the faster the autoregulation response. Various techniques have been employed to oscillate arterial blood pressure but measurement reproducibility has been poor. The purpose of this study was to assess the reproducibility of phase measurements when sinusoidal lower body negative pressure is used to vary blood pressure. Five healthy volunteers were assessed at two vacuum levels on each of eight visits. For each measurement a 12 s sinusoidal cycle was maintained for 5 min. The Fourier components of blood pressure and the middle cerebral artery velocity were determined at the oscillation frequency. The phase of velocity consistently led the pressure. The mean phase difference was 42+/-13 degrees for the stronger vacuum and 36+/-42 degrees for the weaker vacuum. The variation given is the within-subjects standard deviation estimated from a one-way analysis of variance. Sinusoidal lower body negative pressure is a useful stimulus for investigating autoregulation; it has advantages over other methods. High vacuums show good reproducibility but are too uncomfortable for patient use.

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More information

Published date: 19 December 2001
Keywords: Adult, Blood Pressure, Blood Pressure Determination, Carbon Dioxide, Cerebrovascular Circulation, Female, Heart Rate, Homeostasis, Humans, Laser-Doppler Flowmetry, Lower Body Negative Pressure, Male, Middle Aged, Reference Values, Reproducibility of Results, Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't

Identifiers

Local EPrints ID: 428312
URI: https://eprints.soton.ac.uk/id/eprint/428312
ISSN: 0967-3334
PURE UUID: 65af08ee-470e-4ec5-a425-f69bc68c2f37
ORCID for A.A. Birch: ORCID iD orcid.org/0000-0002-2328-702X

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Date deposited: 20 Feb 2019 17:30
Last modified: 14 Mar 2019 01:22

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Contributors

Author: A.A. Birch ORCID iD
Author: G. Neil-Dwyer
Author: A.J. Murrills

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