Increased blood pressure variability upon standing up improves reproducibility of cerebral autoregulation indices
Journal
Medical Engineering and Physics
Journal Volume
47
Pages
151-158
Date Issued
2017
Author(s)
Abstract
Dynamic cerebral autoregulation, that is the transient response of cerebral blood flow to changes in arterial blood pressure, is currently assessed using a variety of different time series methods and data collection protocols. In the continuing absence of a gold standard for the study of cerebral autoregulation it is unclear to what extent does the assessment depend on the choice of a computational method and protocol. We use continuous measurements of blood pressure and cerebral blood flow velocity in the middle cerebral artery from the cohorts of 18 normotensive subjects performing sit-to-stand manoeuvre. We estimate cerebral autoregulation using a wide variety of black-box approaches (including the following six autoregulation indices ARI, Mx, Sx, Dx, FIR and ARX) and compare them in the context of reproducibility and variability. For all autoregulation indices, considered here, the intra-class correlation was greater during the standing protocol, however, it was significantly greater (Fisher's Z-test) for Mx (p < 0.03), Sx (p < 0.003) and Dx (p < 0.03). In the specific case of the sit-to-stand manoeuvre, measurements taken immediately after standing up greatly improve the reproducibility of the autoregulation coefficients. This is generally coupled with an increase of the within-group spread of the estimates. ? 2017 IPEM
Subjects
Blood pressure
Flow velocity
Hemodynamics
Tissue
Transient analysis
Arterial blood pressure
Blood pressure variability
Cerebral autoregulation
Cerebral blood flow
Cerebral blood flow velocities
Data collection protocols
Reproducibilities
Variability
Blood vessels
adult
aged
Article
autoregressive with exogenous input
autoregulation index
blood flow velocity
blood pressure measurement
blood pressure variability
brain blood flow
cohort analysis
controlled study
correlation coefficient
diastolic blood pressure
elevated blood pressure
finite impulse response
hemodynamic parameters
human
human experiment
mean arterial pressure
middle cerebral artery
normal human
priority journal
reproducibility
sitting
standing
systolic blood pressure
young adult
blood pressure
body position
brain circulation
female
homeostasis
male
patient positioning
physiology
procedures
sensitivity and specificity
Adult
Aged
Blood Flow Velocity
Blood Pressure
Blood Pressure Determination
Cerebrovascular Circulation
Female
Homeostasis
Humans
Male
Patient Positioning
Posture
Reproducibility of Results
Sensitivity and Specificity
Type
journal article