Frequency-domain analysis of cerebral autoregulation from spontaneous fluctuations in arterial blood pressure

1998 ◽  
Vol 36 (3) ◽  
pp. 315-322 ◽  
Author(s):  
R. B. Panerai ◽  
J. M. Rennie ◽  
A. W. R. Kelsall ◽  
D. H. Evans
Keyword(s):  
Blood Pressure ◽  
Frequency Domain ◽  
Arterial Blood Pressure ◽  
Cerebral Autoregulation ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Arterial Blood ◽  
Spontaneous Fluctuations

scholarly journals Frequency Domain Analysis of Cerebral Blood Flow Velocity and its Correlation with Arterial Blood Pressure

1998 ◽  
Vol 18 (3) ◽  
pp. 311-318 ◽  
Author(s):  
Terry Bo-Jau Kuo ◽  
Chang-Ming Chern ◽  
Wen-Yung Sheng ◽  
Wen-Jang Wong ◽  
Han-Hwa Hu
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Transfer Function ◽  
Flow Velocity ◽  
Frequency Domain ◽  
Blood Flow Velocity ◽  
Low Frequency ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Arterial Blood

We applied frequency domain analysis to detect and quantify spontaneous fluctuations in the blood flow velocity of the middle cerebral artery (MCAFV). Instantaneous MCAFV of normal volunteers was detected using transcranial Doppler sonography. Spectral and transfer function analyses of MCAFV and arterial blood pressure (ABP) were performed by fast Fourier transform. We found the fluctuations in MCAFV, like ABP, could be diffracted into three components at specific frequency ranges, designated as high-frequency (HF, 0.15 to 0.4 Hz), low-frequency (LF, 0.04 to 0.15 Hz), and very low-frequency (VLF, 0.016 to 0.04 Hz) components. The HF and LF components of MCAFV exhibited high coherence with those of ABP, indicating great similarity of MCAFV and ABP fluctuations within the two frequency ranges. However, it was not the case for the VLF component. Transfer function analysis revealed that the ABP-MCAFV phase angle was frequency-dependent in the LF range ( r = −0.79, P < 0.001) but not in the HF range. The time delay between LF fluctuations of ABP and those of MCAFV was evaluated as 2.1 seconds. We conclude that in addition to traditional B-wave equivalents, there are at least two different mechanisms for MCAFV fluctuations: the HF and LF fluctuations of MCAFV are basically secondary to those of ABP, and cerebral autoregulation may operate efficiently in LF rather than HF range. Frequency domain analysis offers an opportunity to explore the nature and underlying mechanism of dynamic regulation in cerebral circulation.

scholarly journals Detection of Impaired Cerebral Autoregulation Improves by Increasing Arterial Blood Pressure Variability

2012 ◽  
Vol 33 (4) ◽  
pp. 519-523 ◽  
Author(s):  
Emmanuel Katsogridakis ◽  
Glen Bush ◽  
Lingke Fan ◽  
Anthony A Birch ◽  
David M Simpson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Cerebral Autoregulation ◽  
Random Sequence ◽  
Step Response ◽  
Arterial Blood ◽  
The Status ◽  
Autoregulation Index ◽  
Spontaneous Fluctuations ◽  
Operator Curve

Although the assessment of dynamic cerebral autoregulation (CA) based on measurements of spontaneous fluctuations in arterial blood pressure (ABP) and cerebral blood flow (CBF) is a convenient and much used method, there remains uncertainty about its reliability. We tested the effects of increasing ABP variability, provoked by a modification of the thigh cuff method, on the ability of the autoregulation index to discriminate between normal and impaired CA, using hypercapnia as a surrogate for dynamic CA impairment. In 30 healthy volunteers, ABP (Finapres) and CBF velocity (CBFV, transcranial Doppler) were recorded at rest and during 5% CO2 breathing, with and without pseudo-random sequence inflation and deflation of bilateral thigh cuffs. The application of thigh cuffs increased ABP and CBFV variabilities and was not associated with a distortion of the CBFV step response estimates for both normocapnic and hypercapnic conditions ( P = 0.59 and P = 0.96, respectively). Sensitivity and specificity of CA impairment detection were improved with the thigh cuff method, with the area under the receiver–operator curve increasing from 0.746 to 0.859 ( P = 0.031). We conclude that the new method is a safe, efficient, and appealing alternative to currently existing assessment methods for the investigation of the status of CA.

Low Variability of Blood Pressure Predicts Abnormal Electroencephalogram in Infants with Hypoxic Ischemic Encephalopathy

2020 ◽  
Author(s):  
Abigail Flower ◽  
Daniel Vasiliu ◽  
Tianrui Zhu ◽  
Robert Andris ◽  
Maryam Abubakar ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Frequency Domain ◽  
Arterial Blood Pressure ◽  
Apgar Score ◽  
Blood Pressure Variability ◽  
Hypoxic Ischemic Encephalopathy ◽  
Arterial Blood ◽  
The Mean ◽  
Minute Apgar Score ◽  
Ischemic Encephalopathy

Objective This study aimed to evaluate the role of an objective physiologic biomarker, arterial blood pressure variability, for the early identification of adverse short-term electroencephalogram (EEG) outcomes in infants with hypoxic-ischemic encephalopathy (HIE). Study Design In this multicenter observational study, we analyzed blood pressure of infants meeting these criteria: (1) neonatal encephalopathy determined by modified Sarnat exam, (2) continuous mean arterial blood pressure (MABP) data between 18 and 27 hours after birth, and (3) continuous EEG performed for at least 48 hours. Adverse outcome was defined as moderate–severe grade EEG at 48 hours. Standardized signal preprocessing was used; the power spectral density was computed without interpolation. Multivariate binary logistic regression was used to identify which MABP time and frequency domain metrics provided improved predictive power for adverse outcomes compared with standard clinical predictors (5-minute Apgar score and cord pH) using receiver operator characteristic analysis. Results Ninety-one infants met inclusion criteria. The mean gestational age was 38.4 ± 1.8 weeks, the mean birth weight was 3,260 ± 591 g, 52/91 (57%) of infants were males, the mean cord pH was 6.95 ± 0.21, and 10/91 (11%) of infants died. At 48 hours, 58% of infants had normal or mildly abnormal EEG background and 42% had moderate or severe EEG backgrounds. Clinical predictor variables (10-minute Apgar score, Sarnat stage, and cord pH) were modestly predictive of 48 hours EEG outcome with area under curve (AUC) of 0.66 to 0.68. A composite model of clinical and optimal time- and frequency-domain blood pressure variability had a substantially improved AUC of 0.86. Conclusion Time- and frequency-domain blood pressure variability biomarkers offer a substantial improvement in prediction of later adverse EEG outcomes over perinatal clinical variables in a two-center cohort of infants with HIE. Key Points

scholarly journals Grading of Cerebral Dynamic Autoregulation From Spontaneous Fluctuations in Arterial Blood Pressure

Stroke ◽  
1998 ◽  
Vol 29 (11) ◽  
pp. 2341-2346 ◽  
Author(s):  
Ronney B. Panerai ◽  
Richard P. White ◽  
Hugh S. Markus ◽  
David H. Evans
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Arterial Blood ◽  
Spontaneous Fluctuations
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