| Wavelet assessment of cerebrospinal compensatory reserve and cerebrovascular reactivity. | |
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MedLine Citation:
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PMID: 17470981 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We introduce a wavelet transfer model to relate spontaneous arterial blood pressure (ABP) fluctuations to intracranial pressure (ICP) fluctuations. We employ a complex continuous wavelet transform to develop a consistent mathematical framework capable of parametrizing both cerebral compensatory reserve and cerebrovascular reactivity. The frequency-dependent gain and phase of the wavelet transfer function are introduced because of the non-stationary character of the ICP and ABP time series. The gain characterizes the dampening of spontaneous ABP fluctuations and is interpreted as a novel measure of cerebrospinal compensatory reserve. For a group of 12 patients who died as a result of cerebral lesions (Glasgow Outcome Scale (GOS) = 1) the average gain in the low-frequency (0.02- 0.07 Hz) range was 0.51 +/- 0.13 and significantly exceeded that of 17 patients with GOS = 2 having an average gain of 0.26 +/- 0.11 with p = 1x10(-4) (Kruskal-Wallis test). A time-averaged synchronization index (which may vary from 0 to 1) defined in terms of the wavelet transfer function phase yields information about the stability of the phase difference of the ABP and ICP signals and is used as a cerebrovascular reactivity index. A low value of synchronization index reflects a normally reactive vascular bed, while a high value indicates pathological entrainment of ABP and ICP fluctuations. Such entrainment is strongly pronounced in patients with fatal outcome (for this group the low-frequency synchronization index was 0.69 +/- 0.17). The gain and synchronization parameters define a cerebral hemodynamic state space (CHS) in which the patients with GOS = 1 are to large extent partitioned away from those with GOS = 2. The concept of CHS elucidates the interplay of vascular and compensatory mechanisms. |
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Authors:
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M Latka; W Kolodziej; M Turalska; D Latka; W Zub; B J West |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2007-04-05 |
Journal Detail:
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Title: Physiological measurement Volume: 28 ISSN: 0967-3334 ISO Abbreviation: Physiol Meas Publication Date: 2007 May |
Date Detail:
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Created Date: 2007-05-01 Completed Date: 2007-08-14 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9306921 Medline TA: Physiol Meas Country: England |
Other Details:
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Languages: eng Pagination: 465-79 Citation Subset: IM |
Affiliation:
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Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, Wroclaw, Poland. miroslaw.latka@pwr.wroc.pl |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Aged Blood Pressure / physiology* Cerebrovascular Circulation / physiology* Female Humans Intracranial Hemorrhages / physiopathology* Intracranial Pressure / physiology* Male Middle Aged Models, Cardiovascular |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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