gms | German Medical Science

57th Annual Meeting of the German Society of Neurosurgery
Joint Meeting with the Japanese Neurosurgical Society

German Society of Neurosurgery (DGNC)

11 - 14 May, Essen

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Continuous autoregulation monitoring by Wigner distribution – Evaluation in an animal model

Kontinuierliche Messung der zerebralen Autoregulation mit der Wigner Verteilung – Evaluierung im Tiermodell

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  • corresponding author S.A. May - Klinik für Neurochirurgie, Klinikum Chemnitz gGmbH
  • F. Noack - Institut für Biomedizinische Technik, TU Dresden
  • M. Kahlbaum - Klinik für Neurochirurgie, Klinikum Chemnitz gGmbH
  • A. Heimann - Institut für Neurochirurgische Pathophysiologie, Mainz
  • O. Kempski - Institut für Neurochirurgische Pathophysiologie, Mainz
  • R. Steinmeier - Klinik für Neurochirurgie, Klinikum Chemnitz gGmbH

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 57. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie. Essen, 11.-14.05.2006. Düsseldorf, Köln: German Medical Science; 2006. DocP 10.157

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgnc2006/06dgnc374.shtml

Published: May 8, 2006

© 2006 May et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objective: Monitoring of cerebral haemodynamics e.g. cerebral autoregulation (CA) is believed to provide important information for the treatment of patients with traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). Recent approaches of CA assessment use spontaneous blood pressure fluctuations as an intrinsic trigger for autoregulatory mechanisms. Unfortunately those triggers show poor reproducibility and appear randomly. Data analysis is restricted to a compromise between a high resolution in either time or frequency e.g. Cross-Correlation-Analysis (CC-analysis). In order to evaluate the degree of stationarity, i.e. reproducibility, of spontaneous arterial blood pressure (ABP) oscillations we applied the Wigner Distribution to recordings of ABP and cerebral blood flow velocity (CBFV). The Wigner Distribution allows a high temporal resolution of a frequency spectrum. The aim of this study was the evaluation of this method in an animal model. We used static rate of regulation test (sRoR) and CC-analysis for evaluation.

Methods: We measured 12 pigs. All were mechanical ventilated and sedated. Arterial blood pressure was recorded invasively. CBFV was determined by transcranial Doppler ultrasound in the middle cerebral artery in both hemispheres. We used a TBI model (acute subdural haematoma by own blood instillation). After preprocessing of the data the Wigner distribution was applied to the signals. Results were compared to sRoR and CC-Analyses pre- and posttrauma.

Results: Intermethod agreement was highly significant (p=0,008). It could be shown that Mayer and B waves do not occur as stationary frequency components.

Conclusions: The new method allows a continuous monitoring of cerebral autoregulation. The dynamic character of cerebral haemodynamics justifies the application of the Wigner distribution to improve reliability of measurement results.