gms | German Medical Science

58. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

26. bis 29.04.2007, Leipzig

Drift in a novel device for measuring regional cerebral blood flow: The impact of the fixation system

Drift in einem neuen Gerät zur Messung der regionalen Hirndurchblutung: Einfluss des Fixierungssystems

Meeting Abstract

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  • corresponding author S. Wolf - Klinik für Neurochirurgie, Akademisches Lehrkrankenhaus München-Bogenhausen, Technische Universität München, München, Deutschland
  • L. Schürer - Klinik für Neurochirurgie, Akademisches Lehrkrankenhaus München-Bogenhausen, Technische Universität München, München, Deutschland
  • C. B. Lumenta - Klinik für Neurochirurgie, Akademisches Lehrkrankenhaus München-Bogenhausen, Technische Universität München, München, Deutschland

Deutsche Gesellschaft für Neurochirurgie. 58. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC). Leipzig, 26.-29.04.2007. Düsseldorf: German Medical Science GMS Publishing House; 2007. DocP 114

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2007/07dgnc369.shtml

Veröffentlicht: 11. April 2007

© 2007 Wolf et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective: Bedside measurement of regional cerebral blood flow (rCBF) is a promising technology to detect vasospasm after aneurysmal subarachnoid hemorrhage [1]. The Bowman® rCBF monitor facilitates continuous and quantitative assessment of brain tissue perfusion in ml/100g tissue/minute via thermodiffusion micro probes. As the fixation of the probe is not specified by the manufacturer, we examined the impact of different systems on the temporal stability of the rCBF measurement.

Methods: In nineteen patients with aneurysmal subarachnoid hemorrhage, a Bowman® rCBF probe was implanted in the vascular territory of the aneurysm-harboring vessel. Fixation was performed either with a one- or two-way Licox® brain tissue oxygenation surgical steel bolt (4 vs. 5 patients), a Raumedic® or Codman® plastic bolt (6 vs. 2 patients) developed for ICP probes or the probe was implanted at the time of aneurysm surgery without separate fixation (2 patients).

Automatic recalibration of the rCBF device was performed every 30 minutes, thus yielding measurement periods of 25 minutes. CBF was recorded once per second. Data was averaged over one minute and all measurement cycles pooled. Drift analysis was performed using analysis of variance for repeated measurements.

Results: 8359 measurement cycles with a mean monitoring time of 7.3 days per patient were analyzed. Mean rCBF was 24.7 ml/100g/min at the beginning and 23.9 ml/100g/min at the end of the measurement cycles between two recalibration periods, thus representing a mean drift of -0.8 ml/100g/min per 25 minute measurement period (ANOVA, p<0.001). This drift was heterogeneous in different patients (range -3.6 to 4.2 ml/100g/min), mostly showing a logarithmic decline and a positive value in only one of the nineteen patients. The drift was pronounced most when rCBF was low and in the rCBF probes fixated with the Licox® one- or two-way devices.

Conclusions: The current implementation of the Bowman® rCBF monitor shows a predominantly downward measurement drift which may be clinically relevant especially at low CBF states. The drift can be partially avoided by the clinician using a proper fixation device for the probe.


References

1.
Vajkoczy P et al. Regional cerebral blood flow monitoring in the diagnosis of delayed ischemia following aneurysmal subarachnoid hemorrhage. JNS. 2003;98:1227–34.