gms | German Medical Science

62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH)

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

07. - 11. Mai 2011, Hamburg

Changes in cortex and white matter pO2 during a reversible epidural mass lesion

Meeting Abstract

  • J. Warnat - Department of Neurosurgery, University of Regensburg, Germany
  • A. Hösl - Department of Neurosurgery, University of Regensburg, Germany
  • G. Liebsch - Presens, Regensburg, Germany
  • E.M. Stoerr - Department of Neurosurgery, University of Regensburg, Germany
  • A. Brawanski - Department of Neurosurgery, University of Regensburg, Germany

Deutsche Gesellschaft für Neurochirurgie. Polnische Gesellschaft für Neurochirurgen. 62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH). Hamburg, 07.-11.05.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. DocMO.06.01

DOI: 10.3205/11dgnc029, URN: urn:nbn:de:0183-11dgnc0294

Veröffentlicht: 28. April 2011

© 2011 Warnat 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 vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective: State of the art intensive care for SAH and TBI patients relies to a certain degree on neuromonitoring data including local brain tissue pO2 measurements. Usually local pO2 probes are placed in the white matter around 2 cm below the cortex. Here we compare a opto-chemical method of planar oxygen detection for measuring changes of cortex pO2 to an intraparenchymal Licox probe during a reversibly introduced epidural mass lesion.

Methods: 9 male Wistar rats (m = 305 ± 22 g) were sedated (midazolam, fentanyl, medetomidine), intubated and ventilated. A cortical window was prepared with a translucent porphyrine containing sensor foil. The sensor was excited by short light pulses (λ= 405 nm) and pO2 dependent light emissions were recorded with a CCD camera of the measurement device (Biocam, Regensburg). A balloon device, which simulated an epidural mass lesion, was placed over the contra lateral hemisphere. Throughout the experiment, the balloon was inflated up to an ICP of approx. 40 mmHg for 60 minutes and then deflated. Licox pO2, cortex pO2, ICP, RR, body temperature, EEG and cortex pO2 were recorded and blood gas samples were drawn.

Results: Cortex pO2 maps were recorded with 6 Hz. Altogether 5621 cortex measurements were registered. Cortical pO2 decreased from 24.3 ± 12.7 mmHg to 13.2 ± 9.5 mmHg due to the epidural lesion. Cortical pO2 values correlated with Licox parenchymal pO2 values (r = 0.32; p < 0.001) as long as ICP was low (< 15 mmHg). During balloon inflation (ICP = 48 ± 12 mmHg) the correlation was not detectable any longer (p = 0.22). Absolute values of cortical pO2 differed significantly from Licox pO2 (p > 0.05). Drops in cortex pO2 due to low FiO2 are not consistently paralleled in correspondent changes in Licox pO2. Vice versa, fluctuations in Licox pO2 with stable cortex pO2 were observed.

Conclusions: Cortical pO2 values and Licox/white matter pO2 appeared to be weakly correlated, while absolute values differed. In some sections of the experiment, a completely different behaviour of the two probes was observed. Measuring cortex pO2 appears to be complementary to the detection of white matter pO2 and may serve as an additive neuromonitoring tool for selected cases.