gms | German Medical Science

59th Annual Meeting of the German Society of Neurosurgery (DGNC)
3rd Joint Meeting with the Italian Neurosurgical Society (SINch)

German Society of Neurosurgery (DGNC)

1 - 4 June 2008, Würzburg

A novel opto-chemical pO2 measurement on the cortex in comparison with the intraparenchymal Licox-probe

Vergleich einer neuen opto-chemischen pO2-Messung an der Kortexoberfläche mit der intraparenchymalen Licox-Sonde

Meeting Abstract

  • corresponding author J. Warnat - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg, Deutschland
  • E. M. Stoerr - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg, Deutschland
  • G. Liebsch - Biocam GmbH, Regensburg, Deutschland
  • A. Brawanski - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg, Deutschland
  • C. Woertgen - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg, Deutschland

Deutsche Gesellschaft für Neurochirurgie. Società Italiana di Neurochirurgia. 59. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3. Joint Meeting mit der Italienischen Gesellschaft für Neurochirurgie (SINch). Würzburg, 01.-04.06.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocP 116

The electronic version of this article is the complete one and can be found online at:

Published: May 30, 2008

© 2008 Warnat et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: The measurement of the brain tissue pO2 is an important component of the neuromonitoring of critically ill patients with SAH or TBI. Here we compare the typical intraparenchymal pO2 measurement with a novel opto-chemical measurement on the cortex surface. The Method is based on oxygen dependant luminescence quenching of a porphyrine dye in the sensor foil.

Methods: The measurement device (prototype, Biocam, Regensburg) was placed after a craniectomy on the cortex of intubated and ventilated wistar rats (n=6, m=355±27g). The sensor foil is excited by LED light flashes; the luminescence of the foil and also normal images of the measurement area are detected by a CCD-camera, which is coupled to the foil via a NMDA cylinder. The data is processed with PC software (IDL, Creaso). Regions of interest were defined over a cortical vein, an arteriole and the parenchyma. A Licox-probe was placed in the frontal cortex of the opposite side. Arterial pO2 and pCO2 were varied by changing FiO2 and ventilation settings. Blood gas values, arterial pressure, heart rate and brain pO2 were recorded simultaneously.

Results: The intraparenchymal (Licox) pO2 correlated at best with the pO2 over the cortex parenchyma (correletation coefficient =0,55; p<0,001; n=93). Correlations with the pO2 over veins (c.c.=0,36; p<0,001) and arterioles (c.c.=0,24; p<0,05) were weaker. The correlation coefficient of the arterial pO2 (paCO2 33-47 mmHg) with the Licox-measures was 0,37 (p<0,001), and with the cortical pO2 it was 0,75 (arteriole, p<0,001), 0,73 (vein, p<0,001) und 0,37 (parenchyma, p<0,001). Variation of paCO2 (n=54, paO2 70-130 mmHg) had no effect on the Licox measures (c.c.=-0,06, p=0,68) and small influence on the cortex pO2 (vein: 0,04, p=0,76; arteriole: 0,30, p<0,05, parenchyma: 0,28, p<0,05).

Conclusions: The two dimensional pO2 detection on the cortex surface allows differentiated and simultaneous measurements of the anatomical structures. The Licox measurement in the white matter correlated most of all with the pO2 over the cortex parenchyma. The cortical measurement provides additional pO2 values of arterioles and veins. The oxygenation of these vessels as well as probable drops in the cortex pO2 may not be detected by the intraparenchymal pO2 probe.