gms | German Medical Science

55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

25. bis 28.04.2004, Köln

Evaluation of a new fiberoptic pressure microprobe for intraparenchymal ICP measurements in rats

Evaluierung eines neuen fiberoptischen Drucksensors zur intraparenchymalen ICP-Messung bei Ratten

Meeting Abstract

Suche in Medline nach

  • corresponding author Martin Barth - Neurochirurgische Klinik, Ruprecht-Karls-Universität, Heidelberg, Mannheim
  • P. Nguyen - Institut MABEL, Ruprecht-Karls-Universität, Heidelberg, Mannheim
  • P. Herrmann - Anästhesiologische Klinik, Ruprecht-Karls-Universität, Heidelberg, Mannheim
  • L. Schilling - Neurochirurgische Klinik, Ruprecht-Karls-Universität, Heidelberg, Mannheim

Deutsche Gesellschaft für Neurochirurgie. Ungarische Gesellschaft für Neurochirurgie. 55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie. Köln, 25.-28.04.2004. Düsseldorf, Köln: German Medical Science; 2004. DocP 01.2

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2004/04dgnc0285.shtml

Veröffentlicht: 23. April 2004

© 2004 Barth 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

Accurate measurement of intracranial pressure (ICP) in small animals is challenging. Mostly, conventional pressure transducers connected to intraventricularly located microcatheters are used. However, these systems have proven inaccuracy in detecting rapid changes of ICP. Recently, the accuracy and sensitivity of a new fiberoptic pressure microprobe has been demonstrated for cardiovascular measurements. For cerebral measurements we evaluated the practicability of this microprobe in rats for high ICP using a weight drop trauma model (i), and for low ICP using artificial cerebrospinal fluid (aCSF) injections into the basal cisterns (ii).

Methods

Male wistar rats (250-350g) were anesthetized using inactin (100μg/ml, 0.1ml/100g body weight). The new microprobe (Samba-Sensor, OD 0.38mm, Samba-Sensors, Gothenburg, Sweden) protected by a PE tubing (OD 0.8, ID 0.4 mm) was inserted via a parietal burr hole into the parietal cortex of male wistar rats and fixed to the skull with dental cement. Arterial and venous microcatheters (OD 0.8, ID 0.4 mm) were placed into the femoral vessels for monitoring of macrohemodynamic parameters. Sensors were connected to a multiparameter monitoring apparatus with sampling rates of 1024-2048 hertz. Rats were placed under a weight drop device and several intensities applied (10, 20, 30, 40, and 100cm; bolt-weight, 500g) (i), or received intermittent bolus injections of 0.1 ml aCSF. Data were digitally stored on a personal computer and rewiewed using customized software packages of National Instruments and Microsoft Corp.

Results

Baseline ICP values after probe insertion showed interindividual differences of 30 mmHg caused by persistent counterpressure of the surrounding tissue to the sensor membrane, which is located at the tip of the sensor. In the trauma model, a dose dependent increase of intracranial peak pressures (duration, 2 ms) was found ranging from 169 ± 81 mmHg to 409 ±122 mmHg at 20 cm or 50 cm height of fall, respectively (mean ± SD). ICP’s showed posttraumatic oscillations with a maximum duration of 10 ms at 50 cm height of fall. After injection of aCSF, ICP increased to 150% compared to baseline values and showed increased amplitudes of ICP oscillations due to reduced brain compliance.

Conclusions

The new fiberoptic pressure microprobe is able to measure rapid ICP changes at different pressure ranges. With its small size it may preferentially be used in small animals. However, practicability is limited due to the high fragility of the sensor membrane and its location on the tip of the sensor.