gms | German Medical Science

60th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Benelux countries and Bulgaria

German Society of Neurosurgery (DGNC)

24 - 27 May 2009, Münster

Comparison of LiquoGuard® and Spiegelberg® ICP pressure measurement

Meeting Abstract

  • S. Linsler - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg/Saar
  • M. Schmidtke - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg/Saar
  • R. Eymann - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg/Saar
  • W.I. Steudel - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg/Saar
  • M. Kiefer - Neurochirurgische Klinik, Universitätskliniken des Saarlandes, Homburg/Saar

Deutsche Gesellschaft für Neurochirurgie. 60. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit den Benelux-Ländern und Bulgarien. Münster, 24.-27.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. DocP01-03

doi: 10.3205/09dgnc251, urn:nbn:de:0183-09dgnc2517

Published: May 20, 2009

© 2009 Linsler 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 LiquoGuard is a new device for intracranial pressure (ICP) controlled drainage of cerebrospinal fluid (CSF) through external drains. ICP is measured with an external transducer in the LiquoGard device, and drainage regulated according to a preset pressure level. However, the accuracy of ICP measurement based on external transducers has been challenged over decades. Especially in cases of slit ventricles ICP measurement via external transducers can be misleading. We examined the accuracy of the LiquoGuard by comparing its ICP data, which are the fundament for its CSF drainage management, to ICP data measured simultaneously via a tip-transducer.

Methods: Overall, a total of 1074 monitoring hours ranging from 56 to 259h was compared in 8 patients with various reasons for external CSF drainage. All patients received an intraventricular Spiegelberg III probe the drainage catheter of which had been connected to the LiquoGuard. ICP readings from both devices were collected and compared on an hourly basis. Statistics: Pearson correlation, Wilcoxon matched pair-test; significance level: p<0.05.

Results: Overall measured ICP was 10±5mm Hg (Spiegelberg) and 9±8mm Hg (LiquoGuard), respectively, and accordingly the values measured with both devices correlated well (p=0.013; Pearson correlation=0.315). In two patients episodes of significant difference between the measured values could be observed, which were due to slit ventricles impeding reliable measurement with external transducers. A typical pattern of “jumping” ICP slope, claimed by the manufacturer to indicate slit ventricles, did not occur. The only hint at unreliable measurement was the loss of ICP pulse amplitude.

Conclusions: The LiquoGuard is a valuable new tool in intensive care medicine for reliable CSF drainage in EVD as long as there are no slit ventricles, because the typical drawbacks of ICP drainage in EVD controlled by hydrostatic pressure can be avoided. However, we recommend additional ICP measurement with tip-sensor devices to avoid dangerous misinterpretation. Even the loss of ICP pulse amplitude as a potential hint at unreliable data might be of no use for data validation in patients with large craniectomies.