gms | German Medical Science

70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

12.05. - 15.05.2019, Würzburg

Long pressure reactivity index (LPRX) predicts outcome in 205 patients with severe TBI

Nutzen des Long Pressure Reactivity Index (LPRx) zur Vorhersage des Outcomes bei 205 Patienten mit schwerem SHT

Meeting Abstract

  • presenting/speaker Alexander Younsi - Universitätsklinikum Heidelberg, Neurochirurgie, Heidelberg, Deutschland
  • Lennart Riemann - Universitätsklinikum Heidelberg, Neurochirurgie, Heidelberg, Deutschland
  • Manuel Cabeleira - University of Cambridge, Division of Neurosurgery, Cambridge, United Kingdom
  • Oliver Sakowitz - Neurochirurgie Zentrum Ludwigsburg-Heilbronn, Ludwigsburg, Deutschland
  • Andreas W. Unterberg - Universitätsklinikum Heidelberg, Neurochirurgie, Heidelberg, Deutschland

Deutsche Gesellschaft für Neurochirurgie. 70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie. Würzburg, 12.-15.05.2019. Düsseldorf: German Medical Science GMS Publishing House; 2019. DocV251

doi: 10.3205/19dgnc270, urn:nbn:de:0183-19dgnc2704

Published: May 8, 2019

© 2019 Younsi et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Objective: The pressure reactivity index (PRx) quantifies cerebrovascular pressure reactivity and shows good correlation with outcome after traumatic brain injury (TBI). A similar index of low-frequency pressure reactivity, the LPRx, has been introduced more recently. While PRx is calculated from a moving correlation coefficient between arterial blood pressure (ABP) and intracranial pressure (ICP) within a frequency of usually 0.003 Hz, LPRx uses longer 1-min ABP and ICP averages, is therefore much easier to obtain, but analyses much slower changes of cerebrovascular reactivity within a frequency of 0.0008 Hz. The aim of this study was to calculate PRx and LPRx from adult TBI patients in the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) high-resolution (HRICU) substudy and compare both indices for 6 months outcome prediction.

Methods: All HRICU patients in the CENTER-TBI database with continuous ICP/ABP monitoring were retrospectively screened and only cases with available GCS/GOSE values on admission/at 6 months follow-up were selected for further analysis. Demographic data was collected and ICM+ was used to calculate CPP, PRx and LPRx. The predictive power and discriminant abilities of both indices were compared using univariate analyses.

Results: A total of 205 eligible TBI patients were identified. Mean age at ICU admission was 50±18 years and the mean GCS score was 8±4. Continuous monitoring of ICP/ABP was performed for a median of 150 hrs (4–2230 hrs). At 6 months follow-up, 55 patients (27%) had died and 73 patients (36%) were severely disabled, 27% were moderately disabled and good recovery occured in 10% of cases. The PRx and L-PRx correlation was good (R=0.64, p<0.001; Spearman test). In univariate analysis, higher age (p<0.001) as well as lower PRx (p<0.001) and also LPRx values (p<0.001) were associated with fatal outcome (death) within 6 months after TBI. Interestingly, neither PRx nor LPRx showed a significant correlation with a better Quality of Life after Brain Injury (QoLIBRI) or Rivermead Post-Concussion Symptoms Questionnaire (RPQ) score at 6 months follow-up.

Conclusion: In this study, LPRx showed a good correlation with PRx. Both indices predicted fatal outcome within 6 months after TBI but did not correlate with other (functional) outcome parameters. Further analyses will have to assess the CPPopt values derived from PRx and LPRx and compare their use for outcome prediction.