Abstract
Introduction: Since its introduction into clinical practice, the Bowman Hemedex® regional cerebral blood flow (CBF) monitor has provided a valuable tool for the bedside assessment of CBF in neurointensive care. The purpose of our study was to estimate the accuracy of CBF measurements between automatically performed self-calibration cycles at regular intervals.
Methods: We analyzed data from 75 CBF probes, predominantly implanted into patients after severe subarachnoid hemorrhage. Automatic recalibration of the regional CBF device was performed every 30 min. CBF data were averaged once per minute and the measurement cycles pooled. Statistical analysis was performed with generalized additive modeling and bootstrapping methods.
Results: Mean regional CBF was 24 mL/100 g/min after calibration and showed a mean drift of 2.3 mL/100 g/min per measurement cycle (p < 0.001). In every patient, the drift over the measurement cycle followed an exponential trend, with large heterogeneity between patients (−3.67 to 12.0 mL/100 g/min). A highly significant difference in drift was found for the internal software versions of the monitoring devices (p < 0.001).
Conclusions: Data from the Bowman Hemedex® regional CBF monitor shows an upward measurement drift of clinically relevant magnitude. As the drift follows a stable exponential function over time, recalculation of drift-corrected data is possible after termination of the measurement.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Vajkoczy P, Roth H, Horn P, Lucke T, Thomé C, Hubner U et al (2000) Continuous monitoring of regional cerebral blood flow: experimental and clinical validation of a novel thermal diffusion microprobe. J Neurosurg 93(2):265–274
Vajkoczy P, Horn P, Thome C, Munch E, Schmiedek P (2003) Regional cerebral blood flow monitoring in the diagnosis of delayed ischemia following aneurysmal subarachnoid hemorrhage. J Neurosurg 98(6):1227–1234
Muench E, Horn P, Bauhuf C, Roth H, Philipps M, Hermann P et al (2007) Effects of hypervolemia and hypertension on regional cerebral blood flow, intracranial pressure, and brain tissue oxygenation after subarachnoid hemorrhage. Crit Care Med 35(8):1844–1851
Wolf S, Martin H, Landscheidt JF, Rodiek SO, Schürer L, Lumenta CB (2010) Continuous selective intraarterial infusion of nimodipine for therapy of refractory cerebral vasospasm. Neurocrit Care 12(3):346–351
R Development Core Team (2010) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL: http://www.R-project.org/
Wood SN (2006) Generalized additive models: an introduction with R. Chapman & Hall, Boca Raton
Davison AC, Hinkley D (1997) Bootstrap methods and their application. Cambridge University Press, New York
Critchley LA, Critchley JA (1999) A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques. J Clin Monit Comput 15(2):85–91
Acknowledgement
The authors are indebted to Prof. Dr. Friedrich Leisch, Department of Statistics, Ludwig-Maximilians-University, Munich, Germany, for statistical consultation and advice.
Conflict of interest statement
We declare that we have no conflict of interest.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2012 Springer-Verlag/Wien
About this chapter
Cite this chapter
Wolf, S., Vajkoczy, P., Dengler, J., Schürer, L., Horn, P. (2012). Drift of the Bowman Hemedex® Cerebral Blood Flow Monitor Between Calibration Cycles. In: Schuhmann, M., Czosnyka, M. (eds) Intracranial Pressure and Brain Monitoring XIV. Acta Neurochirurgica Supplementum, vol 114. Springer, Vienna. https://doi.org/10.1007/978-3-7091-0956-4_36
Download citation
DOI: https://doi.org/10.1007/978-3-7091-0956-4_36
Published:
Publisher Name: Springer, Vienna
Print ISBN: 978-3-7091-0955-7
Online ISBN: 978-3-7091-0956-4
eBook Packages: MedicineMedicine (R0)