Validation of Pressure Reactivity and Pulse Amplitude Indices against the Lower Limit of Autoregulation, Part I: Experimental Intracranial Hypertension.
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Authors
Lee, Jennifer K
Brady, Ken
Kim, Dong-Joo
Publication Date
2018-12-01Journal Title
J Neurotrauma
ISSN
0897-7151
Publisher
Mary Ann Liebert Inc
Volume
35
Issue
23
Pages
2803-2811
Language
eng
Type
Article
Physical Medium
Print-Electronic
Metadata
Show full item recordCitation
Zeiler, F., Donnelly, J., Calviello, L., Lee, J. K., Smielewski, P., Brady, K., Kim, D., & et al. (2018). Validation of Pressure Reactivity and Pulse Amplitude Indices against the Lower Limit of Autoregulation, Part I: Experimental Intracranial Hypertension.. J Neurotrauma, 35 (23), 2803-2811. https://doi.org/10.1089/neu.2017.5603
Abstract
The purpose of this study was to provide validation of intracranial pressure (ICP) derived continuous indices of cerebrovascular reactivity against the lower limit of autoregulation (LLA). Utilizing an intracranial hypertension model within white New Zealand rabbits, ICP, transcranial Doppler (TCD), laser Doppler flowmetry (LDF), and arterial blood pressure were recorded. Data were retrospectively analyzed in a cohort of 12 rabbits with adequate signals for interrogating the LLA. We derived continuous indices of cerebrovascular reactivity: PRx (correlation between ICP and mean arterial pressure [MAP]), PAx (correlation between pulse amplitude of ICP [AMP] and MAP), and Lx (correlation between LDF-based cerebral blood flow [CBF] and cerebral perfusion pressure [CPP]). LLA was derived via piecewise linear regression of CPP versus LDF or CPP versus systolic flow velocity (FVs) plots. We then produced error bar plots for PRx, PAx, and Lx against 2.5 mm Hg bins of CPP, to display the relationship between these indices and the LLA. We compared the CPP values at clinically relevant thresholds of PRx and PAx, to the CPP defined at the LLA. Receiver operating curve (ROC) analysis was performed for each index across the LLA using 2.5 mm Hg bins for CPP. The mean LLA was 51.5 ± 8.2 mm Hg. PRx and PAx error bar plots demonstrate that each index correlates with the LLA, becoming progressively more positive below the LLA. Similarly, CPP values at clinically relevant thresholds of PRx and PAx were not statistically different from the CPP derived at the LLA. Finally, ROC analysis indicated that PRx and PAx predicted the LAA, with areas under the curve (AUCs) of 0.795 (95% confidence interval [CI]: 0.731-0.857, p < 0.0001) and 0.703 (95% CI: 0.631-0.775, p < 0.0001), respectively. Both PRx and PAx generally agree with LLA within this experimental model of intracranial hypertension. Further analysis of clinically used indices of autoregulation across the LLA within pure arterial hypotension models is required.
Keywords
Animals, Rabbits, Intracranial Hypertension, Homeostasis, Cerebrovascular Circulation, Intracranial Pressure, Female, Male, Arterial Pressure
Identifiers
External DOI: https://doi.org/10.1089/neu.2017.5603
This record's URL: https://www.repository.cam.ac.uk/handle/1810/284127
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