Influence of mild-moderate hypocapnia on intracranial pressure slow waves activity in TBI
Authors
Czosnyka, Marek
Lalou, Afroditi D.
Zeiler, Frederick A.
Fedriga, Marta
Steiner, Luzius A.
Chieregato, Arturo
Smielewski, Peter
Publication Date
2019-12-16Journal Title
Acta Neurochirurgica
ISSN
0001-6268
Publisher
Springer Vienna
Volume
162
Issue
2
Pages
345-356
Language
en
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Beqiri, E., Czosnyka, M., Lalou, A. D., Zeiler, F. A., Fedriga, M., Steiner, L. A., Chieregato, A., & et al. (2019). Influence of mild-moderate hypocapnia on intracranial pressure slow waves activity in TBI. Acta Neurochirurgica, 162 (2), 345-356. https://doi.org/10.1007/s00701-019-04118-6
Description
Funder: University of Cambridge
Abstract
Abstract: Background: In traumatic brain injury (TBI) the patterns of intracranial pressure (ICP) waveforms may reflect pathological processes that ultimately lead to unfavorable outcome. In particular, ICP slow waves (sw) (0.005–0.05 Hz) magnitude and complexity have been shown to have positive association with favorable outcome. Mild-moderate hypocapnia is currently used for short periods to treat critical elevations in ICP. Our goals were to assess changes in the ICP sw activity occurring following sudden onset of mild-moderate hypocapnia and to examine the relationship between changes in ICP sw activity and other physiological variables during the hypocapnic challenge. Methods: ICP, arterial blood pressure (ABP), and bilateral middle cerebral artery blood flow velocity (FV), were prospectively collected in 29 adult severe TBI patients requiring ICP monitoring and mechanical ventilation in whom a minute volume ventilation increase (15–20% increase in respiratory minute volume) was performed as part of a clinical CO2-reactivity test. The time series were first treated using FFT filter (pass-band set to 0.005–0.05 Hz). Power spectral density analysis was performed. We calculated the following: mean value, standard deviation, variance and coefficient of variation in the time domain; total power and frequency centroid in the frequency domain; cerebrospinal compliance (Ci) and compensatory reserve index (RAP). Results: Hypocapnia led to a decrease in power and increase in frequency centroid and entropy of slow waves in ICP and FV (not ABP). In a multiple linear regression model, RAP at the baseline was the strongest predictor for the decrease in the power of ICP slow waves (p < 0.001). Conclusion: In severe TBI patients, a sudden mild-moderate hypocapnia induces a decrease in mean ICP and FV, but also in slow waves power of both signals. At the same time, it increases their higher frequency content and their morphological complexity. The difference in power of the ICP slow waves between the baseline and the hypocapnia period depends on the baseline cerebrospinal compensatory reserve as measured by RAP.
Keywords
Original Article - Brain trauma, Brain trauma, ICP slow waves, Hypocapnia, TBI, Cerebral autoregulation, Compensatory reserve, RAP
Identifiers
s00701-019-04118-6, 4118
External DOI: https://doi.org/10.1007/s00701-019-04118-6
This record's URL: https://www.repository.cam.ac.uk/handle/1810/315403
Rights
Licence:
http://creativecommons.org/licenses/by/4.0/