Impact of duration and magnitude of raised intracranial pressure on outcome after severe traumatic brain injury: A CENTER-TBI high-resolution group study.


Type
Article
Change log
Authors
Åkerlund, Cecilia Ai  ORCID logo  https://orcid.org/0000-0003-4918-1482
Donnelly, Joseph 
Zeiler, Frederick A 
Helbok, Raimund 
Holst, Anders 
Abstract

Magnitude of intracranial pressure (ICP) elevations and their duration have been associated with worse outcomes in patients with traumatic brain injuries (TBI), however published thresholds for injury vary and uncertainty about these levels has received relatively little attention. In this study, we have analyzed high-resolution ICP monitoring data in 227 adult patients in the CENTER-TBI dataset. Our aim was to identify thresholds of ICP intensity and duration associated with worse outcome, and to evaluate the uncertainty in any such thresholds. We present ICP intensity and duration plots to visualize the relationship between ICP events and outcome. We also introduced a novel bootstrap technique to evaluate uncertainty of the equipoise line. We found that an intensity threshold of 18 ± 4 mmHg (2 standard deviations) was associated with worse outcomes in this cohort. In contrast, the uncertainty in what duration is associated with harm was larger, and safe durations were found to be population dependent. The pressure and time dose (PTD) was also calculated as area under the curve above thresholds of ICP. A relationship between PTD and mortality could be established, as well as for unfavourable outcome. This relationship remained valid for mortality but not unfavourable outcome after adjusting for IMPACT core variables and maximum therapy intensity level. Importantly, during periods of impaired autoregulation (defined as pressure reactivity index (PRx)>0.3) ICP events were associated with worse outcomes for nearly all durations and ICP levels in this cohort and there was a stronger relationship between outcome and PTD. Whilst caution should be exercised in ascribing causation in observational analyses, these results suggest intracranial hypertension is poorly tolerated in the presence of impaired autoregulation. ICP level guidelines may need to be revised in the future taking into account cerebrovascular autoregulation status considered jointly with ICP levels.

Description
Keywords
Adult, Blood Pressure, Brain Injuries, Traumatic, Cerebrovascular Circulation, Female, Hemorrhage, Humans, Intensive Care Units, Intracranial Hypertension, Intracranial Pressure, Middle Aged, Monitoring, Physiologic, Motor Activity
Journal Title
PLoS One
Conference Name
Journal ISSN
1932-6203
1932-6203
Volume Title
15
Publisher
Public Library of Science (PLoS)
Rights
All rights reserved
Sponsorship
European Commission (602150)