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Time spent above optimal cerebral perfusion pressure is not associated with failure to improve in outcome in traumatic brain injury.

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BACKGROUND: Optimal cerebral perfusion pressure (CPPopt) has emerged as a promising personalized medicine approach to the management of moderate-to-severe traumatic brain injury (TBI). Though literature demonstrating its association with poor outcomes exists, there is yet to be work done on its association with outcome transition due to a lack of serial outcome data analysis. In this study we investigate the association between various metrics of CPPopt and failure to improve in outcome over time. METHODS: CPPopt was derived using three different cerebrovascular reactivity indices; the pressure reactivity index (PRx), the pulse amplitude index (PAx), and the RAC index. For each index, % times spent with cerebral perfusion pressure (CPP) above and below its CPPopt and upper and lower limits of reactivity were calculated. Patients were dichotomized based on improvement in Glasgow Outcome Scale-Extended (GOSE) scores into Improved vs. Not Improved between 1 and 3 months, 3 and 6 months, and 1- and 6-month post-TBI. Logistic regression analyses were then conducted, adjusting for the International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) variables. RESULTS: This study included a total of 103 patients from the Winnipeg Acute TBI Database. Through Mann-Whitney U testing and logistic regression analysis, it was found that % time spent with CPP below CPPopt was associated with failure to improve in outcome, while % time spent with CPP above CPPopt was generally associated with improvement in outcome. CONCLUSIONS: Our study supports the existing narrative that time spent with CPP below CPPopt results in poorer outcomes. However, it also suggests that time spent above CPPopt may not be associated with worse outcomes and is possibly even associated with improvement in outcome.


Acknowledgements: Not applicable.

Funder: Manitoba Public Insurance (MPI) Chair in Neuroscience/TBI Research Endowment

Funder: Canadian Institutes of Health Research; doi:

Funder: MPI Neuroscience Research Operating Fund

Funder: Health Sciences Centre Foundation Winnipeg, the Canada Foundation for Innovation (CFI)

Funder: University of Manitoba VPRI Research Investment Fund (RIF)


CPPopt, Optimal cerebral perfusion pressure, Outcome transition, TBI, Traumatic brain injury

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Intensive Care Med Exp

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Springer Science and Business Media LLC
NSERC (DGECR-2022-00260, RGPIN-2022-03621, ALLRP-578524-22, ALLRP-576386-22, I2IPJ 586104–23, ALLRP 586244-23)
Research Manitoba (3906, 5429)