Cerebrovascular pressure reactivity and brain tissue oxygen monitoring provide complementary information regarding the lower and upper limits of cerebral blood flow control in traumatic brain injury: a CAnadian High Resolution-TBI (CAHR-TBI) cohort study.

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Sekhon, Mypinder 
Griesdale, Donald 
Froese, Logan 
Yang, Eleen 

BACKGROUND: Brain tissue oxygen tension (PbtO2) and cerebrovascular pressure reactivity monitoring have emerged as potential modalities to individualize care in moderate and severe traumatic brain injury (TBI). The relationship between these modalities has had limited exploration. The aim of this study was to examine the relationship between PbtO2 and cerebral perfusion pressure (CPP) and how this relationship is modified by the state of cerebrovascular pressure reactivity. METHODS: A retrospective multi-institution cohort study utilizing prospectively collected high-resolution physiologic data from the CAnadian High Resolution-TBI (CAHR-TBI) Research Collaborative database collected between 2011 and 2021 was performed. Included in the study were critically ill TBI patients with intracranial pressure (ICP), arterial blood pressure (ABP), and PbtO2 monitoring treated in any one of three CAHR-TBI affiliated adult intensive care units (ICU). The outcome of interest was how PbtO2 and CPP are related over a cohort of TBI patients and how this relationship is modified by the state of cerebrovascular reactivity, as determined using the pressure reactivity index (PRx). RESULTS: A total of 77 patients met the study inclusion criteria with a total of 377,744 min of physiologic data available for the analysis. PbtO2 produced a triphasic curve when plotted against CPP like previous population-based plots of cerebral blood flow (CBF) versus CPP. The triphasic curve included a plateau region flanked by regions of relative ischemia (hypoxia) and hyperemia (hyperoxia). The plateau region shortened when cerebrovascular pressure reactivity was disrupted compared to when it was intact. CONCLUSIONS: In this exploratory analysis of a multi-institution high-resolution physiology TBI database, PbtO2 seems to have a triphasic relationship with CPP, over the entire cohort. The CPP range over which the plateau exists is modified by the state of cerebrovascular reactivity. This indicates that in critically ill TBI patients admitted to ICU, PbtO2 may be reflective of CBF.


Funder: Canadian Institutes of Health Research; doi: http://dx.doi.org/10.13039/501100000024

Funder: Manitoba Public Insurance (MPI) Neuroscience Research Operating Fund

Funder: Health Sciences Centre Foundation Winnipeg

Funder: Canada Foundation for Innovation; doi: http://dx.doi.org/10.13039/501100000196; Grant(s): Project #: 38583

Funder: Research Manitoba; doi: http://dx.doi.org/10.13039/100008794; Grant(s): Grant #: 3906

Funder: University of Manitoba VPRI Research Investment Fund

Funder: University of Manitoba MPI Professorship in Neuroscience

Funder: University of Manitoba Dean’s Fellowship

Funder: Manitoba Medical Service Foundation; doi: http://dx.doi.org/10.13039/100008795

Funder: R. Samuel McLaughlin Research Fellowship

Funder: Institute of Neurosciences, Mental Health and Addiction; doi: http://dx.doi.org/10.13039/501100000034; Grant(s): Grant #: 472286

Funder: University of Manitoba - Biomedical Engineering (BME) Fellowship Grant

Funder: University of Manitoba Graduate Enhancement of Tri-Agency Stipend

Funder: Strategic Research Area Neuroscience (StratNeuro, Karolinska Institutet

Funder: Svenska Kulturfonden, Medicinska Understödsföreningen Liv & Hälsa

Funder: Finska Läkaresällskapet; doi: http://dx.doi.org/10.13039/100010135

Research Articles, Traumatic brain injury, Brain tissue oxygen tension, Cerebrovascular reactivity, Multi-modal monitoring, Cerebrovascular physiology
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Intensive Care Med Exp
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Springer Science and Business Media LLC
Natural Sciences and Engineering Research Council of Canada (DGECR-2022-00260, RGPIN-2022-03621, ALLRP-576386-22, ALLRP-576386-22)
The Erling-Persson Family Foundation and Region Stockholm Clinical Research Appointment (FoUI-955376)