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Prognostic value of near-infrared spectroscopy regional oxygen saturation and cerebrovascular reactivity index in acute traumatic neural injury: a CAnadian High-Resolution Traumatic Brain Injury (CAHR-TBI) Cohort Study.

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BACKGROUND: Near-infrared spectroscopy regional cerebral oxygen saturation (rSO2) has gained interest as a raw parameter and as a basis for measuring cerebrovascular reactivity (CVR) due to its noninvasive nature and high spatial resolution. However, the prognostic utility of these parameters has not yet been determined. This study aimed to identify threshold values of rSO2 and rSO2-based CVR at which outcomes worsened following traumatic brain injury (TBI). METHODS: A retrospective multi-institutional cohort study was performed. The cohort included TBI patients treated in four adult intensive care units (ICU). The cerebral oxygen indices, COx (using rSO2 and cerebral perfusion pressure) as well as COx_a (using rSO2 and arterial blood pressure) were calculated for each patient. Grand mean thresholds along with exposure-based thresholds were determined utilizing sequential chi-squared analysis and univariate logistic regression, respectively. RESULTS: In the cohort of 129 patients, there was no identifiable threshold for raw rSO2 at which outcomes were found to worsen. For both COx and COx_a, an optimal grand mean threshold value of 0.2 was identified for both survival and favorable outcomes, while percent time above - 0.05 was uniformly found to have the best discriminative value. CONCLUSIONS: In this multi-institutional cohort study, raw rSO2was found to contain no significant prognostic information. However, rSO2-based indices of CVR, COx and COx_a, were found to have a uniform grand mean threshold of 0.2 and exposure-based threshold of - 0.05, above which clinical outcomes markedly worsened. This study lays the groundwork to transition to less invasive means of continuously measuring CVR.


Acknowledgements: We would like to acknowledge the patients and staff of the Foothills Medical Centre, Health Sciences Centre Winnipeg, Maastricht University Medical Center and the Vancouver General Hospital, without which the data from this study would not be possible.

Funder: Canadian Institutes of Health Research; doi:

Funder: Natural Sciences and Engineering Research Council of Canada; doi:

Funder: Research Manitoba; doi:

Funder: The Brain Canada Thompkins Travel Scholarship

Funder: The Graduate Enhancement of Tri-Council Stipends (GETS) – University of Manitoba

Funder: Karolinska Institutet Funds

Funder: The Swedish Brain Foundation

Funder: The Swedish Society of Medicine

Funder: Region Stockholm ALF

Funder: Region Stockholm Clinical Research Appointment

Funder: The Swedish Cultural Foundation in Finland

Funder: Finska Läkaresällskapet; doi:

Funder: Helsinki university hospital state funded research grant

Funder: University of Manitoba R.G. and E.M. Graduate Fellowship (Doctoral) in Biomedical Engineering

Funder: University of Manitoba MD/PhD program

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

Funder: The MPI Neuroscience Research Operating Fund

Funder: The Health Sciences Centre Foundation Winnipeg

Funder: Canada Foundation for Innovation; doi:

Funder: University of Manitoba VPRI Research Investment Fund


Cerebrovascular reactivity, Multimodal monitoring, Near-infrared spectroscopy, Traumatic brain injury, Adult, Humans, Cohort Studies, Prognosis, Retrospective Studies, Spectroscopy, Near-Infrared, Oxygen Saturation, Canada, Brain Injuries, Traumatic

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Crit Care

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