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Characterising the dynamics of cerebral metabolic dysfunction following traumatic brain injury: A microdialysis study in 619 patients.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Guilfoyle, Mathew R 
Helmy, Adel 
Donnelly, Joseph 
Stovell, Matthew G 
Timofeev, Ivan 

Abstract

Traumatic brain injury (TBI) is a major cause of death and disability, particularly amongst young people. Current intensive care management of TBI patients is targeted at maintaining normal brain physiology and preventing secondary injury. Microdialysis is an invasive monitor that permits real-time assessment of derangements in cerebral metabolism and responses to treatment. We examined the prognostic value of microdialysis parameters, and the inter-relationships with other neuromonitoring modalities to identify interventions that improve metabolism. This was an analysis of prospective data in 619 adult TBI patients requiring intensive care treatment and invasive neuromonitoring at a tertiary UK neurosciences unit. Patients had continuous measurement of intracranial pressure (ICP), arterial blood pressure (ABP), brain tissue oxygenation (PbtO2), and cerebral metabolism and were managed according to a standardized therapeutic protocol. Microdialysate was assayed hourly for metabolites including glucose, pyruvate, and lactate. Cerebral perfusion pressure (CPP) and cerebral autoregulation (PRx) were derived from the ICP and ABP. Outcome was assessed with the Glasgow Outcome Score (GOS) at 6 months. Relationships between monitoring variables was examined with generalized additive mixed models (GAMM). Lactate/Pyruvate Ratio (LPR) over the first 3 to 7 days following injury was elevated amongst patients with poor outcome and was an independent predictor of ordinal GOS (p<0.05). Significant non-linear associations were observed between LPR and cerebral glucose, CPP, and PRx (p<0.001 to p<0.05). GAMM models suggested improved cerebral metabolism (i.e. reduced LPR with CPP >70mmHg, PRx <0.1, PbtO2 >18mmHg, and brain glucose >1mM. Deranged cerebral metabolism is an important determinant of patient outcome following TBI. Variations in cerebral perfusion, oxygenation and glucose supply are associated with changes in cerebral LPR and suggest therapeutic interventions to improve cerebral metabolism. Future prospective studies are required to determine the efficacy of these strategies.

Description

Funder: National Institute for Health Research (NIHR)

Keywords

Adult, Arterial Pressure, Brain, Brain Injuries, Traumatic, Female, Glasgow Coma Scale, Glucose, Humans, Intracranial Pressure, Lactic Acid, Male, Microdialysis, Middle Aged, Oxygen Saturation, Pyruvic Acid, Young Adult

Journal Title

PLoS One

Conference Name

Journal ISSN

1932-6203
1932-6203

Volume Title

16

Publisher

Public Library of Science (PLoS)
Sponsorship
Medical Research Council (G1002277)
Royal College of Surgeons of England (2016/2017)
Evelyn Trust (21/29)
Medical Research Council (G0802251)
Medical Research Council (G0600986)
Medical Research Council (G9439390)
TCC (None)
Medical Research Council (G0600986/1)
Medical Research Council (G0802251/1)
Medical Research Council (G1002277/1)