title: Patient-Specific Thresholds and Doses of Intracranial Hypertension in Severe Traumatic Brain Injury.
abstract: Based on continuous monitoring of the pressure reactivity index (PRx), we defined individualized intracranial pressure (ICP) thresholds by graphing the relationship between ICP and PRx. We hypothesized that an "ICP dose" based on individually assessed ICP thresholds might correlate more closely with 6-month outcome compared with ICP doses derived from the recommended universal thresholds of 20 and 25 mmHg. Data from 327 patients with severe traumatic brain injury (TBI) were analyzed. ICP doses were computed as the cumulative area under the curve above the defined thresholds in graphing ICP versus time. The term Dose 20 (D20) was used to refer to an ICP threshold of 20 mm Hg. The markers D25 and DPRx were calculated similarly. The discriminative ability of each dose with regard to mortality was assessed by receiver operating characteristics analysis using fivefold cross-validation (CV). DPRx was found to be the best discriminator of mortality, despite the fact that D20 was twice as large as DPRx. Individualized doses of intracranial hypertension were stronger predictors of mortality than doses derived from the universal thresholds of 20 and 25 mm Hg. The PRx could offer a method of individualizing the ICP threshold.
authors.affiliation: Divisions of Neurocritical Care and Vascular Neurology, Department of Neurology, Baylor College of Medicine, 6501 Fannin Street, MS: NB320, Houston, TX, 77030, USA. lazaridi@bcm.edu.|Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, UK. lazaridi@bcm.edu.
authors.forename: Christos
authors.initials: C
authors.lastname: Lazaridis
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Smielewski
authors.affiliation: University Department of Anaesthesia, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK.
authors.forename: David K
authors.initials: DK
authors.lastname: Menon
authors.affiliation: Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Hutchinson
authors.affiliation: Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, UK.
authors.forename: John D
authors.initials: JD
authors.lastname: Pickard
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
mesh_terms: D019540:Area Under Curve; D000070642:Brain Injuries, Traumatic / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D023261:Glasgow Outcome Scale; D006801:Humans; D019586:Intracranial Hypertension / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*; D016015:Logistic Models; D008991:Monitoring, Physiologic; D057285:Precision Medicine; D011379:Prognosis; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015599:Trauma Severity Indices
keywords: Cerebrovascular pressure reactivity; Clinical outcome; Intracranial pressure; Neuromonitoring; Traumatic brain injury