Repository logo
 

Observations on the Cerebral Effects of Refractory Intracranial Hypertension After Severe Traumatic Brain Injury.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Smielewski, Peter 
Adams, Hadie 
Zeiler, Frederick A  ORCID logo  https://orcid.org/0000-0003-1737-0510
Cardim, Danilo 

Abstract

BACKGROUND: Raised intracranial pressure (ICP) is a prominent cause of morbidity and mortality after severe traumatic brain injury (TBI). However, in the clinical setting, little is known about the cerebral physiological response to severe and prolonged increases in ICP. METHODS: Thirty-three severe TBI patients from a single center who developed severe refractory intracranial hypertension (ICP > 40 mm Hg for longer than 1 h) with ICP, arterial blood pressure, and brain tissue oxygenation (PBTO2) monitoring (subcohort, n = 9) were selected for retrospective review. Secondary parameters reflecting autoregulation (including pressure reactivity index-PRx, which was available in 24 cases), cerebrospinal compensatory reserve (RAP), and ICP pulse amplitude were calculated. RESULTS: PRx deteriorated from 0.06 ± 0.26 a.u. at baseline levels of ICP to 0.57 ± 0.24 a.u. (p < 0.0001) at high levels of ICP (> 50 mm Hg). In 4 cases, PRx was impaired (> 0.25 a.u.) before ICP was raised above 25 mm Hg. Concurrently, PBTO2 decreased from 27.3 ± 7.32 mm Hg at baseline ICP to 12.68 ± 7.09 mm Hg at high levels of ICP (p < 0.001). The pulse amplitude of the ICP waveform increased with increasing ICP but showed an 'upper breakpoint'-whereby further increases in ICP lead to decreases in pulse amplitude-in 6 out of the 33 patients. DISCUSSION: Severe intracranial hypertension after TBI leads to decreased brain oxygenation, impaired pressure reactivity, and changes in the pulse amplitude of ICP. Impaired pressure reactivity may denote increased risk of developing refractory intracranial hypertension in some patients.

Description

Keywords

Autoregulation, Cerebral hemodynamics, Cerebral oxygenation, Cerebral perfusion pressure, Intracranial hypertension, Intracranial pressure, Traumatic brain injury, Adolescent, Adult, Arterial Pressure, Brain, Brain Injuries, Traumatic, Cerebrovascular Circulation, Decompressive Craniectomy, Female, Glasgow Coma Scale, Homeostasis, Humans, Intracranial Hypertension, Male, Mortality, Oxygen, Retrospective Studies, Severity of Illness Index, Time Factors, Young Adult

Journal Title

Neurocrit Care

Conference Name

Journal ISSN

1541-6933
1556-0961

Volume Title

32

Publisher

Springer Science and Business Media LLC