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Effects of the neurological wake-up test on intracranial pressure and cerebral perfusion pressure in brain-injured patients
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
2009 (English)In: Neurocritical care, ISSN 1541-6933, Vol. 11, no 2, 135-142 p.Article in journal (Refereed) Published
Abstract [en]

OBJECTIVE: To evaluate the effects of the neurological "wake-up test" (NWT), defined as interruption of continuous propofol sedation and evaluation of the patient's level of consciousness, on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in patients with severe subarachnoid hemorrhage (SAH) or traumatic brain injury (TBI). METHODS: A total of 127 NWT procedures in 21 severely brain-injured adult patients with either TBI (n = 12) or SAH (n = 9) were evaluated. ICP and CPP levels prior to, during and after the NWT procedure were recorded. RESULTS: During the NWT, ICP increased from 13.4 +/- 6 mmHg at baseline to 22.7 +/- 12 (P < 0.05) and the CPP increased from 75.6 +/- 11 to 79.1 +/- 21 mmHg (P < 0.05) in TBI patients. Eight patients showed a reduced CPP during the NWT due to increased ICP. In SAH patients, ICP increased from 10.6 +/- 5 to 16.8 +/- 8 mmHg (P < 0.05) and the CPP increased from 76.9 +/- 13 to 84.6 +/- 15 mmHg (P < 0.05). CONCLUSION: When continuous propofol sedation was interrupted and NWT was performed in severely brain-injured patients, the mean ICP and CPP levels were modestly increased. A subset of patients showed more pronounced changes. To date, the role of the NWT in the neurointensive care of TBI and SAH patients is unclear. Although the NWT is safe in the majority of patients and may provide useful clinical information about the patient's level of consciousness, alternate monitoring methods are suggested in patients showing marked ICP and/or CPP changes during NWT.

Place, publisher, year, edition, pages
2009. Vol. 11, no 2, 135-142 p.
Keyword [en]
Intracranial pressure, Cerebral perfusion pressure, Sedation, Propofol, Wake-up test, Neurological examination, Reaction Level Scale, Glasgow Coma Scale
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:uu:diva-110758DOI: 10.1007/s12028-009-9255-3ISI: 000269902300002PubMedID: 19644774OAI: oai:DiVA.org:uu-110758DiVA: diva2:278201
Available from: 2009-11-24 Created: 2009-11-24 Last updated: 2012-08-01Bibliographically approved
In thesis
1. The Neurological Wake-up Test in Neurocritical Care
Open this publication in new window or tab >>The Neurological Wake-up Test in Neurocritical Care
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The neurological wake-up test, NWT, is a clinical monitoring tool that can be used to evaluate the level of consciousness in patients with traumatic brain injury (TBI) and subarachnoid haemorrhage (SAH) during neurocritical care (NCC). Since patients with severe TBI or SAH are often treated with mechanical ventilation and sedation, the NWT requires that the continuous sedation is interrupted. However, interruption of continuous sedation may induce a stress response and the use of the NWT in NCC is controversial.

The effects of the NWT on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were evaluated in 21 patients with TBI or SAH. Compared to baseline when the patients were sedated with continuous propofol sedation, the NWT resulted in increased ICP and CPP (p<0.05). Next, the effects of the NWT on the stress hormones adrenocorticotrophic hormone (ACTH), cortisol, epinephrine and norepinephrine were evaluated in 24 patients. Compared to baseline, the NWT caused a mild stress response resulting in increased levels of all evaluated stress hormones (p<0.05). To compare the use of routine NCC monitoring tools, the choice of sedation and analgesia and the frequency of NWT in Scandinavian NCC units, a questionnaire was used. The results showed that all 16 Scandinavian NCC units routinely use ICP and CPP monitoring and propofol and midazolam were primary choices for patient sedation in an equal number of NCC units. In 2009, the NWT was not routinely used in eight NCC units whereas others used the test up to six times daily.

Finally, intracerebral microdialysis (MD), brain tissue oxygenation (PbtiO2) and jugular bulb oxygenation (SjvO2) were used in 17 TBI patients to evaluate the effect of the NWT procedure on focal neurochemistry and cerebral oxygenation. The NWT did not negatively alter interstitial markers of energy metabolism or cerebral oxygenation.

In conclusion, the NWT induced a mild stress response in patients with TBI or SAH that did not result in a detectable, significant secondary insult to the injured brain. These results suggest that the NWT may safely be used as a clinical monitoring tool in the NCC of severe TBI and SAH in a majority of patients.

 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 70 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 777
Keyword
Intracranial pressure, Cerebral perfusion pressure, Propofol sedation, Wake-up test, stress hormones; intracerebral microdialysis, brain tissue oxygenation, jugular venous oxygenation
National Category
Medical and Health Sciences
Research subject
Neurosurgery
Identifiers
urn:nbn:se:uu:diva-172798 (URN)978-91-554-8374-6 (ISBN)
Public defence
2012-05-31, Robergsalen, ing 40, vån 4, Akademiska sjukhuset, Uppsala, 09:15 (Swedish)
Opponent
Supervisors
Available from: 2012-05-09 Created: 2012-04-16 Last updated: 2012-08-01Bibliographically approved

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