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The Neurological Wake-up Test in Neurocritical Care
Uppsala University, Disciplinary Domain of Medicine and Pharmacy. (Enh. för neurokirurgi)
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. , p. 70
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 777
Keyword [en]
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: urn:nbn:se:uu:diva-172798ISBN: 978-91-554-8374-6 (print)OAI: oai:DiVA.org:uu-172798DiVA: diva2:516942
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
List of papers
1. Effects of the neurological wake-up test on intracranial pressure and cerebral perfusion pressure in brain-injured patients
Open this publication in new window or tab >>Effects of the neurological wake-up test on intracranial pressure and cerebral perfusion pressure in brain-injured patients
2009 (English)In: Neurocritical care, ISSN 1541-6933, Vol. 11, no 2, p. 135-142Article 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.

Keyword
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:nbn:se:uu:diva-110758 (URN)10.1007/s12028-009-9255-3 (DOI)000269902300002 ()19644774 (PubMedID)
Available from: 2009-11-24 Created: 2009-11-24 Last updated: 2012-08-01Bibliographically approved
2. The neurological wake-up test increases stress hormone levels in patients with severe traumatic brain injury
Open this publication in new window or tab >>The neurological wake-up test increases stress hormone levels in patients with severe traumatic brain injury
2012 (English)In: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 40, no 1, p. 216-222Article in journal (Refereed) Published
Abstract [en]

Objectives: The "neurological wake-up test" is needed to evaluate the level of consciousness in patients with severe traumatic brain injury. However, the neurological wake-up test requires interruption of continuous sedation and may induce a stress response and its use in neurocritical care is controversial. We hypothesized that the neurological wake-up test induces an additional biochemical stress response in patients with severe traumatic brain injury.

Patients: Twenty-four patients who received continuous propofol sedation and mechanical ventilation after moderate to severe traumatic brain injury (Glasgow Coma Scale score <= 8; patient age 18-71 yrs old) were analyzed. Exclusion criteria were age <18 yrs old, ongoing pentobarbital infusion, or markedly increased intracranial pressure on interruption of continuous sedation.

Design: Single-center prospective study. During postinjury days 1-8, 65 neurological wake-up tests were evaluated. Adrenocorticotrophic hormone, epinephrine, and norepinephrine levels in plasma and cortisol levels in saliva were analyzed at baseline (during continuous intravenous propofol sedation) and during neurological wake-up test. Data are presented using medians and 25th and 75th percentiles.

Setting: The study was performed in a university hospital neurocritical care unit.

Interventions: None.

Measurements and Main Results: At baseline, adrenocorticotrophic hormone and cortisol levels were 10.6 (6.0-19.4) ng/L and 16.0 (10.7-31.8) nmol/L, respectively. Immediately after the neurological wake-up test, adrenocorticotrophic hormone levels increased to 20.5 (11.1-48.4) ng/L (p < .05) and cortisol levels in saliva increased to 24.0 (12.3-42.5) nmol/L (p < .05). The plasma epinephrine and norepinephrine levels increased from a baseline of 0.3 (0.3-0.6) and 1.6 (0.9-2.3) nmol/L, respectively, to 0.75 (0.3-1.4) and 2.8 (1.28-3.58) nmol/L, respectively (both p < .05).

Conclusions: The neurological wake-up test induces a biochemical stress response in patients with severe traumatic brain injury. The clinical importance of this stress response remains to be established but should be considered when deciding the frequency and use of the neurological wake-up test during neurocritical care.

Keyword
ACTH, catecholamines, cerebral perfusion pressure (CPP), cortisol, epinephrine, intracranial pressure (ICP), neurological wake-up test, norepinephrine, propofol, sedation
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-168113 (URN)10.1097/CCM.0b013e31822d7dbd (DOI)000298379800031 ()
Available from: 2012-02-07 Created: 2012-02-06 Last updated: 2017-12-08Bibliographically approved
3. Monitoring and sedation differences in the management of severe head injury and subarachnoid hemorrhage among neurocritical care centers.
Open this publication in new window or tab >>Monitoring and sedation differences in the management of severe head injury and subarachnoid hemorrhage among neurocritical care centers.
(English)Article in journal (Refereed) Submitted
Keyword
wake-up test, sedation, monitoring, traumatic brain injury, subarachnoid haemorrhage
National Category
Clinical Medicine
Identifiers
urn:nbn:se:uu:diva-173428 (URN)
Available from: 2012-04-24 Created: 2012-04-24 Last updated: 2012-08-01Bibliographically approved
4. The neurological wake-up test does not negatively influence brain oxygentaion and interstitial markers of cerebral energy metabolism in patients with severe traumatic brain injury
Open this publication in new window or tab >>The neurological wake-up test does not negatively influence brain oxygentaion and interstitial markers of cerebral energy metabolism in patients with severe traumatic brain injury
Show others...
(English)Manuscript (preprint) (Other academic)
Keyword
Traumatic brain injury, intracerebral microdialysis, brain tissue oxygenation, jugular venous oxygenation, neurological wake up test
National Category
Clinical Medicine
Identifiers
urn:nbn:se:uu:diva-173430 (URN)
Available from: 2012-04-24 Created: 2012-04-24 Last updated: 2012-11-14

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