Clinical trial NCT00641563: Effects of Two Different Sedation Regimes on Auditory Evoked Potentials and Electroencephalogram (EEG)
Official title: The Effects of Dexmedetomidine/Remifentanil and Midazolam/Remifentanil on Auditory-evoked Potentials and Electroencephalogram at Light-to-moderate Sedation Levels in Healthy Subjects
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Conscious Sedation
Deep Sedation
Critical Care
Keywords: dexmedetomidine
midazolam
remifentanil
Electroencephalography
Event related potentials
BIS
Bispectral Index
Response Entropy
State Entropy
Lead sponsor: Insel Gruppe AG, University Hospital Bern
Sponsor class: OTHER
Collaborators: name: GE Healthcare
First posted: 2008-03-24
Enrollment: 10
Sex: MALE
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: Sedation may be necessary in intensive care to facilitate diverse therapeutic interventions, but the use of sedative drugs may increase the risk of delirium and long-term cognitive impairment. Thus the implementation and monitoring of sedation remains difficult despite the use of sedation protocols and clinical sedation scores. Attempts to improve sedation monitoring through the use of the electroencephalogram(EEG) have been disappointing. Derived variables based on the unstimulated EEG fail to predict the response to external stimuli at the clinically most relevant light-to-moderate sedation levels, and the overlap between moderate and deep sedation levels is wide. We have demonstrated that long-latency auditory evoked potentials (ERPs)can be used to avoid deep levels of sedation in healthy volunteers during propofol sedation, independent of the concomitant administration of remifentanil. This approach has a potential clinical application for improved monitoring of sedation. Since the effects of different sedative drugs on the EEG may vary widely, the use of ERPs to monitor sedation needs to be evaluated with different sedative drugs. Therefore we will administer two widely used drug combinations (dexmedetomidine/remifentanil and midazolam/remifentanil) in healthy volunteers and record ERPS and processed EEG during clinical relevant sedation levels

Detailed description: Sedation may be necessary in intensive care to facilitate diverse therapeutic interventions, but the use of sedative drugs may increase the risk of delirium and long-term cognitive impairment. Thus the implementation and monitoring of sedation remains difficult despite the use of sedation protocols and clinical sedation scores. Attempts to improve sedation monitoring through the use of the electroencephalogram (EEG) have been disappointing. Derived variables based on the unstimulated EEG fail to predict the response to external stimuli at the clinically most relevant light-to-moderate sedation levels, and the overlap between moderate and deep sedation levels is wide. We have demonstrated that long-latency auditory evoked potentials (ERPs)can be used to avoid deep levels of sedation in healthy volunteers during propofol sedation, independent of the concomitant administration of remifentanil. This approach has a potential clinical application for improved monitoring of sedation. Since the effects of different sedative drugs on the EEG may vary widely, the use of ERPs to monitor sedation needs to be evaluated with different sedative drugs. The alpha-2 agonist dexmedetomidine (dex) has been approved for short-term sedation in surgical intensive care unit (ICU) patients. Preliminary data suggest that the risk of delirium may be substantially reduced when dexmedetomidine is used to produce sedation. Since dexmedetomidine acts via different receptors and brain areas than do benzodiazepines and propofol, its impact on the brain electrophysiology may also be different. The assessment of dexmedetomidine's effects on the EEG and ERPs at various sedation levels has been limited in humans. We hypothesized that the combinations DEXMEDETOMIDINE/REMIFANTANIL (dex/remi) and MIDAZOLAM/REMIFENTANIL (mida/remi) would induce the same changes in EEG and long-latency ERPs during light-to-moderate levels of sedation in healthy subjects, despite the different quality of sedation that they provide. The opioid remifentanil was added because virtually all patients in the ICU have some level of pain and receive an opioid analgesic in combination with a sedative. 10 healthy subjects were assessed with both drug combinations (dex/remi and mida/remi), at least 7 days apart. The sequence of the drug combinations were randomized.

Eligibility criteria: Inclusion Criteria:

* age 18 years and older
* healthy

Exclusion Criteria:

* History of problems during anesthesia
* Impairment of the auditory system

Primary outcomes:
measure: Amplitudes (in Micro Volts) of Acoustic Event Related Potentials (Time-locked Amplitudes in the Electroencephalogram 100 Milliseconds After the Acoustic Stimulus, Averaged Over 40 Stimuli)Awake and at 3 Different Drug-induced Sedation Levels
timeFrame: awake + 3 sedation levels (RS2/3/4) (20 minutes each)
Secondary outcomes:
measure: BIS-Index Awake and 3 Sedation Levels (RS 2/3/4)
timeFrame: awake and 3 sedation levels (RS 2/3/4) 20 min each
Other outcomes:
Locations:
city: Bern
country: Switzerland
facility: Departement of Intensive Care Medicine - University Hospital Bern - Inselspital
Study officials:
affiliation: University of Bern
name: Matthias Haenggi, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Haenggi M, Ypparila H, Takala J, Korhonen I, Luginbuhl M, Petersen-Felix S, Jakob SM. Measuring depth of sedation with auditory evoked potentials during controlled infusion of propofol and remifentanil in healthy volunteers. Anesth Analg. 2004 Dec;99(6):1728-1736. doi: 10.1213/01.ANE.0000135634.46493.0A.
citation: Haenggi M, Ypparila H, Hauser K, Caviezel C, Korhonen I, Takala J, Jakob SM. The effects of dexmedetomidine/remifentanil and midazolam/remifentanil on auditory-evoked potentials and electroencephalogram at light-to-moderate sedation levels in healthy subjects. Anesth Analg. 2006 Nov;103(5):1163-9. doi: 10.1213/01.ane.0000237394.21087.85.
citation: Haenggi M, Ypparila-Wolters H, Hauser K, Caviezel C, Takala J, Korhonen I, Jakob SM. Intra- and inter-individual variation of BIS-index and Entropy during controlled sedation with midazolam/remifentanil and dexmedetomidine/remifentanil in healthy volunteers: an interventional study. Crit Care. 2009;13(1):R20. doi: 10.1186/cc7723. Epub 2009 Feb 19.