Postoperative ComplicationsNCT04529304
EEG-based Depth of Anesthesia-monitoring, Effects on Dosage and Cognition
A study testing Bilateral Bispectral Index and EEG in people with Postoperative Complications and Delayed Emergence From Anesthesia, run by Oslo University Hospital at 1 site in Norway.
Trial summary
Depth of anesthesia-monitoring based on EEG changes demands knowledge about the effects of the different anesthetic medications on EEG waveforms. The investigators want to investigate the use of the raw-EEG waveform in addition to indexes (BIS) and EEG spectrogram analyses for depth of anesthesia monitoring. Read more about this study
- Who is it for?
- Ages 18 to 85 years
- Conditions the study is for
- Postoperative Complications, Delayed Emergence From Anesthesia, Cognitive Dysfunction
- What is being tested?
- Bilateral Bispectral Index and EEG
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteNorway
- Study dates
- 8 Jan 2021to 13 Mar 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 85 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- .
- Participants are eligible to be included in the study only if all of the following criteria apply:
- Age
- Participant must be above the age of 18 years , at the time of signing the informed consent.
- Sex
- Male and/or female
- Informed Consent
- Capable of giving signed informed consent as described in protocol which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol
Who cannot join
- Participants are excluded from the study if any of the following criteria apply:
- Psychiatric disorders
- Pregnancy
- Breast feeding
- Using antiepileptic drugs.
- Central neurological disease
- Unable to complete baseline CANTAB-test.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: EEG-based Depth of Anesthesia-monitoring During General Anesthesia - Effects on Time to Wake-up and Post-operative Cognition
Depth of anesthesia-monitoring based on EEG changes demands knowledge about the effects of the different anesthetic medications on EEG waveforms. The investigators want to investigate the use of the raw-EEG waveform in addition to indexes (BIS) and EEG spectrogram analyses for depth of anesthesia monitoring. The investigators hypothesize that with the use of this monitoring, anaesthesia providers will be able to better individualize the dosage of anesthetic drugs, and that this will reduce the total consumption of anesthetic medication , thus reducing time to wake-up after surgery. Some studies have indicated that too deep anesthesia, confirmed by "burst-suppression" or isoelectric-EEG , is associated with increased postoperative cognitive dysfunction (POCD). The investigators will therefore assess the patients with the Cambridge Neuropsychological Test Automated Battery tests in mild cognitive impairment (CANTAB-MCI) cognitive function assessment tool.
Read the detailed description
It has been over 80 years since Gibbs et al showed how the electroencephalogram (EEG) systematically changed in concurrence with increasing doses of hypnotic drugs such as penthobarbital and Ether. The study concluded that "Electroencephalography may therefore be of value in controlling depth of anesthesia and sedation". In spite of a solid documentation of the systematic connection between dosing of anesthetic drugs, EEG-patterns and level of sedation/anesthesia , EEG-based DoA has not become a part of standard of care in anesthetic management. There is abundant evidence of how different anesthetic drugs leads to characteristic fluctuations in human brain electrical activity, relating to depth of anesthesia, anesthetic drug of choice, and age . These anesthetic induced fluctuations are readily visible as changes in the patients EEG.
Anesthetic drugs are usually administered in pharmacological models based on a population taking into account their age, weight and height. However, there is a significant difference in how patients respond to these models. In adults there is evidence that the doses needed to achieve consciousness varies with a factor of 2 above and below suggested doses. In under-dosing of anesthetics there is a risk of peroperative awareness . On the other hand there is also evidence that overdosing of anesthetics has harmful effects; children receiving more than 4% Sevoflurane can demonstrate epileptiform activity , and adults overdosing into "burst suppression" during anesthesia has a higher risk of postoperative delirium (POD) and increased occurrence of postoperative cognitive dysfunction (POCD) .
Bispectral Index (BIS) is an algorithm developed by Aspect Medical Systems in 1994, which is based on weighted sums of EEG subparameters to present an index from 0 to 100 for depth of anesthesia, where 100 is wide awake, and 0 is an isoelectric EEG. The BIS target for a deep enough anesthesia is set to be between 40 and 60. The BIS number is often in concurrence with other clinical observations related to anesthetic depth, however there is also an experience of divergence. BIS and other EEG-based indices are programmed from adult cohorts, and cannot be directly trusted in children, or the elderly . There is also an incapability in these preprogrammed indices (BIS and other) to integrate how specific anesthetic drugs affect the EEG, and thenceforth the BIS value. An example of this is how the drug Ketamine induces a specific gamma-frequency in the EEG, which the BIS-index translate as a lighter anesthesia, even though the drug is administered "on top of" an already deep level of anesthesia.
- Being tested
- Bilateral Bispectral Index and EEG
- Keywords
- Depth of Anesthesia Monitoring, Post operative cognitive dysfunction (POCD)
- Medical subject headings
- Postoperative Complications, Delayed Emergence from Anesthesia, Cognitive Dysfunction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Bilateral Bispectral Index and EEGDevice
raw-EEG and spectrographic EEG-visualization based on the Medtronic Device "Bilateral BiSpectral Index"
| Study group | Role | What they receive |
|---|---|---|
| Visual EEG | Experimental | Individual dosing of anesthetic medications based on EEG AND other standardized clinical observations (BP, HR) Receives: Device: Bilateral Bispectral Index and EEG |
| Blinded EEG | Experimental | Individual dosing of anesthetic medications based on standardized clinical observations (BP, HR). Receives: Device: Bilateral Bispectral Index and EEG |
What is being measured
The primary outcome is the main question the study is designed to answer.
EEG-based Depth of anesthesia-monitoring and dosage of anesthetic medications
Summarizing the total amount of anesthetic drugs used, mg/kg/hr
Measured: 24 hours
EEG-based Depth of anesthesia-monitoring and dosage of vasopressor medications during anesthesia
Summarizing the total amount of vasopressor drugs used, micg/kg/min
Measured: 24 hours
EEG-based Depth of anesthesia-monitoring and time to wake-up after surgery
Time from the end of intravenous infusion of anesthetic - to motoric and verbal response.
Measured: 24 hours
Evaluation of cognitive function using CANTAB-MCI
Baseline assessment 1 day preoperatively, assessment 2-3 hours after wake-up, and 24 hours after wake-up using CANTAB-MCI
Measured: 1 day preoperatively to 24 hours after wake-up
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Aug 2020
- Study start8 Jan 2021
- Primary completion12 Mar 2026
- Study completion13 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (46)Papers the sponsor has linked to this study.
- Other trials for Postoperative ComplicationsStudies of the same condition, open and under way.
- More trials run by Oslo University HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Two groups with 50 participants in each group. We want to compare one group with visible EEG-monitor with a group where the EEG monitor is invisible to the anesthetic team.
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 100 participants (actual)
Sponsor and investigators
- Lead sponsor
- Oslo University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Luis George Romundstad, Oslo University Hospital
- Investigators
- Luis G Romundstad, MD, PhD, Principal investigator, Oslo University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04529304
- Sponsor's protocol ID
- 2019/32173
- Other IDs
- 2019
- Status last verified
- Mar 2026
- First submitted
- 13 Mar 2020
- Last updated
- 16 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data storage and management will follow GCP and GDPR requirements. Data sharing after end of study will follow the current data sharing policy at Oslo University Hospital. Data set can be made available for journal peer review process.
Publications
Gibbs FA, Gibbs LE, Lennox WG. Effects on the electroencephalogram of certain drugs which influence nervous activity. Arch Intern Med. 1937;60:154-66
KIERSEY DK, BICKFORD RG, FAULCONER A Jr. Electro-encephalographic patterns produced by thiopental sodium during surgical operations; description and classification. Br J Anaesth. 1951 Jul;23(3):141-52. doi: 10.1093/bja/23.3.141. No abstract available.
PubMed 14848401Tinker JH, Sharbrough FW, Michenfelder JD. Anterior shift of the dominant EEG rhytham during anesthesia in the Java monkey: correlation with anesthetic potency. Anesthesiology. 1977 Apr;46(4):252-9. doi: 10.1097/00000542-197704000-00005.
PubMed 402870John ER, Prichep LS, Kox W, Valdes-Sosa P, Bosch-Bayard J, Aubert E, Tom M, di Michele F, Gugino LD. Invariant reversible QEEG effects of anesthetics. Conscious Cogn. 2001 Jun;10(2):165-83. doi: 10.1006/ccog.2001.0507.
PubMed 11414713Gugino LD, Chabot RJ, Prichep LS, John ER, Formanek V, Aglio LS. Quantitative EEG changes associated with loss and return of consciousness in healthy adult volunteers anaesthetized with propofol or sevoflurane. Br J Anaesth. 2001 Sep;87(3):421-8. doi: 10.1093/bja/87.3.421.
PubMed 11517126Feshchenko VA, Veselis RA, Reinsel RA. Propofol-induced alpha rhythm. Neuropsychobiology. 2004;50(3):257-66. doi: 10.1159/000079981.
PubMed 15365226Cimenser A, Purdon PL, Pierce ET, Walsh JL, Salazar-Gomez AF, Harrell PG, Tavares-Stoeckel C, Habeeb K, Brown EN. Tracking brain states under general anesthesia by using global coherence analysis. Proc Natl Acad Sci U S A. 2011 May 24;108(21):8832-7. doi: 10.1073/pnas.1017041108. Epub 2011 May 9.
PubMed 21555565Purdon PL, Pierce ET, Mukamel EA, Prerau MJ, Walsh JL, Wong KF, Salazar-Gomez AF, Harrell PG, Sampson AL, Cimenser A, Ching S, Kopell NJ, Tavares-Stoeckel C, Habeeb K, Merhar R, Brown EN. Electroencephalogram signatures of loss and recovery of consciousness from propofol. Proc Natl Acad Sci U S A. 2013 Mar 19;110(12):E1142-51. doi: 10.1073/pnas.1221180110. Epub 2013 Mar 4.
PubMed 23487781Ching S, Cimenser A, Purdon PL, Brown EN, Kopell NJ. Thalamocortical model for a propofol-induced alpha-rhythm associated with loss of consciousness. Proc Natl Acad Sci U S A. 2010 Dec 28;107(52):22665-70. doi: 10.1073/pnas.1017069108. Epub 2010 Dec 13.
PubMed 21149695Supp GG, Siegel M, Hipp JF, Engel AK. Cortical hypersynchrony predicts breakdown of sensory processing during loss of consciousness. Curr Biol. 2011 Dec 6;21(23):1988-93. doi: 10.1016/j.cub.2011.10.017. Epub 2011 Nov 17.
PubMed 22100063Chauvette S, Crochet S, Volgushev M, Timofeev I. Properties of slow oscillation during slow-wave sleep and anesthesia in cats. J Neurosci. 2011 Oct 19;31(42):14998-5008. doi: 10.1523/JNEUROSCI.2339-11.2011.
PubMed 22016533Lewis LD, Weiner VS, Mukamel EA, Donoghue JA, Eskandar EN, Madsen JR, Anderson WS, Hochberg LR, Cash SS, Brown EN, Purdon PL. Rapid fragmentation of neuronal networks at the onset of propofol-induced unconsciousness. Proc Natl Acad Sci U S A. 2012 Dec 4;109(49):E3377-86. doi: 10.1073/pnas.1210907109. Epub 2012 Nov 5.
PubMed 23129622Li D, Voss LJ, Sleigh JW, Li X. Effects of volatile anesthetic agents on cerebral cortical synchronization in sheep. Anesthesiology. 2013 Jul;119(1):81-8. doi: 10.1097/ALN.0b013e31828e894f.
PubMed 23508217Wang K, Steyn-Ross ML, Steyn-Ross DA, Wilson MT, Sleigh JW. EEG slow-wave coherence changes in propofol-induced general anesthesia: experiment and theory. Front Syst Neurosci. 2014 Oct 29;8:215. doi: 10.3389/fnsys.2014.00215. eCollection 2014.
PubMed 25400558Vizuete JA, Pillay S, Ropella KM, Hudetz AG. Graded defragmentation of cortical neuronal firing during recovery of consciousness in rats. Neuroscience. 2014 Sep 5;275:340-51. doi: 10.1016/j.neuroscience.2014.06.018. Epub 2014 Jun 18.
PubMed 24952333
Study at a glance
From the registry record, last updated by the sponsor on 16 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- EEG-based Depth of Anesthesia-monitoring During General Anesthesia - Effects on Time to Wake-up and Post-operative Cognition
- ClinicalTrials.gov ID
- NCT04529304
- Acronym / sponsor ID
- 2019/32173
- Keywords
- Depth of Anesthesia Monitoring, Post operative cognitive dysfunction (POCD)
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 100 participants (actual)
- Lead sponsor
- Oslo University HospitalUniversity, hospital or other
- Study start
- 8 Jan 2021 (actual)
- Primary completion
- 12 Mar 2026 (actual)
- Study completion
- 13 Mar 2026 (actual)
- First posted
- 27 Aug 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Depth of anesthesia-monitoring based on EEG changes demands knowledge about the effects of the different anesthetic medications on EEG waveforms. The investigators want to investigate the use of the raw-EEG waveform in addition to indexes (BIS) and EEG spectrogram analyses for depth of anesthesia monitoring. The investigators hypothesize that with the use of this monitoring, anaesthesia providers will be able to better individualize the dosage of anesthetic drugs, and that this will reduce the total consumption of anesthetic medication , thus reducing time to wake-up after surgery. Some studies have indicated that too deep anesthesia, confirmed by "burst-suppression" or isoelectric-EEG , is associated with increased postoperative cognitive dysfunction (POCD). The investigators will therefore assess the patients with the Cambridge Neuropsychological Test Automated Battery tests in mild cognitive impairment (CANTAB-MCI) cognitive function assessment tool.
Detailed description
It has been over 80 years since Gibbs et al showed how the electroencephalogram (EEG) systematically changed in concurrence with increasing doses of hypnotic drugs such as penthobarbital and Ether. The study concluded that "Electroencephalography may therefore be of value in controlling depth of anesthesia and sedation". In spite of a solid documentation of the systematic connection between dosing of anesthetic drugs, EEG-patterns and level of sedation/anesthesia , EEG-based DoA has not become a part of standard of care in anesthetic management. There is abundant evidence of how different anesthetic drugs leads to characteristic fluctuations in human brain electrical activity, relating to depth of anesthesia, anesthetic drug of choice, and age . These anesthetic induced fluctuations are readily visible as changes in the patients EEG.
Anesthetic drugs are usually administered in pharmacological models based on a population taking into account their age, weight and height. However, there is a significant difference in how patients respond to these models. In adults there is evidence that the doses needed to achieve consciousness varies with a factor of 2 above and below suggested doses. In under-dosing of anesthetics there is a risk of peroperative awareness . On the other hand there is also evidence that overdosing of anesthetics has harmful effects; children receiving more than 4% Sevoflurane can demonstrate epileptiform activity , and adults overdosing into "burst suppression" during anesthesia has a higher risk of postoperative delirium (POD) and increased occurrence of postoperative cognitive dysfunction (POCD) .
Bispectral Index (BIS) is an algorithm developed by Aspect Medical Systems in 1994, which is based on weighted sums of EEG subparameters to present an index from 0 to 100 for depth of anesthesia, where 100 is wide awake, and 0 is an isoelectric EEG. The BIS target for a deep enough anesthesia is set to be between 40 and 60. The BIS number is often in concurrence with other clinical observations related to anesthetic depth, however there is also an experience of divergence. BIS and other EEG-based indices are programmed from adult cohorts, and cannot be directly trusted in children, or the elderly . There is also an incapability in these preprogrammed indices (BIS and other) to integrate how specific anesthetic drugs affect the EEG, and thenceforth the BIS value. An example of this is how the drug Ketamine induces a specific gamma-frequency in the EEG, which the BIS-index translate as a lighter anesthesia, even though the drug is administered "on top of" an already deep level of anesthesia.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
- Model description
- Two groups with 50 participants in each group. We want to compare one group with visible EEG-monitor with a group where the EEG monitor is invisible to the anesthetic team.
| Arm | Type | Receives |
|---|---|---|
| Visual EEG | Experimental | Device: Bilateral Bispectral Index and EEGIndividual dosing of anesthetic medications based on EEG AND other standardized clinical observations (BP, HR) |
| Blinded EEG | Experimental | Device: Bilateral Bispectral Index and EEGIndividual dosing of anesthetic medications based on standardized clinical observations (BP, HR). |
Who may qualify
- Ages
- 18 to 85 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- .
- Participants are eligible to be included in the study only if all of the following criteria apply:
- Age
- Participant must be above the age of 18 years , at the time of signing the informed consent.
- Sex
Key exclusion criteria (7 listed)
- Psychiatric disorders
- Pregnancy
- Breast feeding
- Using antiepileptic drugs.
- Central neurological disease
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Bilateral Bispectral Index and EEGraw-EEG and spectrographic EEG-visualization based on the Medtronic Device "Bilateral BiSpectral Index" | Device | Blinded EEG, Visual EEG |
Primary outcome
EEG-based Depth of anesthesia-monitoring and dosage of anesthetic medications
Time frame: 24 hours
Summarizing the total amount of anesthetic drugs used, mg/kg/hr
EEG-based Depth of anesthesia-monitoring and dosage of vasopressor medications during anesthesia
Time frame: 24 hours
Summarizing the total amount of vasopressor drugs used, micg/kg/min
EEG-based Depth of anesthesia-monitoring and time to wake-up after surgery
Time frame: 24 hours
Time from the end of intravenous infusion of anesthetic - to motoric and verbal response.
Evaluation of cognitive function using CANTAB-MCI
Time frame: 1 day preoperatively to 24 hours after wake-up
Baseline assessment 1 day preoperatively, assessment 2-3 hours after wake-up, and 24 hours after wake-up using CANTAB-MCI
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Mar 2026.
- BackgroundGibbs FA, Gibbs LE, Lennox WG. Effects on the electroencephalogram of certain drugs which influence nervous activity. Arch Intern Med. 1937;60:154-66
- Background: PubMed 14848401KIERSEY DK, BICKFORD RG, FAULCONER A Jr. Electro-encephalographic patterns produced by thiopental sodium during surgical operations; description and classification. Br J Anaesth. 1951 Jul;23(3):141-52. doi: 10.1093/bja/23.3.141. No abstract available.
- Background: PubMed 402870Tinker JH, Sharbrough FW, Michenfelder JD. Anterior shift of the dominant EEG rhytham during anesthesia in the Java monkey: correlation with anesthetic potency. Anesthesiology. 1977 Apr;46(4):252-9. doi: 10.1097/00000542-197704000-00005.
- Background: PubMed 11414713John ER, Prichep LS, Kox W, Valdes-Sosa P, Bosch-Bayard J, Aubert E, Tom M, di Michele F, Gugino LD. Invariant reversible QEEG effects of anesthetics. Conscious Cogn. 2001 Jun;10(2):165-83. doi: 10.1006/ccog.2001.0507.
- Background: PubMed 11517126Gugino LD, Chabot RJ, Prichep LS, John ER, Formanek V, Aglio LS. Quantitative EEG changes associated with loss and return of consciousness in healthy adult volunteers anaesthetized with propofol or sevoflurane. Br J Anaesth. 2001 Sep;87(3):421-8. doi: 10.1093/bja/87.3.421.
- Background: PubMed 15365226Feshchenko VA, Veselis RA, Reinsel RA. Propofol-induced alpha rhythm. Neuropsychobiology. 2004;50(3):257-66. doi: 10.1159/000079981.
- Background: PubMed 21555565Cimenser A, Purdon PL, Pierce ET, Walsh JL, Salazar-Gomez AF, Harrell PG, Tavares-Stoeckel C, Habeeb K, Brown EN. Tracking brain states under general anesthesia by using global coherence analysis. Proc Natl Acad Sci U S A. 2011 May 24;108(21):8832-7. doi: 10.1073/pnas.1017041108. Epub 2011 May 9.
- Background: PubMed 23487781Purdon PL, Pierce ET, Mukamel EA, Prerau MJ, Walsh JL, Wong KF, Salazar-Gomez AF, Harrell PG, Sampson AL, Cimenser A, Ching S, Kopell NJ, Tavares-Stoeckel C, Habeeb K, Merhar R, Brown EN. Electroencephalogram signatures of loss and recovery of consciousness from propofol. Proc Natl Acad Sci U S A. 2013 Mar 19;110(12):E1142-51. doi: 10.1073/pnas.1221180110. Epub 2013 Mar 4.
- Background: PubMed 21149695Ching S, Cimenser A, Purdon PL, Brown EN, Kopell NJ. Thalamocortical model for a propofol-induced alpha-rhythm associated with loss of consciousness. Proc Natl Acad Sci U S A. 2010 Dec 28;107(52):22665-70. doi: 10.1073/pnas.1017069108. Epub 2010 Dec 13.
- Background: PubMed 22100063Supp GG, Siegel M, Hipp JF, Engel AK. Cortical hypersynchrony predicts breakdown of sensory processing during loss of consciousness. Curr Biol. 2011 Dec 6;21(23):1988-93. doi: 10.1016/j.cub.2011.10.017. Epub 2011 Nov 17.
- Background: PubMed 22016533Chauvette S, Crochet S, Volgushev M, Timofeev I. Properties of slow oscillation during slow-wave sleep and anesthesia in cats. J Neurosci. 2011 Oct 19;31(42):14998-5008. doi: 10.1523/JNEUROSCI.2339-11.2011.
- Background: PubMed 23129622Lewis LD, Weiner VS, Mukamel EA, Donoghue JA, Eskandar EN, Madsen JR, Anderson WS, Hochberg LR, Cash SS, Brown EN, Purdon PL. Rapid fragmentation of neuronal networks at the onset of propofol-induced unconsciousness. Proc Natl Acad Sci U S A. 2012 Dec 4;109(49):E3377-86. doi: 10.1073/pnas.1210907109. Epub 2012 Nov 5.
- Individual participant dataSharing planned: Yes. Data storage and management will follow GCP and GDPR requirements. Data sharing after end of study will follow the current data sharing policy at Oslo University Hospital. Data set can be made available for journal peer review process.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Luis G Romundstad, MD, PhD principal investigator
Oslo University Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Bilateral Bispectral Index and EEG in people with Postoperative Complications and Delayed Emergence From Anesthesia, run by Oslo University Hospital at 1 site in Norway.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
EEG-based Depth of anesthesia-monitoring and dosage of anesthetic medications (time frame: 24 hours). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04529304, which also lists 46 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Mar 2026.