ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12613000801718

Ethics application status

Approved

Date submitted

17/07/2013

Date registered

19/07/2013

Date last updated

5/08/2013

Type of registration

Prospectively registered

Titles & IDs

Public title

Correlation between alcohol concentration and an electroencephalogram (EEG) measure of anaesthetic depth

Scientific title

The correlation between increasing breath alcohol concentration and Bispectral Index in anaesthetic registrars

Secondary ID [1]

Nil

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

The impact of increasing alcohol on BIS (a measure of EEG activity used as a surrogate for anaesthetic depth)

Condition category

Condition code

Anaesthesiology

Other anaesthesiology

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Participants will attend just one study day (for one four hour session). They will be asked to refrain from consuming caffeine from 10am on the study day. Only participants who are not rostered for clinical duties over the ensuing 24 hours will be able to participate in the study. Alcohol will be provided for study participants to consume over 3 hours. They will be asked to drink a similar amount of alcohol to that which they would normally drink at home or when out. The type and amount of alcohol consumed throughout the study will be recorded. Wine, beer, nonalcoholic drinks and snacks will be provided during the study period, and a meal will be provided at the end of the study. Four measurments of breath alcohol, and of BIS, will be taken for each participant (hourly, over the four hour study period) plus one set of baseline measurements. A single blood sample will be taken at the end of the study to confirm blood alcohol levels.

Intervention code [1]

Other interventions

Comparator / control treatment

There is no comparator or control treatment for this study - as we are assessing the relationship between breath alcohol levels and BIS all participants will drink alcohol over the study period.

Control group

Uncontrolled

Outcomes

Primary outcome [1]

Correlation between end-expired (breathalyser) alcohol concentration and BIS.

Timepoint [1]

Baseline (before drinking) and then every hour over four hours

Secondary outcome [1]

Correlation between blood alcohol concentration and BIS.

Timepoint [1]

Four hours after starting drinking (at study end)

Secondary outcome [2]

Agreement and correlation between Anaesthetic Trainees’ predicted blood alcohol concentration and measured blood alcohol concentration

Timepoint [2]

At each breath alcohol concentration reading (1, 2, 3 and 4 hours)

Eligibility

Key inclusion criteria

Anaesthetic Trainees (age between 25 and 40 years) who have completed their clinical duties on a Friday afternoon and are not rostered to work for at least 24 hours.

Minimum age

25 Years

Maximum age

40 Years

Sex

Both males and females

Can healthy volunteers participate?

Yes

Key exclusion criteria

History of epilepsy; currently taking any sedating medication including analgesics such as codeine and opioids, benzodiazepines, anti-epileptics and sleeping medications; history of liver disease or impaired liver function; currently pregnant.

Study design

Purpose of the study

Diagnosis

Allocation to intervention

Non-randomised trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

No allocation of treatment or concealment of treatment in this study.

Potential participants will be notified of the upcoming study at a department inservice. Potential participants (ie those not rostered on for working during the weekend following the study date) will be approached by a study coordinator.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Single group

Other design features

Phase

Not Applicable

Type of endpoint/s

Pharmacokinetics / pharmacodynamics

Statistical methods / analysis

Correlation between blood alcohol concentration and BIS will be determined. This will be followed by multivariate regression analysis including various participant characteristics to further delineate the relationship between blood alcohol concentration and BIS. Sample size calculation for this kind of study is unreliable. A previous study on healthy patients showed mean baseline BIS scores to be in the mid 90s with minimal variation.[1] We plan to study 10-20 patients. With the benefit of repeated measurements, a sample size of 10 subjects measured on 4 occasions should provide power of greater than 80% (with an alpha value set at 0.05 and beta value of 0.2) to detect a correlation of 0.3 which would be clinically relevant.

1. Cortinez, L.I., et al., Performance of the cerebral state index during increasing levels of propofol anesthesia: a comparison with the bispectral index. Anesth Analg, 2007. 104(3): p. 605-10

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

25/07/2013

Actual

2/08/2013

Date of last participant enrolment

Anticipated

1/08/2013

Actual

2/08/2013

Date of last data collection

Anticipated

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

VIC

Recruitment hospital [1]

The Alfred - Prahran

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Auckland

Funding & Sponsors

Funding source category [1]

University

Name [1]

University of Auckland

Address [1]

Department of Anaesthesiology
University of Auckland
Private Bag 92019
Auckland
New Zealand
1023

Country [1]

New Zealand

Primary sponsor type

University

Name

University of Auckland

Address

Department of Anaesthesiology
University of Auckland
Private Bag 92019
Auckland
New Zealand
1023

Country

New Zealand

Secondary sponsor category [1]

Hospital

Name [1]

The Alfred

Address [1]

55 Commercial Rd, Melbourne VIC 3004, Australia

Country [1]

Australia

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Health and Disability Ethics Committee

Ethics committee address [1]

Ministry of Health
No 1 The Terrace
PO Box 5013
Wellington
6011

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

16/05/2013

Approval date [1]

16/07/2013

Ethics approval number [1]

13/NTA/90

Ethics committee name [2]

Alfred Hospital Ethics Committee

Ethics committee address [2]

55 Commercial Rd, Melbourne VIC 3004, Australia

Ethics committee country [2]

Australia

Date submitted for ethics approval [2]

18/03/2013

Approval date [2]

17/06/2013

Ethics approval number [2]

183/13

Summary

Brief summary

Bispectral Index monitoring is commonly used intraoperatively to decrease the risk of awareness. Multiple drugs are known to affect the bispectral index and many have been studied in detail. Our aim is to determine the relationship between alcohol concentration and BIS.

Awareness is an uncommon but potentially stressful complication of anaesthesia occurring in 0.1-0.2% of surgical patients.[1] The BIS monitor processes EEG activity with time-domain, frequency domain, and bispectral analysis producing a dimensionless number between 0 and 100 with 40-60 being appropriate for surgery.[2] Large trials have shown a decrease in the occurrence of awareness when using BIS in high-risk patients.[1, 3] 
Studies have demonstrated that BIS decreases in patients with head injuries [4, 5], those with cognitive impairment such as dementia [6] and with sedation [7].  There has been a single case report detailing a case of intracranial arterial alcohol embolization in which the BIS decreased to zero[8]. We hypothesise that BIS will decrease with alcohol consumption. 
The effect of multiple drugs such as nitrous oxide, ketamine and opioid on bispectral index has been studied in detail.[2] Alcohol, a commonly consumed drug has not. Miner et al published a paper using BIS to validate the use of Altered Mental Status Scale in intoxicated patients.[9] This study did not aim to determine a relationship between alcohol concentration and BIS and included patients who may have consumed other drugs. Thus, there were potentially many confounding factors that may have influenced the relationship between alcohol concentration and BIS.

1.	Myles, P.S., et al., Bispectral index monitoring to prevent awareness during anaesthesia: the B-Aware randomised controlled trial. Lancet, 2004. 363(9423): p. 1757-63.
2.	Dahaba, A.A., Different conditions that could result in the bispectral index indicating an incorrect hypnotic state. Anesth Analg, 2005. 101(3): p. 765-73.
3.	Ekman, A., et al., Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol Scand, 2004. 48(1): p. 20-6.
4.	Haug, E., et al., Bispectral electroencephalographic analysis of head-injured patients in the emergency department. Acad Emerg Med, 2004. 11(4): p. 349-52.
5.	Ebtehaj, M., et al., Correlation between BIS and GCS in patients suffering from head injury. Ir J Med Sci, 2012. 181(1): p. 77-80.
6.	Erdogan, M.A., et al., The effects of cognitive impairment on anaesthetic requirement in the elderly. Eur J Anaesthesiol, 2012. 29(7): p. 326-31.
7.	Liu, J., H. Singh, and P.F. White, Electroencephalographic bispectral index correlates with intraoperative recall and depth of propofol-induced sedation. Anesth Analg, 1997. 84(1): p. 185-9.
8.	Unnikrishnan, K.P., et al., Case report: alterations in bispectral index following absolute alcohol embolization in a patient with intracranial arteriovenous malformation. Can J Anaesth, 2007. 54(11): p. 908-11.
9.	Miner, J.R., A. Gaetz, and M.H. Biros, The association of a decreased level of awareness and blood alcohol concentration with both agitation and sedation in intoxicated patients in the ED. Am J Emerg Med, 2007. 25(7): p. 743-8.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

A/Prof Simon Mitchell

Address

Department of Anaesthesiology
University of Auckland
Private Bag 92019
Auckland
New Zealand
1023

Country

New Zealand

Phone

+64 9 3737599 ext 89300

Fax

sj.mitchell@auckland.ac.nz

Contact person for public queries

Name

Jacqueline Hannam

Address

Department of Anaesthesiology
University of Auckland
Private Bag 92019
Auckland
New Zealand
1023

Country

New Zealand

Phone

+64 9 3737599 ext 89308

Fax

j.hannam@auckland.ac.nz

Contact person for scientific queries

Name

Jacqueline Hannam

Address

Department of Anaesthesiology
University of Auckland
Private Bag 92019
Auckland
New Zealand
1023

Country

New Zealand

Phone

+64 9 3737599 ext 89308

Fax

j.hannam@auckland.ac.nz

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Acute alcohol intoxication and bispectral index monitoring.	2015	https://dx.doi.org/10.1111/aas.12546

N.B. These documents automatically identified may not have been verified by the study sponsor.

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Documents added automatically