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Trial registered on ANZCTR


Registration number
ACTRN12621001494820
Ethics application status
Approved
Date submitted
3/09/2021
Date registered
3/11/2021
Date last updated
28/08/2024
Date data sharing statement initially provided
3/11/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
The Delta-max trial- Brainwave measurement of depth of anaesthesia in patients having elective surgery.
Scientific title
Delta-Max: An Observational study targeting maximal EEG Delta wave activity during general anaesthesia
Secondary ID [1] 305394 0
RD021091
Universal Trial Number (UTN)
U1111-1268-1858
Trial acronym
Delta-Max
Linked study record
N/A

Health condition
Health condition(s) or problem(s) studied:
Accidental Awareness 323488 0
Condition category
Condition code
Anaesthesiology 321056 321056 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Realtime analysis of Frontal electroencephalogram (EEG) waveform to maximise Delta-wave formation for elective surgery patients having general anaesthesia.
Patients formally consented prior to surgery
Frontal stickers attached before surgery- often routine practise.
Subtle titration and adjustment of volume of anaesthetic agents to achieve maximal delta-wave formation during operation.
isolated forearm test (IFT) involving a inflated cuff on the arm twice to check for loss of consciousness- after induction and after first incision.
Researcher in theatre reviewing EEG. Research assistant helping with EEG capture and IFT
Research co-ordinator in theatre for blood sampling in the first 20 patients to measure anaesthetic and analgesic levels.
quality of recovery measurements and awareness questionnaire in recovery room.
Subtle refinements of anaesthetic delivery compared to usual practise only. The expected variation in anaesthetic amounts compared to usual practise is estimated at 10% less to 20% more.
The study will not lengthen the anaesthetic time for the participant.

Anaesthesia will be conducted using standard, commonly used, drug combinations: midazolam, fentanyl, propofol, sevoflurane, +/- muscle relaxants, +/-anti-nausea drugs, +/-vasopressors.
Adjunctive drugs will also be allowed as per the clinician’s judgement: dexmedetomidine, lignocaine, and ketamine in analgesic doses. Anaesthesia will be induced using fentanyl and propofol as per the discretion of the clinician, and then converted to sevoflurane or propofol for maintenance of anaesthesia
A person from the research team will be present for each anaesthetic/operation to review the EEG waveform to aid in adherence to protocol.
Intervention code [1] 321803 0
Prevention
Comparator / control treatment
N/A
Control group
Uncontrolled

Outcomes
Primary outcome [1] 328832 0
Proportion of patients achieving delta-max within the clinical timeframe (ie before the first incision (around 15minutes)
Delta wave data is collected using entropy and multichannel EEG recordings in real-time and assessed by the research personnel.
Timepoint [1] 328832 0
During surgery
Secondary outcome [1] 400560 0
Presence or absence of a volitional isolated forearm response before and after first incision.
using the Isolated Forearm test post induction and post first surgical incision and using the Brice awareness form in recovery and post op day 3.
Timepoint [1] 400560 0
During surgery and in recovery room and day 3 post-op
Secondary outcome [2] 400561 0
Intraoperative cardiovascular stability. This will be assessed as the percentage of time that
heart rate and blood pressure are greater than +/-20% of the pre-incision levels for each patient.
Timepoint [2] 400561 0
During surgery
Secondary outcome [3] 401290 0
Acceptable emergence trajectories: The routine PACU evaluation at 30 minutes of: pain
(numerical scale 0-10),

Timepoint [3] 401290 0
In recovery room until post op day 3
Secondary outcome [4] 402005 0
The dosing of vasopressor drugs (metaraminol and ephedrine) will be recorded. Comparison will be made with pre-existing audit data, matched for operation type, duration and patient age.
Timepoint [4] 402005 0
During surgery
Secondary outcome [5] 402006 0
delirium rates (Richmond agitation scale and 3D-CAM
Timepoint [5] 402006 0
In the recovery room
Secondary outcome [6] 402007 0
nausea (subjective rating 0-3) will be recorded and compared with existing audit data – matched for operation type, duration and patient age.
Timepoint [6] 402007 0
In recovery room

Eligibility
Key inclusion criteria
Adult patients (18-90years) presenting for routine surgery under general anaesthesia
Minimum age
18 Years
Maximum age
90 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Operations on head that would preclude placement of EEG.

Inability to give informed study consent for any reason

Moribund patients not expected to survive 24 hours, or those needing planned postoperative ICU admission.

Study design
Purpose of the study
Prevention
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
.not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
.n/A
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
.N/A
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
Using the recognised 5% rate for the positive isolated forearm test, the 95% confidence interval for 112 patients is 1.62% to 11.67%. Since our isolated forearm test incidence from 112 patients is 0, it lies below the 1.62% lower confidence interval bound - which suggests that the SWAS titration probably reduces awareness under general anaesthesia. We will additionally use the Brice awareness questionnaire, administered on emergence and three days post-operatively. Any unexplained IFT positive results or awareness from the Brice questionnaire will result in termination of the study because it would indicate that the study assumption of delta-max perception failure was incorrect.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
30/04/2022
Actual
26/04/2022
Date of last participant enrolment
Anticipated
30/04/2024
Actual
30/11/2023
Date of last data collection
Anticipated
3/05/2024
Actual
4/12/2023
Sample size
Target
112
Accrual to date
Final
112
Recruitment outside Australia
Country [1] 24093 0
New Zealand
State/province [1] 24093 0
waikato

Funding & Sponsors
Funding source category [1] 309595 0
Other Collaborative groups
Name [1] 309595 0
MRC
Country [1] 309595 0
United Kingdom
Primary sponsor type
Hospital
Name
Waikato District health Board
Address
Waikato Hospital
Anaesthetic Research Department
Waiora building level 4
Pembroke st
3240
Hamilton
New Zealand
Country
New Zealand
Secondary sponsor category [1] 310605 0
University
Name [1] 310605 0
Oxford university
Address [1] 310605 0
Wellington Square, Oxford, OX1 2JD United Kingdom
Country [1] 310605 0
United Kingdom

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 309371 0
Northern A Health and Disability Ethics Committee
Ethics committee address [1] 309371 0
Ministry of Health Health and Disability Ethics Committees PO Box 5013. Wellington 6140
Ethics committee country [1] 309371 0
New Zealand
Date submitted for ethics approval [1] 309371 0
15/10/2021
Approval date [1] 309371 0
11/03/2022
Ethics approval number [1] 309371 0

Summary
Brief summary
General anaesthesia is delivered to individuals during an operation to stop them being aware of what is going around them, prevent any pain and immobilise the body so surgery can be carried out safely. Unfortunately, the anaesthetists do not currently have a reliable way of measuring the exact point when an individual's brain becomes unconscious during the surgery. They tend to judge the amount of anaesthetic they give depending on when the average person would lose consciousness. They then increase or decrease the dose for that person depending on how their heart or the lungs react during the operation.

This study will look at the EEG of participants and target a specific waveform- called Deltawaves- as a marker of loss of consciousness and inability to form memory.
The study aims to show that titrating the anaesthetic to achieve delta is achievable in a busy clinical theatre without delaying surgery. Additionally patients should not be able to respond or recall events when in Delta for the duration of the surgery.
The study will also look at vital signs of patients on the trial to make sure this is as stable as is usually seen in current practise.
Trial website
N/A
Trial related presentations / publications
Public notes
Accidental awareness with recall although very rare is distressing to the patient. Current depth of anaesthesia monitors have limitations.
Exploring EEG to gain more assurance of loss of consciousness is needed to reduce awareness during anaesthesia

Contacts
Principal investigator
Name 113918 0
Dr Katie Warnaby
Address 113918 0
University of Oxford, UK, Clinical Neurosciences Division department
Wellcome Centre for Integrative Neuroimaging
Wellington Square, Oxford, OX1 2JD United Kingdom
Country 113918 0
United Kingdom
Phone 113918 0
+4401865 611 465
Fax 113918 0
Email 113918 0
[email protected]
Contact person for public queries
Name 113919 0
Jamie Sleigh
Address 113919 0
Waikato Hospital
Waiora Buidling level 4
Pembroke st
3240 Hamilton
New Zealand
Country 113919 0
New Zealand
Phone 113919 0
+64 7 839 8899
Fax 113919 0
Email 113919 0
[email protected]
Contact person for scientific queries
Name 113920 0
Jamie Sleigh
Address 113920 0
Waikato Hospital
Waiora Buidling level 4
Pembroke st
3240 Hamilton
New Zealand
Country 113920 0
New Zealand
Phone 113920 0
+64 7 839 8899
Fax 113920 0
Email 113920 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
Raw EEG that is annonymised will be loaded into an open access file repository and made freely available for 20 years
When will data be available (start and end dates)?
Once the study has been published the files will be released and available for 20 years.
Available to whom?
Anyone who wishes to use them
Available for what types of analyses?
EEG analysis
How or where can data be obtained?
Following study completion, all EEG data will be available in an open access repository, such as the Oxford Research Archive - Data (ORA-Data). https://www.bodleian.ox.ac.uk/about/libraries/our-work/digital-library
This repository will allow the data to be accessed by any user for a period of 20 years.


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
No additional documents have been identified.