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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Does the choice of anaesthetic drug influence the control of blood flow to the brain during robot-assisted prostate surgery?
Scientific title
A randomized comparison of the effects of Propofol versus Sevoflurane on cerebral autoregulation when conducting general anaesthesia for robot-assisted prostate surgery.
Secondary ID [1] 297803 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
anaesthesia 312165 0
cerebral oedema 312166 0
cerebral autoregulation 312167 0
Condition category
Condition code
Anaesthesiology 310713 310713 0 0

Study type
Description of intervention(s) / exposure
Patients undergoing robotic prostate surgery will have anaesthesia initiated by Propofol. After initiation, patients will then be randomised to have their anaesthesia maintained using the volatile anaesthetic agent, sevoflurane (control), or the intravenous agent, propofol (intervention).
A Bispectral Index (BIS) monitor will be used to measure the depth of anaesthesia in subjects. The target BIS score is 45 +/- 5. The dosage of Propofol or Sevoflurane will vary between subjects in order to keep the BIS constant. Propofol and Sevoflurane will be constantly administered throughout the operation.
Autoregulation will be tested at hourly intervals, starting at the initiation of the steep Trendelenburg position and every hour thereafter. Autoregulation testing will require the hourly administration of phenylephrine. Phenylephrine will be administered in order to alter Mean Arterial Pressure (MAP) between 80-100 mmHg. This is required in order to test cerebral autoregulation.
The intraoperative opioid will be remifentanil, administered by a target-controlled infusion with a targeted effect-site concentration of 2 mcg/mL - 4 mcg/mL.
Cerebral autoregulation will be tested using a TransCranial Doppler (TCD) machine. Initially this will be conducted by the anaesthetist, after training of the university research student associated with this project, they may then be able to conduct TCD testing.
Intervention code [1] 314044 0
Treatment: Drugs
Comparator / control treatment
Inhalational Sevoflurane
Control group

Primary outcome [1] 319562 0
Cerebral autoregulation will be assessed using a TransCranial Doppler (TCD). This will measure blood flow velocity in the Middle Cerebral Artery (MCA) relative to alterations in Mean Arterial Pressure (MAP). An Autoregulation Index (ARI) will be calculated and cerebral autoregulation will be said to be intact if ARI greater than 0.4 and will be said to not be intact if ARI is equal to or less than 0.4.
Timepoint [1] 319562 0
The last ARI calculated whilst in the Steep Trendelenburg position before returning to the supine position will be used as the primary timepoint to determine whether cerebral autoregulation has been left intact (ARI great than 0.4) or not (ARI less than or equal to 0.4).
Secondary outcome [1] 368753 0
Cerebral autoregulation will be assessed using a TransCranial Doppler (TCD). This will measure blood flow velocity in the Middle Cerebral Artery (MCA) relative to alterations in Mean Arterial Pressure (MAP). An Autoregulation Index (ARI) will be calculated and cerebral autoregulation will be said to be intact if ARI is greater than 0.4 and will be said to not be intact if ARI is equal to or less than 0,4
Timepoint [1] 368753 0
At initiation of Steep Trendelenburg position and every hour after until the completion of surgery

Key inclusion criteria
Robotic prostatectomy
Minimum age
18 Years
Maximum age
No limit
Can healthy volunteers participate?
Key exclusion criteria
History of cerebral vascular disease
Intracranial pathology
Allergy to Propofol.
Contraindication to Sevoflurane, including malignant hyperthermia or history of severe postoperative nausea and vomiting.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The induction of anaesthesia will be carried out using Propofol, after which, numbered opaque envelopes containing a random sequence will be opened and used to allocate the anaesthetic agent used to maintain anaesthesia.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer generated random numbers will be used to assign the agent used for maintenance of anaesthesia.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
The patient will be blind to group allocation.
The treating anaesthetist and investigator will be aware of the anaesthetic agent during data collection.
Investigators will be blind to the agent at the time of data analysis.
Phase 4
Type of endpoint(s)
Statistical methods / analysis
The Individuals in each group (either Propofol or Sevoflurane) will have their Autoregulation Index (ARI) calculated. The groups will then be compared, as we are comparing two independent means, a student’s two sample t-test will be used to determine if there is a significant difference between the ARI of those under Propofol anaesthesia compared with Sevoflurane.
We will also designate each patient as having either intact autoregulation or impaired autoregulation (ARI <0.4). The proportions with impaired autoregulation will be compared using a Fishers Exact test.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 13510 0
Royal Prince Alfred Hospital - Camperdown
Recruitment hospital [2] 14356 0
The Chris O’Brien Lifehouse - Camperdown
Recruitment postcode(s) [1] 26129 0
2050 - Camperdown

Funding & Sponsors
Funding source category [1] 302327 0
Name [1] 302327 0
The University of Sydney
Address [1] 302327 0
Level 3, Jane Foss Russell Building (G02), Darlington Campus, Darlington, NSW, 2008
Country [1] 302327 0
Primary sponsor type
Government body
Sydney Local Health District
575 Canterbury Rd, Campsie NSW 2194
Secondary sponsor category [1] 302232 0
Name [1] 302232 0
Address [1] 302232 0
Country [1] 302232 0

Ethics approval
Ethics application status
Ethics committee name [1] 303000 0
Sydney Local Health District Human Research Ethics Committee (RPAH Zone)
Ethics committee address [1] 303000 0
Level 11, KGV Building Missenden Road
Ethics committee country [1] 303000 0
Date submitted for ethics approval [1] 303000 0
Approval date [1] 303000 0
Ethics approval number [1] 303000 0

Brief summary
Currently there is no standard anesthetic agent recommended for robotic pelvic and abdominal surgery. Anaesthetic agents have variable effects on the cerebral vasculature and as such it has been hypothesized that one may be more suitable for robotic pelvic and abdominal surgery than the others. For instance, Sevoflurane, a volatile anesthetic agent, increases cerebral vasodilation and hence decreases vascular resistance. This may impair cerebral autoregulation. Conversely, Propofol was not found to significantly modify cerebral haemodynamics. It has been reported that cerebrovascular markers have remained within safety limits under Sevoflurane maintained anaesthesia during surgery in the steep Trendelenburg position. A feature of robotic surgery is the requirement for carbon dioxide pneumoperitoneum in conjunction with steep head-down positioning. We hypothesise that the cerebrovasodilatory effects of carbon dioxide combined with the potential for oedema from head-down positioning could render the brain particularly susceptible to the vasodilatory effects of volatile anaesthetics, including sevoflurane.
Cerebral oedema is a recognised, although rare, complication of robotic prostate surgery. These are long procedures with the patient in a steep head-down position. Previous studies have investigated some of the cerebral haemodynamic effects of general anaesthetics during this type of surgery, but we are unaware of any studies comparing different anaesthetic regimens with respect to their effects on cerebral autoregulation.

There is significant potential for adverse post-surgical outcomes following robotic prostate surgery. It has been suggested by several studies that further research is needed into the different outcomes of anaesthetics used in robotic pelvic and abdominal surgery in order to minimise complications. This study will add to the knowledge of the cerebrovascular effects of general anaesthetics during robotic pelvic and abdominal surgery, for which there is no currently recommended first line anaesthetic..
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 92130 0
Dr Tim McCulloch
Address 92130 0
Sydney Local Health District, Post Office Box M30 Missenden Road NSW 2050
Country 92130 0
Phone 92130 0
+61 2 9515 6111
Fax 92130 0
Email 92130 0
Contact person for public queries
Name 92131 0
Mr Tomas Robertson
Address 92131 0
NSW Rugby, David Phillips Sports Complex, Banks Avenue, Daceyville, NSW, 2032
Country 92131 0
Phone 92131 0
+61 448162684
Fax 92131 0
Email 92131 0
Contact person for scientific queries
Name 92132 0
Mr Tomas Robertson
Address 92132 0
NSW Rugby, David Phillips Sports Complex, Banks Avenue, Daceyville, NSW, 2032
Country 92132 0
Phone 92132 0
+61 448162684
Fax 92132 0
Email 92132 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
All data that will be available which does not allow identification of individuals. This includes but is not limited to autoregulation data, drug doses and others non identifiable data.
When will data be available (start and end dates)?
Data will be available immediately after publication and available up to 5 years post publication
Available to whom?
Availability will be available on a case by case basis based on approval from the Sydney Local Health District.
Available for what types of analyses?
For any research purpose
How or where can data be obtained?
Access subject to approval via the Principal Investigator
What supporting documents are/will be available?
Study protocol
How or where can supporting documents be obtained?
Type [1] 1750 0
Study protocol
Citation [1] 1750 0
Link [1] 1750 0
Email [1] 1750 0
Other [1] 1750 0
Summary results
No Results