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Trial registered on ANZCTR


Registration number
ACTRN12624000713594
Ethics application status
Approved
Date submitted
8/05/2024
Date registered
7/06/2024
Date last updated
13/10/2024
Date data sharing statement initially provided
7/06/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Evaluating a software-based model for improving management of the circulation of adult patients undergoing major surgery.
Scientific title
The pressure field: a feasibility trial of a Software-based Model for Optimisation of the Adult Circulation during Surgery (SMOACS).
Secondary ID [1] 312032 0
Nil known
Universal Trial Number (UTN)
U1111-1307-2908
Trial acronym
SMOACS
Linked study record
Not applicable

Health condition
Health condition(s) or problem(s) studied:
Management of perfusion during general anaesthesia 333639 0
Condition category
Condition code
Anaesthesiology 330324 330324 0 0
Anaesthetics
Cardiovascular 330325 330325 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The intervention group is the 'pressure field group'.

Anaesthetists in the pressure field group will receive clinical education on the pressure field method for managing perfusion. The pressure field method consists of defining a patient's baseline haemodynamic zone and defending this distinct haemodynamic zone during surgery.

The education consists of two 1-hour clinical education sessions, using the pressure field software to monitor three patients undergoing surgery, and completing an online questionnaire. The content includes the physiological basis for the haemodynamic zone, the process for determining a patient’s baseline haemodynamic zone, and strategies for maintaining parameters within the zone.

The zone is defined in terms of mean perfusion pressure (MPP), stroke volume (SV), and systemic elastance (Esys). The goal of intraoperative care is to maintain MPP within ±15% of the patient’s MPP baseline values without tolerating any MPP below 60 mmHg, and to maintain SV and Esys within ±15% of the patient’s baseline values. Anaesthetists will use the EV1000 or Hemosphere haemodynamic monitor, and the pressure field software, to support the management of patients.

No fluids, blood products, inotropes, or vasoactive drugs are to be administered prior to commencement of FloTrac monitoring. Roller clamps on fluid lines are to be closed except where fluid is actively being used to optimise the circulation. A vasopressor infusion is to be connected to the patient prior to induction (so that it can be promptly commenced as needed). Choice and titration of fluids, blood products, inotropes, and vasopressors is otherwise at the discretion of the attending anaesthetist.

Implementation scientists will measure the acceptability of the pressure field method by surveying participating anaesthetists at baseline, 6 months post-baseline, and 12 months post-baseline; assess the fidelity of intervention delivery by reviewing protocol deviations at 1, 6, and 12 months post-baseline (by auditing case report forms); and conduct semi-structured interviews with participating anaesthetists based on the Theoretical Domains Framework to identify and understand implementation barriers at 12 months post-baseline. If acceptability or intervention fidelity delivery is below 80%, enhancement strategies will be applied. Enhancement strategies may include additional clinical education or additional clinical research coordinator support in completing case report forms.

Anaesthetist participants will use the pressure field method until recruitment of the target number of patient participants in the pressure field group is complete.
Intervention code [1] 328478 0
Treatment: Devices
Intervention code [2] 328479 0
Treatment: Other
Comparator / control treatment
Anaesthetists in the control group will receive clinical education (a 1 hour lecture) on advanced haemodynamic monitoring and the evidence for avoiding hypotension.

The goal of intraoperative care is to maintain MPP within ±15% of the patient’s MPP baseline value without tolerating any MPP below 60 mmHg.

Anaesthetists will use the EV1000 or Hemosphere haemodynamic monitor to support the management of patients.

No fluids, blood products, inotropes, or vasoactive drugs are to be administered prior to commencement of FloTrac monitoring. Choice and titration of fluids, blood products, inotropes, and vasopressors is otherwise at the discretion of the attending anaesthetist.
Control group
Active

Outcomes
Primary outcome [1] 338077 0
Percentage of patients for whom complete haemodynamic data, key event data, and intervention data is available. This will be assessed as a composite outcome.
Timepoint [1] 338077 0
At the conclusion of study.
Secondary outcome [1] 434399 0
Percentage of patients with arterial line inserted prior to start of anaesthesia (induction)
Timepoint [1] 434399 0
At the conclusion of study.
Secondary outcome [2] 434400 0
Percentage of patients with central line inserted prior to start of anaesthesia (induction).
Timepoint [2] 434400 0
At the conclusion of study.
Secondary outcome [3] 434401 0
Percentage of patients with pre-operative and post-operative arterial blood gases (ABGs) taken.
Timepoint [3] 434401 0
At the conclusion of study.
Secondary outcome [4] 434402 0
Recruitment rate (patients recruited per site per week).
Timepoint [4] 434402 0
Measured after patient recruitment closes.
Secondary outcome [5] 434403 0
Percentage of patients in the pressure field group for which a ‘target haemodynamic zone’ was selected by the attending anaesthetist prior to start of anaesthesia (induction).
Timepoint [5] 434403 0
At the conclusion of study.
Secondary outcome [6] 434404 0
Percentage of intraoperative case time patients spend with an MPP within ±15% of their pre-induction value.
Timepoint [6] 434404 0
Measured on the day of the primary operation for each patient.
Secondary outcome [7] 434405 0
Percentage of intraoperative case time that SV and Esys each remain within ±15% of the pre-induction values (as well as MPP within ±15% of the pre-induction value). This will be assessed as a composite outcome.
Timepoint [7] 434405 0
Measured on the day of the primary operation for each patient.
Secondary outcome [8] 434406 0
Percentage of intraoperative case time with MPP < 60mmHg.
Timepoint [8] 434406 0
Measured on the day of the primary operation for each patient.
Secondary outcome [9] 434407 0
Total fluid volumes (mL) administered during the intraoperative case time (including volume administered with drugs).
Timepoint [9] 434407 0
Measured on the day of the primary operation for each patient.
Secondary outcome [10] 434408 0
Change in haemoglobin (g/L) from pre-operation to post-operation (based on the pre-operative and post-operative ABGs).
Timepoint [10] 434408 0
Measured on the day of the primary operation for each patient.
Secondary outcome [11] 434409 0
Units of allogeneic red blood cells transfused during the intraoperative case time.
Timepoint [11] 434409 0
Measured on the day of the primary operation for each patient.
Secondary outcome [12] 434410 0
Total dose of vasopressors administered during the intraoperative case time expressed in ‘norepinephrine equivalents’.
Timepoint [12] 434410 0
Measured on the day of the primary operation for each patient.
Secondary outcome [13] 434411 0
Net recorded 48-hour fluid balance (for the day of surgery and day following surgery).
Timepoint [13] 434411 0
Collected on or about post-operative day 2 following the primary operation.
Secondary outcome [14] 434412 0
Acceptability of the pressure field as a method for managing perfusion.
Timepoint [14] 434412 0
Measured at baseline, 6 months post-baseline, and 12 months post-baseline.
Secondary outcome [15] 434413 0
Fidelity of intervention delivery in the pressure field group.
Timepoint [15] 434413 0
Measured at 1 month post-baseline, 6 months post-baseline, and 12 months post-baseline.
Secondary outcome [16] 434414 0
Implementation barriers for the pressure field method of managing perfusion.
Timepoint [16] 434414 0
Measured at 12 months post-baseline.

Eligibility
Key inclusion criteria
Anaesthetists: consultant anaesthetists who are regular users of advanced haemodynamic monitoring and who regularly provide anaesthetic care for major intra-abdominal surgery at a trial site.

Patients: scheduled for an elective intermediate- to high-risk abdominal surgical procedure and expected to be managed using a peripheral arterial catheter and central venous catheter connected to an EV1000 or Hemosphere monitor.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Anaesthetists: Anaesthetists who do not expect to be regularly providing care for major intra-abdominal surgery throughout the trial period.

Patients: Pregnancy or participation in a conflicting interventional clinical trial.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The randomisation will be generated by an independent statistician at the University of Melbourne (Australia).
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Anaesthetists will be randomly allocated to one of the two groups with 1:1 allocation via a computer-generated randomisation schedule.
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
Anaesthetist and patient outcomes will be summarised.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
28/08/2024
Actual
Date of last participant enrolment
Anticipated
1/06/2026
Actual
Date of last data collection
Anticipated
1/07/2026
Actual
Sample size
Target
100
Accrual to date
0
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 316383 0
Charities/Societies/Foundations
Name [1] 316383 0
Australia and New Zealand College of Anaesthetists Research Foundation
Country [1] 316383 0
Australia
Primary sponsor type
Hospital
Name
Austin Health
Address
Country
Australia
Secondary sponsor category [1] 318565 0
None
Name [1] 318565 0
None
Address [1] 318565 0
Country [1] 318565 0
Other collaborator category [1] 283015 0
Hospital
Name [1] 283015 0
Peter MacCallum Cancer Centre
Address [1] 283015 0
Country [1] 283015 0
Australia
Other collaborator category [2] 283016 0
University
Name [2] 283016 0
University of Melbourne
Address [2] 283016 0
Country [2] 283016 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 315189 0
Austin Health Human Research Ethics Committee
Ethics committee address [1] 315189 0
https://www.austin.org.au/Office-for-Research/
Ethics committee country [1] 315189 0
Australia
Date submitted for ethics approval [1] 315189 0
15/04/2024
Approval date [1] 315189 0
24/07/2024
Ethics approval number [1] 315189 0

Summary
Brief summary
A critical part of an anaesthetist’s job is to make sure that the cells of a patient’s body continue to receive the right amount of oxygen. Oxygen delivery can't be directly measured, and anaesthetists rely on the surrogate measure of blood pressure. The pressure field software is real-time monitoring software which enables anaesthetists to understand how the heart and the body’s vessels are working together to generate blood pressure. This information, combined with a treatment algorithm, assists an anaesthetist in understanding what fluids or drugs will most help a patient. This may be particularly helpful for anaesthetists when they are caring for elderly patients, in whom it can be more challenging to know what fluids or drugs will work best. A large clinical trial evaluating the impact of the pressure field method on patient outcomes is being planned and this feasibility trial will 'road test' key elements of the planned large trial.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 133934 0
Dr Stephen Woodford
Address 133934 0
c/o Austin Hospital, 145 Studley Rd Heidelberg VIC 3084
Country 133934 0
Australia
Phone 133934 0
+61 467 979 118
Fax 133934 0
Email 133934 0
[email protected]
Contact person for public queries
Name 133935 0
Stephen Woodford
Address 133935 0
c/o Austin Hospital, 145 Studley Rd Heidelberg VIC 3084
Country 133935 0
Australia
Phone 133935 0
+61 467 979 118
Fax 133935 0
Email 133935 0
[email protected]
Contact person for scientific queries
Name 133936 0
Stephen Woodford
Address 133936 0
c/o Austin Hospital, 145 Studley Rd Heidelberg VIC 3084
Country 133936 0
Australia
Phone 133936 0
+61 467 979 118
Fax 133936 0
Email 133936 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?
Non-identifiable individual participant data underlying published results. No data that may be used to re-identify participants will be shared.
When will data be available (start and end dates)?
Beginning 3 months and ending 5 years following main results publication.
Available to whom?
On a case-by-case basis to academic authors. Requests from industry unaffiliated with an academic body such as a university will not be considered.
Available for what types of analyses?
Research which is an extension of or closely related to this study, for which there is a study protocol with ethics approval, and at the discretion of the Principal Investigator.
How or where can data be obtained?
By emailing the principal coordinating investigator at [email protected].


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.