Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12625001096448
Ethics application status
Approved
Date submitted
19/09/2025
Date registered
8/10/2025
Date last updated
8/10/2025
Date data sharing statement initially provided
8/10/2025
Type of registration
Prospectively registered

Titles & IDs
Public title
Australasian MARS: Multicentre Aspiration Risk Study. A comparison of pulmonary aspiration rates for patients undergoing anaesthesia allowed to drink clear fluids before surgery versus those managed with traditional, fluid-restrictive fasting protocols
Scientific title
Australasian MARS: Multicentre Aspiration Risk Study. A pragmatic, multicentre observational cohort study comparing the incidence of pulmonary aspiration in hospitals with liberal (Sip Til Send) versus restrictive (usual care) preoperative fluid fasting
Secondary ID [1] 315195 0
None
Universal Trial Number (UTN)
Trial acronym
MARS
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pulmonary aspiration under anaesthesia 338922 0
Condition category
Condition code
Anaesthesiology 335225 335225 0 0
Anaesthetics
Respiratory 335336 335336 0 0
Other respiratory disorders / diseases

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
The intervention being studied is liberal preoperative fluid fasting, consisting of allowing clear fluids until the time of surgery, also known as "Sip Til Send".

The study is observational in nature, there is no change to any hospital's current fasting protocol due to participation in the study and no alteration to routine patient care. The project will require a study population of more than 200,000 anaesthetics for adequate statistical power, and has ethics approval for a waiver of patient consent due to the impracticality of consenting this number of patients for the de-identified data collection.

Pulmonary aspiration events occurring during anaesthesia are identified clinically by the treating anaesthetist caring for the patient. The events can then be flagged to the principal investigator at each hospital site via internal audit mechanisms. The audit mechanism varies depending on the hospital size and what electronic systems are in use, but many sites are using dedicated QR codes present in all anaesthetising locations.

The data collected for each aspiration event will be extracted anonymously from patient medical records by the local principal investigator. The information will include patient characteristics, details of when and how the event occurred during anaesthesia, risk factors for aspiration, and the severity of the event (e.g. whether it resulted in unplanned hospital or ICU admission, ventilator therapy, antibiotics or mortality).

In addition, the study will involve high volume, de-identified data extraction from electronic operating records of the total number of anaesthetic cases ("denominator") in order to be able to calculate an overall incidence of aspiration. Basic information will be extracted for the total number of cases including
- Age on date of procedure
- Date of procedure
- Name of procedure and specialty
- Urgency of case (elective/emergency)
- Type of anaesthetic (general, sedation, regional)
- American Society of Anaesthesiologists Physical Status Classification score
- Time of last fluid intake

Data will be extracted at 3-monthly intervals from each participating site, to allow assessment of progress towards the target sample size. The estimated total prospective data collection period is around 9 months, with no ongoing follow up or further data extraction required after this time.

As the ideal comparison group for this study would be pre- and post-intervention data from the same hospitals, MARS will incorporate retrospective data when available. As pulmonary aspiration rates under Sip Til Send are unknown, many hospitals adopting this novel fasting practice chose to audit local aspiration rates and monitor for adverse events during its implementation, prior to and independent of the MARS project. We will therefore include this data where available, if it was collected using a reliable audit method which is continuous with the method that will be used for prospective data collection. The audit must have been clearly publicised within the department with instructions to report every suspected aspiration and not only cases of special interest, medico-legal significance or educational value (which may be the case with traditional morbidity and mortality reporting or incident management systems). The duration of retrospective data collected for MARS will be determined by the period for which reliable data is available, and will be different for each hospital depending on when they started to audit aspiration events.
Intervention code [1] 332021 0
Not applicable
Comparator / control treatment
Traditional/fluid restrictive preoperative fasting, consisting of restricting clear fluid intake to 2hr before surgery for adults and 1-2hr for paediatric patients
Control group
Active

Outcomes
Primary outcome [1] 342830 0
Pulmonary aspiration
Timepoint [1] 342830 0
From induction of anaesthesia to emergency in the recovery room
Secondary outcome [1] 452297 0
Pulmonary aspiration events resulting in admission to either high dependency or intensive care unit (composite outcome)
Timepoint [1] 452297 0
As a direct result of pulmonary aspiration events occurring from anaesthetic induction to emergence in the recovery room
Secondary outcome [2] 452298 0
Pulmonary aspiration events resulting in death
Timepoint [2] 452298 0
As a direct result of pulmonary aspiration events occurring from anaesthetic induction to emergence in the recovery room
Secondary outcome [3] 452299 0
Pulmonary aspiration events requiring unplanned postoperative ventilator therapy
Timepoint [3] 452299 0
As a direct result of aspiration events occurring from anaesthetic induction to emergence in the recovery room

Eligibility
Key inclusion criteria
All anaesthetic cases performed in participating sites over the study period
Minimum age
0 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
None

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Timing
Both
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
20/10/2025
Actual
Date of last participant enrolment
Anticipated
20/10/2026
Actual
Date of last data collection
Anticipated
20/10/2026
Actual
Sample size
Target
250000
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW,NT,QLD,SA,TAS,WA,VIC
Recruitment outside Australia
Country [1] 27365 0
New Zealand
State/province [1] 27365 0

Funding & Sponsors
Funding source category [1] 319763 0
Charities/Societies/Foundations
Name [1] 319763 0
Far North Queensland Hospital Foundation
Country [1] 319763 0
Australia
Primary sponsor type
Hospital
Name
Cairns and Hinterland Hospital and Health Service
Address
Country
Australia
Secondary sponsor category [1] 322272 0
None
Name [1] 322272 0
Address [1] 322272 0
Country [1] 322272 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 318322 0
Townsville Hospital and Health Service Human Research Ethics Committee
Ethics committee address [1] 318322 0
Ethics committee country [1] 318322 0
Australia
Date submitted for ethics approval [1] 318322 0
17/03/2025
Approval date [1] 318322 0
09/04/2025
Ethics approval number [1] 318322 0
HREC/QTHS/115991
Ethics committee name [2] 318535 0
Northern B Health and Disability Ethics Committee 
Ethics committee address [2] 318535 0
Ethics committee country [2] 318535 0
New Zealand
Date submitted for ethics approval [2] 318535 0
20/03/2025
Approval date [2] 318535 0
23/04/2025
Ethics approval number [2] 318535 0
2025 EXP 22462

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 143802 0
Dr Phuong Markman
Address 143802 0
Cairns Hospital, 165 The Esplanade, Cairns QLD 4870
Country 143802 0
Australia
Phone 143802 0
+61742266968
Fax 143802 0
Email 143802 0
[email protected]
Contact person for public queries
Name 143803 0
Phuong Markman
Address 143803 0
Cairns Hospital, 165 The Esplanade, Cairns QLD 4870
Country 143803 0
Australia
Phone 143803 0
+61742266968
Fax 143803 0
Email 143803 0
[email protected]
Contact person for scientific queries
Name 143804 0
Phuong Markman
Address 143804 0
Cairns Hospital, 165 The Esplanade, Cairns QLD 4870
Country 143804 0
Australia
Phone 143804 0
+61742266968
Fax 143804 0
Email 143804 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No
No IPD sharing reason/comment: Data cannot be shared publicly due to institutional ethics, privacy and confidentiality regulations.



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.