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Trial registered on ANZCTR


Registration number
ACTRN12619000938101
Ethics application status
Approved
Date submitted
25/06/2019
Date registered
5/07/2019
Date last updated
10/09/2023
Date data sharing statement initially provided
5/07/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Low-cost, at home cooling strategies for older adults during hot-and-dry heatwaves
Scientific title
Assessing the physiological and perceptual efficacy of low cost cooling strategies for older adults in hot-and-dry heatwaves.
Secondary ID [1] 298559 0
None
Universal Trial Number (UTN)
U1111-1235-7682
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Heat related cardiovascular strain 313385 0
Thermal perception (comfort and sensation) 313386 0
Sweating impairments 313387 0
Thermoregulatory strain 313388 0
Heat-related cognitive decline 313389 0
Condition category
Condition code
Injuries and Accidents 311822 311822 0 0
Other injuries and accidents
Public Health 311823 311823 0 0
Other public health
Cardiovascular 311940 311940 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Intervention

Each participant will take part in four three hour exposures which be randomised;
1. No fan with no skin wetting (comparator)
2. Fan use with no skin wetting
3. No fan use with skin wetting
4. Fan use with skin wetting

They will be asked to sit in a thermally regulated environmental chamber at a temperature of 45°C and 15% relative humidity.

In all fan exposures, participants will be seated 1.25m from an 18" diameter fan with an airflow of ~4.0m/s. This is the velocity of a typical fan at highest speed.

For the skin wetting exposures, approx 770mL, 18ºC tap water will be applied to the skin using a commercially available spray bottle to the face, neck, arms and legs by a researcher.

Additionally, in all exposures they will be given cold (~18ºC) water equivalent to 1ml per kg of body weight every 20 minutes in an attempt to offset dehydration.

There will be a minimum of 72 hours washout between each exposure.
Intervention code [1] 314811 0
Prevention
Comparator / control treatment
No fan with no skin wetting exposure
Control group
Active

Outcomes
Primary outcome [1] 320494 0
Core temperature via rectal thermometer

Rectal temperature sensor: The participant will be asked to insert a flexible sensor 10-12cm into their rectum. A marker is placed on the sensor using sterile surgical tape. The participant will insert the sensor until the tape reaches their anal surface. The insertion of the sensor may cause some mild discomfort and minor irritation; however, this sensation soon passes. The participant will receive proper instruction regarding the placement of the sensor to ensure their safety and comfort. The participant will be responsible for the insertion of this sensor. It will provide the researcher with an indication of the amount of heat stored in their body and will be tracked throughout the entirety of each experimental session
Timepoint [1] 320494 0
Immediately following the end of exposure
Primary outcome [2] 320495 0
Rate pressure product measured via blood pressure and heart rate

An automated blood pressure monitor will be strapped to the participants arm and blood pressure will be used by researchers to calculate RPP(heart rate x systolic blood pressure).
Timepoint [2] 320495 0
Immediately following the end of exposure
Primary outcome [3] 320496 0
Whole body sweat loss

The participant will be weighed on a platform scale immediately before and at the completion of the heatwave exposure in order to compare whole-body sweat losses.
Timepoint [3] 320496 0
Immediately following the end of exposure
Secondary outcome [1] 371793 0
Thermal comfort

The participant will be asked to rate how uncomfortable the heat makes them on a visual analogue scale
Timepoint [1] 371793 0
Immediately following the end of exposure
Secondary outcome [2] 371794 0
Skin temperature

Four skin sensors will be taped to the participants skin surface with hypoallergenic tape. Some hair may need to be shaved (by the use of disposable razors) in order to secure the sensors adequately. These sensors give an indication of skin temperature and dry heat loss from the skin and will be recorded throughout the entirety of each experimental session
Timepoint [2] 371794 0
Immediately following the end of exposure
Secondary outcome [3] 371795 0
Skin blood flow

A flexible laser probe will measure skin blood flow non-invasively at the upper back and forearm during the entirety of each experimental session.
Timepoint [3] 371795 0
Immediately following the end of exposure
Secondary outcome [4] 371796 0
Local sweat rate

A small plastic capsule connected to plastic tubing will be placed on the participants upper back and forearm. Dry air is passed through this capsule and a humidity sensor will pick up humidity from the skin and provides a measurement of local sweat rate throughout each experimental session.
Timepoint [4] 371796 0
Immediately following the end of exposure
Secondary outcome [5] 371797 0
Cognitive performance

The participant will be asked to complete a short-form of the Stroop Colour and Word Test (SCWT) immediately before and at the completion of the heatwave exposure. This test involves them looking at various words and identifying which colour the words are shown in.
Timepoint [5] 371797 0
Immediately following exposure
Secondary outcome [6] 371798 0
Evidence of orthostatic hypotension

At the half way stage of each exposure (1 hour and 30 minutes) and at the completion of the heatwave exposure the participants blood pressure will be taken. They will then be asked to stand up and their blood pressure will be taken after 1 minute of standing and then again after 3 minutes of standing. This test is carried out to see if there is evidence of postural hypotension (a drop in blood pressure within 3 minutes of standing from a seated position).
Timepoint [6] 371798 0
Immediately following the end of exposure
Secondary outcome [7] 371799 0
Thermal sensation

The participant will be asked to rate how warm they feel on a visual analogue scale during each experimental session.
Timepoint [7] 371799 0
Immediately following the end of exposure
Secondary outcome [8] 371800 0
Heart rate

Heart rate will be measured using a 12 lead ECG monitoring system
Timepoint [8] 371800 0
Immediately following the end of exposure
Secondary outcome [9] 371801 0
Blood pressure

Blood pressure: An automated blood pressure monitor will be strapped to the participants arm and duplicate blood pressure measurements will be taken every 20 minutes. This measure will also enable calculations of mean arterial pressure in combination with HR.
Timepoint [9] 371801 0
Immediately following the end of exposure

Eligibility
Key inclusion criteria
Non smokers (or at least 1 year since quitting)
Over 60 years of age
Controlled hypertension or healthy older adult
Minimum age
60 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Oestrogen therapy
Fluid or electrolyte disorders
Anaemia
Abnormal thyroid function
Arrhythmias
Diabetes
Renal disease
Liver disease
Uncontrolled hypertension
Significant cognitive impairment and / or degenerative neurological condition
History of substance abuse
Taking anticholinergic medication
Known atherosclerotic disease
Severe respiratory disease
Known aneurysms
Progressive neurological disorders
Active cancer treatment

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomisation via a computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Permuted block randomisation
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Participants will be randomised via a central computer database in a balanced order of males and females and participants with hypertension and no hypertension
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The primary research outcomes are change in rate pressure product (RPP), change in rectal temperature (Tre), whole body sweat loss (WBSL) and thermal sensation (TS).

Secondary research outcomes include heart rate (HR), blood pressure (BP), thermal comfort (TC), skin temperature (Tsk).

Tertiary research outcomes include skin blood flow (SkBF), local sweat rate (LSR), cognitive performance, and evidence of orthostatic hypotension (OH).

Data will be combined with data from our partner site at the Montreal Heart Institute (MHI, ClinicalTrials.gov: NCT03832504) for all trials, except the very hot dry fan trials (fan and fan+skin wetting) because participants at the MHI (i.e., those with Coronary Artery Disease) will not undergo the fan trials due to safety concerns.

Changes from pre- trial to end- 3 hr exposure (using the last 5 min average) will be compared between each intervention and the control (no cooling) trial for all primary variables. In the very hot dry trial with the fans (i.e., CON vs FAN & FSW), all data will be assessed using a paired t-test (CON vs FAN, FSW). The risk of type II error will be controlled for using a Holm-bonferroni correction.

To analyse differences between the control and skin wetting trials (with participants from University of Sydney and Montreal Heart Institute), a 2-way mixed effects Analysis of Variance (ANOVA) model will be performed with the repeated factor of intervention (CON vs. SW) and non-repeated factor of group (with and without heart disease). A significant interaction between main effects will be investigated with paired t-tests comparing intervention to CON within each group with post-hot comparisons adjusted with Holm-Bonferroni corrections.

All statistical analyses will be performed with SPSS.

Recruitment
Recruitment status
Stopped early
Data analysis
Data collected is being analysed
Reason for early stopping/withdrawal
Safety concerns
Date of first participant enrolment
Anticipated
15/07/2019
Actual
5/01/2020
Date of last participant enrolment
Anticipated
1/11/2022
Actual
22/11/2022
Date of last data collection
Anticipated
31/12/2022
Actual
19/05/2023
Sample size
Target
56
Accrual to date
Final
20
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment outside Australia
Country [1] 21627 0
Canada
State/province [1] 21627 0
Montreal

Funding & Sponsors
Funding source category [1] 303100 0
Government body
Name [1] 303100 0
National Health and Medical Research Council
Country [1] 303100 0
Australia
Primary sponsor type
University
Name
University of Sydney
Address
The University of Sydney
Camperdown
NSW
2006
Country
Australia
Secondary sponsor category [1] 303093 0
None
Name [1] 303093 0
Address [1] 303093 0
Country [1] 303093 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303645 0
The University of Sydney Human Research Ethics Committee
Ethics committee address [1] 303645 0
Ethics committee country [1] 303645 0
Australia
Date submitted for ethics approval [1] 303645 0
30/07/2018
Approval date [1] 303645 0
29/08/2018
Ethics approval number [1] 303645 0
2018/496

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

Contacts
Principal investigator
Name 94378 0
A/Prof Ollie Jay
Address 94378 0
Thermal Ergonomics Laboratory, Room 901
Susan Wakil Health Building
The University of Sydney
Camperdown, NSW 2006
Country 94378 0
Australia
Phone 94378 0
+61 293519328
Fax 94378 0
Email 94378 0
[email protected]
Contact person for public queries
Name 94379 0
Ollie Jay
Address 94379 0
Thermal Ergonomics Laboratory, Room 901
Susan Wakil Health Building
The University of Sydney
Camperdown, NSW 2006
Country 94379 0
Australia
Phone 94379 0
+61 293519328
Fax 94379 0
Email 94379 0
[email protected]
Contact person for scientific queries
Name 94380 0
Ollie Jay
Address 94380 0
Thermal Ergonomics Laboratory, Room 901
Susan Wakil Health Building
The University of Sydney
Camperdown, NSW 2006
Country 94380 0
Australia
Phone 94380 0
+61 293519328
Fax 94380 0
Email 94380 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?
Individual participant data underlying published results only
When will data be available (start and end dates)?
Immediately following publication - no end date
Available to whom?
Case by case basis at the discretion of the primary sponsor
Available for what types of analyses?
Meta-analysis
How or where can data be obtained?
Access subject to approvals by the Principle Investigator with a requirement to sign data access agreements


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
2402Informed consent form    377830-(Uploaded-20-06-2019-14-57-52)-Study-related document.doc
2403Ethical approval    377830-(Uploaded-20-06-2019-14-58-37)-Study-related document.pdf
2404Study protocol    377830-(Uploaded-20-06-2019-15-17-16)-Study-related document.docx



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
Dimensions AIElectric fans: A potential stay-at-home cooling strategy during the COVID-19 pandemic this summer?2020https://doi.org/10.1016/j.scitotenv.2020.141180
N.B. These documents automatically identified may not have been verified by the study sponsor.