ANZCTR - Registration

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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

Date results information initially provided

10/09/2023

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]

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

Thermal perception (comfort and sensation)

Sweating impairments

Thermoregulatory strain

Heat-related cognitive decline

Condition category

Condition code

Injuries and Accidents

Other injuries and accidents

Public Health

Other public health

Cardiovascular

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]

Prevention

Comparator / control treatment

No fan with no skin wetting exposure

Control group

Active

Outcomes

Primary outcome [1]

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]

Immediately following the end of exposure

Primary outcome [2]

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]

Immediately following the end of exposure

Primary outcome [3]

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]

Immediately following the end of exposure

Secondary outcome [1]

Thermal comfort

The participant will be asked to rate how uncomfortable the heat makes them on a visual analogue scale

Timepoint [1]

Immediately following the end of exposure

Secondary outcome [2]

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]

Immediately following the end of exposure

Secondary outcome [3]

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]

Immediately following the end of exposure

Secondary outcome [4]

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]

Immediately following the end of exposure

Secondary outcome [5]

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]

Immediately following exposure

Secondary outcome [6]

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]

Immediately following the end of exposure

Secondary outcome [7]

Thermal sensation

The participant will be asked to rate how warm they feel on a visual analogue scale during each experimental session.

Timepoint [7]

Immediately following the end of exposure

Secondary outcome [8]

Heart rate

Heart rate will be measured using a 12 lead ECG monitoring system

Timepoint [8]

Immediately following the end of exposure

Secondary outcome [9]

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]

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

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

NSW

Recruitment outside Australia

Country [1]

Canada

State/province [1]

Montreal

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

National Health and Medical Research Council

Address [1]

16 Marcus Clarke St
Canberra
ACT
2601

Country [1]

Australia

Primary sponsor type

University

Name

University of Sydney

Address

The University of Sydney
Camperdown
NSW
2006

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

The University of Sydney Human Research Ethics Committee

Ethics committee address [1]

Research Integrity & Ethics Administration
Research Portfolio
Level 3, F23 Administration Building
The University of Sydney
NSW
2006

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

30/07/2018

Approval date [1]

29/08/2018

Ethics approval number [1]

2018/496

Summary

Brief summary

This study aims to identify the most appropriate cooling strategy for older adults with and without hypertension during a simulated hot and dry heatwave (45°C and 15% relative humidity)

Research questions:
The primary research question guiding this project is:
1. Are fans and/or skin-wetting effective in decreasing the physiological strain experienced by elderly during a simulated hot, dry heatwave (45°C and 15% relative humidity)

The research hypotheses going into this study are:
1. All interventions will result in reductions in thermal and cardiovascular strain compared to no intervention (control) With fan and skin-wetting (FSW) being the most effective, then no fan and skin-wetting (NFSW), then fan (F), and finally, the control, no-fan (NF).

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

A/Prof Ollie Jay

Address

Thermal Ergonomics Laboratory, Room 901
Susan Wakil Health Building
The University of Sydney
Camperdown, NSW 2006

Country

Australia

Phone

+61 293519328

Fax

[email protected]

Contact person for public queries

Name

A/Prof Ollie Jay

Address

Thermal Ergonomics Laboratory, Room 901
Susan Wakil Health Building
The University of Sydney
Camperdown, NSW 2006

Country

Australia

Phone

+61 293519328

Fax

[email protected]

Contact person for scientific queries

Name

A/Prof Ollie Jay

Address

Thermal Ergonomics Laboratory, Room 901
Susan Wakil Health Building
The University of Sydney
Camperdown, NSW 2006

Country

Australia

Phone

+61 293519328

Fax

[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.	Type	Attachment
2402	Informed consent form	377830-(Uploaded-20-06-2019-14-57-52)-Study-related document.doc
2403	Ethical approval	377830-(Uploaded-20-06-2019-14-58-37)-Study-related document.pdf
2404	Study 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

Source	Title	Year of Publication	DOI
Dimensions AI	Electric fans: A potential stay-at-home cooling strategy during the COVID-19 pandemic this summer?	2020	https://doi.org/10.1016/j.scitotenv.2020.141180

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically