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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
A trial comparing body warming devices during surgery.
Scientific title
Comparison of Easywarm Blanket with Cocoon Forced Air Warming Blanket in Preventing Intraoperative Hypothermia in patients undergoing Elective Surgery in Supine position.
Secondary ID [1] 286329 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Prevention of intraoperative hypothermia 294437 0
Condition category
Condition code
Anaesthesiology 294742 294742 0 0

Study type
Description of intervention(s) / exposure
Patients will be randomised into control group ( Cocoon warming blanket group) and Easywarm blanket group. Control group will be warmed intraoperatively using Cocoon forced air warming blanket and Easywarm group will be warmed using Easywarm blankets.
Easywarm self-heating blanket consists of pockets of iron with other elements which when exposed to air leads to an exothermic reaction resulting from oxidation of iron. This heats the blanket to 44 degree celcius which lasts upto 10 hours.
It can be separated into two parts and used for both the upper and the lower body.
Intervention code [1] 291378 0
Treatment: Devices
Intervention code [2] 291452 0
Comparator / control treatment
Using Cocoon forced air warming (FAW) blanket to warm patients intraoperatively which is the standard practice at Austin Hospital.
Cocoon FAW consists of an electrical heating unit with a fan which drives air into the blanket which is placed over upper and/or the lower body of the patient depending on the surgical location.
Temperature can be adjusted on the Cocoon blankets depending on the temperature of the patient.
Control group

Primary outcome [1] 294505 0
Nasopharyngeal temperature at the end of the operation.
The nasopharyngeal temperature is measured using nasopharyngeal temperature probe.
Timepoint [1] 294505 0
Final temperature at completion of wound closure.
Secondary outcome [1] 313481 0
Average temperature throughout the case.
All temperature recording will be via the Nasopharyngeal temperature probe. Average temperature will be calculated by adding the temperatures and dividing by the number of temperature points recorded.
Timepoint [1] 313481 0
Baseline temperature (at completion of draping) then every hour and final temperature at wound closure.

Key inclusion criteria
Elective surgery (open or laparoscopic) in supine position which lasts for at least 1 hour requiring relaxant general anaesthesia.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Sepsis, untreated thyroid dysfunction, fever, children, BMI>40, Severe peripheral vascular disease.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Suitable patients will be selected by the research team. The anaesthetist involved will be approached and explained about the trial. The patients will then be randomised into one of the groups. Patients will be warmed using Cocoon forced air warming (FAW) blanket if selected into Control group or Easywarm blanket if selected into Easywarm group.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
40 patients will be randomised to either Cocoon FAW blanket (Control group) or Easywarm blanket group in 1:1 ratio.
Randomisation will be by random selection of shuffled opaque envelopes containing group allocation.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Descriptive statistical terms will be used to describe the demographics of our study group. If data is normally distributed t-test will be used. If variables do not have a normal distribution then Wilcoxon signed rank test will be used. The p value, 95% confidence interval will be reported for normally distributed values. Median and interquartile range will be reported for non-parametric values.
Sample size calculation:
A significant difference between the two groups would be a temperature difference of 0.5 degree Celcius. With an alpha level (p value) of 0.05 and beta value of 0.8% an estimated standard deviation of 0.5 degrees and an estimated change in temperature of 0.5 degrees we would need a sample size of 31 patients.
To allow for data loss we aim to recruit 40 patients. Sample size is based on primary outcome only.

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] 3553 0
Austin Health - Austin Hospital - Heidelberg
Recruitment postcode(s) [1] 9358 0
3084 - Heidelberg

Funding & Sponsors
Funding source category [1] 290900 0
Name [1] 290900 0
Department of Anaesthesia
Austin Hospital.
Address [1] 290900 0
Austin Hospital
145 Studley Road, Heidelberg, Vic 3084
Country [1] 290900 0
Primary sponsor type
Department of Anaesthesia, Austin Hospital.
Austin Hospital
145 Studley Road, Heidelberg, Vic 3084
Secondary sponsor category [1] 289582 0
Name [1] 289582 0
Address [1] 289582 0
Country [1] 289582 0

Ethics approval
Ethics application status
Ethics committee name [1] 292503 0
Human Research Ethics Committee (HREC)
Ethics committee address [1] 292503 0
Office for Research, Austin Health
145 Studley Road, Heidelberg Vic 3084
Ethics committee country [1] 292503 0
Date submitted for ethics approval [1] 292503 0
Approval date [1] 292503 0
Ethics approval number [1] 292503 0

Brief summary
Multiple clinical trials have shown that perioperative hypothermia affects multiple organ systems and leads to adverse surgical outcomes.
Cocoon Forced Air Warming (FAW) Blanket is one of the devices being used in Austin Hospital to minimise intraoperative hypothermia.
Our aim is to compare the efficacy of Easywarm self-heating blankets with Cocoon FAW blanket in preventing intraopearative hypothermia by conducting a small randomised control trial.
Patients undergoing relaxant general anaesthesia in supine position will be randomised into two groups. The control group will be warmed using Cocoon FAW and the other group will be warmed using Easywarm blanket.
Easywarm blanket has not yet been compared with the FAW devices. The information we obtain from the project will help us to choose the optimal warming device in clinical practice.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 55630 0
A/Prof Philip Peyton
Address 55630 0
Austin Hospital,
145 Studley Road, Heidelberg, Vic 3084
Country 55630 0
Phone 55630 0
Fax 55630 0
Email 55630 0
Contact person for public queries
Name 55631 0
A/Prof Philip Peyton
Address 55631 0
Austin Hospital
145 Studley Road, Heidelberg, Vic 3084
Country 55631 0
Phone 55631 0
Fax 55631 0
Email 55631 0
Contact person for scientific queries
Name 55632 0
A/Prof Philip Peyton
Address 55632 0
Austin Hospital
145 Studley Road, Heidelberg, Vic 3084
Country 55632 0
Phone 55632 0
Fax 55632 0
Email 55632 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary