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Trial registered on ANZCTR


Registration number
ACTRN12619000842167
Ethics application status
Approved
Date submitted
27/05/2019
Date registered
12/06/2019
Date last updated
27/07/2020
Date data sharing statement initially provided
12/06/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
A pilot study comparing the zero-heat-flux temperature monitoring device to oesophageal temperature monitoring in orthopaedic surgery.
Scientific title
A comparison of non-invasive zero-heat-flux thermometry with
invasive oesophageal measurements for consistent
perioperative temperature monitoring: a pilot study
Secondary ID [1] 298331 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Orthopaedic surgery 312977 0
Temperature monitoring 312978 0
Condition category
Condition code
Surgery 311482 311482 0 0
Other surgery

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
a) Description of the device.
The study will compare the zero heat flux monitoring device (Bair Hugger™, 3M, St Paul, MN) to oesophageal temperature monitoring (DeRoyal™, Powell, TN . The zero-heat-flux device (Bair Hugger™, 3M, St Paul, MN) measures tissue temperature at 1-2cm below the skin surface of the forehead, and this is considered to approximate core temperature. The device is comprised of a thermal insulator placed on the skin, and covered by an electric heater. Heat flow through the insulator is eliminated by the servo-control of the heater, so that the heater and skin temperature becomes equal. Oesophageal temperature monitoring will be achieved by utilising a temperature probe inserted utilizing videolargyngoscopy to a distance of 15cm to ensure placement in the oesophagus at the time of intubation.
b) Procedures
Preoperative phase: On arrival to the pre-operative holding area, and prior to the induction of anaesthesia, the Research Nurse will attach the zero heat flux monitoring Bair Hugger™ device to the forehead, above the orbital ridge. After a ramp-up time of 3 minutes, temperature data will be retrieved from the control unit at 15 minute intervals by the research assistant (Research Nurse). Device failure and other adverse events will be recorded.

Intraoperative phase: after transfer to the operating theatre, and during induction of anaesthesia, an oesophageal temperature monitoring (DeRoyal™) probe will be inserted in the distal oesophagus near the left atrium by the study anaesthetist. After adequate measurement depth is confirmed, the probe will be secured with the endotracheal tube. Standard monitoring, including electrocardiogram (ECG), pulse oximetry and non-invasive blood pressure (NIBP) will also be attached, as per usual care. General anaesthesia will commence in accordance with the study anaesthetic protocol developed in agreement with anaesthetic medical staff. Bladder temperature monitoring will be conducted via the indwelling urinary catheter, only if forming part of routine planned care for each participant.

All patients will be covered with a warmed cotton blanket, receive fluid warming to 38.5°C via fluid warmer and full or partial body forced air warming, dependent upon surgical site, commencing at 47°C and then automatically decreasing to 45°C , as per the study protocol (and as per the normal operating function of the Covidien Warm Touch™ forced air warmer). Ambient temperature will be recorded.

Postoperative phase: zero-heat-flux monitoring will continue upon transfer to the Post Anaesthetic Care Unit (PACU) and data will be recorded upon admission by the Research Nurse. Ambient temperature, warming interventions and acceptability of the device (from the patient’s perspective) will be assessed.
c) Who will deliver the intervention
The Research Nurse will attach the zero heat flux device and the anaesthetist will insert the oesophageal temperature monitoring probe.
d) Mode of delivery
Not applicable - see details above.
e) Number of times intervention delivered & over what period of time.
The zero heat flux device is attached preoperatively and will remain in place until admission to the Post Anaesthetic Care Unit. Oesophageal temperature monitoring remains in place only during general anaesthesia.
f) Setting where the intervention occurs
In the perioperative suite: in the preoperative holding area, through surgery and into the Post Anaesthetic Care Unit.
g) Strategies used to assess adherence to the intervention
Details of insertion and attachment of devices, as well as device failure, will be recorded.
Intervention code [1] 314571 0
Early detection / Screening
Comparator / control treatment
Oesophageal monitoring device (DeRoyal™, Powell, TN): despite the level of accuracy to PA measurements, the usefulness of this device is limited only to anaesthetised patients. Oesophageal temperature monitoring is achieved by utilising a temperature probe inserted utilizing videolargyngoscopy to a distance of 15cm to ensure placement in the oesophagus at the time of intubation. In contrast, the zero-heat-flux device is non-invasive and can therefore be utilized for awake patients.

Control group
Active

Outcomes
Primary outcome [1] 320186 0
Measurement accuracy of core temperature: assessed by comparing readings from zero heat flux monitoring device and oesophageal monitoring device. Agreement between monitoring routes will be analysed using a repeated measures Bland Altman random effects method (via MedCalc™). The acceptable limit of agreement between measurements will be +/- 0.5°C, which is the conventional acceptable limit of agreement for temperature monitoring devices. The mean difference between devices, the variability of the individual differences, and the intra-class correlation coefficient (ICC) will be reported,
Timepoint [1] 320186 0
Intraoperative temperature monitoring to first recorded temperature in Post Anaesthetic Care Unit.
Secondary outcome [1] 370799 0
Sensitivity and specificity to detect hypothermia. assessed by comparing readings from zero heat flux monitoring device and oesophageal monitoring device, assessing positive predictive values and negative predictive values for hypothermia. Receiver operating characteristic curves (ROC) will be plotted for detection of hypothermia (temperature <36. °C) and the areas under the curve will be calculated.
Timepoint [1] 370799 0
Intraoperative phase of care.
Secondary outcome [2] 370801 0
Acceptability of the device (as per patient's assessment) : measured by asking two questions (I felt comfortable wearing the temperature monitoring device;
I would be prepared to wear this device again during any future surgical procedures) measured via the following scale: Strongly agree / Agree / Unsure / Disagree / Strongly agree
Timepoint [2] 370801 0
Measured postoperatively in Post Anaesthetic Care Unit or upon return to ward (as appropriate).
Secondary outcome [3] 371135 0
Sensitivity and specifivity to detect fever: sensitivity, assessed by comparing readings from zero heat flux monitoring device and oesophageal monitoring device - assessing specificity, positive predictive values and negative predictive values for fever. Receiver operating characteristic curves (ROC) will be plotted for detection of fever (temperature of 37.5°C), and the areas under the curve will be calculated.
Timepoint [3] 371135 0
Intraoperative phase of care.

Eligibility
Key inclusion criteria
Patients undergoing elective orthopaedic surgery
Endotracheal tube placement with oesophageal temperature monitoring
General anaesthesia
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Forehead/neck rash or infection
Unexpected blood loss
Oesophageal varices
American Society of Anaesthesiologists (ASA) score >III
Patients not expected to receive endotracheal tube placement
Surgery under neuraxial anaesthesia

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
Phase
Phase 4
Type of endpoint/s
Efficacy
Statistical methods / analysis
Agreement between monitoring routes will be analysed using a repeated measures Bland Altman random effects method (via MedCalc™). The acceptable limit of agreement between measurements will be +/- 0.5°C, which is the conventional acceptable limit of agreement for temperature monitoring devices. The mean difference between devices, the variability of the individual differences, and the intra-class correlation coefficient (ICC) will be reported, as well as sensitivity, specificity, positive predictive values and negative predictive values for hypothermia and fever. Receiver operating characteristic curves (ROC) will be plotted for detection of hypothermia (temperature <36. °C) and fever (temperature of 37.5°C), and the areas under the curve will be calculated. Demographic data, and device failure rates, will be reported, with means and standard deviations or medians and ranges. A pilot study sample size of 30 participants is proposed.
This will allow the sample size for a larger trial to be computed to ensure a sufficient sample size to allow 95% limits of agreement, for measurements within 0.5°C. A significance level of P< 0.05 will be utilised.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
26/11/2018
Date of last participant enrolment
Anticipated
Actual
3/07/2019
Date of last data collection
Anticipated
Actual
3/07/2019
Sample size
Target
30
Accrual to date
Final
30
Recruitment in Australia
Recruitment state(s)
QLD

Funding & Sponsors
Funding source category [1] 302873 0
University
Name [1] 302873 0
QUT School of Nursing Pilot Grant Funding
Country [1] 302873 0
Australia
Primary sponsor type
University
Name
Queensland University of Technology
Address
School of Nursing, Queensland University of Technology, Victoria Park Road, Kelvin Grove, QLD 4059
Country
Australia
Secondary sponsor category [1] 302826 0
None
Name [1] 302826 0
Address [1] 302826 0
Country [1] 302826 0
Other collaborator category [1] 280710 0
Hospital
Name [1] 280710 0
Royal Brisbane and Women's Hospital
Address [1] 280710 0
Butterfield St, Herston QLD 4029
Country [1] 280710 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303448 0
Royal Brisbane and Women's Hospital Human Research Ethics Committee
Ethics committee address [1] 303448 0
Royal Brisbane and Women’s Hospital Human Research Ethics Committee
Lower ground Floor , Dr James Mayne Building
Herston QLD 4029
Ethics committee country [1] 303448 0
Australia
Date submitted for ethics approval [1] 303448 0
Approval date [1] 303448 0
17/09/2018
Ethics approval number [1] 303448 0
Ethics committee name [2] 303449 0
QUT Human Research Ethics Committee
Ethics committee address [2] 303449 0
OREI - Office of Research Ethics and Integrity
GPO Box 2434 QLD 4000
Ethics committee country [2] 303449 0
Australia
Date submitted for ethics approval [2] 303449 0
Approval date [2] 303449 0
27/09/2018
Ethics approval number [2] 303449 0

Summary
Brief summary
The overall aim of this study is to improve methods of temperature monitoring for patients undergoing surgery. There are concerns about how accurate the most commonly used, non- invasive methods of temperature monitoring are. The most accurate methods of measuring core temperature are very invasive, and therefore not routinely used for all patients undergoing surgery. Accurate and consistent measurement of temperature is important when patients are undergoing surgery to detect abnormal temperatures including fever, and perioperative hypothermia – that is, a very low temperature related to undergoing surgery and anaesthesia. Perioperative hypothermia is linked with range of adverse side effects. Therefore, it is very important that health care staff monitor temperature using the most effective, yet practical and safe mode of measurement.
This study specifically seeks to test the zero-heat-flux temperature monitoring device (Bair HuggerTM). The device will be tested in comparison to oesophageal temperature monitoring, which involves the insertion of a temperature monitoring probe into the oesophagus. This is often undertaken as part of routine care, as this method is considered an accurate method of core temperature measurement. The zero-heat- flux device is completely non-invasive, yet existing research suggests that it may offer greater accuracy in monitoring core temperature than other non-invasive devices in use. This study will assess the accuracy of the device, ability to detect hypothermia, as well as assessing the feasibility of a larger trial of the clinical application of the device. This device will be compared with the standard of care (oesophageal) device and all participants will receive both forms of monitoring.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 93690 0
Dr Judy Munday
Address 93690 0
Rm 529, N Block, School of Nursing, Queensland University of Technology, Victoria Park Road, Kelvin Grove, QLD 4059
Country 93690 0
Australia
Phone 93690 0
+61 7 3138 8209
Fax 93690 0
7 3138 3814
Email 93690 0
[email protected]
Contact person for public queries
Name 93691 0
Judy Munday
Address 93691 0
Rm 529, N Block, School of Nursing, Queensland University of Technology, Victoria Park Road, Kelvin Grove, QLD 4059
Country 93691 0
Australia
Phone 93691 0
+61 7 3138 8209
Fax 93691 0
7 3138 3814
Email 93691 0
[email protected]
Contact person for scientific queries
Name 93692 0
Judy Munday
Address 93692 0
Rm 529, N Block, School of Nursing, Queensland University of Technology, Victoria Park Road, Kelvin Grove, QLD 4059
Country 93692 0
Australia
Phone 93692 0
+61 7 3138 8209
Fax 93692 0
7 3138 3814
Email 93692 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Aggregated data only.


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
SourceTitleYear of PublicationDOI
EmbaseZero-heat-flux and esophageal temperature monitoring in orthopedic surgery: An observational study.2021https://dx.doi.org/10.2147/JMDH.S313310
N.B. These documents automatically identified may not have been verified by the study sponsor.