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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 Comparative study of airway pressures generated by non-invasive respiratory support used in cardiac surgical patients
Scientific title
A Comparative Study of airway pressures generated in cardiac surgical patients using nasal high flow and facemask continuous positive airway pressure (CPAP).
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Non-invasive respiratory support post cardiac surgery 4592 0
Condition category
Condition code
Respiratory 4886 4886 0 0
Other respiratory disorders / diseases

Study type
Description of intervention(s) / exposure
Patients undergoing cardiac surgery will be invited pre-operatively to participate in this study. Participants will have pressure measurements carried out with both Optiflow trademark and facemask non-invasive ventilation (NIV).
Following surgery, whilst the participant is sedated and ventilated in the Intensive Care Unit, a 10F catheter will be inserted into the nasopharynx via the nose.
Once the patient has been woken and extubated a baseline airway pressure measurement will be performed while the patient breathes spontaneously on their routine oxygen therapy device e.g. standard nasal cannulae or facemask.
Pressure measurements will be carried out following a random sequence for both the Optiflow trademark system and NIV delivered via a facemask. Participants will have 3 measurements performed on the Optiflow interface at 30, 40 and 50 litres per minute and 3 measurements performed on NIV at 4,6 and 8 cmH2O via a facemask.

For each group, pressure measurement for each flow/pressure will be recorded over one minute of breathing using precision pressure transducer (PPT). This procedure is expected to take around 30 mins. The catheter will be removed at the end of this period.
Intervention code [1] 4356 0
Treatment: Devices
Comparator / control treatment
Facemask CPAP
Control group

Primary outcome [1] 5740 0
Mean nasopharyngeal airway pressure as determined by measurements taken over one minute of breathing. Specially designed software will be used to carry out the measurements and calculate the mean.
Timepoint [1] 5740 0
Six measurements in total will be undertaken - one at each flow level for Optiflow and one at each pressure level for facemask CPAP. Each measurement is continuous over one minute. Mean airway pressure is calculated by averaging the peak and trough pressures over the entire minute of breathing.
Secondary outcome [1] 241688 0
Timepoint [1] 241688 0

Key inclusion criteria
Consent has been obtained.
Patient is over 18 years of age.
Patient is to undergo cardiac surgery.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
The patient has significant nasal septum deviation.
High flow nasal oxygen therapy is contraindicated.
Non-invasive ventilation is contraindicated
Following surgery the patient is unable to follow simple commands once awake and extubated.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled 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)
Latin squares used to allocate treatment order.
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

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 1726 0
New Zealand
State/province [1] 1726 0

Funding & Sponsors
Funding source category [1] 4778 0
Commercial sector/Industry
Name [1] 4778 0
Fisher and Paykel Healthcare Limited
Address [1] 4778 0
15 Maurice Paykel Place
East Tamaki
Auckland 1741
Country [1] 4778 0
New Zealand
Primary sponsor type
Auckland City Hospital
Park Road
Auckland, 1010
New Zealand
Secondary sponsor category [1] 4315 0
Name [1] 4315 0
Address [1] 4315 0
Country [1] 4315 0

Ethics approval
Ethics application status
Ethics committee name [1] 6823 0
Northern X Regional Ethics Committee
Ethics committee address [1] 6823 0
Ministry of Health. 3rd floor. Unisys Building. 650 Great South Road. Penrose. Auckland, 1061
Ethics committee country [1] 6823 0
New Zealand
Date submitted for ethics approval [1] 6823 0
Approval date [1] 6823 0
Ethics approval number [1] 6823 0

Brief summary
This study will compare the airway pressure generated in cardiac surgical patients receiving high flow humidified nasal oxygen therapy to that generated in the same patient when receiving non-invasive ventilation via a face mask.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 29485 0
Address 29485 0
Country 29485 0
Phone 29485 0
Fax 29485 0
Email 29485 0
Contact person for public queries
Name 12732 0
Rachael Parke
Address 12732 0
Cardiothoracic and Vascular Intensive Care Unit, Private Bag 92024, Auckland 1010
Country 12732 0
New Zealand
Phone 12732 0
+64 9 3074949 ext. 24489
Fax 12732 0
+64 9 6236463 ext. 24473
Email 12732 0
Contact person for scientific queries
Name 3660 0
Shay McGuinness
Address 3660 0
Cardiothoracic and Vascular Intensive Care Unit, Private Bag 92024, Auckland 1010
Country 3660 0
New Zealand
Phone 3660 0
+64 9 3074949 ext. 24470
Fax 3660 0
+64 9 6236463 ext. 24473
Email 3660 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