The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Airway oxygen concentration with high flow nasal oxygen
Scientific title
Airway oxygen concentration in patients undergoing airway surgery with high flow nasal oxygen as the primary oxygenation technique
Secondary ID [1] 295421 0
nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hypopharyngeal surgery 308660 0
laryngotracheal surgery 308941 0
Condition category
Condition code
Anaesthesiology 307599 307599 0 0
Surgery 307840 307840 0 0
Other surgery

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
The group being observed is patients undergoing elective airway surgery with apnoeic oxygenation and high flow nasal oxygen (HFNO) as their primary oxygenation technique.
The outcome or condition we are observing is the oxygen concentration in the airway, at the surgical site.
The exposure is that delivered oxygen concentration (FiO2) will be decreased from 100% to 30% for 60 seconds.
Intervention code [1] 301727 0
Not applicable
Comparator / control treatment
No control group
Control group

Primary outcome [1] 306607 0
Change in airway oxygen concentration.

This will be measured using a gas sampling line placed in the airway using surgical forceps. The line delivers respiratory gases to the AS5 gas analysis module fitted to GE Aisys anaesthetic machines.
Timepoint [1] 306607 0
Airway oxygen concentration will be measured continuously for 60 seconds following the change in delivered oxygen concentration.

This will be carried out once with the tip of the gas sampling line at 1cm beyond the end of the rigid laryngoscope and once with the tip of the line 6cm beyond the end of the rigid laryngoscope.

Following these two measurements the sampling line will be removed and surgery will proceed.
Primary outcome [2] 306608 0
Rate of change of oxygen concentration (% per second).

As above, this will be measured with a gas sampling line in the airway.
Timepoint [2] 306608 0
As above, airway O2 concentration will be measured continuously for 60seconds. This will provide both an overall rate of change (average over 1 minute) and a profile of the change ie exponential vs linear.

This will be carried out with the gas sampling line at 1cm and 6cm beyond the rigid laryngoscope.
Secondary outcome [1] 348990 0
Total anaesthetic apnoeic time (minutes).

This will be recorded by stopwatch from time of rocuronium administration to whichever is sooner of 1. time first spontaneous breath is taken or 2. first positive pressure ventilation breath is administered.
Timepoint [1] 348990 0
The secondary outcome is a timepoint and will be measured in minutes + seconds.
Secondary outcome [2] 348991 0
Lowest recorded O2 saturation.

O2 saturations are measured by the GE Datex monitors in real time. Lowest O2 saturation will be recorded by the anaesthetist during the anaesthetic and will be corroborated by retrospective interrogation of monitor data.
Timepoint [2] 348991 0
Lowest recorded O2 saturation during the apnoeic period.
Secondary outcome [3] 348992 0
Change of anaesthetic technique.

If prior to completion of surgery positive pressure ventilation is undertaken at the discretion of the anaesthetist, including
- bag mask ventilation
- jet ventilation
- placement of an endotracheal tube
- placement of an laryngeal mask airway

this will be considered a change of anaesthetic technique.
Timepoint [3] 348992 0
For the duration of the surgical procedure

Key inclusion criteria
Patients undergoing elective hypopharyngeal or laryngotracheal surgery where apnoeic oxygenation with High Flow Nasal Oxygen (HFNO) is the chosen anaesthetic technique

Patients aged 18-75 years

Patients deemed ASA 1-3
Minimum age
18 Years
Maximum age
75 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Unable to give valid consent
BMI >35
Not otherwise suitable for HFNO technique as deemed by anaesthetist
ASA 4-5

Study design
Natural history
Defined population
Statistical methods / analysis
Data will be presented as mean +/- standard deviation and p values will be calculated using the unpaired student's t-test

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] 10616 0
New Zealand
State/province [1] 10616 0
Christchurch, canterbury

Funding & Sponsors
Funding source category [1] 300007 0
Name [1] 300007 0
Christchurch Public Hospital
Address [1] 300007 0
Department of Anaesthesia
Christchurch public hospital
2 Riccarton ave
Christchurch 8011
Country [1] 300007 0
New Zealand
Primary sponsor type
Christchurch public hospital
Department of Anaesthesia
2 Riccarton AVe
Christchurch 8011
New Zealand
Secondary sponsor category [1] 299393 0
Name [1] 299393 0
Address [1] 299393 0
Country [1] 299393 0

Ethics approval
Ethics application status
Ethics committee name [1] 300861 0
Health and disability ethics committee NZ
Ethics committee address [1] 300861 0
Ministry of Health
Health and Disability Ethics Committee
PO box 5013
Wellington 6140
Ethics committee country [1] 300861 0
New Zealand
Date submitted for ethics approval [1] 300861 0
Approval date [1] 300861 0
Ethics approval number [1] 300861 0

Brief summary
This is an observational study looking at patients undergoing airway surgery where High Flow Nasal Oxygen (HFNO) is used for patient oxygenation during a period of sustained apnoea.

The study aims to characterise the change in oxygen (O2) concentration in the airway when O2 delivered by HFNO is decreased from 100% down to 30%

This will enable us to objectively quantify oxygen levels at the surgical site when HFNO is being used to provide sustained apnoeic oxygenation

As such it is anticipated that the study will represent a valuable contribution to patient safety by informing strategies that ensure safe and optimal surgical conditions during airway surgery in the presence of an ignition source.
Trial website
Trial related presentations / publications
nil as yet
Public notes
Attachments [1] 2898 2898 0 0

Principal investigator
Name 85070 0
Dr Nick Abbott
Address 85070 0
Department of Anaesthesia
Christchurch Public hospital
2 Riccarton ave
Christchurch 8011
Country 85070 0
New Zealand
Phone 85070 0
Fax 85070 0
Email 85070 0
Contact person for public queries
Name 85071 0
Dr Nick Abbott
Address 85071 0
Department of Anaesthesia
Christchurch Public hospital
2 Riccarton ave
Christchurch 8011
Country 85071 0
New Zealand
Phone 85071 0
Fax 85071 0
Email 85071 0
Contact person for scientific queries
Name 85072 0
Dr Pippa Jerram
Address 85072 0
Department of Anaesthesia
Christchurch public hospital
2 Riccarton ave
Christchurch 8011
Country 85072 0
New Zealand
Phone 85072 0
Fax 85072 0
Email 85072 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
their is no provision in the consent for participation in this study, for individual data to be shared.
What supporting documents are/will be available?
Informed consent form
Ethical approval
How or where can supporting documents be obtained?
Type [1] 5127 0
Informed consent form
Citation [1] 5127 0
Link [1] 5127 0
Email [1] 5127 0
Other [1] 5127 0
Type [2] 5128 0
Ethical approval
Citation [2] 5128 0
Link [2] 5128 0
Email [2] 5128 0
Other [2] 5128 0
Summary results
No Results