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Trial registered on ANZCTR


Registration number
ACTRN12623000575639
Ethics application status
Approved
Date submitted
5/05/2023
Date registered
25/05/2023
Date last updated
30/05/2024
Date data sharing statement initially provided
25/05/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
Laryngeal oxygen concentration and apnoea time during microlaryngeal surgery using transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) with different oxygen concentrations: A randomised controlled clinical trial
Scientific title
Laryngeal oxygen concentration and apnoea time during microlaryngeal surgery using transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) with different oxygen concentrations: A randomised controlled clinical trial
Secondary ID [1] 309604 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Airway management during microlaryngeal surgery 329916 0
Ventilation during general anaesthesia for microlaryngeal laser surgery 329917 0
Condition category
Condition code
Anaesthesiology 326825 326825 0 0
Other anaesthesiology

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The study includes the following steps:
1. The patient is identified when seen in the otolaryngology outpatient clinic as potentially suitable to participate in the study. Participation is discussed with the patient and informed consent to participate is obtained.
2. The patient is randomised to one of two groups,either Group A: ‘Apnoea Group’ (no delivery of high-flow oxygen, environmental room air oxygen only) or Group B: ‘30% Oxygen Group’ (Delivery of high-flow oxygen at 30% concentration), using an online randomisation tool. The patient is assigned a study ID which is on all further study documentation.
3. Patient enters the operating room. An investigator (DDN, DN, or a clinical fellow) enters demographic data into the Data Collection Form using patient’s study ID. All data collection throughout the procedure is recorded by an associate investigator or member of the clinical team.
4. The anaesthetic team will administer the intervention. The patient (both groups) is provided with pre-oxygenation using an Optiflow High Flow Nasal Oxygen at 100%, starting at 40L/Min prior to induction of anaesthesia and increasing to 70 litres/minute (once the patient is asleep). Duration of pre-oxygenation is at least three minutes. Baseline oxygen saturation and vital parameters are recorded using readings shown in a monitor screen during pre-oxygenation.
5. Anaesthesia is implemented by the anaesthetist. Oxygen delivery is maintained at 100%, 70 litres/minute. The time anaesthesia starts is recorded in the Data Collection Form.
6. Microlaryngeal surgical procedure starts. The start time of the procedure is recorded in the Data Collection Form.
7. Oxygen concentration in the larynx is measured using a cannula connected to a gas sampling tube which is in turn connected to a sampling unit built into the anaesthetic machine. The oxygen concentration (%) is shown on the monitor screen and is recorded in the Data Collection Form.
8. Delivered high-flow nasal oxygen is either switched off completely (Group A) or reduced to 30% oxygen (Group B). For patient from Group A, delivery of high-flow oxygen will cease and the patient will be apnoeic. For patients from Group B, high-flow would be reduced to 30% oxygen concentration. A sampling cannula is used to measure the real-time laryngeal oxygen concentration after these adjustments. The time from adjusting oxygen concentration until the laryngeal oxygen concentration drops is measured using a stopwatch. Vital parameters and oxygen saturation data are recorded from the readings shown in the monitor screen.
9. Microlaryngeal procedure proceeds as planned. Patient’s vital parameters (e.g. breathing rate, heart rate, blood pressure) and oxygen saturation (SpO2) is monitored intra-operatively as per normal practice.
10. When patient’s oxygen saturation reaches 89%, the delivery of 100% oxygen/70 litre min-1 is resumed and rescue supraglottic jet ventilation is employed as required. The time from the decrease in delivered oxygen concentration until rescue is recorded in the data collection form. The 89% oxygen saturation is used as a guideline for initiation of rescue ventilation, however, the ultimate decision as to when this occurs will be determined by the anaesthetist who may advise earlier implementation of rescue ventilation, in which case patient oxygen saturation at that point will be recorded. Should rescue jet ventilation fail to recover oxygen saturations, the next line of intervention will be endotracheal intubation as per our standard practice, and timing of this will be guided by the anaesthetist.

The intervention will be in place until rescue jet ventilation is required or until the end of the case if rescue ventilation is not required.

The same parameters (e.g. vital parameters, oxygen saturation and desaturation rate) will be collected from the two groups. The same nasal cannula will be in place for both groups. The length of the intervention is one of the outcome measures that we are trying to measure for comparing between the two groups.

11. When surgery is complete and patient resumes spontaneous breathing, end-tidal carbon dioxide is recorded. An anaesthetic chart is printed out from the anaesthetic machine. The study procedure is complete.
12. This study will be overseen by a DSMB comprised of three experts, an ENT surgeon, anaesthetist and biostatistician. They will meet initially, following recruitment of the first three patients, every six months and then again at the conclusion of the trial. The DSMB will be guided by a charter which outlines their responsibilities.
13. Follow up of the participants in this study will not be different to their routine clinical follow up which is guided by their clinical pathology. All patients will be reviewed post-operatively prior to discharge from the hospital.

Review of anaesthetic chart and anaesthetist's notes will be used to assess adherence to the intervention.
Intervention code [1] 326026 0
Treatment: Other
Comparator / control treatment
The ‘Apnoea Group’ will receive no delivery of high-flow oxygen. This group will receive environmental room air oxygenation.
Apnoea group will be the reference comparator.
Control group
Dose comparison

Outcomes
Primary outcome [1] 334678 0
Apnoea time between 30% oxygen concentration and apnoeic conditions following pre-oxygenation with 100% oxygen with THRIVE (ie. Time from reducing oxygen delivery concentration to “laser-safe” level until rescue jet ventilation is required).

Time will be assessed using clock on anaesthetic machine (start and stop times) and also using stopwatch / timer on mobile phone to measure in seconds.
Timepoint [1] 334678 0
Timepoint 1: Baseline (15 minutes prior to surgery)
Timepoint 2: Administration of THRIVE with 100% oxygenation (10 minutes prior to surgery)
Timepoint 3: Administration of either 30% oxygenation using THRIVE or room air oxygenation (approximately 30-45 seconds prior to laser surgery)
Timepoint 4: Oxygen saturation starts to drop (during laser surgery).
Timepoint 5: Oxygen saturation reaches a critical level requiring rescue (during laser surgery).
Timepoint 6: Jet rescue ventilation starts (during surgery).
Secondary outcome [1] 421632 0
Time for laryngeal oxygen to reach laser safe levels after 100% oxygen delivery cessation at the two different oxygenation conditions.

This will be assessed using a stopwatch.
Timepoint [1] 421632 0
Timepoint 1: Administration of either 30% oxygenation using THRIVE or room air oxygenation (approximately 30-45 seconds prior to laser surgery)
Timepoint 2: Oxygen concentration in the larynx equalizes the delivered oxygen concentration.
Secondary outcome [2] 421991 0
Change in vital parameters, oxygen saturations, rate of oxygen desaturation between the two groups

These parameters will be assessed based on printout from anaesthetic machine and real time anaesthetic machine monitoring output. Recorded by surgical assistant.

This outcome measure is considered to assess the safety of using THRIVE at laser-safe oxygenation deliveries.

These components will be assessed as a composite secondary outcome.
Timepoint [2] 421991 0
Timepoint 1: Baseline (15 minutes prior to surgery)
Timepoint 2: Administration of THRIVE with 100% oxygenation (10 minutes prior to surgery)
Timepoint 3: Administration of either 30% oxygenation using THRIVE or room air oxygenation (approximately 30-45 seconds prior to laser surgery)
Timepoint 4: Oxygen saturation starts to drop (during laser surgery).
Timepoint 5: Oxygen saturation reaches a critical level requiring rescue (during laser surgery).
Timepoint 6: Jet rescue ventilation starts (during surgery).
Timepoint 7: End of THRIVE (after laser procedure is completed)
Timepoint 8: End of surgery.
Secondary outcome [3] 422182 0
Rescue ventilation – total time and number of jet ventilations.

This will be assessed using a stopwatch. The number of jet ventilations is recorded by surgical assistant.
Timepoint [3] 422182 0
Timepoint 1: Start of jet ventilation
Timepoint 2: End of jet ventilation
Secondary outcome [4] 422183 0
Duration of surgery.

This will be assessed using a stopwatch.
Timepoint [4] 422183 0
Timepoint 1: Start of surgery.
Timepoint 2: End of surgery.
Secondary outcome [5] 422185 0
Anaesthetic agents used and dosage

This will be assessed using clinical notes of the anaesthetist.
Timepoint [5] 422185 0
Timepoint 1: Start of anaesthetic induction.
Timepoint 2: Patient resumes normal breathing.

Eligibility
Key inclusion criteria
- Age > 18 years
- Elective microlaryngeal surgeries, including but not limited to the following procedures:
• Microlaryngoscopy with or without biopsy (MBS item number: 41855)
• Microlaryngoscopy with removal of laryngeal lesion (MBS item number: 41861)
• Microlaryngoscopy with removal of lesion including laser (MBS item number: 41861)
• Microlaryngoscopy and laryngeal injection (MBS item number: 41870)
• Microlaryngoscopy and treatment of subglottic stenosis
- Willingness of the participant’s treating anaesthetist to enrolthe participant, in the absence of any identified contraindications.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
- Baseline oxygen saturation level less than 95%
- Know history of lung disease, including but not limited to COPD and Type I or Type II respiratory failure.
- Body Mass Index (BMI) greater than 31.

Study design
Purpose of the study
Treatment
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)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?


The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/08/2024
Actual
Date of last participant enrolment
Anticipated
29/08/2025
Actual
Date of last data collection
Anticipated
19/12/2025
Actual
Sample size
Target
102
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW,SA

Funding & Sponsors
Funding source category [1] 313785 0
University
Name [1] 313785 0
Dr Liang Voice Program, The University of Sydney
Country [1] 313785 0
Australia
Primary sponsor type
University
Name
Dr Liang Voice Program, The University of Sydney
Address
Faculty of Medicine and Health, The University of Sydney, Susan Wakil Health Building, Western Ave, Camperdown NSW 2050
Country
Australia
Secondary sponsor category [1] 315618 0
None
Name [1] 315618 0
N/A
Address [1] 315618 0
N/A
Country [1] 315618 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 312953 0
Sydney Local Health District Ethics Review Committee (RPAH Zone)
Ethics committee address [1] 312953 0
RESEARCH ETHICS AND GOVERNANCE OFFICE
ROYAL PRINCE ALFRED HOSPITAL
CAMPERDOWN NSW 2050
Ethics committee country [1] 312953 0
Australia
Date submitted for ethics approval [1] 312953 0
Approval date [1] 312953 0
24/04/2023
Ethics approval number [1] 312953 0

Summary
Brief summary
Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) is an oxygen insufflation method that has been widely accepted for both preoxygenation and apnoeic oxygenation. The use of THRIVE in laryngeal surgeries has advantages over endotracheal intubation in providing surgeons with excellent access to the surgical field. Additionally, the main benefit of THRIVE over subglottic or supraglottic manual jet ventilation is absence of movement artefact within the surgical field, humidification of delivered gases and decreased risk of high-pressure injuries from jet ventilation. However, the use of THRIVE at 100% oxygen concentration renders a risk of ignition and fire during laser surgeries. It is therefore necessary to investigate the safety of using different laser-safe oxygenation deliveries. No study has compared desaturation rates, real-time laryngeal oxygen concentration, and vital parameters between different oxygenation deliveries via THRIVE across 100%, 30%, and apneic conditions with rescue jet ventilation. In the present clinical trial, we aim to: 1) Compare apnoea time and real-time laryngeal oxygen concentration between 30% oxygen and apnoeic conditions following pre-oxygenation with THRIVE at 100% oxygen concentration; and 2) Explore patient factors which predict successful application of THRIVE at 100% and 30% oxygenation vs apnoeic conditions during microlaryngeal surgery. Recruited patients indicated to undergo microlaryngeal surgery will be randomly allocated to one of two groups, either Group A: ‘Apnoea Group’ (no delivery of high-flow oxygen, environmental room air oxygen only) or Group B: ‘30% Oxygen Group’ (Delivery of high-flow oxygen at 30% concentration). Both groups will have initial pre-oxygenation at 100% oxygen concentration with THRIVE. Laryngeal oxygen concentration, oxygen saturation data, and vital parameters will be collected during the procedure and will be compared between the two groups.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 126462 0
A/Prof Daniel Novakovic
Address 126462 0
Sydney ENT Specialists, Suite 1, Level 1, 66 Pacific Hwy, St. Leonards, NSW 2065.
Country 126462 0
Australia
Phone 126462 0
+61 1300 286 423
Fax 126462 0
Email 126462 0
daniel.novakovic@sydney.edu.au
Contact person for public queries
Name 126463 0
A/Prof Daniel Novakovic
Address 126463 0
Sydney ENT Specialists, Suite 1, Level 1, 66 Pacific Hwy, St. Leonards, NSW 2065.
Country 126463 0
Australia
Phone 126463 0
+61 1300 286 423
Fax 126463 0
Email 126463 0
daniel.novakovic@sydney.edu.au
Contact person for scientific queries
Name 126464 0
A/Prof Daniel Novakovic
Address 126464 0
Sydney ENT Specialists, Suite 1, Level 1, 66 Pacific Hwy, St. Leonards, NSW 2065.
Country 126464 0
Australia
Phone 126464 0
+61 1300 286 423
Fax 126464 0
Email 126464 0
daniel.novakovic@sydney.edu.au

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


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
23763Statistical analysis plan    385851-(Uploaded-09-05-2024-14-50-08)-Study-related document.docx



Results publications and other study-related documents

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