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Trial registered on ANZCTR

Registration number

ACTRN12621001635853

Ethics application status

Approved

Date submitted

19/10/2021

Date registered

29/11/2021

Date last updated

12/07/2023

Date data sharing statement initially provided

29/11/2021

Type of registration

Prospectively registered

Titles & IDs

Public title

Flexible Bronchoscopy Insufflated and High-Flow Nasal Oxygen Pilot Trial in Children

Scientific title

Flexible Bronchoscopy Insufflated and High-Flow Nasal Oxygen Pilot Trial in Children

Secondary ID [1]

Nil Known

Universal Trial Number (UTN)

U1111-1270-5316

Trial acronym

BUFFALO Pilot Trial

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Hypoxemia during Flexible Bronchoscopy

Condition category

Condition code

Anaesthesiology

Anaesthetics

Respiratory

Other respiratory disorders / diseases

Surgery

Other surgery

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Intervention: High flow nasal oxygen insufflation

Description: High-Flow Nasal Oxygen Insufflation (HFNOI) is insufflation of heated (37 degrees Celsius) and humidified (100%) oxygen at weight-related flow rates matching peak inspiratory flow thereby allowing a known inspired fraction of inspired oxygen.

HFNOI will be delivered during the bronchoscopy via the Optiflow™ device at weight-specific flow rates as per the table below delivering a FiO2 of 1.0.

Weight HFNOI Flow rates
0-12 kg 2L/kg/min
13-15kg 30L/min
15-30 kg 35L/min
30-50 kg 40L/min
>50 kg 50L/min

Jaw thrust will be applied to ensure a patent airway until airway instrumentation begins.
Anaesthesia will be maintained via a Total Intravenous Venous Anaesthesia (TIVA) using a combination of dexmedetomidine, propofol +/- an opioid (either remifentanil or alfentanil) at the discretion of the attending anaesthetist. Anaesthetists may wish to omit opioids in certain circumstances and this will be at the discretion of the anaesthetist e.g. neonates. Anaesthesia infusions will be adjusted to maintain both adequate depth of anaesthesia and spontaneous ventilation during the procedure. TIVA is used because inhalation agents can not be delivered when using HFNOI, TIVA is not the intervention of interest.
The adherence to the intervention will be monitored by the research assistant present in the room collecting data and recorded on a case report form.

Intervention code [1]

Treatment: Devices

Intervention code [2]

Prevention

Comparator / control treatment

Standard facemask /LMA technique

Description: Oxygen insufflation will be at a flow rate of up to 6L/min via an anaesthesia facemask or LMA as per local hospital policy or practices . Anaesthesia will be maintained at the discretion of the anaesthetist, via inhalational anaesthesia, intravenous agents, or a combination of both. Intravenous agents as per choice of the attending anaesthetist.
The adherence to the intervention will be monitored by the research assistant present in the room collecting data and recorded on a case report form.

Control group

Active

Outcomes

Primary outcome [1]

The rate of participant recruitment assessed by completion of screening and enrollment log

Timepoint [1]

Screening will occur daily by the research assistant until the recruitment target has been met.

Primary outcome [2]

Adherence to the protocol without deviation assessed by completion of case report form completed by the research assistant during the bronchoscopy

Timepoint [2]

During the bronchoscopy for children enrolled

Secondary outcome [1]

The proportion of children experiencing a hypoxaemic event defined by a oxygen saturation < 90%, within 10% of baseline collected by pulse oximeter data captured during the bronchoscopy

Timepoint [1]

Continuous pulse oximetry will be taken during the surgical procedure

Secondary outcome [2]

The proportion of children requiring interruption of the procedure to rescue the oxygenation by positive pressure assisted ventilation assessed by observation and completion of case report form completed by the research assistant during the bronchoscopy

Timepoint [2]

Continuous observation by the research assistant for the duration of the surgical procedure

Secondary outcome [3]

The severity of the hypoxaemic event described by the area under the curve of time below SpO2 of 90% collected by pulse oximeter data captured during the bronchoscopy

Timepoint [3]

Continuous pulse oximetry will be taken during the surgical procedure

Secondary outcome [4]

Significant adverse events requiring treatment will be graded using the CTCAE5.
AEs for this study are defined as:
*Hypoxaemia leading to cardiac massage
*Cardiac arrest: Loss of spontaneous cardiac output
*Mortality
*OR any life-threatening medical event or reaction which the clinician believes may be study-related
*Hypotension: requiring treatment with fluid and/or vasoconstrictors
*Bradycardia of <60/min or < 40 if older than 6 years

Timepoint [4]

Continuous observation by the research assistant for the duration of the surgical procedure

Eligibility

Key inclusion criteria

* 0 (>37 weeks gestational age) – 16 years of age (15 years + 364 days)
• Elective flexible bronchoscopy
*Clinicians approval for inclusion

Minimum age

0 Weeks

Maximum age

16 Years

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

• Known choanal atresia
• HFNOI contraindication (recent cranial and/or mid-face surgery/trauma; CSF leak)
• Emergency airway cases out of hours (after hours during week and weekend)

Study design

Purpose of the study

Prevention

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Central randomisation via computer will be used to achieve allocation concealment.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Patients will be allocated to a treatment arm using a computer based randomisation schedule and an allocation of 1:1 per treatment arm. Randomisation will be stratified by age (<1 year, 1-5 year and 5-16 year of age), with randomly varied block sizes within each stratum.

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Parallel

Other design features

Phase

Not Applicable

Type of endpoint/s

Safety

Statistical methods / analysis

Descriptive statistics will be used to report on the baseline characteristics of the total study cohort and each treatment group, as well as by site. As this is a pilot trial, formal statistical comparisons will not be undertaken. All outcomes will be presented as estimates along with 95% confidence interval (CI); feasibility outcomes will be presented only for the total cohort, while safety and efficacy outcomes will be presented for the total cohort, as well as per treatment group. Analyses will be undertaken using intention-to-treat, however the number and type of protocol deviations will be reported to assist in feasibility assessment.

Recruitment

Recruitment status

Recruiting

Date of first participant enrolment

Anticipated

1/02/2022

Actual

3/05/2022

Date of last participant enrolment

Anticipated

1/12/2023

Actual

Date of last data collection

Anticipated

31/12/2023

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

QLD,WA

Recruitment hospital [1]

Queensland Children's Hospital - South Brisbane

Recruitment hospital [2]

Perth Children's Hospital - Nedlands

Recruitment postcode(s) [1]

4101 - South Brisbane

Recruitment postcode(s) [2]

6009 - Nedlands

Funding & Sponsors

Funding source category [1]

Hospital

Name [1]

Queensland Children's Hospital

Address [1]

501 Stanley Street
South Brisbane, QLD 4101

Country [1]

Australia

Primary sponsor type

University

Name

University of Queensland

Address

288 Herston Road
Herston QLD 4006, Australia

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Human Research Ethics Committee Centre for Children’s Health Research

Ethics committee address [1]

Human Research Ethics Committee
Centre for Children’s Health Research
Queensland Children’s Hospital Precinct
Level 7, 62 Graham Street
South Brisbane QLD 4101

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

11/10/2021

Approval date [1]

17/11/2021

Ethics approval number [1]

HREC/21/QCHQ/76582

Summary

Brief summary

Infants and children with an abnormality in their airway and lungs often require procedures to further investigate their lungs and improve their breathing. During the anaesthesia for this procedure, the anaesthetist delivers oxygen and monitors the adequacy of the child’s breathing. In this situation both the proceduralist and the anaesthetist share the child’s airway for delivery of oxygen and for placement of a small telescope to directly view the anatomy within the airway and lungs. It is impractical for the anaesthetist to place a breathing tube into the airway for delivery of oxygen as this obstructs the view.

It is not uncommon for the oxygen levels in the blood to fall (hypoxaemia) during these procedures. The procedure may need to be interrupted to correct this which can potentially compromise the safety of the child, prolong the procedure, increase exposure to anaesthetic agents and affect the success of the procedure. At Queensland Children’s Hospital, we reviewed the anaesthetic care of children undergoing flexible bronchoscopy procedures and found that 28% of children experienced low oxygen levels one or more times during the procedure.
 
The method which the anaesthetist chooses to give the oxygen to the child may help to prevent the occurrence of low oxygen levels. Traditionally anaesthetists have delivered oxygen via face mask or airway device which is placed inside the mouth above the voice box part of the airway at flow rates of up to 6 litres per minute. Our research team have recently investigated a new mode of oxygen delivery called Nasal High. Flow. In Nasal High Flow, warm and humidified oxygen is delivered to the airway via nasal cannulae, at a rate determined by the child’s weight. For example, Nasal High Flow can be delivered at rates of 2L/kg/min. Therefore, a 10kg infant would receive 20 litres per minute. Matching the flow delivered to the patient’s breathing allows the anaesthetist to deliver oxygen to the child at the required concentration. Our recent studies have demonstrated Nasal High Flow is an effective alternative technique for oxygen delivery that can be safely used in infants and children with abnormal airways. 
To date there have been no large-scale studies evaluating Nasal High Flow in comparison to other oxygenation techniques during flexible bronchoscopy in children. Therefore, we aim to compare the two techniques using a randomised controlled trial in infants and children during flexible bronchoscopy. If we can determine that Nasal High Flow reduces the risk of low oxygen levels, this has the potential to both improve both the safety and the success of these procedures for children.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

A/Prof Susan Humphreys

Address

Centre for Children's Health Research
Level 7
62 Graham St
South Brisbane
QLD, 4101

Country

Australia

Phone

+617 3069 7480

Fax

susan.humphreys@uq.edu.au

Contact person for public queries

Name

Susan Humphreys

Address

Centre for Children's Health Research
Level 7
62 Graham St
South Brisbane
QLD, 4101

Country

Australia

Phone

+617 3069 7480

Fax

susan.humphreys@uq.edu.au

Contact person for scientific queries

Name

Susan Humphreys

Address

Centre for Children's Health Research
Level 7
62 Graham St
South Brisbane
QLD, 4101

Country

Australia

Phone

+61 7 3069 7480

Fax

susan.humphreys@uq.edu.au

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

De-identified data on a case-by-case basis at the discretion of Principal Investigator A/Prof Susan Humphreys and Primary Sponsor

When will data be available (start and end dates)?

3 months following publication and ending 5 years following main results publication

Available to whom?

De-identified data on a case-by-case basis at the discretion of Principal Investigator A/Prof Susan Humphreys and Primary Sponsor of researchers with a sound proposal

Available for what types of analyses?

De-identified data on a case-by-case basis at the discretion of Principal Investigator A/Prof Susan Humphreys of researchers for secondary analysis with a sound proposal

How or where can data be obtained?

Access subject to approvals by Principal Investigator A/Prof Susan Humphreys susan.humphreys@uq.edu.au

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

Source	Title	Year of Publication	DOI
Dimensions AI	Flexible bronchoscopy insufflated and high-flow nasal oxygen pilot trial (BUFFALO protocol pilot trial)	2024	https://doi.org/10.1186/s40814-024-01464-w

N.B. These documents automatically identified may not have been verified by the study sponsor.

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