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Trial registered on ANZCTR

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

Titles & IDs
Public title
Oxygen therapy for treating patients with residual sleep apnoea following upper airway surgery
Scientific title
Oxygen therapy for treating patients with residual obstructive sleep apnoea following upper airway surgery
Secondary ID [1] 292779 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obstructive Sleep Apnoea 304578 0
Condition category
Condition code
Respiratory 303910 303910 0 0
Sleep apnoea
Surgery 303994 303994 0 0
Other surgery

Study type
Description of intervention(s) / exposure
Oxygen therapy will be administered to patients as they sleep in the sleep laboratory at Monash Medical Centre.
100% Oxygen will be administered at a flow rate of 4L/min via nasal cannula.
The treatment will be administered by trial investigators who are sleep scientist/technicians employed by Monash Health and who are experienced in delivering oxygen to sleeping patients which they do as part of their routine work.
The Oxygen treatment will be delivered over a single night of sleep (typically 6-7hrs), i.e. one session.
The control/placebo treatment will be Room Air delivered at a flow rate of 4L/min via nasal cannula.
The control/placebo will be delivered continuously while patients sleep (typically 6-7hrs).
Sleep studies will be conducted within one week of one another.
Intervention code [1] 299014 0
Treatment: Drugs
Comparator / control treatment
The control treatment is Room Air delivered at 4L/min via nasal cannula.
Control group

Primary outcome [1] 303245 0
Apnea hypopnea index
Timepoint [1] 303245 0
On the study night where the treatment intervention is administered and when the control intervention is administered (i.e. study night one and study night two).
Secondary outcome [1] 338338 0
Blood pressure
Timepoint [1] 338338 0
taken before and after study night one and two in the same arm.
Secondary outcome [2] 338339 0
Pulse oximetry
Timepoint [2] 338339 0
Recorded continuously in study night one and study night two.
Secondary outcome [3] 338340 0
Arousal index
Timepoint [3] 338340 0
recorded continuously during study night one and study night two.

Key inclusion criteria
Patients will be selected from a cohort of patients suffering from obstructive sleep apnoea who have had upper airway surgery to treat their sleep apnoea but who have failed to respond to surgical treatment and who have ongoing sleep apnoea.
Minimum age
18 Years
Maximum age
80 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table generated by computer software.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Each patient will undergo a sleep study on both the treatment and on the control, as such each patient will act as their own control.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The primary and secondary end points will be compared between the study night on treatment and the study night on placebo. Group data will be compared via and independent samples t-test.
A responder analysis will be performed to determine patient factors that predict response to oxygen therapy treatment. The patients will be divided into responders/non-responders on the basis of the primary outcome measure on the treatment study night.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 8917 0
Monash Medical Centre - Clayton campus - Clayton
Recruitment postcode(s) [1] 17289 0
3168 - Clayton

Funding & Sponsors
Funding source category [1] 297409 0
Name [1] 297409 0
Monash Health
Address [1] 297409 0
Monash Medical Centre
246 Clayton Rd
Clayton 3168, VIC
Country [1] 297409 0
Primary sponsor type
Monash Health
Monash Health, Monash Medical Centre
246 Clayton Rd
Clayton, Vic, 3168
Secondary sponsor category [1] 296400 0
Name [1] 296400 0
Address [1] 296400 0
Country [1] 296400 0

Ethics approval
Ethics application status
Ethics committee name [1] 298514 0
Monash Health HREC
Ethics committee address [1] 298514 0
Monash Health
246 Clayton Rd
Clayton, Vic, 3168
Ethics committee country [1] 298514 0
Date submitted for ethics approval [1] 298514 0
Approval date [1] 298514 0
Ethics approval number [1] 298514 0
HREC/17/MonH/128 or RES-17-0000-165A

Brief summary
Obstructive sleep apnoea (OSA) is a condition in which the upper airway of patients closes off during sleep. This leads to low levels of oxygen and multiple awakenings during the night. There are many factors contributing to the abnormal blockage of the upper airway including the shape, length and strength of the airway itself. Upper airway surgery can help influence these factors. However, there are still patients with residual sleep apnoea despite upper airway surgery.

The aim of this study is to test the impact of oxygen therapy in patients with residual sleep apnoea following upper airway surgery. Oxygen therapy will lower the sensitivity of participants ventilator control system and is expected to help further improve their OSA. The study is intended to discover if the combination of oxygen therapy and upper airway surgery can completely resolve OSA in patients where surgery is not able to resolve OSA on its own.

The study will involve each identified participant to undergo two sleep studies over two nights. These visits will tell us if the administration of oxygen therapy after upper airway surgery can completely resolve OSA in patients who still snore. All participants will receive one night without oxygen, and one night with oxygen, to be used as a direct comparison. Measurements of breathing pattern, heart beat, blood pressure, muscle activity, eye movements, brain activity and the level of oxygen in the blood in the blood will be recorded and later interpreted by investigators specialized in OSA.

We believe that the combination of oxygen and upper airway surgery could positively impact patients OSA and their quality of life. It can potentially provide additional treatment options for sufferers of residual OSA despite surgical management.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 77322 0
Dr Bradley Edwards
Address 77322 0
Sleep and Circadian Medicine Laboratory
264 Ferntree Gully Road | Notting Hill, VIC 3168, Australia
Country 77322 0
Phone 77322 0
Fax 77322 0
Email 77322 0
Contact person for public queries
Name 77323 0
Dr Michael Tan
Address 77323 0
Monash Lung and Sleep
246 Clayton Rd
Clayton, Vic, 3168
Country 77323 0
Phone 77323 0
Fax 77323 0
Email 77323 0
Contact person for scientific queries
Name 77324 0
Dr Bradley Edwards
Address 77324 0
Sleep and Circadian Medicine Laboratory
264 Ferntree Gully Road | Notting Hill, VIC 3168, Australia
Country 77324 0
Phone 77324 0
Fax 77324 0
Email 77324 0

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