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

Trial ID
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Measuring the benefit of buccal oxygenation in the apnoeic patient
Scientific title
Apneic oxygenation during prolonged laryngoscopy in obese patients: a randomized, controlled trial of buccal RAE tube oxygen administration
Secondary ID [1] 282716 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 289434 0
Desaturation during laryngoscopy (anaesthesia) 289435 0
Condition category
Condition code
Anaesthesiology 289763 289763 0 0
Respiratory 289793 289793 0 0
Other respiratory disorders / diseases

Study type
Description of intervention(s) / exposure
In theatre patients will receive a standardised induction of anesthesia . For the the laryngoscopy (procedure to visualise the vocal cords and therefore entrance into the windpipe) and intubation (placement of the endotracheal tube into the windpipe) in the anaesthetised and apnoeic patient, the oxygen administration is traditionally interrupted for a short time until the breathing tube is connected to the ventilator. In this study the patients are either receiving additional oxygen (10 l/min flow) via a 3.5 mm RAE tube in the buccal space during laryngascopy or no additional oxygen. During artificially prolonged laryngoscopy the saturation will be recorded for a maximum of 10 min or until the saturation starts to drop to 95%. The patient will then be intubated and anaesthesia will be continued as per routine.

Intervention code [1] 287377 0
Intervention code [2] 287402 0
Treatment: Other
Comparator / control treatment
Oxygen 10 l/min versus no flow
Control group

Primary outcome [1] 289848 0
Desaturation (SpO2 to 95%) monitored with pulse oximetry
Timepoint [1] 289848 0
Time to reach SpO2 95% in seconds or 10 min if no desaturation occurs
Secondary outcome [1] 303376 0
Timepoint [1] 303376 0

Key inclusion criteria
1) Adult patients requiring general anaesthesia with endotrachel intubation for scheduled surgery
2) BMI 30-40
3) ASA1-2
4) Agree to and capapble of understanding and signing the consent form

Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Study population - Exclusion criteria:
1) Age < 18
2) Chronic Respiratory Disease
3 ) SpO2 <98% despite preoxygenation with 100% O2
4) History of difficult intubation or anticipated difficult intubation
5) Uncontrolled hypertension
6) Ischaemic Heart disease or congestive Heart Failure
7) Increased intracranial pressure
7) Gastroesophageal reflux disease
8) Non fasting patients
9) Emergency procedures

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
computerised sequence generation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
A power analysis was performed to determine the number of subjects required for the study.
We expected a minimum of 60 seconds difference between the SpO2>95% times of the two groups. Based on this assumption and Type I and Type II errors of 5% and 20%, respectively(power 80%), 15 patients per group were required to prove the hypothesis.
To account for withdrawasls and fall-outs n=20 will be recruited for each group.
All continuous data were identified as nonparameteric and the Mann Whitney U test was used to determine statistical significance between groups. Pearson's chi-squared test and Fisher's exact test will be used to show significant differences between the two groups in frequency data. Statistical analysis(SPSS15.0 for Windows Software) will be used to perform the statistical analysis.

Recruitment status
Not yet recruiting
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] 1147 0
Royal Perth Hospital - Perth
Recruitment postcode(s) [1] 6994 0
6847 - Perth

Funding & Sponsors
Funding source category [1] 287487 0
Self funded/Unfunded
Name [1] 287487 0
Address [1] 287487 0
Country [1] 287487 0
Primary sponsor type
Department of Anaesthesia, Royal Perth Hospital
Wellington Street Campus
BOX X2213, GPO
Perth 6847
Western Australia
Secondary sponsor category [1] 286227 0
Name [1] 286227 0
Address [1] 286227 0
Country [1] 286227 0

Ethics approval
Ethics application status
Ethics committee name [1] 289463 0
Human Research Ethics Committee
Ethics committee address [1] 289463 0
Level 5 Colonial House, Royal Perth Hospital, GPO Box X2213 Perth WA 6001
Ethics committee country [1] 289463 0
Date submitted for ethics approval [1] 289463 0
Approval date [1] 289463 0
Ethics approval number [1] 289463 0
REG 13-050

Brief summary
Patients having operations under general anaesthesia will be asleep for the duration of the procedure and their own breathing efforts will be reduced by the anaesthetic drugs. The anaesthetist will support the patients breathing and will place a breathing tube into his/her windpipe as soon as the patient have drifted off to sleep. Normally, the anaesthetist discontinues the administration of oxygen during this manoeuvre as it usually takes only a short time to insert the breathing tube.

We believe that continuing the supply of oxygen through a small tube into the inside of the patients cheek at this stage will keep the body oxygen levels higher than they would be otherwise. This is especially important for patients who are overweight or pregnant and also in children as their oxygen reserves exhaust more quickly. Computer programs and our understanding of the biology of people have suggested this would be the case. However, we do not have proof of this at present.
Trial website
Trial related presentations / publications
1. Altermatt FR, Munoz HR, Delfino AE, Cortinez LI. Pre-oxygenation in the obese patient: effects of position on tolerance to apnoea. Br J Anaesth 2005;95:706-9.
2. Gander S, Frascarolo P, Suter M, Spahn DR, Magnusson L. Positive end-expiratory pressure during induction of general anesthesia increases duration of nonhypoxic apnea in morbidly obese patients. Anesth Analg 2005;100:580-4.
3. Dixon BJ, Dixon JB, Carden JR, Burn AJ, Schachter LM, Playfair JM, Laurie CP, O'Brien PE. Preoxygenation is more effective in the 25 degrees head-up position than in the supine position in severely obese patients: a randomized controlled study. Anesthesiology 2005;102:1110-5; discussion 5A.
4. Jense HG, Dubin SA, Silverstein PI, O'Leary-Escolas U. Effect of obesity on safe duration of apnea in anesthetized humans. Anesth Analg 1991;72:89-93.
5. Teller LE, Alexander CM, Frumin MJ, Gross JB. Pharyngeal insufflation of oxygen prevents arterial desaturation during apnea. Anesthesiology 1988;69:980-2.
6. Baraka AS, Taha SK, Siddik-Sayyid SM, Kanazi GE, El-Khatib MF, Dagher CM, Chehade JM, Abdallah FW, Hajj RE. Supplementation of pre-oxygenation in morbidly obese patients using nasopharyngeal oxygen insufflation. Anaesthesia 2007;62:769-73.
7. Ramachandran SK, Cosnowski A, Shanks A, Turner CR. Apneic oxygenation during prolonged laryngoscopy in obese patients: a randomized, controlled trial of nasal oxygen administration. J Clin Anesth;22:164-8.

Public notes

Principal investigator
Name 40958 0
Dr Andrew Heard
Address 40958 0
Department of Anaesthesia and Pain Medicine
Royal Perth Hospital
Wellington Street Campus
BOX X2213, GPO, Perth 6487
Western Australia
Country 40958 0
Phone 40958 0
+61 8 92241037
Fax 40958 0
+61 8 92241111
Email 40958 0
Contact person for public queries
Name 40959 0
Dr Andrew Heard
Address 40959 0
Department of Anaesthesia and Pain Medicine
Royal Perth Hospital
Wellington Street Campus
BOX X2213, GPO, Perth 6487
Western Australia
Country 40959 0
Phone 40959 0
+61 8 92241037
Fax 40959 0
+61 8 92241111
Email 40959 0
Contact person for scientific queries
Name 40960 0
Dr Andrew Heard
Address 40960 0
Department of Anaesthesia and Pain Medicine
Royal Perth Hospital
Wellington Street Campus
BOX X2213, GPO, Perth 6487
Western Australia
Country 40960 0
Phone 40960 0
+61 8 92241037
Fax 40960 0
+61 8 92241111
Email 40960 0