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Trial registered on ANZCTR


Registration number
ACTRN12617000173392
Ethics application status
Approved
Date submitted
25/01/2017
Date registered
2/02/2017
Date last updated
7/03/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
Airway oxygen concentration during administration of oxygen from the inside of the cheek under general anaesthesia
Scientific title
Physiological evaluation of buccal oxygen administration during apnoea: A generalizable method to assess apnoeic oxygenation device performance
Secondary ID [1] 290850 0
none
Universal Trial Number (UTN)
U1111-1191-3646
Trial acronym
Linked study record
ACTRN12613000697785

Health condition
Health condition(s) or problem(s) studied:
Apnoeic oxygenation under anaesthesia 301530 0
Condition category
Condition code
Anaesthesiology 301251 301251 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
100% oxygen will be given via a standard anaesthetic facemask until end tidal oxygen (EtO2) is >0.8. 10L/min 100% oxygen will then be delivered to patients in the intervention group from the moment that EtO2 is >0.8 until the patient is intubated. This will be delivered via a 3.5mm internal diameter, oral south facing Ring-Adair-Elwyn (RAE) tube taped to sit on the inside of the cheek. Anaesthesia will be induced with standard monitoring including a transcutaneous monitor for O2 and CO2. The induction method will use intravenous Propofol target controlled infusion (Schnider model) started at 7mcg/mL (effect site concentration) (titrated to Entropy 40-60), intravenous Remifentanil target controlled infusion using Minto model at 4ng/mL (effect site concentration) (titrated to Entropy 40-60) and then intravenous Rocuronium infusion at 0.9mg/kg started 60s after the start of the infusions. Fentanyl 2-3 mcg/kg was used when Remifentanil was not available. The infusions will continue until the patient is intubated, at which point the lead anaesthetist clinically responsible for the case can take over the administration of the anaesthetic.
Intervention code [1] 296792 0
Prevention
Intervention code [2] 297028 0
Treatment: Devices
Comparator / control treatment
100% oxygen will be given via a standard anaesthetic facemask until end tidal oxygen is >0.8. A 3.5mm internal diameter, oral south facing RAE tube will still be taped to sit on the inside of the cheek. No buccal oxygen will be delivered to patients in the control group. Anaesthesia will be induced with standard monitoring including a transcutaneous monitor for O2 and CO2. The induction method will use Propofol target controlled infusion (Schnider model) started at 7mcg/mL (effect site concentration) (titrated to Entropy 40-60), Remifentanil using Minto model at 4ng/mL (effect site concentration) (titrated to Entropy 40-60) and then Rocuronium at 0.9mg/kg started 60s after the start of the infusions. Fentanyl 2-3 mcg/kg was used when Remifentanil was not available. The infusions will continue until the patient is intubated, at which point the lead anaesthetist clinically responsible for the case can take over the administration of the anaesthetic.
Control group
Active

Outcomes
Primary outcome [1] 300663 0
Time taken for tracheal oxygen concentration to reach <70% as measured by a Bedfont G210 gas analyser connected so that gas in sampled from and returned to the airway via the proximal and medial ports (12G) of a 12Ch central venous catheter whose tip is sat at the glottic inlet.
Timepoint [1] 300663 0
750 seconds of apnoea induced by anaesthesia. This incorporates time for muscle relaxant to work and placement of the tracheal monitoring lines.
Secondary outcome [1] 330536 0
Airway pressure as measured by the VT plus HF gas flow (pressure) analyser (FLUKE Biomedical) to distal port (16G) of the central venous catheter whose tip is sat at the glottic inlet. .
Timepoint [1] 330536 0
750 seconds of apnoea induced by anaesthesia. This incorporates time for muscle relaxant to work and placement of the tracheal monitoring lines.
Secondary outcome [2] 330537 0
Change in transcutaneous carbon dioxide.
Timepoint [2] 330537 0
750 seconds of apnoea induced by anaesthesia. This incorporates time for muscle relaxant to work and placement of the tracheal monitoring lines.

Eligibility
Key inclusion criteria
1) Adult patients requiring general anaesthesia with endotracheal intubation for scheduled or expedited surgery.
2) Body Mass Index 20-30
3) American Society of Anaesthesiologists - 1-2
4) Agree to and capable of understanding and signing the consent form.
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
1) Age <18
2) Chronic Respiratory Disease
3) SpO2 <98% following pre-oxygenation
4) History of difficult intubation or anticipated difficult intubation.
5) Uncontrolled hypertension
6) Ischaemic Heart Disease / Congestive Cardiac Failure
7) Increased Intra-Cranial Pressure
8) Gastro-oesophageal Reflux Disease
9) Non fasted patients
10) Emergencies
11) Known allergy or contraindications to propofol, remifentanil or rocuronium
12) Contraindication to buccal
13) Inability to secure buccal or monitoring line for O2(e.g. beard)


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)
Patients will be randomised to buccal or facemask oxygen via a computer generated random sequence in an opaque envelope method.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A random number sequence will be generated by computer.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Phase 1 / Phase 2
Type of endpoint(s)
Safety/efficacy
Statistical methods / analysis
Sample size is calculated to detect a difference between the proportion of patients in each group reaching the primary end-point. Buccal oxygenation is anticipated to be highly effective with at least 80% patients maintaining glottic oxygen concentration >0.7 and less than 10% of control patients achieving the same. To achieve 90% power at a significance level of 0.05, 9 patients in each group are required. A 10% inflation to cover any patient withdrawals brings the total sample size required to 20 patients. The primary end-point will be assessed with Kaplan-Meier survival curves. The secondary outcome of mean glottic pressure and rate of rise of transcutaneous CO2 will be assessed using the unpaired t-test.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 7400 0
Royal Perth Hospital - Perth
Recruitment postcode(s) [1] 15199 0
6000 - Perth

Funding & Sponsors
Funding source category [1] 295302 0
Other
Name [1] 295302 0
Department of Anaesthesia, Royal Perth Hospital
Address [1] 295302 0
Royal Perth Hospital, Wellington Street, Perth. WA 6000.
Country [1] 295302 0
Australia
Primary sponsor type
Hospital
Name
Royal Perth Hospital
Address
Department of Anaesthesia, Royal Perth Hospital, Wellington Street, Perth. WA 6000
Country
Australia
Secondary sponsor category [1] 294127 0
None
Name [1] 294127 0
Address [1] 294127 0
Country [1] 294127 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 296634 0
Royal Perth Hospital Human Research Ethics Committee
Ethics committee address [1] 296634 0
East Metropolitan Health Service
Level 3, Colonial House, Royal Perth Hospital, Perth WA 6000
Ethics committee country [1] 296634 0
Australia
Date submitted for ethics approval [1] 296634 0
26/10/2016
Approval date [1] 296634 0
13/01/2017
Ethics approval number [1] 296634 0
2016-229

Summary
Brief summary
Aims and Justification
The induction of anaesthesia can be associated with a drop in oxygen saturation particularly when there is difficulty in intubation (the placement of a flexible plastic tube into the trachea (windpipe) to maintain an open airway). We have recently published a study which showed that buccal (attached to the inside of the cheek) oxygen administration was highly effective at prolonging the time to oxygen desaturation in obese patients, at induction of anaesthesia. Nevertheless, a third of patients desaturated earlier than expected. This may have been due to the development of pulmonary shunt (collapse of the small airways) or a failure of the device to maintain a high oxygen concentration at the open glottis (start of the windpipe). The device may also be limited by accumulation of carbon dioxide during breaks in breathing (apnoea), and the degree of positive pressure generation at the glottis.

This follow up study will repeat the methodology of the original project, whilst assessing glottic oxygen concentration and pressure, as well as carbon dioxide accumulation. The objective is to ascertain the reliability of this technique at maintaining glottic oxygen concentration >0.7 over 10 min apnoea. This will help us to further evaluate and refine this technique for oxygenation during apnoea.

Project Design and Participant Groups
This will be an open label, randomised, controlled trial in healthy, non-obese patients due for elective surgery.

Methods
The protocol is based on our previous study with two study groups:

(a) 10 l/min oxygen via a buccal RAE tube attached to the inside of the cheek as the intervention group, compared to:
(b) Standard care.

Measurements of glottic oxygen concentration (FO2), glottic airway pressure and transcutaneous carbon dioxide (CO2) concentration will be taken during 10 min of apnoea from induction of anaesthesia. The primary outcome will be the maintenance of glottic oxygen concentration >0.7 after 10 min apnoea. We hypothesise that >80% patients will maintain a glottic FO2> 0.7 at 10 min apnoea using buccal oxygen in comparison to the <10% of control patients. Our secondary aim is to find out the pressure at the glottis and rate of rise of CO2 during this technique. This secondary information will delineate the possible length of its clinical use and further evaluate this technique.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 71486 0
Dr Andrew Toner
Address 71486 0
Department of Anaesthesia, Royal Perth Hospital, Wellington Street, Perth. WA 6000
Country 71486 0
Australia
Phone 71486 0
+61 892242244
Fax 71486 0
Email 71486 0
andrew.toner@health.wa.gov.au
Contact person for public queries
Name 71487 0
Dr Andrew Toner
Address 71487 0
Department of Anaesthesia, Royal Perth Hospital, Wellington Street, Perth. WA 6000
Country 71487 0
Australia
Phone 71487 0
+61 892242244
Fax 71487 0
Email 71487 0
andrew.toner@health.wa.gov.au
Contact person for scientific queries
Name 71488 0
Dr Andrew Toner
Address 71488 0
Department of Anaesthesia, Royal Perth Hospital, Wellington Street, Perth. WA 6000
Country 71488 0
Australia
Phone 71488 0
+61 892242244
Fax 71488 0
Email 71488 0
andrew.toner@health.wa.gov.au

No information has been provided regarding IPD availability
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