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Trial registered on ANZCTR


Registration number
ACTRN12615000528550
Ethics application status
Approved
Date submitted
10/05/2015
Date registered
27/05/2015
Date last updated
30/03/2017
Type of registration
Retrospectively registered

Titles & IDs
Public title
A comparison of preoxygenation methods for prehospital intubation in patients with a simulated mask leak
Scientific title
The effect of nasal prongs in healthy individuals with simulated mask leak, compared to not using nasal prongs, for preoxygenation with either non-rebreather mask or bag-valve mask as measured by end-tidal oxygen.
Secondary ID [1] 286676 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Preoxygenation 295020 0
mask leak 295021 0
Condition category
Condition code
Anaesthesiology 295281 295281 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The study design is four-period crossover study (repeated measures design) with two arms. There will be a non-rebreather arm and BVM arm, participants will be randomly allocated to either arm. Each participant will be required to complete four trials of 3-minutes pre-oxygenation with 100% oxygen in only one of the arms (mask alone, mask and nasal-prongs, mask and nasal-prongs with leak, mask alone with leak). The simulated leak will be created using 16F nasogastric tube taped to both sides of the mask. At the end of each trial oxygen will be measured by an expiratory breath into an oxygen analyser. This will be followed by a washout period of 2 minutes after which the ETO2 will be remeasured to ensure it is within 1% of the participants baseline.

The sequence of the trials will be randomised in a balanced design.
Intervention code [1] 291826 0
Treatment: Drugs
Intervention code [2] 291924 0
Treatment: Devices
Comparator / control treatment
There is no comparator/control. As this is a repeated measures design the participants will be their own controls.
Control group
Active

Outcomes
Primary outcome [1] 295023 0
End-tidal oxygen after 3-minutes of preoxygenation will be assessed with a paramagnetic oxygen analyser from a standard anaesthetic machine. The same analyser will be used for all trials.
Timepoint [1] 295023 0
3 minutes
Secondary outcome [1] 314612 0
End-tidal carbondioxide by infra-red analysis from a standard anaesthetic machine.
Timepoint [1] 314612 0
At 3 minutes
Secondary outcome [2] 314613 0
Comfort of breathing as measured by visual analog scale
Timepoint [2] 314613 0
3 minutes

Eligibility
Key inclusion criteria
No regular cardiovascular or respiratory medication, no history of chronic respiratory disease.

Employees of St George Hospital. We are currently not allowed to recruit outside of this site.
Minimum age
18 Years
Maximum age
70 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Pregnancy, lung disease, known or suspected coronary or cerebrovascular disease, treatment for asthma or
COPD, previous exposure to bleomycin, participants with beards, dentures or facial abnormalities affecting mask
seal.

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)
Participants will be randomised to either NRB or
BVM. This randomisation will be performed using a random sequence of ‘NRB ‘ or ‘BVM’ and has been
generated using the statistical software “R”. Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Random sequence generation by statistical software package.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
The sequence by which the trial are to conducted within each preoxygenation method, for each participant, will by a
balanced Latin-Squares design. This allows the sequence of trials to be randomised, but balanced so that, if one participant was to conduct the trials in a particular order, another participant will perform their trials in the reverse of that order.
Phase
Not Applicable
Type of endpoint/s
Pharmacokinetics
Statistical methods / analysis
Analysis will be performed using using the statistical software R (version 3.1.2). Participant demographics will be reported as mean plus or minus standard deviation, whilst non-normal data will be reported as median and interquartile range. Categorical data will be reported as counts and proportions.
The analysis of ETO2 will be completed separately for the NRB and BMV groups. This will be performed using a within-subject repeated measures ANOVA, with ETO2 and then ETCO2 as the dependant variable and method of preoxygenation as the within subjects variable and participant as the between
subjects variable. Planned post-hoc comparisons will use Tukey HSD to identify significant differences
between the trials of preoxygenation. A 2-sided p-value < 0.05 will be considered statistically significant.
Analysis of the visual analogue scales for breathing comfort will be performed using the Wilcoxon signed-rank test. A 2-sided p-value < 0.05 will be considered statistically significant.
To compare whether there is a difference between the NRB and BMV masks in each condition, an
independent T Test will be conducted if the data are parametric or Mann-Whitney U test if nonparametric
with Bonferroni corrections applied for the number of comparisons. It is planned to only compare preoxygenation methods with their similar conditions. For example, a comparison will be made between BVM+leak+NP and NRB+leak+NP but not BVM+leak+NP to NRB alone.

Two methods were used to calculate the sample size, using the statistical software R (version 3.1.2).
The clinically significant difference we have chosen is an ETO2 of 5%, as this would equate to 30sec of extra apnoea time ([5% x 2400ml] / 250mls/min oxygen consumption) in an 80kg male. This value is consistent with previous research.
The sample size calculated is for each arm, as out primary outcome of interest is whether nasal prongs
increase the value of ETO2 for each preoxygenation method in the presence of a leak.
The pooled standard deviation from previous studies is 6.84. The effect size was calculated as (mean difference / standard deviation) = 0.74.
The above values were applied to a sample size calculation using Cohen’s method14, with a power of 0.8 and significance of 0.05, and returned a sample size of 26.

As a check of this sample size, a second calculation was made for an independent two-samples t test as this can also be used to calculate sample size for crossover study designs. This returned a sample size of 30 using a significance level of 0.05 and power of 0.8.
In summary a sample size of 30 in each arm will be required for us to detect a 5% ETO2 difference at a
5% significance level with a power of 80%, making a total sample size of 60 participants.
Assuming a drop out rate of 10%, a total of 66 participants will be needed to provide 30 participants for each group.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
10/05/2015
Actual
14/05/2015
Date of last participant enrolment
Anticipated
Actual
5/07/2015
Date of last data collection
Anticipated
Actual
30/07/2015
Sample size
Target
60
Accrual to date
Final
60
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 3779 0
St George Hospital - Kogarah
Recruitment postcode(s) [1] 9663 0
2217 - Kogarah

Funding & Sponsors
Funding source category [1] 291251 0
Self funded/Unfunded
Name [1] 291251 0
Nil
Country [1] 291251 0
Primary sponsor type
Hospital
Name
St George Hospital
Address
Gray St
Kogarah 2217
NSW
Country
Australia
Secondary sponsor category [1] 289926 0
None
Name [1] 289926 0
n/a
Address [1] 289926 0
n/a
Country [1] 289926 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 292813 0
South Eastern Sydney Local Health District
Ethics committee address [1] 292813 0
Research Support Office G71,
East Wing Edmund Blacket Building
Prince of Wales Hospital,
Randwick NSW 2031
Ethics committee country [1] 292813 0
Australia
Date submitted for ethics approval [1] 292813 0
Approval date [1] 292813 0
16/03/2015
Ethics approval number [1] 292813 0
l5/019 HREC/15/POWH/54

Summary
Brief summary
We aim to measure the adequacy of preoxygenation by NRB and BVM in the abscence and presence of a simulated
mask leak, and whether the addition of oxygen via NP significantly improves preoxygenation in these conditions, as
measured by ETO2.
We propose to perform a four-period crossover study (repeated measures design) with two arms, using healthy
volunteers. There will be a NRB arm and BVM arm. After informed consent participants with be randomised to NRB
and BVM. They will then be randomised to a sequence of 3minutes preoxygenation using the NRB, NRB+NP, NRB
and simulated leak, NRB+NP and simulated leak in the NRB arm; or BVM, BVM+NP, BVM and simulated leak,
BVM+NP and simulated leak in the BVM arm.
ETO2 and endtidal carbon dioxide (ETCO2) will be measured using the gas sample analyser on an anaesthetic machine. Participants will also be asked to rate their comfort with each preoxygenation method.
Trial website
Trial related presentations / publications
Hayes-Bradley C, Lewis A, Burns B, Miller M.Efficacy of Nasal Cannula Oxygen as a Preoxygenation Adjunct in Emergency Airway Management. Ann Emerg Med. 2016 Aug;68(2):174-80. doi: 10.1016/j.annemergmed.2015.11.012. Epub 2015 Dec 31.
Public notes

Contacts
Principal investigator
Name 57138 0
Dr Clare Hayes-Bradley
Address 57138 0
Ambulance Service New South Wales Rescue Helicopter Base
Drover Road
Bankstown
NSW2200
Country 57138 0
Australia
Phone 57138 0
+61 416 470625
Fax 57138 0
Email 57138 0
[email protected]
Contact person for public queries
Name 57139 0
Matthew Miller
Address 57139 0
Department of Anaesthesia
St George Hospital
Gray Street
Kogarah
NSW 2217
Country 57139 0
Australia
Phone 57139 0
+61415579511
Fax 57139 0
Email 57139 0
[email protected]
Contact person for scientific queries
Name 57140 0
Matthew Miller
Address 57140 0
Department of Anaesthesia
St George Hospital
Gray Street
Kogarah
NSW 2217
Country 57140 0
Australia
Phone 57140 0
+61415579511
Fax 57140 0
Email 57140 0
[email protected]

No information has been provided regarding IPD availability


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
SourceTitleYear of PublicationDOI
EmbaseEfficacy of Nasal Cannula Oxygen as a Preoxygenation Adjunct in Emergency Airway Management.2016https://dx.doi.org/10.1016/j.annemergmed.2015.11.012
N.B. These documents automatically identified may not have been verified by the study sponsor.