Addition of nasal cannula can either impair or enhance preoxygenation with a bag valve mask: a randomised crossover trial comparing oxygen flow rates

Comparison of end-tidal oxygen at 3-minutes using a combination nasal cannulae at different flow rates and a bag valve mask in healthy volunteers

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12617000337370

Enrollment

Registered

2017-03-03

Start date

2016-03-01

Completion date

2016-06-01

Last updated

2017-08-21

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

Objectives A critical safety component of emergency anaesthesia is the avoidance of hypoxaemia during the apnoeic phase of a rapid sequence intubation. Preoxygenation with a bag valve mask (BVM) or anaesthetic circuit may be improved with supplemental oxygen by nasal cannulae (NC) if there is a mask leak. In addition, NC are recommended for apnoeic oxygenation after induction and may be placed prior to preoxygenation . However, the optimum NC flow rate for preoxygenation or whether presence of NC itself creates a mask leak remains unclear. Methods We performed a randomized crossover study on healthy volunteers comparing BVM alone and BVM with NC flow rates of 0 (NC-0), 5 (NC-5), 10 (NC-10) and 15 (NC-15) litres per minute . Our primary outcome was end tidal oxygen (ETO2) after 3-minutes preoxygenation.

Interventions

The study design is five-period crossover study (repeated measures design). Participants will be required to complete five trials of 3-minutes pre-oxygenation with 100% oxygen in using a bag valve mask (BVM) (at 15l/min) and nasal cannula (NC) in all of the following conditions; BVM alone, BVM+NC at 0l/min, BVM+NC at 5l/min, BVM+NC at 10l/min, BVM+NC at 15l/min, At the end of each trial, oxygen will be measured by an expiratory breath into an oxygen analyser. There will be followed by a washout

Study design

Allocation

Randomised controlled trial

Intervention model

Crossover

Primary purpose

Treatment

Masking

Open (masking not used)

Eligibility

Sex/Gender

All

Age

16 Years to 70 Years

Healthy volunteers

Yes

Inclusion criteria

No regular cardiovascular or respiratory medication, no history of chronic respiratory disease. Attendees at the Greater Sydney Area HEMS governance day,

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.

Outcome results