None listed
Conditions
Brief summary
The 2 most common breathing methods of pre-oxygenation involve 8 deep breaths over 60 seconds or 3 minutes of tidal volume breathing (normal breathing) using high flow oxygen. In the operating theatre this involves an anaesthesia machine that can deliver 100% oxygen at 15L/minute. In the emergency department, an anaesthesia machine is not present so a simple non rebreather mask or a bag valve /mask kit is used. Typically both of these devices can only deliver 60 -70% oxygen, so pre-oxygenation is often inadequate in these settings. In the recent KEMH anaesthesia preoxygenation trial we found that nasal prongs improved preoxygenation effectiveness when used with the anaesthesia machine. We are examining if nasal prong oxygen also improves preoxygenation when non rebreather mask and bag valve / masks are used.
Interventions
Randomised crossover trial
The five preoxygenation techniques include:
1. “Non rebreather” mask
Non-rebreather mask involves wearing a mask over the mouth and nose, held by an elastic round the back of the head. The mask is attached to a reservoir bag which re-fills with oxygen from a tank as the participant inhale. The oxygen flow rate is 15L/minute.
2. “Non rebreather” mask at maximum flow rate.
The flow rate is unmeasured but approximately 30-40L/min.
3. ”Non rebreather” mask at 15l/min
Randomised crossover trial The five preoxygenation techniques include: 1. “Non rebreather” mask Non-rebreather mask involves wearing a mask over the mouth and nose, held by an elastic round the back of the head. The mask is attached to a reservoir bag which re-fills with oxygen from a tank as the participant inhale. The oxygen flow rate is 15L/minute. 2. “Non rebreather” mask at maximum flow rate. The flow rate is unmeasured but approximately 30-40L/min. 3. ”Non rebreather” mask at 15l/min + Nasal Oxygen 10l/min Nasal Oxygen involves wearing nasal prongs in the nose with oxygen delivered at 10L/minute 4. Bag valve / mask Bag valve /mask involves wearing a tightly held mask over the mouth and nose. The mask is attached a oxygen source at 15L/min. 5. Bag valve / mask 15l/min+ Nasal Oxygen 10l/min 100% Oxygen was used for all run at the flow rates listed above Each participant will do each of the above techniques (1-5) in a random order. Each technique will consist of a run with 16 deep breaths over 2 minutes, followed by a washout period of 3 minutes then a run with 3 minutes tidal breathing for each technique. After each technique (that is, both 16 deep breaths and 3 minutes tidal breathing runs) there will be a 3 minute wash out period before the next technique End tidal oxygen fraction will be measure by capnography on the anaesthesia machine Results will be logged
Sponsors
King Edward Memorial Hospital
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used) (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
1. Fit and healthy 2. Age > 18 3. English speaking
Exclusion criteria
1. Significant cardiac or respiratory disease 2. No consent 3. Pregnancy
Outcome results
None listed