Anaesthetics: Airway Management Flashcards
MUST REVISE HEAD & NECK:
- 10a.) Larynx
- See Conduct of Anaesthesia for more
Remind yourself of the flow and approximately FiO2 for following oxygen delivery devices:
- Facemask
- Nasal cannulae
- Non-rebreathe mask
- High flow nasal oxygen
- Venturi mask (all colours)
- Facemask: 5-10L/min, FiO2: 40-60%
- Nasal cannulae: 1-2L/min, 24-28%
- Non-rebreathe mask: 15L/min, 95-100%
- High flow nasal oxygen: 50-100L/min,
- Venturi mask: see image
Remind yourself of the different types of airway we can use to support an airway/keept it patent
- Nasopharyngeal
- Oropharyngeal (Guedel)
- Larygneal mask airway
- i-gel
- Intubation
Describe how you measure an oropharyngeal airway
Estimate size by selecting an airway with a length equal to the vertical distance between the pts incisors and the angle of the jaw
Describe how you measure a nasopharyngeal airway
Nostril to tragus of ear
Describe how you measure an i-gel
For each of the following, discuss whent they would be a suitable airway:
- Nasopharyngeal
- Oropharyngeal
- i-gel
- Larygneal mask airway
Nasopharyngeal airways should not be used in pts with…
Suspected base of skull fracture
Remind yourself how to insert oropharyngeal airway
Explain, numerically in terms of fraction of inspired oxygen and volume of oxygen, the need for preoxygenation
- In a fit & healthy adult, 250mL of oxygen extracted by tissues per minute
- Fraction of oxygen in room air is 21% however as we breathe in and move down airways fraction of inspired oxygen becomes less; eventually in alveolus fraction of oxygen is 14%.
- Fit & healthy adult (70kg man) FRC is 2500mL therfore 350mL of oxygen
- Therefore, FRC would only last 1.4 minutes/apnoea hypoxia time is 1.4 minutes
- If we give pre-oxygenation and get fraction of O2 in alveolus to 90% then we have 2250mL of oxygen therefore have hypoxia time of 9 minutes
NOTE: effects of obestiy, illness etc on graph image
