For nasal cannulae, tell me about:
- What they are used for
- O2 delivery
- How to administer
- Potential problems
- Mild hypoxia, non-acute situations
- 24-30% O2(maximum flow rate of 4L/min)
- Placed around a patient’s face with the prongs positioned at the nostrils; secured behind ears
- High flows will dry and irritate nasal passages. Do not closely control FiO2
For Hudson mask, tell me about:
- What they are used for
- O2 delivery
- How to administer
- Potential problems
- Mild to moderate hypoxia
- 30-40% O2 on 5-10L/min
- The mask is positioned over the patient’s nose and mouth with the elastic strap behind their head.
- Do not closely control FiO2. Risk of aspiration
For a Reservoir/non-rebreathe mask, tell me about:
- What they are used for
- O2 delivery
- How to administer
- Potential problems
- Significant hypoxia (moderate to severe)
- 70% O2 with 15L
- Mask fits over the patient’s nose and mouth and can be secured to the face using elastic straps
- For the mask to work effectively, the reservoir bag needs to be filled before the mask is fitted to the patient. To fill the reservoir bag, obstruct the valve with your finger until the bag is filled with O2. Reservoir masks don’t have a true seal, so some entraining of the surrounding air is unavoidable
For a Venturi mask, tell me about:
- What they are used for
- O2 delivery
- How to administer
- Potential problems
Venturi masks are designed to deliver constant FiO2regardless of the patient’s respiratory rate and flow pattern (i.e. a fixed-performance device).
- COPD
- Details of required flow rate and percentage oxygen delivery are shown on the coloured mask fittings
- The Venturi mask fits over the patient’s nose and mouth like a Hudson mask
- If the flow rate of the oxygen is lower than the recommended amount for a specific Venturi mask, the mask won’t deliver the stated FiO2. If you increase the oxygen flow rate beyond the rate recommended for the mask, it will not continue to increase FiO2.
How would you perform a head-tilt chin-lift?
- Place one hand on the patient’s forehead and the other under the chin.
- Tilt the forehead back whilst lifting the chin forwards to extend the neck.
How would you perform a jaw thrust?
Use both hands to apply force behind the ramus of the mandible, displacing the lower jaw forwards and upwards.
What do you know about oropharyngeal (Guedel) airways?
An oropharyngeal airway can help prevent the tongue and soft tissues of the pharynx from obstructing the airway.
Size a patient’s airway by measuring the Guedel against a patient’s face: when the tip is placed at the angle of the jaw the flange should align with the centre of the top teeth (i.e. hard airway = measure “hard to hard”).
Insert into the patient’s mouth upside down, pass to the back of the throat and rotate 180 degrees to fit behind the tongue base. In children, the Guedel should be inserted the right way up (i.e. not upside down).
What do you know about nasopharyngeal airways?
Nasopharyngeal airways (NPAs) are typically used to bypass obstructions in the mouth, nose, nasopharynx or base of the tongue.
The appropriate NPA size can be calculated by measuring from the tip of the patient’s nose to the tragus of the ear (i.e. soft airway = measure “soft to soft”). The diameter should not exceed that of the patient’s little finger.
To insert an NPA, lubricate the tip and insert it into the right nostril aiming perpendicularly to the face to pass along the nasal passage and down into the pharynx.
They should not be used in patients with suspected base of skull fracture.
What do you know about supraglottic airways?
Supraglottic airways are a group of devices that sit abutting the larynx, above the vocal cords.
They are typically used as alternatives to endotracheal airways in short or low-risk anaesthetic cases.
The tube is inserted blind into the patient’s mouth and guided over the tongue until resistance is encountered.
The tube can then be connected to a ventilation device and airway patency confirmed with chest movement, fogging of the tube and a COtrace.
What do you know about laryngeal mask airways?
A laryngeal mask airway (LMA) is a reusable supraglottic device.
The inflatable mask rim forms a low-pressure seal over the laryngeal inlet.
Proseal is a type of LMA that has an additional inflatable segment that provides a greater seal within the larynx and a gastric port for drainage of gastric secretions.
What do you know about iGel airways?
An iGel is a single-use supraglottic airway device.
It is made up of a non-inflatable thermoplastic elastomer that has been designed to create an anatomical seal around the larynx and peri-laryngeal structures when warmed to body temperature.
An iGel is inserted via the same method discussed above, however, it does not require inflation to form a seal.
