Airway Management Flashcards
(40 cards)
Why do we need to secure an airway?
Allows delivery of oxygen and inhaled anaesthetic gas:
- Most anaesthetics cause respiratory depression (securing airway allows mechanical ventilation)
- Loss of airway reflexes = prone to airway obstruction
- Brachycephalics especially can obstruct
- All the above cause hypoxia
Allows scavenging and environmental protection
Allows ventilation of the patient
‘Protects the airway’ (from silent regurgitation - content can enter lungs)
Why are red rubber ET-tubes worse than PVC/silicone?
High risk as they are low volume, high pressure tube - when they are inflated they exert a lot of pressure on the trachea
Opaque so cannot assess cleanliness
How can ET tubes be tested prior to use?
Inflate prior to use and check it does not leak (remember to deflate before use)
What types of ET tube is best?
High-volume, low-pressure cuffs
What is the benefit of armoured tubes?
Cannot bend/kink
What is the benefit of the Murphy’s eye on an ET tube?
If the end of the ET tube is blocked - it allows gas to flow through still
How do you select the correct sized ET tube?
Palpate trachea to estimate diameter
Choose 3 different sizes (1 bigger, 1 smaller than your estimation)
Measure the tube from nares to point of shoulder
What can happen if an ET tube is too long?
Can enter thoracic cavity down bifurcation => anaesthetise a single lung (intrathoracic or bronchial intubation)
What is the function of intubeaze?
Cats have sensitive larynx - prone to laryngeal spasm => obstruction
Intubeaze contains lidocaine which (after ~60s) relaxes the larynx
Not needed in dogs
Describe the intubation of horses
Range from 14-30 mm
Cuffed (air injected into balloon)
Gag required for intubation
Intubation without direct visualization
Tube is not cut to length, lubricated
Horse is placed in lateral recumbency and head is extended
What is the function of supraglottic airway devices or v-gels?
Do not go down trachea - prevent risk of damage (useful in rabbits)
Can obstruct entire airway if it twists - use a capnograph to monitor
Describe the use of a face mask
Should cover nose and mouth:
- Not whole head
- Avoid eyes
Beware of dead space – choose the shape
Transparent masks preferable - can still see MM etc.
What is the function of an AMBU bag?
Can ventilate an animal without need to intubate or connect to oxygen
Can use room air or connect oxygen
Can connect to mask or endotracheal tube
What are the risks of airway management?
High pressure/low volume (red rubber) exert pressure on a small part of the tracheal mucosa
May see tracheitis or pressure necrosis
Extreme cases may see tracheal rupture
ALWAYS disconnect from breathing system when changing position whenever a change in recumbency is needed
Always inflate carefully preferably with manometer
Label this breathing system
What is the function of a breathing system?
Supply O2, volatile agent to the patient
Remove CO2 from expired gas
by means of “washout” (non-rebreathing systems) or chemical absorption (rebreathing systems)
What is active scavenging?
Breathing system catches any escaped gas and releases into atmosphere
What are non-rebreathing systems?
CO2 removed by flow of fresh gas (need high flow ‘flushes)
What are rebreathing systems?
CO2 in expired
gas is removed by reacting with soda lime
What is the function of an Adjustable Pressure Limiting (APL) Valve?
Allow exhaled waste gases and fresh gas to leave the breathing system when the pressure within the system exceeds the valves opening pressure
Why must the reservoir bag volume be greater (3-4x) than the patients inspiratory capacity?
When should a lack and mini lack be used?
Why is a lack system better than other non rebreathing systems?
More oxygen efficient than other non-rebreathing systems
but cannot do IPPV with it (causes rebreathing in patient)
What size of dog can a Bain be used for?
