Airway management

Question 1

Why do we manage airways?

Answer 1

• To support patients respiratory system throughout anaesthesia
• To deliver fresh oxygen and inhaled anaesthetic agents
• To protect patient’s airways throughout a period of unconsciousness
• To enable rapid intervention in the case of an anaesthetic emergency
• To allow the provision of IPPV

Question 2

Types of airway management

Answer 2

• ET Tubes
• Supraglottic devices
• Masks
• Flow by nasal tubing

Question 3

Equipment for airway management

Answer 3

• Anaesthetic machine and vapouriser - delivery of fresh gas, such as oxygen
• Delivery of inhalation agents
• Laryngoscope
• Local anaesthetic agents
• Lubricant
• Selection of appropriately sized ET tubes or supraglottic devices. ET tube sizes are measured by their inner diameter
• Tube tie
• Cuff inflator
• Stylet

Question 4

ET tubes

Answer 4

• Magill - simple bevel, shorter end
• Murphy - acute bevel, Murphy’s eye
• PVC, rubber or silicone
• High pressure, low volume cuff - typically Magill, creates areas of high pressure in trachea
• Low pressure, high volume cuff - requires more air to seal, but distributes pressure over wider area
• Appropriate cuff inflation - reduces the risk of aspiring mucous, vomit

Question 5

ET tubes - prep and placement

Answer 5

• Laryngoscope (with working bulb)
• Selection of appropriately sized, leak tested tubes
• Tie
• Sterile lubricant
• Local anaesthetic spray
• Cuff inflation device

Question 6

Supraglottic devices

Answer 6

• Suitable for dogs, cats and rabbits
• Quick and easy to place
• Reduced risk of trauma to larynx
• Can remain in-situ for longer on recovery
• More reliant on capnography to confirm placement
• Reduced protection against aspiration
• Can sometimes slip if not correctly sized for patient

Question 7

Risks and complications - Oesophageal intubation

Answer 7

• Placement of endotracheal tube into the oesophagus rather than the trachea
• Risk is reduced by using a laryngoscope and capnograph to confirm placement

Question 8

R&C’s - Endobrachial intubation

Answer 8

• Placement of ET tube into a single bronchus
• Risk is reduced by ensuring tubes are appropriately cut to length

Question 9

R&C’s - Trauma

Answer 9

• Avulsion, rupture, puncture wounds
• Can be caused by repeated attempts at intubation and poor technique
• Risk is reduced by using a laryngoscope to clearly visualise whilst intubating

Question 10

R&C’s - Obstruction

Answer 10

• Mucous plugs, occlusion of airways
• Identification through capnography and vigilant monitoring - increased resistance and pressure within the system

Question 11

R&C’s - Leakages

Answer 11

• Identified through capnography, inappropriate depth of anaesthesia, smell (anaesthetic gases)
• Reduced by appropriate leak testing of tubes and tubing, ensuring cuff pressure

Question 12

Extubation

Answer 12

• Recovery period has a higher morality rate than anaesthesia itself
• 47% of all anaesthetic related deaths in canine patients, and 60% in feline patients occurred in recovery
• Ensuring patients are able to maintain their own airway before extubating is critical
• Supraglottic devices can be left in position until the patient will no longer tolerate it
• Brachiocephalic patients are particularly prone to adverse airway events on recovery and should be treated with special precautions

Question 13

Legislation

Answer 13

• Intubation is a schedule 3 task under the Veterinary Surgeons Act 1966
• Tasks must be performed under direct and constant supervision
• RCVS Day One Skills for Veterinary Nurses (small animals)
• Section 10 anaesthesia covers airway management in regards to placement, maintenance and removal