Large Animal Recovery from Anaesthesia

Question 1

What do you need in a recover box?

Answer 1

Dry floor
Towels
Nasal tubes
Oxygen
Sedatives
De-cuffing syringe - may need to be quick when extubating
Emergency drugs

Question 2

How do you move a horse back into a recovery box?

Answer 2

• Reconnect to hoist
• Switch of inhalational agent
• Support head to prevent over extension of neck
• Positioned in recovery box depending on position on table
  ○ Allow best access to IV line
• Extubated when swallowing returns
  ○ Demand valve used to stimulate breathing
• Anaesthetist tends to stay in recovery box until reflexes return:
  ○ Nystagmus
  ○ Blinking
  Swallowing - last to return before extubating

Question 3

What should you look out for in Recovery Phase?

Answer 3

Upper Airway Obstruction
Laryngeal Obstruction
Nasal Oedema
Pulmonary Oedema

Question 4

Upper Airway Obstruction

Answer 4

(Horses are obligate nasal breathers)
Occurs in nasal passages or at larynx
Stridor or stertor following tracheal extubation
Loud respiratory noise
Nostril flaring on inspiration
Increased abdominal respiratory effort
Exaggerated thoracic excursion
Absence of airflow at nostrils

Question 5

Laryngeal Obstruction

Answer 5

Re intubate horse with appropriate ET tube and insert gently
Causes:
Dorsal displacement of soft palate
If extubated before upper airway reflexes fully return
Epiglottic retroversion
Following laryngeal surgery may leave ET tube in place for recovery
Secured appropriately
If obstruction occurs be prepared to reintubate
May need more drugs to hand
Emergency tracheostomy in severe cases

Question 6

Nasal Oedema

Answer 6

Common
○ Particularly if in dorsal recumbency or long surgery
Usually resolves as horse stands
Use nasopharyngeal tubes or phenylephrine (or both)
○ Tubes will usually fall out once horse attempts to stand
○ Risk of epistaxis (bleeding from nose)
Can recover horse to standing with ET tube in place
○ Can get around the blockage of nasal passages

Question 7

Pulmonary Oedema

Answer 7

Occurs in transition from being ventilated to spontaneous respiration
○ Related to changed in venous return and influx of fluid into alveoli of lungs as horse takes big breaths
○ Increases negative pressure in thorax
First signs to see are exaggerated respiratory efforts and cyanosis
Frothy pinkish fluid at nostrils after horse has been reintubated and airway patency returned
Treatment
○ Remove obstruction
○ Provide oxygen
Compromising normal respiration
○ Frusemide to reduce some of the fluid in chest
○ Dexamethasone to reduce inflammation