Problems in Equine Anesthesia 2: Post Anesthetic (Recovery) Complications

What are the common recovery complications in equines following anesthesia?

• Myopathy (EPAM)

• Neuropathy

• Central

• Peripheral

• Trauma

• Orthopaedic

• Soft tissue

• Airway obstruction

• Colic

• Catheter problems

What are the main features of Equine post-Anesthetic myopathy or EPAM?

• How does it present clinically?

• May affect ability to stand after anaesthetic

• May be delayed in onset by a few hours or can happen very quickly

• Biochemical changes - result of a hypoperfused muscle

• Can affect one or more muscle groups

• Muscle swollen, painful, hard, hot?

• Myoglobinuria in severe cases

• Horse appears swollen or engorged, cannnot use or straighten leg, sometimes cast has to be used to help support → until return of function

Why does myopathy develop?

All of which causes damage to muscle cells

• Positioning important to reduce compression, arterial supply more protected than venous due to lack of support in veins

• Blood keeps pumping into muscle but cannot leave - explaining why muscle looks engorged → muscle can even necroses

• Nerves can become stretched as well

What are the main procedures to prevent and treat EPAM?

Samples - urine - black from the myoglobinuria, takes several days to clear and recover

• Marker of muscle damage but also can impair renal function

• Fluids very important to flush it out

What are some peripheral neuropathies?

• What are the main treatment options?

Face - left sided damage, pulled towards side that is functioning

Why is positioning of the horse so important?

• Pull forward (lower foreleg) - prevent splaying

• Parallel support

• Padding, padding (and more) padding

What are some common equine genetic muscular diseases?

What is spinal cord myelomalacia - central neuropathy?

• Rare but devastating - spinal cord turns to “mush”

• Young, male horses more common

• More common dorsal recumbency

• No apparent problems during anaesthesia

• Aetiology unclear

What occular trauma can occur during recovery?

• Physical

• Bruising periocular area

• straw or other f.b.

• Desiccation of cornea

• Ulceration

• Remember damage due to skin cleaning and preparation solutions

**Sometimes helmets are used but may actually worsen recovery due to fear

What symptoms may indicate airway obstruction?

Airway obstruction

• Sudden and rapidly terminal complication

• Stridor (inspiratory) - high pitched noise

• Stertor (expiratory) - heavy snoring sound

• Nostril flaring

• Paradoxical ventilation?

• Absence of airflow at nostril

What are the main causes of airway obstruction?

• Nose in corner of box

• Nasal congestion

• Laryngeal paralysis

• Airway swelling

What are the main features of nasal congestion?

What are the main features of laryngeal complications?

• Trauma/swelling

• Laryngeal paralysis

• Pre-existing

• Stretching nerve - having the head over extended

• Unilateral or Bilateral

How do we avoid airway obstruction?

• Prevention much better than cure

• • Gentle intubation

  • Head position

  • Avoid overextension neck

  • Gentle extubation

  • Checking airflow immediately on extubation

• Careful positioning of horse in recovery box

• Diligent monitoring of horse during recovery

How should you deal with an airway obstruction?

• This is a very dangerous situation for all involved

• May need to wait for horse to go down in box

• Re-anaesthetise?

• Re-intubate?

• Tracheostomy?

• Steroids (if inflamed)

• Furosemide (if pulmonary oedema)

What are common IV cannula complications?

• Infections

• Thrombophlebitis

• Can lead to jugular obstruction

• Kink/obstruct

• Cap come off in recovery

• Haemorrhage (if 'up')

• Air embolus (if 'down')

What are the main recovery studies findings?

What are the main recovery techniques following anesthesia?

• +Features of the recovery box

Recovery using head and tail ropes

What is assisted recovery?

Improves chances of successful recovery

What is an ideal head & tail rope recovery?

What are common recovery emergencies?

Post recovery procedures for equine should include?

Post recovery

• Elective cases

• Allow free access to water

• Withold feed for 3-4 hours then reintroduce slowly

• Check later for signs of lameness, myopathy and pain

• Monitor urine and faecal output overnight

• Colic check for 24 hours after anaesthetic in all animals