Anaesthesia

• What are the considerations for anaesthetising a horse in the field?

  Behaviour, heart rate, temperature, RR, MM colour, CRT, MM moisture, Lung auscultation, heart auscultation, abdominal palpation, nasal discharge, BCS

  
  

  Flat, grassy ground, no nearby rocks
• What is the normal heart beat for horse

  28-40 bpm
• What is the normal RR for horses?

  10-30
• How to prepare a horse for field anaesthesia?

  Fasting 12-18 hours

  allow to graze but no big feed, wash mouth after

  Remove shoes
• Pre-medication prior to field anaesthesia may require?

  Acepromazine, xylazine IV

  double the dose for IM
• Induction, the most commonly used technique?

  Alpha 2 agonist
• Induction steps?

  step 1: ensure heavily sedated with xylazine or romifidine

  step 2: rapidly administer diazepam and ketamine

  step 3: controlling the fall
• why is heavy sedation and benzodiazepine used in combination with ketamine?

  offset muscle rigidity associated with ketamine
• What is the dose and onset of action of xylazine for sedation of horses?

  Dose: 1.1 -1.3 mg/kg

  onset: 2-3 minutes
• What is the dose for romifidine and onset of action?

  dose: 0.08-0.1 mg/kg

  onset: 5-10 minutes
• Pros and cons for intubation in field?

  Pros

  • maintain patent airway
  • allow delivery of oxygen

  Cons

  • time
  • providing oxygen
• When there is a need to prolong anaesthesia in the field, what are your options?

  option 1: incremental alpha2 agonist and ketamine

  option 2: constant rate infusion of triple drip
• How much of incremental alpha2 and ketamine to give prolong field anaesthesia?

  1/3rd dose used for sedation and induction, combine drugs in one syringe

  recommended maximum is 2 boluses
• How to check depth of anaesthesia of a horse?

  +/- increased RR

  +/- increasing nystagmus
• Infusion 'triple drip' what drugs?

  xylazine 500mg + ketamine 1000mg + 500mL 10% GG

  At 1mL/kg/hour