ANAESTHESIA - Ruminant and Pig Anaesthesia Flashcards
What should you do to prepare for ruminant anaesthesia?
Fast your patient
Establish intravascular access (if possible)
How long should you fast calves for prior to anaesthesia?
8 - 12 hours for food, 8 hours for water
How long should you fast mature cows for prior to anaesthesia?
12 - 24 hours for food, 12 hours for water
How long should you fast mature bulls for prior to anaesthesia?
24 - 36 hours for food, 24 hours for water
Which vessels can you use to establish vascular access in ruminants?
Jugular vein
Auricular vein
Which procedure will you commonly need to do to gain access the jugular vein in ruminants?
Venous cut down procedure because of their thick skin
What is the standard premedication combination for ruminants?
α2 agonist and Butorphanol
Which α2 agonists are licensed in ruminants?
Xylazine
Detomidine
Which opioid is licensed in ruminants?
Butorphanol
Which two risks should you be aware of when administering α2 agonists to ruminants?
Arterial hypoxaemia
Pulmonary oedema
What should you always have on hand when administering α2 agonists to ruminants?
Oxygen supplementation just in case they develop arterial hypoxaemia and/or pulmonary oedema
What can you do to reduce the risk of arterial hypoxaemia and pulmonary oedema in ruminants following α2 agonist administration?
Administer the α2 agonist IM as there is an increased risk of side effects with IV administration
What is the standard intravenous (IV) anaesthetic induction protocol in ruminants?
Ketamine ± Thiopentone
Why is thiopentone often combined with ketamine to IV induce ruminants?
Ketamine is a dissociative anaesthetic and thus the swallowing reflex will be maintained which makes intubation very challenging. Thiopentone reduces swallowing reflex making intubation less challenging
Why is it so important to properly cuff the endotracheal tube when using thiopentone as an IV induction drug in ruminants?
Thiopentone causes regurgitation in ruminants so it is important to properly cuff the endotracheal tube to protect the airway from aspiration
Why should thiopentone only be administered IV?
Thiopentone should only be administered IV as it causes perivascular irritation and tissue necrosis
What is the standard intramuscular (IM) anaesthetic induction protocol in ruminants?
α2 agonist and ketamine
Which inhalant anaesthetic drug is used for maintenance in ruminants?
Isoflurane
Why is endotracheal intubation so important in ruminants?
Endotracheal intubation is so important in ruminants as they are at such a high risk of regurgitation and aspiration of rumenal content and saliva
How should you recover ruminants from anaesthesia?
Ruminants should be recovered in sternal recumbency with their head elevated and their endotracheal tube left in (still cuffed) which should not be removed until the patient begins to chew the tube. This all reduces the risk of regurgitation and aspiration
What are the two most common complications seen in ruminant anaesthesia?
Regurgitation and aspiration of rumenal content and saliva
Rumenal tympany (rumen bloat)
What should you do to prepare for pig anaesthesia?
Fast your patient
Get a patient weight
Establish vascular access (if possible)
How long should you generally fast pigs prior to anaesthesia?
8 - 12 hours for food and water
How long should you fast pigs due to undergo abdominal surgery?
24 hours for food and water
Which vessel can you use to establish vascular access in pigs?
Auricular vein
Why do you generally have to use intramuscular (IM) administration in pigs?
It is very challenging to gain intravascular access in pigs so intramuscular (IM) injection is generally more realistic
Where should you carry out intramuscular (IM) injections in pigs?
Behind the ears
Why should you carry out intramuscular (IM) injections behind the ears in pigs?
Behind the ears has the least subcutaneous fat so you reduce the risk of intrafat injections and there is not valuable meat behind the ears that you can risk damaging
What are the two most common premedication combinations in pigs?
Azaperone and ketamine
Detomidine, butorphanol and ketamine
Why is azaperone and ketamine as a premedication often an unrealistic choice?
Azaperone and ketamine require a quiet environment for the pig to become sedated which is often unrealistic on a piggary
What is the standard anaesthetic induction protocol in pigs?
Ketamine ± Thiopentone
Which inhalant anaesthetic drug is used for maintenance in pigs?
Isoflurane
Why is endotracheal intubation important in pigs?
Pigs are prone to regurgitation and aspiration
However ET intubation is very challenging in pigs so mask induction is also an option
What are the three most common complications seen in pig anaesthesia?
Regurgitation and aspiration
Hypothermia
Porcine malignant hyperthermia
Which two factors can trigger porcine malignant hyperthermia?
Stress
Inhalant anaesthetic agents
Which three breeds of pig are predisposed to porcine malignant hyperthermia?
Pietrain
Landrace
Largewhite
Explain the pathophysiology of porcine malignant hyperthermia
Porcine malignant hyperthermia is a ryanodine receptor mutation which causes an uncontrolled release of calcium from the sarcoplasmic reticulum causing sustained muscle contraction which causes hyperthermia and increases the metabolic demand of those skeletal muscle cells resulting in increased oxygen consumption, increased carbon dioxide production and an ATP depletion. This ATP depletion leads to a loss in cell membrane integrity resulting in potassium, myoglobin and creatine kinase release into the bloodstream
What are the seven clinical signs of porcine malignant hyperthermia?
Generalised muscle rigidity
Blotchy skin
Severe, sustained hyperthermia
Hypercapnia
Metabolic acidosis
Hyperkalaemia
Cardiac arrhythmias
Which five methods should you use to treat porcine malignant hyperthermia?
- Stop anaesthesia
- Remove the vaporiser and replace the breathing system with an uncontaminated one
- Intermittent positive pressure ventilation (IPPV) with 100% oxygen
- Cool down patient
- Symptomatic treatment of hyperkalaemia, cardiac arrythmias and metabolic acidosis
Which three methods can you use to cool down a patient with porcine malignant hyperthermia?
Drench with cold water
Cold IV boluses
Cold enemas
Which sedative drug can reduce the risk of porcine malignant hyperthermia?
Azaperone
What is the prognosis for porcine malignant hyperthermia?
Poor prognosis
When are benzodiazepines used in ruminants and pigs?
Benzodiazepines are used in research ruminants and pigs
