PILB

Question 1

What is general anaesthesia?

Answer 1

total unconsciousness, resulting from the administration of drugs that
depress brain function

Question 2

What is local anaesthesia?

Answer 2

loss of sensation to part of the body, produced by applying drugs which block
nerve conduction

Question 3

What is regional anaesthesia?

Answer 3

loss of sensation in a region of the body produced by application of local
anaesthetic to the nerves supplying that region; e.g., epidural anaesthesia

Question 4

What are sedatives?

Answer 4

Relieve anxiety and cause drowsiness

Question 5

What are tranquillizers?

Answer 5

Relieve anxiety without causing drowsiness. Animals may still be readily roused

Question 6

What are the advantages of using sedatives or tranquillizers?

Answer 6

Sedatives and tranquillizers potentiate the action of anaesthetics. They are useful in calming the animal
before induction of anaesthesia and in reducing the dose of other drugs required to produce general
anaesthesia. Administration of sedative doses of drugs before the induction of full general anaesthesia is
known as ‘pre-medication’ and is often used in large animals.

Question 7

What are the advantages of using anaesthetics?

Answer 7

Control the level of pain

Question 8

What are the disadvantages of using anaesthetics?

Answer 8

Anaesthesia can result in depression of
cardiovascular and respiratory systems and can cause death – the overdose of anaesthetic is a Schedule 1
method for humane killing

Question 9

What kind of mice should be anaesthetized?

Answer 9

Healthy, stress-free

Question 10

What preparations should be done before anaesthetics?

Answer 10

Acclimatization: Acclimatise to the environment before anaesthesia to recover from transport stress.

Health status: Ensure the animal is breathing regularly and the mucous membranes are pink. Some animal models may be particularly susceptible to problems under anaesthesia, e.g. neonatal or aged animals and animals with cardiovascular phenotypes.

Pre-anaesthetic fasting: Monogastric animals such as dogs cats and pigs benefit from being fasted before anaesthesia to prevent vomiting on induction. Small animals, such as rodents and rabbits, should not be fasted.

Question 11

What are examples of opioids?

Answer 11

Morphine, pethidine, fentanyl, buprenorphine, or butorphanol provide analgesia for relief of moderate to severe pain

Question 12

What are examples of non-steroidal anti-inflammatories?

Answer 12

Carprofen, ketoprofen, flunixin, or meloxicam are effective in the treatment of mild to moderate pain

Question 13

What are examples of sedatives or tranquillizers?

Answer 13

Benzodiazepines, alpha 2 adrenergic agonists, butyrophenones, phenothiazines, and ketamine

Question 14

What are examples of anticholinergics?

Answer 14

Atropine and glycopyrrolate may be used in some animals to reduce salivary
secretions

Question 15

What are the types of local anaesthetics and what examples can be suggested?

Answer 15

Anaesthetics that can be applied topically, e.g. EMLA cream; anaesthetics that can be injected, e.g. lignocaine, bupivacaine; anaesthetics that can be injected to nerve trunk for desensitization over a large area, e.g. epidural or paravertebral block.

Question 16

What is the role of narcosis?

Answer 16

Loss of consciousness

Question 17

What is the role of analgesia?

Answer 17

Absence of pain sensation

Question 18

What is the definition of relaxation?

Answer 18

Loss of muscule tone and reflexes

Question 19

Why does ‘balanced’ anaesthesia need to be produced?

Answer 19

There is no single agent that alone provides satisfactory narcosis, muscle relaxation and analgesia. Consequently, the best anaesthesia is usually
achieved by combining several agents (including sedatives, analgesics and anaesthetics) to give what is
termed ‘balanced’ anaesthesia.

Question 20

What are the considerations to choose anaesthetic agents?

Answer 20

1. The species and age of the animal
2. The duration of the procedure
3. The depth of anaesthesia required
4. The purpose of the investigation
5. The equipment available
6. The experience of the staff

Question 21

What are the two phases of anaesthesia?

Answer 21

1. Induction
2. Maintenance

Question 22

What are the administrative ways for anaesthesia?

Answer 22

Injection, inhalation and immersion

Question 23

What are the pros of injectable anaesthesia?

Answer 23

1. No need for complicated equipment
2. Simple to administer
3. Minimal cost
4. Induction with intravenous agents is very rapid

Question 24

What are the cons of injectable anaesthesia?

Answer 24

1. Difficult to adjust the level of anaesthesia
2. Easy to overdoes
3. Variable length of anaesthesia
4. Variable in sex, age and strain
5. Agents can be metabolized

Question 25

What are the benefits of intravenous injection of anaesthetics?

Answer 25

Drugs are administered directly into the circulation and can be titrated to effect.

Question 26

What are the consequences of intra-peritoneal, intra-muscular and sub-cutaneous injection of anaesthetics?

Answer 26

Drugs are administered as a single dose.
There is a risk of over- or under-dosing, induction and recovery can be slow, a larger total dose is required, and there can be pain on administration. These are used if handling is a problem

Question 27

What is the equation for calculating the dose to be delivered?

Answer 27

weight of the animal (kg) times the dose required in mg/kg divided by the concentration of the drug in mg/kg

Question 28

What are examples of injectable agents?

Answer 28

1. Ketamine and sedative combinations
2. Hypnorm (fentanyl/fluanisone) and sedative combinations
3. Propofol
4. Alfaxalone
5. Urethane, Alpha-chloralose (for terminal anaesthesia only)

Question 29

What are the advantages of reversal agents for injectable anaesthetics?

Answer 29

1. Animals become active more rapidly and will be less at risk of hypothermia. Many anaesthetic drugs depress respiration; this is reversed with antagonist drugs.
2. When reversing an opioid such as fentanyl with another opioid (e.g. nalbuphine or buprenorphine), the adverse effects of the fentanyl are reversed. Still, the analgesia persists because of the action of the agonist/antagonist. This is known as sequential analgesia.

Question 30

What are the pros of inhalable agents?

Answer 30

1. Rapid induction and recovery
2. Easy to adjust the depth and duration, safer to control
3. Minimised metabolism
4. Good for rapid procedures
5. Good for high-frequency anaesthetics

Question 31

What are the cons of inhalable agents?

Answer 31

1. Bulky equipment
2. Disposal of waste gas
3. More operative skills required
4. Expensive equipment
5. Induction is stressful in some species

Question 32

What equipment is required to administer volatile agents?

Answer 32

1. A source of oxygen
2. A flowmeter to measure the oxygen flow
3. An anaesthetic vaporiser: these deliver a controlled percentage of vapour independent of the flow rate.
4. A delivery system from the vaporiser to the animal. There are several types of delivery systems that may be used to achieve this. These include induction chambers, face masks, and endotracheal tubes. Each has its advantages and disadvantages.
5. A mechanism to deal with waste gases

Question 33

What are the effects of anaesthetics and are there any examples?

Answer 33

1. Alpha-chloralose: a very prolonged recovery period associated with considerable involuntary excitement
2. Urethane: severe peritoneal irritation and carcinogenic
3. Chloral hydrate: poorly analgesic
   and can cause paralytic ileus following anaesthesia in the rat.

Question 34

What should be considered after anaesthesia?

Answer 34

1. Warmth: Continue to provide heat in the post anaesthetic period until the animal is fully recovered and able to maintain its own temperature.
2. Bedding: Ensure the animals are given comfortable, absorbent bedding and cannot push the bedding to one side and end up lying on the cage floor.
3. Fluid therapy: Animals may not drink in the post-anaesthetic period and could suffer dehydration. Continue to monitor fluid intake and supplement as required.
4. Urine and faecal output: These indicate whether the animal’s physiology returns to normal. Lack of urine may indicate dehydration or pain, and lack of faeces may indicate ileus (gut stasis).
5. Feeding: Animals in the post anaesthetic period may not want to move to feed and may not be able to reach the food hopper. They may require a convalescent diet and may need food to be placed within reach on the floor of the cage.
6. Monitoring of body weight: This is advised following anaesthesia. Supplements may be required.
7. Analgesia: Acute pain can be alleviated by centrally or peripherally acting analgesic drugs administered systemically,
   by local anaesthetics, or by applying supporting bandages or other means of protecting and immobilising damaged tissues. The selection of a particular treatment regimen will vary, depending
   upon the nature of the pain, its cause, and its estimated severity and duration.

Question 35

What should be checked during and after anaesthesia?

Answer 35

1. AIRWAY - Check the airway is unobstructed
2. BREATHING – Switch off the vaporiser (or stop continuous infusions), give 100% oxygen, and assist ventilation– 20-30 breaths/minute.
3. CIRCULATION - Give fluids to maintain blood pressure. In larger animals, heart massage may be appropriate.
4. DRUGS – Give an anaesthetic antagonist if available (unless surgery is still in progress). Respiratory stimulants can also be used

Question 36

What health and safety issues should be considered when performing anaesthesia?

Answer 36

1. Where volatile anaesthesia is used, there must be adequate scavenging methods to avoid personnel exposure to waste gases. Care should be taken to use pressurised gas cylinders properly.
2. Anaesthetic set-ups should be regularly checked and serviced to make sure they are fit for purpose.
3. If immersion anaesthesia is used the wastewater should be disposed of in accordance with local rules.
4. With injectable agents, needles should not be recapped to avoid accidental self-injection. This can also occur if animals are inadequately restrained and move suddenly. All pre-filled syringes should
   be clearly labelled as to their contents.

Question 37

What are the ranks in the personal license?

Answer 37

Category A – minor procedures with no anaesthesia

Category B – minor procedures with brief anaesthesia (corresponds to PILB training)

Category C – major surgical procedures with recovery anaesthesia or prolonged non-recovery anaesthesia (corresponds to PILC training)

Category D – use of neuromuscular blocking agents

Question 38

What are the ranks in the project license?

Answer 38

AA: No anaesthesia when the technique is applied
AB (L): Recovery anaesthesia (local)
AB (R): Recover anaesthesia (regional)
AB (G): General anaesthesia with subsequent recovery
AC: General anaesthesia without subsequent recovery
AD: General anaesthesia with the use of neuromuscular blocking agents