Anaesthesia for sicker patients

Question 1

ASA Physical Status 1

Answer 1

A normal healthy patient

Question 2

ASA Physical Status 1 Examples

Answer 2

Non-brachycephalic
Normal body condition score
No underlying disease present
Procedures such as neutering or simple fracture repair

Question 3

ASA Physical Status 2

Answer 3

A patient with mild systemic disease (animal well compensating)

Question 4

ASA Physical Status III

Answer 4

A patient with severe systemic disease (animal not compensating fully)

Question 5

ASA Physical Status IV

Answer 5

A patient severe disease that is a constant threat to life

Question 6

ASA physical Status V

Answer 6

A moribund patient who is not expected to survive without this procedure

Question 7

Addition of letter ‘E’ to physical status

Answer 7

Denotes an emergency defined as existing when delay in treatment of the patient would lead to a significant increase in the threat to life or body part

Question 8

Is a sinus rhythm normal

Answer 8

Normal in dogs, abnormal in cats

Question 9

What is a gallop rhythm an indicator of

Answer 9

Myocardial disease

Question 10

Effect of cardiovascular disease

Answer 10

Reduced cardiac output and stroke volume -> poor profusion, this has other organs such as on GFR

Question 11

What to do before anaesthetising a patient with cardiovascular disease

Answer 11

Try to get a diagnosis- echocardiogram
Try to stabilise patient

Question 12

How does cardiac disease affect drugs for anaesthesia

Answer 12

• Longer onset for drugs given IM or IV
• Quicker increases in plasma concentration of inhalation anaesthetics due to reduced CO
• Effects of drugs less predictable due to altered volume distribution
• Lower doses needed if patient has reduced albumin levels
• Longer duration of drugs if blood flow to liver reduced

Question 13

Examples of Drug combinations for patients with cardiovascular disease

Answer 13

Midazolam (benzo) and opioid OR
Alfaxalone (low dose) and opioid
May consider co-induction - propofol/midazolam

Question 14

Measures for patients with cardiovascular disease

Answer 14

Preoxygenation
Prompt intubation at induction
Avoid stress and nociception
Be prepared to give IPPV
Avoid increasing vagal tone- careful with eyes and moving head
Care with IVFT as this can create more work for the heart
Have emergency drugs drawn up or to hand

Question 15

Pre-operative assessment of patient with renal disease

Answer 15

Check dehydration/hypovolaemia
Is the patient blocked?
History- PUPD, weight loss
Bloods- determine degree of azotaemia, anaemia, hypokalaemia

Question 16

How to stabilise patient with renal disease

Answer 16

IVFT- dehydration
Anti-emetics- prevent emesis and risks of regurgitation
Blood transfusion- severe anaemia
Relieve blockage- cysto or urinary catheter

Question 17

MAP under which renal autoregulation of blood flow no longer functoins

Answer 17

<80mmHg, after this point perfusion is proportional to blood flow

Question 18

Main cause of hypovolaemia under anaesthetic

Answer 18

Inhalation agents

Question 19

Ionotropic Agents ( examples and use)

Answer 19

Dobutamine, dopamine
Used to maintain/ increase Cardiac Output

Question 20

Drug alterations for patients with renal disease

Answer 20

NSAIDs are contraindicated
Reduce renally excreted drugs to prevent accumulation

Question 21

Why are NSAIDs contraindicated in renal disease

Answer 21

Inhibit prostaglandin and therefore afferent vasodilatory mechanisms

Question 22

Considerations when anaesthetising patients with GI disease

Answer 22

Provide anti-emetics
Treat dehydration/hypovolaemia/pre-renal azotaemia
Use cuffed ET to prevent regurg
Analgesia- for chronic or acute pain (NSAIDs contra-indicated_
Titre drugs to effect- if low albumin-> more free drug

Question 23

Considerations in Anaesthetic for animal with severe liver disfunction

Answer 23

• Metabolism in liver reduced-> effects will be prolonged
• Albumin is produced in the liver so less albumin -> more free drug-> reduce doses
• Gluconeogenesis and glycogenolysis occur in liver so patient may be hypoglycaemic
• Patient may be hypotensive as bile acids affect the endothelium of the blood vessels
• Increased risk of infection

Question 24

Considerations for anaesthetic in animal with Diabetes insipidus

Answer 24

• caused by lack of ADH or a failure of kidneys to respond to it
• Patients will have severe polyuria with compensatory polydipsia
• They can become easily dehydrated and hypovolaemic so can end up with v high sodium concentrations (hypernatremia) in the blood
• Don’t deprive them of water and maintain vascular volume
• Start treatment with desmopressin to improve the patient’s condition before GA

Question 25

Analgesia for ASA 5

Answer 25

Aim to calm animal Pure mu opioids Rarely require alpha-2-agonsitsts

Question 26

Induction agent for ASA 5

Answer 26

is often not requires

Question 27

Anaesthetic protocol for ASA 5

Answer 27

- Preoxygenate, prepare ET tubes, laryngoscope - Combine induction/premedication to save time - Secure IV access, give IVFT

Question 28

Example anaesthetic drugs used for ASA 5

Answer 28

Benzodiazpine+ opioid + induction agent IV (alfaxlone/ketamine/propofol). or Benzodizipine +induction agent IV (opioid IM)

Question 29

Drugs to avoid for ASA 5

Answer 29

Alpha-2-agonist, ACE, propofol (can cause apnoea and reduce HR and BP)

Question 30

Anaesthesia for Caesarean

Answer 30

Choose dugs with a short duration of action Use the lowest possible dose Provide oxygen and intubate (if GA) Opioids to the dam Use LA if possible t reduce MAC & provide analgesia monitor ABP, give fluids

Question 31

Preventing emesis and aspiration in caesarean

Answer 31

GI changes during pregnancy and post-op pneumonia are reported

Question 32

Drugs to use in pregnant dam

Answer 32

All perioperative drugs may have an effect on neonates Xylazine- associated with neonatal mortality (newer alpha-2-agonists may not have the same effect however the vasoconstriction and decreased cardiac output associated wiht the is likely to have a negative effect on dam and fetuses- may be required with turly fear or fractious animals) ACP- should be used cautiously as it is long acting, irreversible and ay reuse in hypotension Careful assessment of anaesthetic agent frequent pain scoring required

Question 33

Which gauge IV access should be used in an emergency

Answer 33

18 gauge (in each cephalic) to allow shock rate fluid if necessary

Question 34

Considerations for GDV

Answer 34

Is it possible to decompress with a stomach tube Electrolyte imbalances can cause arrhythmias Possible regurgitation and aspiration Pain and distress metabolic acidosis and increased lactate

Question 35

Pre-med for GDV

Answer 35

Full mu opioid for alangesia If the patient is obtunded it may not be necessary Drugs with major cardiovascular effects- such as alpha-2s- should be avoided

Question 36

Induction for GDV

Answer 36

Any agent can be used Dose to minimal effect v important

Question 37

What is a sinus rhythm