Week 2 - Anaesthesia for the cardiac compromised patient

Question 1

What do you have the be careful with when choosing sedation and anaesthetics for the cardiac compromised patient?

Answer 1

They can make things worse!

Need to choose careful and use multimodal anaesthesia to reduced doses and therefore side effects.

Oxygen always helps!

Question 2

What is better…heavy sedation or general anaesthesia?

Answer 2

GA as it ensures a secured airway and control.

Question 3

How much stabilisation is needed in the following patients before anaesthesia:

1. No clinical signs but pre-existing cardiac disease
2. Mild to moderate clinical signs at rest or during exercise of a re-existing cardiac disease
3. Clinical signs of a fulminant heart failure

Answer 3

1. No preanesthetic stabilisation is mandatory prior to anaesthesia
2. Significant stabilisation with medications and/or hospitalisation is required

Emergency = immediate stabilisation is mandatory and comprehensive and invasive monitoring needed due to unstable nature

3. Anaesthesia it totally contraindicated until the patient is stabilised. Avoid anaesthesia but if necessary for life saving procedures, bet carry the highest risk!

Question 4

What are some general rules for stabilisation?

Answer 4

1. Oral medication to be given at home (reduce anxiety/stress)
2. Reduce stress in hospital (pheromones, good handling, decrease waiting time, sedation)
3. Pre-oxygenate
4. Avoid calcium channel inhibitors and beta blockers (exacerbate hypotention)
5. Continue OR stabilise with pimobendan IV or diuretic IV to be better anaesthetic candidate.
6. Drain pleural effusions

Question 5

What drugs can be used as a sedative or pre-medication in cardiac compromised patients?

Answer 5

Acepromazine
- Good for patients with mitral valve disease as causes vasodilation and therefore decreases afterload.

Alpha 2 agonist
- low dose dexmedatomidine preferred for stressed patients
- can be reversed
- can causes SEVERE effects on cardiovascular system -> vasoconstriction and increased resistance - AVOIDED

Benzodiazepine
- minimal cardiovascular compression
- often combined as on their own is a light sedation

Opioids
- combine with a benzo to lower the dose and the risk of bradycardia
- sedation - butorphanol
- Pain relief - methadone/ burprenophine

Question 6

What are the advantages of using local anaesthetics?

Answer 6

Reduce injectable and inhaled anaesthetic drug doses

Low dose = anti arrhythmic effect

High doses = can produce cardiac toxicity

Question 7

What are the choice of induction agents in the cardiac compromised patient?

Answer 7

Propfol
- Can cause vasodilation and apnea
- Co-induce with a benzo or low dose opiod

Alfaxalone
- less risk of apnea

Ketamine
- can increase HR so be aware of those patients who are already tachycardiac

Question 8

What are some emergency drugs that can be used to stabilise patients?

What are some non-medical options to keep patient stable

Answer 8

Anticholinergics
- good for bradycardia
- can increase vascular resistance
- balance pros/cons

Inotropes
- Dobutamine, dopamine
- increase muscular contraction

Vasopressors
- Norepinephrine
- Vasoconstriction = increase BP

Antiarrhythmics
- lidocaine, beta blockers

Non-medical
- IVFT and switch down volatile
- Keep GA short!

Question 9

What are the monitoring options for the cardiac compromised patient?

Answer 9

Haematology & biochemistry (beforehand)
Manual methods (CRT, PR, HR, pulse strength, RR, colour)
Oesophageal stethoscope
Pulse oximetry
Blood pressure (Doppler, Oscillometric, invasive)
Capnography
Temperature
ECG