Anaesthesia and Cardiovascular Disease

Question 1

Anaesthesia and Cardiovascular Disease

Answer 1

A. Hypertension
B. Ischemic Heart Disease
C. Valvular Heart Disease
D. Cardiac Failure
E. Dysrhythmias

Question 2

Effect of anaesthesia on hypertension

Answer 2

Hypertensive crises with potent stimuli:
Laryngoscopy and intubation
Surgical stimulation
Increased sensitivity to vasodilatation of anaesthetic agents  hypotension
Often volume depleted and tolerate fluid or blood loss poorly
Low cardiac output may compromise organ perfusion
Anti-hypertensive drugs affect anaesthesia

Question 3

Interactions of hypertensive medication

Answer 3

Diuretic:
Fluid depletion and electrolyte disturbances (esp K)
B-blockers: Bradycardia/ negatively inotropic
Ca2+ blockers: hypotension
ACE inhibitors (exaggerated hypotension GA)
Irritable airways

Question 4

Hypertension risk evaluation

Answer 4

Treated and well-controlled hypertensives= normal anaesthetic risk
Treated, uncontrolled patients= higher risk
Untreated, uncontrolled patients= have the highest risk
Diastolic BP >120 for elective surgery= BP control =>Postpone for 2 - 6 weeks

Question 5

Assessing the hypertensive patient

Answer 5

BP chart with regular BP recordings (trend)
Effort tolerance
Effort tolerance
ECG and CXR to assess cardiac hypertrophy

Question 6

Principles of Management

Answer 6

Optimise BP control if time allows
CONTINUE anti-hypertensive therapy
Good premed to minimise anxiety
Blunt the intubation response
Avoid ≥25% ↓ in Systolic / Mean BP 
Adequate post-op analgesia

Question 7

Ischaemic heart disease

Answer 7

Common
Major cause of peri-operative deaths
Anaesthesia may aggravate or precipitate acute coronary syndrome
Peri-operative myocardial infarction has a
± 50% mortality

Question 8

IHD Risk Evaluation

Answer 8

Acute coronary syndrome (unstable angina + myocardial infarction) is an extremely high anaesthetic risk
Patients with “stable angina” AND RECENT MI < 6MONTHS) and poor effort tolerance: elevated risk
Good effort tolerance (>2 flights of stairs) normal risk

Question 9

Peri-operative management (IHD)

Answer 9

Good Premed
Maintain Cardiovascular i.e. slow rate and good diastolic pressure.
Monitor ST segment; 5-lead ECG; consider invasive arterial line
Appropriate Agent selection:
Etiomidate (propofol slowly and cautiously)
Acceptable volatiles: Isoflurane, sevoflurane
ALL muscle relaxants
Good analgesia
Fentanyl gold standard; morphine acceptable
Consider: LA or regional techniques
IV paracetamol
Careful with NSAIDs

Question 10

Post-operative Placement

IHD

Answer 10

Most peri-operative myocardial infarcts occur in the first 48-72 hours following surgery
Need good monitoring and analgesia post-operatively, and supplemental oxygen if needed