Assessment of exercise tolerance

Question 1

Define exercise tolerance

Answer 1

The upper limit of the patient’s ability to perform aerobic exercise and is an indication of cardiorespiratory reserve

Question 2

By what % does oxygen consumption increase in the postoperative period?

Answer 2

50 %

Question 3

What is the purpose of preoperative exercise tolerance assessment?

Answer 3

Risk analysis
Further investigations
Cardiorespiratory optimization

Question 4

What symptoms of cardiovascular disease would you target in your history?

Answer 4

FUNCTINAL CAPACITY
HISTORY
Angina distance
Dyspnoea distance

• ADLs?
• Walking distance?
• Climbing stairs?

EXAM

• observe
• walk (the shuttle walk - 10 m to and fro)
• climb with patient

Question 5

When should cardiopulmonary exercise testing be used

Answer 5

When standard bedside tests/ the shuttle test is not possible due to a condition such as OA of lower limbs

• CPX provides an objective and reproducible assessment of cardiac and respiratory reserve and the equipment can be adjusted according to any condition prohibiting normal limb function

Question 6

What should be done if CPX is not possible in a patient

Answer 6

Investigation using pharmacological stressors - e.g. dobutamine stress ECHO

Question 7

Describe the New York Heart Association (NYHA) functional and objective assessment of cardiovascular disease.

Answer 7

Class 1 - Patients with cardiac disease with no fatigue/palpitations/dyspnoea/angina with ordinary activity

Class 2 - Patients with cardiac disease comfortable at rest but with fatigue/palpitations/dyspnoea/angina with ordinary activity

Class 3 - Patients with cardiac disease comfortable at rest but with fatigue/palpitations/dyspnoea/angina with less than ordinary activity

Class 4 - Symptoms of cardiac failure or of angina may be present even at rest. If any physical activity is undertaken discomfort is increased.

Question 8

Which scoring system that quantifies exercise tolerance uses metabolic equivalents (METs)?

Answer 8

The Duke Activity Status Index

Question 9

What is 1 MET

Answer 9

1 MET is equivalent to BMR - One MET of energy is required when a person is sitting quietly at rest

1 MET = 3.5 mlO2/kg/min = 1 kCal/kg/hr

Question 10

Describe activities associated with 1 - 10 METs

Answer 10

1 MET
Eating, watching TV

2 METs
Dressing

4 METs
Climbing a flight of stairs

6 METs
Running a short distance

7 METs
Heavy housework

8 METs
Cycling

10 METs
Strenuous sports

Question 11

Below what maximum MET score is the patient is at higher risk of morbidity perioperatively

Answer 11

Below 4 METs - If the patient can’t climb one flight of stairs without becoming symptomatic there is increased morbidity

Question 12

Which conditions may warrant further investigation or treatment

Answer 12

Unstable conditions

Unstable coronary syndromes (severe angina or recent MI)
Decompensated heart failure (NYHA functional Class IV)
Significant arrhythmias
Severe valvular disease

Question 13

Classify and give examples of surgical risk of cardiac complications (death and non-fatal myocardial infarction) based on the proposed operation

Answer 13

Low risk (<1 %) for example:

Cataract surgery
Endoscopic procedures
Intermediate risk (1 – 5 %) for example:

Orthopaedic surgery
Intraperitoneal surgery
High risk (>5 %) for example:

Aortic surgery
Peripheral vascular surgery