6.9: Exercise capacity

Question 1

Why is it easier to ventilate the base of the lung rather than the apex

Answer 1

Tissue stretched at apex compared to base
Base more readily ventilates as it is more compliment

Question 2

Ventilation at the apex of the lung

Answer 2

Pleural pressure is more negative
Greater transmural pressure gradient
Alveoli larger and less compliant
So less ventilation

Question 3

Ventilation at the base of the lung

Answer 3

Pleural pressure is less negative
Smaller transmural pressure
Alveoli smaller and more compliant
More ventilation

Question 4

Perfusion at the apex of the lung

Answer 4

Lower intravascular pressure (gravity effect)
Less recruitment
Greater resistance
Lower flow rate

Question 5

Perfusion at the base of the lung

Answer 5

Higher intravascular pressure (gravity effect)
More recruitment
Less resistance
Higher flow rate

Question 6

Excersise is

Answer 6

Purposeful, structured activity that involves gross muscular activity to improve physical condition

Question 7

Physical activity is

Answer 7

Holistic term that includes all muscular activity of all intensities

Question 8

Activities of daily living are

Answer 8

Basic independent self-care tasks done on daily basis that require coordination, strength and range of motion

Question 9

4 factors affecting exercise capacity

Answer 9

Neurological (motor control)
Respiratory (ability for lungs to ventilate,gas exchange)
Cardiovascular (ability for heart to receive blood from lungs and pump to working muscles)
Muscular (local perfusion)

Question 10

Outline why ventilation perfusion matching is important

Answer 10

Efficient gas exchange needs maximum coupling between ventilation and perfusion

Inadequacy of either gas or blood has significant impacts on removal of CO2 and blood oxygenation

Question 11

3 ways to measure exercise capacity

Answer 11

Cardiopulmonary excersise test
Six-minute walk test
Incremental shuttle walk test

Question 12

What is involved in the cardiopulmonary exercise test

Answer 12

Uses cycle ergo meter or treadmill
Intensity is incremental
Undertaken under close clinical supervision in controlled environment
ECG, ventilation, O2 and CO2 routinely measured

Question 13

Outputs of cardiopulmonary exercise test

Answer 13

Lots of data
Peak VO2 - primary outcome
ECG changes monitored throughout

Question 14

Advantages of cardiopulmonary exercise test

Answer 14

Quantifies performance in relation to metabolism
Precise and reproducible
Safety - continuous monitoring

Question 15

Disadvantages of cardiopulmonary exercise test

Answer 15

Requires skilled technical support
Very expensive
Needs dedicated space

Question 16

Process of six-minute walk test

Answer 16

Uses 20-30m flat course
Objective is to cover greatest distance as possible in 6min
Externally timed by assessor
Sub-maximal test

Question 17

Outputs of six minute walk test

Answer 17

Total distance walked - primary outcome
Heart rate, pulse oximetry - secondary variables

Question 18

Advantages of six minute walk test

Answer 18

Patient driven pace
Cheap
Validated in clinical populations

Question 19

Disadvantages of six minute walk test

Answer 19

Requires unobstructed course
Pace nit reregulated

Question 20

Incremental shuttle walk test involves

Answer 20

10m circuit
Externally paced by audio recording
Each minute has one extra length than previous minute

Question 21

Outputs of incremental shuttle walk test

Answer 21

Total distance - primary outcome
Perceived exertion scales, heart rate, pulse oximetry - secondary variables

Question 22

Advantages of incremental shuttle walk test

Answer 22

Cheap
Validated
External pacing helps achieve mex levels

Question 23

Disadvantages of incremental shuttle walk

Answer 23

Requires an unobstructed course
For some incremental walking is difficult
Patient can be penalised for poor pace management

Question 24

An exercise stress test to rule out ischemic heart disease is positive when

Answer 24

The ST segment of the ECG is depressed