Physiology: pulmonary compliance & work of breathing

Question 1

what is pulmonary compliance

Answer 1

the measure of effort that has to go into strecthing or distending the lungs

Question 2

what factors decrease pulmonary compliance

Answer 2

pulmonary fibrosis, pulmonary oedema, lung collapse, pneumonia, absence of surfactant

Question 3

what does a decrease in pulmonary compliance cause

Answer 3

lungs are stiffer, causes shortness of breath especially on exertion

Question 4

how would decreased pulmonary compliance be seen on spirometry

Answer 4

with a restrictive disease pattern

Question 5

what may cause compliance to be abnormally increased

Answer 5

loss of elastic recoil of lungs, e.g. in emphysema

Question 6

how can pulmonary compliance be increased naturally

Answer 6

increases with age

Question 7

in what situations is work of breathing increased (4)

Answer 7

when pulmonary compliance decreased, airway resistance increased, elastic recoil decreased or there is need for increased ventilation

Question 8

what is the normal work of breathing

Answer 8

lungs usually operate at around “half full”

requires 3% of total energy expenditure for normal quiet breathing