Lung Volumes And Capacities

Question 1

Measuring lung volumes and ventilation

Answer 1

Measure tidal volume using spirometry - tidal volume x frequency gives minute (total) ventilation.

Question 2

Forced vital capacity and forced expiratory volume in one second

Answer 2

FVC - from full breath, forced expiration until no longer air to release gives, remaining volume is residual volume, which cannot be measured.
FEV1 - the volume of air that can be expired within one second, usually 80% of the FVC.

Question 3

Flow volume loop

Answer 3

Used to determine the forced vital capacity and peak expiration flow rate (max flow rate achieved - diagnostic of certain conditions).
FEFx where x is the % of air that has been exhaled, dependent on conditions.

Question 4

Obstructive respiratory diseases

Answer 4

When there is an obstruction to the flow of air INCREASING RESISTANCE to the movement of air.
- can be inside the lumen, in the airway wall, or surrounding the airway.
- ex. asthma, chronic bronchitis, aspiration of foreign material (choking).

Question 5

Restrictive respiratory diseases

Answer 5

Inability to fully fill the lungs to max volume, RESTRICTION in some manner.
- May be due to stiffening of the lungs or chest wall, problems with muscles/nerves, or physical abnormalities.
— Alterations in the parenchyma
— diseases of the pleura, chest wall, or neuromuscular apparatus.
- ex. pulmonary fibrosis.

Question 6

Asthmatic bronchial wall

Answer 6

Hyper-responsiveness of the airways to various stimuli, resulting in the narrowing of the airways (bronchioconstriction).
- excessive mucous secretion
- chronic inflammation
- chest tightening, wheezing, cough.

Question 7

FVC and FEV1 of patients with obstructive lung diseases

Answer 7

Decreased FVC and proportionally decreased FEV1.
ex —
FEV1 = 1.3
FVC = 3.1
% = 42%

Question 8

FVC and FEV1 of patients with restrictive lung diseases

Answer 8

Decreased FVC but proportionally increased FEV1.
ex —
FEV1 = 2.8
FVC = 3.1
% = 90%

Question 9

Examples of obstructive lung diseases

Answer 9

Asthma, COPD (emphysema/chronic bronchitis), localised airway obstruction.

Question 10

Examples of restrictive lung diseases

Answer 10

Diffuse interstitial pulmonary fibrosis
Diseases of the pleura-pneumothorax
Diseases of the chest wall - scoliosis
Neuromuscular disorders