What is the normal FEV1
3.5-4 litres
What is the normal FVC
5 litres
What is the normal ration of FEV1/FVC
0.7-0.8
What is the predicted FVC based on
age, sex and height
Except for FEV1 and FVC how else can obstructive lung disease be demonstrated
PEFR
What is PEFR
How fast an individual can exhale
What is a normal PEFR
400-600 litres/min
Below what percentage is a marked fall of PEFR
<50%
What are the features of Obstructive Lung Disease (5)
Airflow limitation PEFR is reduced FEV1 is reduced FVC may be reduced FEV1 is less than 70% of FVC
What type of hypersensitivity is bronchial asthma
Type 1
Aetiology of Chronic Bronchitis and Emphysema (5)
Smoking Atmospheric pollution Occupation Alpha-1-antitrypsin deficiency Effect of age and susceptibility
Chronic Bronchitis large airways
Mucous glands and goblet cell hyperplasia
Inflammation
Fibrosis (minor component)
Chronic Bronchitis small airways
Goblet cells appear
Inflammation
Fibrosis (long standing disease)
What is Emphysema
Increase of alveolar space distal to terminal bronchiole arising from dilation or destruction and without obvious fibrosis
Forms of Emphysema
Centri-acinar
Pan-acinar
Bulla
Where is Centri-acinar emphysema more common
Around a central bronchiole and Upper part of the lung as there is more ventilation there
Where is Pan-acinar most common
Lower part of the lungs and causes huge areas of tissue loss
What is a bulla
Emphysematous space greater than 1cm
What can happen if a bulla bursts
It can cause a pneumothorax
What type of emphysema can individuals with alpha-1-antitrypsin get
Bulla
Pathogenesis of Emphysema
Smoking
Protease-antiprotease imbalance
Ageing
A1A deficiency
What is the purpose of anti-elastase (anti-protease)
Counteracts the effects of neutrophils and macrophages when there is a foreign body within the respiratory system
What effect does smoking have on the production of anti-protease
it reduces it and impairs the repair mechanism involved in elastin synthesis
Is emphysema reversible (Y/N)
No
Why does emphysema lead to an increase on CO2 and decrease in O1
Increase in CO2 means 1 O2 molecule cannot occupy the same space so the O2 level drops
What does the high level of CO2 retention cause
Chemoreceptors become less sensitive to the effects of CO2
What does the the decrease in sensitivity to CO2 mean?
The body does not rely on CO2 concentration as the respiration drive but Hypoxia
Those that don’t respond to hypoxia are known as
Blue bloaters