obstrutive airway diseases Flashcards
what are three obstructive airway diseases?
chronic bronchitis
emphysema
asthma
what is FEV1
FEV1 is the Forced Expiratory Volume of air exiting the lung in the first second of this exercise
what is FVC
the Final Total amount or air expired
what is the normal ratio of FEV1:FVC
0.7-0.8
is COPD more common in females or males
males
what are 4 risk factors of COPD
SMOKING
Atmospheric Pollution
Occupation : dust
Alpha-1-antiprotease (antitrypsin) deficiency is an extremely rare cause of emphysema
what is the clinical definition of chronic bronchitis?
Cough productive of sputum most days
in at least 3 consecutive months
for 2 or more consecutive years
what are the morphological changes in chronic bronchitis in large airways?
Mucous gland hyperplasia
Goblet cell hyperplasia
Inflammation and fibrosis is a minor component
what are the morphological changes in chronic bronchitis in small airways?
Goblet cells appear
Inflammation and fibrosis in long standing disease
whats the definition of emphysema?
Increase beyond the normal in the size of airspaces distal to the terminal bronchiole arising either from dilatation or from destruction of their walls and without obvious fibrosis.
what are the forms of emphysema?
CENTRIACINAR PANACINAR PERIACINAR SCAR ‘ irregular’ ‘Bullous emphysema
what happens in centriacinar?
Begins with bronchiolar dilatation
Then alveolar tissue is lost
what is a bulla?
an
emphysematous
space
greater than 1cm
what are bullas and blebs related to?
peri acinar
what is the predicted FVC
4.95
what is the normal range for peak expiratory flow rate?
400-600 litres/min
what is more likely to be reduced in obstructive lung disease? FEV1 or FVC?
FEV1 is defos reduced and FVC may be reduced?
in hyperventilation which falls and rises? PO2 and PCO2?
PCO2 reduces and PO2 rises
in hypoventilation which falls and rises? PO2 and PCO2?
PO2 falls
PCO2 rises
true or false, in obstructive lung disease: FEV1 is less than 70% of FVC
true
is bronchial asthma reversible?
yes
aetiology of COPD
smoking
atmospheric pollution
occupation: dust
alpha 1 antiprotease deficiency
whts the difference between PA and Pa
PA is partial pressure off gas in alveolar air
Pa is partial pressure of gas in arterial blood
what is the four abnormal states associated with hypoaemia?
Ventilation / Perfusion imbalance - V/Q
Diffusion impairment
Alveolar Hypoventilation
Shunt
why does COPD cause hypoxaemia?
Airway Obstruction Alveolar Hypoventilation Reduced Respiratory Drive Diffusion Impairment Loss of Alveolar Surface Area Shunt Only during acute infective exacerbation
what is the commonest cause of hypoxaemia
low V/Q
true or false:
Fall in PaO2 due to hypoventilation is corrected by raising FIO2
true
what is FIO2
the Fraction of Inspired air which is Oxygen
what happens when pulmonary vascular changes in hypoxia?
Physiological pulmonary arteriolar vasoconstriction
When alveolar oxygen tension falls
Can be localised effect
All vessels constrict if there is hypoxaemia
A protective mechanism
Do not send blood to alveoli short of oxygen!
what is chronic cor pulmonale?
Hypertrophy of the Right Ventricle resulting from disease affecting the function and/or the structure of the lung
