Respiratory Diseases Flashcards
(414 cards)
what is FEV1
Forced Expiratory Volume of air exiting the lung in the first second after taking a deep breath and blowing out
is usually about 70-80% of FVC
usually 3.5-4litres
what is FVC
Final Total amount or air expired
around 5 litres
(forced vital capacity)
what is the normal ratio FEV1 : FVC
Normal ratio FEV1 : FVC is 0.7 – 0.8
how do you carry find out FEV1 and FVC
spirometry
how else can obstructive lung diseases be demonstrated
Peak Expiratory Flow Rate (PEFR)
Normal 400 – 600 litres/min
what are the key features in Obstructive Lung Disease
There is AIRFLOW LIMITATION Peak Expiratory Flow Rate (PEFR) is reduced FEV1 is REDUCED FVC may be reduced FEV1 is less than 70% of FVC
what are the most common obstructive airway diseases
CHRONIC BRONCHITIS
EMPHYSEMA
ASTHMA
COPD - chronic obstructive pulmonary disease
what is the aetiology of COPD
smoking
atmospheric - pollution
occuaption - dust
age
what is Chronic Bronchitis defined CLINICALLY as
Cough productive of sputum most days
in at least 3 consecutive months for 2 or more consecutive years
Complicated chronic bronchitis when sputum turns mucopurulent (acute infective exacerbation) or FEV1 falls
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what are morphological changes in chronic bronchitis in large airways
Mucous gland hyperplasia
Goblet cell hyperplasia (increase)
Inflammation and fibrosis is a minor component
what are morphological changes in chronic bronchitis in small airways
Goblet cells appear (produce muscous)
Inflammation and fibrosis in long standing disease
what is 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.
alveoli are damaged. inner walls of the air sacs weaken and rupture — creating larger air spaces instead of many small ones
what is the acinus
everything distal from the terminal bronchi (respiratory zone)
what is centriacinar emphysema
in upper part of lungs
alveoli are damaged, increased spaces in lungs
just after terminal bronchi
what is pan-acinar emphysema
large areas of lung lost in lower parts of lung
what is peri-acinar emphysema
tissue lost around edges of acinus, next to pleura usually
whats a bulla
is an emphysematous space greater than 1cm
what does the term ‘bleb’ mean
air containing spaces just underneath
the pleura
what is the protease-antiprotease imbalance and what induces it
smoking induces
elastase (protease) from neutrophils + macrophages
anti-elastase, protect elastin framework in alveolar tissue as prevent build of elastase
if alpha 1 trypsin deficiency, no anti-elastase, build of elastase = tissue destruction = emphysema
In EMPHYSEMA LOSS OF ALVEOLAR ATTACHMENTS, mechanism of airway obstruction, cant hold alveoli open
hhh bb
what force holds alveoli open
radial force
why do you get hypoxaemia in COPD
- airway obstruction
- reduced respiratory drive
- loss of alveolar surface area
- shunt
what pulmonary vascular changes occur in hypoxia
pulmonary arteriolar vasoconstriction
protective mechanism
Dont send blood to alveoli short of oxygen!