Natalie - Lung Ventilatory Capacity and Disease Flashcards
Name two diseases that alter the volumes of the lung
Asthma
Cigarette-relating lung disease
List the effects of lung diseases such as asthma on the lungs
(3)
Alter the volumes that can be contained within and expired from the lungs
Increase the resistance to gas flow
Cause breathing to become difficult and impair gas exchange
What is vital capacity
The volume of air expelled from the lungs by the deepest possible expiration after they have been filled by the deepest possible inspiration
What is forced vital capacity
When a vital capacity manoeuvre is carried out with maximal effort to expel all the vital capacity in the minimal possible time interval
FEV1 = forced vital capacity in 1 second
What is the normal ratio of FEV1/FVC
FEV1 is normally 80%
What may cause stroke volume to reduce?
(7)
Diseases of the thoracic cage
Acute injuries to thoracic cage
Diseases affecting nerve supply to respiratory muscles- muscular dystrophy
Abnormalities of the pleural cavity - pneumothorax
Pathology in the lung itself - fibrosis
Space-occupying lesions - cysts
Increased pulmonary blood volume - left heart failure
What may cause a change in vital capacity
(2)
A change in stroke volume which is caused by a range of injuries and diseases
Diseases of the airways such as asthma and bronchitis
What may affect Forced Expiratory Volume
Airway resistance affects this
What will reduce airway resistance?
(5)
Bronchoconstriction - asthma
Inhalation of irritants - cigarette smoke
Structural changes in airways - chronic bronchitis
Obstruction in airways - inhaled foreign body or excess mucous
Destructive processes in lung parenchyma - emphysema
List the obstructive disorders
(4)
Asthma
Chronic obstructive pulmonary disease = chronic bronchitis or emphysema or both together
Cystic fibrosis
Lung cancer/tumours
What happens to air in terms of obstructive disorders?
Air inhaled normally but slow to come out
What are the characteristic FVC results of an obstructive disorder?
(3)
Normal or slightly low FVC
Low FEV1
Low ratio e.g. 40-50%
Write a note on chronic bronchitis
(6)
Blue bloaters
Daily productive cough for three months or more, in at least two consecutive years
Overweight
Peripheral oedema
Wheezing
Elevated hemoglobin
Write a note on emphysema
(5)
Permanent enlargement and destruction of airspaces distal to the terminal bronchiole
Older and thin
Severe dyspnea
Quiet chest
X-Ray hyperinflation with flattened diaphragms
List the restrictive disorders
(5)
Pulmonary fibrosis
Damage to rib cage
Skeletal disorder e.g. scoliosis
Muscular disorder e.g. Muscular dystrophy
Pulmonary oedema e.g. cor pulmonale
List the test results of someone with restrictive disorder
(3)
Very low FVC
Low FEV1
High or normal ratio e.g. 90%
Explain what happens to the air in a restrictive disorder
Air does not get in because of restriction
Why are lung diseases a major problem in ireland
High incidence of smoking in young people
High incidence of cystic fibrosis
Why are lung function tests so important
(2)
To diagnose patients early
Because once a patients develops COPD treatment is often disappointing
What do you measure with a spirometer
Vital Capacity
What information does a spirometer give us
(4)
Vital capacity
Tidal volume
Inspiratory capacity
Expiratory reserve volume
What do we use to measure vital capacity
Spirometer
What information does a spirometer not give us
(3)
residual volume
Functional residual capacity
Total lung capacity
How are functional residual capacity and residual volume measured?
Using a body plethysmograph
Write a note on the measurement of functional residual capacity
Measured using the body box
Body plethysmograph is used to measure this volume
Why can’t we use a spirometer to measure FRC
FRC is the volume of air that cannot be moved out of the lung
Therefore we cant measure it using a spirometer
What does FRC detect
Detects disease in the small airways which is caused by smoking
What is residual volume
The volume of gas left in the lungs after maximal forced expiration
What is the residual volume of a healthy person
About 2.5L
Why would residual volume increase in emphysema?
Air cannot escape the lung
The inward alveolar elastic recoil is diminished -> airways collapse -> air gets trapped -> Barrel Chest syndrome
Why is RV increased in obstructive diseases?
RV is raised because airway closure occurs too early and air becomes trapped in the lung
When is reduced FRC and RV seen?
In patients with reduced lung compliance
Explain in what conditions there is a reduced FRC and RV and why this is the case
(2)
Fibrosis -> lung is stiff and recoils to a smaller resting volume -> patient doesn’t get much air into the lung
Obesity -> can reduce compliance of chest wall also
What happens to test results in an emphysema patient
Air in but slow to come out
Very high residual volume in emphysema
What happens to test results in pulmonary fibrosis
Air does not get in - very low volumes
Low volume overall
