COPD Flashcards
What is COPD?
Chronic Obstructive Pulmonary Disorder
Damage due to chronic inflammation which is usually the result of tobacco smoke
What type of lung condition is COPD?
Obstructive
There is little or no reversibility in airflow obstruction
What is the main cause of COPD?
Smoking
How is it different to a smoker’s cough?
A smoker’s cough sees an improvement of symptoms in 90% of people when they stop smoking
COPD is not reversible
How many people in the UK have COPD?
3 million but only 1.2 million have been diagnosed
What % of people over 40 have COPD?
4.5%
What happens to the lungs in COPD?
They become inflamed, damaged and narrowed
What is chronic bronchitis?
Long-term inflammation of both the small and large airways
What is FEV1?
Forced expiratory volume in 1 second
The volume of air that can be expelled from maximum inspiration in the first second
What is FEV1 dependent on and what is it a reflection of?
Time dependent
Reflection of airway calibre
What is FVC?
Forced vital capacity of the lung
Volume of air that can be forcibly expelled from the lung from the maximum inspiration to the maximum expiration
What is FVC dependent on and what is it a reflection of?
Volume dependent
It does NOT reflect lung calibre, it reflects lung volume
How do FVC and FEV1 change in obstructive lung diseases?
FVC does not change as the volume of the lung is unchanged
FVC1 is reduced as less air can be expired in 1 second
What is the FEV1/FVC ratio in COPD?
It is reduced and less than 70%
How does COPD affect peak expiratory flow?
There is little variability
If variability is greater than 20%, this may be asthma
What are the symptoms of COPD?
- Dyspnoea
- Sputum production & purulence during exacerbations
- Cough
- Wheeze
What is dyspnoea?
Breathlessness
What is purulence?
Generation of large amounts of pus
What is an exacerbation?
acute increase in the severity of an illness
What are the 3 risk factors for COPD?
- smoking
- pollution
- alpha-1-antitrypsin deficiency
This is an autosomal recessive disorder
What is the role of alpha-1 antitrypsin?
It is a protease inhibitor which balances out the action of neutrophil elastase
Neutrophil elastase increases in response to inflammation, infection and smoking
What does neutrophil elastase do?
If unregulated, this enzyme disturbs the function of the lung permeability barrier and induces the release of pro-inflammatory cytokines
In which group of people does COPD most commonly occur?
People over the age of 40 with a history of smoking
This can be tobacco or marijuana smoking
How are pack years calculated?
multiplying the number of packs of cigarettes smoked daily by the number of years that the person has smoked
How many pack years are equivalent to smoking 20 cigarettes a day for 1 year?
1 pack year
What is emphysema?
A type of chronic obstructive pulmonary disease
How does emphysema reduce the amount of oxygen in the bloodstream?
The surface area of the lungs is reduced
Damaged alveoli don’t work properly on expiration so old air becomes trapped, leaving no room for fresh oxygen-rich air to enter
What happens in emphysema?
The alveoli are damaged as over time the inner walls of the air sacs weaken and rupture
Damage to the alveolar walls creates many larger air spaces instead of many smaller ones
What are the main causes of emphysema?
- smoking
- deficiency of alpha-1 antitrypsin enzyme
- air pollution
- airway reactivity
- heredity
- male sex
- age
What lung condition do people with emphysema often have?
chronic bronchitis
inflammation of the bronchial tubes which leads to a persistent cough
What is the main symptom of emphysema?
People often have emphysema for many years without developing symptoms
It eventually causes shortness of breath, even when resting
Why is ankle swelling seen in a COPD patient?
Due to the build up of fluid as the right heart struggles to pump due to a build-up of pressure in pulmonary circulation
What can be a problem with oxygen therapy?
If there is a high blood pO2 - patients rely on hypoxic drive
What is type 1 respiratory failure mostly associated with?
Hypoxia
PCO2 is normal as the reason this occurs is V/Q mismatch
What is type 2 respiratory failure mostly associated with?
Hypoxia and hypocapnia due to inadequate ventilation
It is the actual ventilation of the alveoli which is failing
What symptoms are associated with an exacerbation?
increased dyspnoea
increased sputum production
sputum becomes purulent and green
increased cough
What do patients with COPD often look like physically?
Form a posture with pursed lips
They have lots of muscle wasting
CO2 flap is a flap of the hands associated with CO2 retention
What are the types of oxygen therapy that are used?
Long term oxygen therapy
Ambulatory oxygen therapy
Short burst oxygen therapy
What is involved in long term oxygen therapy?
using oxygen for at least 16 hours a day
Why are patients usually started on long term oxygen therapy?
due to ankle swelling and low oxygen saturation
given to COPD patients with a pO2 less than 7.3 kPa
What is the aim of long term oxygen therapy?
To reduce the strain on the heart and maintain oxygen saturation
What is significant about LTOT in COPD patients?
It is the only treatment which can improve survival in COPD patients
When is ambulatory oxygen therapy used?
Used during walking/exercise
Given to patients who have a significant drop in oxygen saturation when walking
What is short burst oxygen therapy?
A short burst of oxygen is given just for relief
How is the breathing process driven normally?
An increase in CO2 in the blood increases the breathing drive
How is the breathing process driven in COPD patients?
There is a chronic increase in CO2 so the receptors for CO2 are no longer responsive
Low pO2 (hypoxaemia) triggers breathing instead
What is a problem with giving patients too much oxygen?
Supplemental oxygen is given so the pO2 is constantly high and the hypoxic drive is not activated
Retention of additional CO2 leads to respiratory acidosis
When are patients prescribed oxygen therapy?
If they have oxygen saturation of 94% or less
If they have a history of CO2 retention, oxygen saturation target is 88-92% to balance risk of hypoxia
How does FEV1 demonstrate the severity of COPD?
The more FEV1 is reduced, the more severe the COPD is
How could quitting smoking prevent COPD from becoming too severe?
The decline in FEV1 depends on when smokers quit smoking and their susceptibility to smoke
Quitting smoking earlier means FEV1 will not be reduced as much
What are the criteria for prescribing oxygen therapy?
pO2 > 7.3 but < 8 kPa when stable and one of:
- secondary polycythaemia
- nocturnal hypoxaemia
- peripheral oedema
- pulmonary hypertension
What are 3 therapies used to treat COPD?
- long term oxygen therapy
- pulmonary rehabilitation
- surgery - bullous disease
What is pulmonary rehabilitation?
A programme specialised in breathing exercises to prevent worsening of symptoms in COPD patients
What happens in bullous disease?
The parenchyma of the lung is completely destroyed
