COPD Flashcards
What is chronic obstructive pulmonary disease (COPD)?
Long-term airflow obstruction
that is progressive
What are the main types of COPD?
Emphysema
Chronic bronchitis
What is emphysema?
Destruction of terminal bronchioles, respiratory bronchioles and alveolar walls
How does emphysema affect the respiratory membrane?
Loss of surface area of respiratory membrane
How does emphysema affect gas exchange in the alveoli?
Reduced gas exchange
How does emphysema affect the air spaces in the lungs?
Large airspaces called bullae
How does emphysema affect expiration?
Reduced expiration
Why does emphysema cause reduced expiration?
Because loss of elastin in alveolar walls
don’t hold terminal bronchioles open
which collapse more easily during expiration
How does emphysema affect the size of the lungs?
Hyper-inflation of lungs
Why does emphysema cause hyper-inflation of lungs?
Less air expired in last breath
more air inspired on top of this
Loss of elastic recoil, lungs are more compliant, bigger increase in volume with same change in pleural pressure
What is chronic bronchitis?
Chronic mucus hypersecretion
What causes mucus hypersecretion with chronic bronchitis?
Inflammation in bronchi
gives mucous gland hyperplasia
How does chronic bronchitis affect the airways?
Narrowing of airways
due to mucus
What is a complication of the mucus hypersecretion in chronic bronchitis?
Traps bacteria
frequent respiratory infections
What are the causes of COPD?
Mostly smoking
Alpha-1-antitrypsin deficiency
What relative proportion of smokers get COPD?
Small proportion
What are the symptoms of COPD?
Cough with sputum
Breathlessness on exertion
What are the signs of COPD?
Purse lip breathing
Tachypnoea
Using accessory muscles
Barrel chest
Wheeze on auscultation
Cyanosis
High pCO2
Right-sided heart failure
Why do patients with COPD show purse lip breathing?
Increases pressure in airways
to delay collapse of small bronchioles
Why do patients with COPD use accessory muscles?
Because the lungs have less elastic recoil
so need to use internal intercostal muscles, abdominal muscles in order to reduce their volume
Why are patients with COPD barrel-chested?
Hyper-inflation of lungs
Why do patients with COPD have cyanosis, high pCO2?
Reduced gas exchange
gives hypoxaemia, cyanosis
and high pCO2
Why do patients with COPD get right-sided heart failure?
In response to low pO2 in alveoli
get hypoxic pulmonary vasoconstriction
increases pulmonary vascular resistance
increases pressure in right side of heart
How is COPD diagosed?
History of symptoms and signs
Spirometry
Chest X ray
High resolution CT
Arterial blood gases
What would spirometry of a patient with COPD show?
Low FEV1
Low FEV1/FVC ratio
How low they each are, correlating with severity
What would a chest X-ray of a patient with COPD show?
Hyper-inflation of lungs
What would a high resolution CT of a patient with COPD show?
Degree of terminal bronchiole, respiratory bronchiole and alveolar wall destruction
What would arterial blood gases of a patient with COPD show?
Type 2 respiratory failure
- low plasma pO2
- high plasma pCO2
Maybe respiratory acidosis
-low plasma pH
What is meant by stable COPD?
Patient has COPD but is able to manage at home
How are patients with stable COPD managed?
Stop smoking
Pulmonary rehabilitation
Drugs
Flu vaccinations
Long term oxygen therapy
Lung volume reduction
How does FEV1 change with age?
After a certain age, decreases
How does smoking affect the decrease in FEV1 with age?
Faster rate of decrease in FEV1
Why are patients with stable COPD advised to stop smoking?
Reduces rate of decrease in FEV1
regardless of how long have been smoking, regardless of age when stop smoking
What is meant by deconditioning of a patient with COPD?
Exercise makes them feel breathless
they avoid exercise
their muscles weaken
they got more breathless
What is pulmonary rehabilitation?
Encourages patients with COPD to exercise, improve their diet
to stop deconditioning
What drugs are used to treat a patient with COPD?
B2 agonist
Steroids
Antimuscarinics
Mucolytics
Matylxanthines
How do B2 agonists treat a patient with COPD?
Cause bronchodilation
What are the side effects of using a B2 agonist to treat a patient with COPD?
Tachycardia, palpitations
Tremors
Why can B2 agonists cause tachycardia, palpitations?
Act on B1 adrenoceptors in the heart
activate them
Why can B2 agonists cause tremors?
Act on B2 adrenoceptors in skeletal muscle
activate them
How do anticholinergics treat a patient with COPD?
Antagonise M3 receptors in the bronchi
preventing bronchoconstriction
What are the side of effects of using anticholingerics to treat a patient with COPD?
Dry mouth
Supraventricular tachycardia
Urinary retention
Why can anticholinergics cause a dry mouth?
Block muscarinic receptors in the salivary glands
loss of parasympathetic stimulation to make them secrete
What can anticholingerics cause a supraventricular tachycardia?
Block M2 receptors in the AV node
loss of parasympathetic stimulation to decrease heart rate
Why can anticholinergics cause urinary retention?
Block M3 receptors in the bladder detrusor muscle
loss of parasympathetic stimulation to make it contract and expel urine
How do methylxanthines treat a patient with COPD?
Bronchodilation
Anti-inflammatory
How do methylxanthines cause bronchodilation?
Inhibit phosphodiesterase
which breaks down cAMP
Less cAMP broken down
more cAMP present
What are the side effects of methylxanthines?
Nausea
Supraventricular tachycardia
Headaches, seizures
What is an example of a methylxanthine?
Aminophylline
When do long-term steroids cause side effects?
High dose of inhaled steroids
Oral steroids
What are the side effects of long-term steroids?
Thin skin, bruising
Adrenal insufficiency
Fluid retention
How do mucolytics treat a patient with COPD?
Reduce thickness of mucus in airways
making it easier to clear
What is an example of a mucolytic?
Carbocysteine
How does long-term oxygen therapy treat a patient with COPD?
Prevents damage by hypoxaemia to organs e.g. heart, kidneys
Why are patients with COPD particularly given flu vaccinations?
To prevent acute exacerbations of COPD
caused by infection
When is long-term oxygen therapy used to treat a patient with COPD?
Persistent hypoxaemia
Cor pulmonale
What are the side effects of long-term oxygen therapy?
High plasma pCO2
Why does long-term oxygen therapy cause high plasma pCO2?
Loss of stimulation to peripheral chemoreceptors
don’t stimulate increased ventilation
ventilation decreases
When is lung volume reduction surgery used to treat a patient with COPD?
When emphysema only affects upper lobes
How does long volume reduction surgery treat a patient with COPD?
Reduces large air spaces, bullae, less dead space
What is an acute exacerbation of COPD?
Temporary worsening of symptoms
- cough with sputum
- breathlessness on exertion
Type 2 respiratory failure, respiratory acidosis
What causes an acute exacerbation of COPD?
Infection
How is an acute exacerbation of COPD treated?
Controlled oxygen therapy
Nebulised bronchodilators
Oral or IV steroids
Antibiotics if have infection
In don’t improve, non-invasive ventilation, invasive ventilation
What is non-invasive ventilation?
Ventilatory support through patient’s upper airway
using a facial mask
When should non-invasive ventilation not be used to treat a patient with an acute exacerbation of COPD?
Untreated pneumothroax
Impaired concsciousness
Upper airway secreions
Facial injury
Vomiting
