Dynamic Lung Mechanics Flashcards
What is the regulation of the pulmonary vasculature and glands by the autonomic nervous system?
Parasympathetic
- muscarinic
- contracts smooth muscle
- causes mucus gland secretion
Sympathetic
- alpha - constricts blood vessels
- beta 2 - relaxes respiratory smooth muscle
What is asthma?
A chronic inflammatory condition in which there is recurrent reversible airway obstruction in response to irritant stimuli
What types of asthma are there?
Extrinsic
- associated with specific allergic reactions
Intrinsic
- not associated with any known allergen
Give some examples of asthma triggers
Upper respiratory infections
Weather changes
Allergens
Exercise
Emotions
Certain medications
What happens when asthma is triggered?
Antigen binds to mast cell
Release of histamine, prostaglandins, interleukins
- mucous production
- bronchoconstriction
Also caused by vagal activation
- increased vascular permeability - oedema
What are the delayed responses to an asthma trigger?
Increased vascular permeability
Immune cell infiltration
- eosinophils
- monocytes
-basophils
- T lymphocytes
Cytokine release
- IL 4,5,13
Inflammation
- oedema
- impaired mucociliary clearance
- reduced air flow
- airway hyperactivity
- airway injury
What do bronchodilators do?
Reverse bronchoconstriction
Reduce airway resistance
Treat wheeze
What do anti-inflammatory drugs do?
Relieve bronchial inflammation
Prevent further inflammation
Give examples of bronchodilators
Beta 2 adrenoreceptor agonists
Xanthines
Muscarinic antagonists
Leukotriene synthesis inhibitors and antagonists
What are short acting bronchodilators?
They last 3-5hrs
Salbutamol
Terbutaline
What are long acting bronchodilators?
They last 8-12hrs
Salmeterol
Formoterol
How do muscarinic receptor antagonists work?
Bronchodilation
Inhibits excess mucus secretion
Increases mucocilary clearance of bronchial secretions
No effect on late inflammatory stage
What are short lasting muscarinic receptor antagonists?
Last <5hrs
Ipratropium bromide
What are long acting muscarinic receptor antagonists?
Last <15hrs
Tiotropium bromide
How do cysteinyl leukotriene synthesis inhibitors and receptor anatagonists work?
Prevent aspirin sensitive and exercise induced asthma
Decreases immediate and delayed responses
Action is additive with beta 2 adrenoreceptor agonists
What are the two forms of any-inflammatory drugs?
Steroids
- glucocorticoids
Non-steroids
- Xanthines
- disodium cromoglycate
How do steroids work?
Inhaled corticosteroids
Decreases cytokines
Decreases enzyme activity
Decrease peptides
Decreases adhesion
Decrease inflammation
What is the pathophysiology of COPD
Tobacco smoke / air pollution
Continual bronchial irritation and inflammation
- chronic bronchitis
Breakdown of elastin in connective tissues
- emphysema
- airway instability
Airway obstruction
Air trapping dyspnoea
Frequent infections
- abnormal ventilation perfusion ratio
- hypoxemia
- hypoventilation
How do you treat COPD?
Mild - short acting bronchodilators when needed
Moderate - regular treatment with one or more bronchodilators
- inhaled corticosteroids
Severe - regular treatment with one or more bronchodilators
- inhaled corticosteroids
- antibiotics
- long term O2 therapy
