Asthma Flashcards
What is asthma?
Hypersensitivity of the trachea and bronchi to various stimuli as a result of a narrowing of the airways
What is the pathophysiology of asthma?
Airways narrow and remodel due to
- Spasm of bronchial smooth muscle
- Mucus membranes swelling
- Increased mucus from goblet cells
What are the consequences of air trapping?
Hyperinflation, increased residual volume and decreased vital capacity
How does asthma affect blood oxygen levels?
Asthma creates insufficient alveolar ventilation and results in a drop in O2 saturation levels of arterial blood
What are the triggers of asthma?
Allergens, viruses, air pollution, foods/additives, drugs, occupational factors, emotional stress, cold air and exercise
What is peak expiratory flow (PEF)?
The greatest flow velocity during a forced expiration from fully inflated lungs
What is FEV1?
The forced expiration volume in the first second of maximal expiration after maximal inspiration (i.e. a measure of how quickly the lungs can be emptied)
What are the indicators of reversible airway obstruction?
After bronchodilator medication
- FEV1 increases by 12%
- PEF increases by 20%
What are the categories of asthma?
Mild, moderate, severe
What are the characteristics and symptoms of mild asthma?
- FEV1 = 80-100%
- PEF > 85%
- Infrequent bronchodilator use
- Occasional wheezing, cough and chest tightness
What are the characteristics and symptoms of moderate asthma?
- FEV1 = 60-80%
- PEF = 70-85%
- 1-3 daily bronchodilator use
- Most days wheezing, cough and chest tightness
What are the characteristics and symptoms of severe asthma?
- FEV1 < 60%
- PEF < 70%
- 3-4 daily bronchodilator use
- Most days wheezing, cough and chest tightness
What are the indicators of exercise-induced asthma (EIA)?
- Large changes in the airway resistance
- Symptoms don’t stop after 10 minutes post exercise
- PEF decreases by more than 15%
What lung function changes are associated with EIA?
1st minute: Decreased airway resistance/increased ventilation
After 6 minutes: Increased airway resistance/decreased ventilation
When do FEV and PEF reach their lowest point in EIA?
3-15 minutes post exercise