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
When does the second/latent response occur in EIA?
3-4 hours post exercise
What are the benefits of exercise for asthma sufferers?
- Benefits of non-asthmatics
- Decrease in ventilation required to perform work
- Increased maximum ventilation rate
- Decreased residual volume/air trapping
- Increased tolerance/threshold
What are the factors affecting EIA?
- Duration of the exercise
- Continuous nature of the exercise
- Environmental conditions
- Seasonal/diurnal variations
- Medication
What are the treatment options for EIA?
- Exercise manipulation (aerobic activities are best)
- Trigger avoidance
- Pharmacological
- Longer pre-season aerobic training
What warm-ups are effective in preventing EIA in some sufferers?
- 20 minutes sub-max exercise
- 7 x 30 second sprints 30 minutes before exercise
What are the 3 types of asthma medications?
Relievers, preventers and symptom controllers
What is the function of relievers and when should they be taken?
Relax muscles around the airways (decreasing resistance) and provide relief within minutes. Should be taken during an asthma attack
How should pre-exercise relievers be used?
2-4 inhalations just before exercise
What is the function of preventers and when should they be taken?
Reduce swelling/inflammation inside the airways, mucus production and trigger sensitivity. Should be taken daily
Who are preventers prescribed for?
Asthmatics using reliever medication more than 3-4 times weekly
How should pre-exercise preventers be used?
2-4 inhalations just before exercise
What is the function of symptom-controllers and how long do they last?
Long acting relievers, last up to 12 hours
How should pre-exercise symptom controllers be used?
2 inhalations at least 30 minutes before exercise
What are the side effects of asthma medication?
Tremor, palpitations, severe headache, dizziness, nausea
What are the asthma-related contra-indicated substances?
Beta-blockers, aspirin, NSAIDs, royal jelly, sedatives
When is continuation of exercise inadvisable for EIA?
If PEF is not at least 80% of normal unobstructed value
What can exercise during bronchoconstriction lead to?
Hypoxia, hypercapnia, hyperinflation of the lungs, increased residual volume, respiratory muscle fatigue, dehydration, respiratory acidosis, coma or death
What is the first aid procedure for EIA?
- Sit upright
- Use reliever drug with spacer - 1 puff/4 breaths/4 exposures every 4 minutes
What is the asthma management plan?
- Assess asthma severity
- Achieve best lung function with medication
- Avoid triggers
- Use minimum doses of medication
- Develop action plan for problems
- Review regularly
