ASTHMA
What is it?
Asthma is a chronic inflammatory disorder of
the bronchial mucosa, which leads to bronchial
hyperresponsiveness, constriction of the airways,
and reversible airflow obstruction.
Causes:
Pathophysiology
- Episodic attack of bronchospasm,
bronchial inflammation, mucosal
edema, and increased mucous
production.
Early asthmatic response (first 30
mins)
Vasodilation
Increase capillary permeability
Mucosal edema
bronchospasm
Tenacious mucous secretion
Exposure to allergens, viral infection, pollution,
smoking, or extreme temperatures.
Inflammatory Mediators:
Mast cells, during inflammation, release
histamine, prostaglandins, leukotrienes, and
bradykinins > recruitment of neutrophils,
lymphocytes, basophils, and eosinophils.
Late asthmatic response (4-8 hrs)
Symptoms:
- Usually asymptomatic between
attacks
- Expiratory wheeze on auscultation,
rapid onset, difficult expiration,
nonproductive cough, dyspnea.,
tachypnea, tachycardia
- Pulsus paradoxus (BP decreases
with inspiration but increases with
expiration)
- Status asthmaticus (does not
respond to bronchodilators and
corticosteroids > Life-threatening)
Inflammatory response (recruitment
of WBCs)
Airway scarring
Increased bronchial
hyperresponsiveness
Impaired mucociliary function
Decreased Treg cells
Treatments:
- Beta2-agonist bronchodilators and oxygen
- Leukotriene antagonists
- Immunotherapy (monoclonal antibodies to IgE)
Complications:
- Status asthmaticus
- Acute respiratory failure
Nursing Considerations:
-
Educate patients regarding allergens, irritants, and peak flow meters
Environment should be free of allergen-laden
Monitor for exacerbation, respiratory failure, and status asthmaticus
Monitor breathing pattern, auscultate lungs every 4 hrs, and monitor pulse ox.
Daily monitoring with peak flowmeter is high recommended.