Asthma pathophysiology involves chronic inflammation of the airways that causes bronchoconstriction (constriction/narrowing of the smooth muscle of the bronchioles), leading to airway hyperresponsiveness (narrowing bronchioles in response to allergens), excessive mucus production and retention (cilia become paralysed in airway during chronic inflammation), and airway oedema. Asthmatic patients with airway inflammation, which is reversible, tend to experience symptom-free periods as well as acute asthma exacerbations.
Causes of asthma include allergies, exposure to airway allergens and air pollutants, exercise, stress, and medication such as NSAIDS (Ibuprofen, Voltaren etc.) and non-selective Type 2 Beta Blockers.
Asthma Signs and Symptoms:
- Frequently presents at night or early morning
- Dyspnoea
- Wheezing (mostly on expiration…if present also at inhalation, patient condition is worse)
- Cough with or without sputum
- Central cyanosis (eg. blue lips)
- Sweating
- Tachycardia
- Widened pulse pressure (a significant difference between the systolic and diastolic BP)
- Other comorbidities such as GERD, COPD or respiratory tract infections increase risk for asthma
Asthma Complications:
- Status asthmaticus (life threatening severe continuous reaction in which asthma exacerbation is completely unresponsive to bronchodilator treatment)
- Pneumonia (infection originating from microorganisms that find their way to the lungs that inflames the alveoli in one or both lungs, causing accumulation of mucus, leading to cough with sputum, fever, chills and dyspnoea)
- Respiratory failure (indicated by a decrease in BP, respiratory rate and heart rate)
Asthma Diagnosis Factors:
- Family history of asthma
- Reversibility (characteristic that differentiates asthma from other respiratory diseases)
- Spirometry
- Peak Expiratory Flow Rate (PEFR)
- Respiratory acidosis is a very common acid base disturbance in acute severe asthma. Its early recognition and treatment is vital for the final outcome, as it can lead to respiratory failure and arrest if prolonged.
Asthma Pharmacological Therapy
QUICK RELIEF
- short-acting beta 2 adrenergic agonists – bronchodilators eg. Salbutamol (Ventolin) that relieve bronchospasm by relaxing the smooth muscle leading to a decrease in bronchoconstriction as well as decrease excessive mucus (side effects include tachycardia, palpitations and nausea).
- anticholinergic drugs – bronchodilators that can be used in combination with short-acting beta 2 adrenergic agonists eg. Ipratropium (Atrovent). Anticholergic drugs also decrease mucus secretions (side effect: dry mouth)
- corticosteroids – eg. Prednisolone suppress inflammation leading to a reduction in hyperresponsiveness as well as a decrease in mucus production (side effect: hyperglycaemia).
LONG TERM MEDICATION
- inhaled corticosteroids eg. Budesonide (Pulmicort) – administered as prophylaxis (as prevention) of acute asthma exacerbation
- long-acting beta 2 adrenergic agonists eg. Tiotropium
- Methylxanthines eg. Theophylline (prevent and treat wheezing, tachypnoea, and chest tightness)
Additional Interventions
- In an emergency situation, quick administration of bronchodilators is recommended to relieve bronchospasms and systemic corticosteriods to reduce the inflammatory response.
- Administration of IV fluids can help replace loss of fluid if patient is sweating profusely
- Encouraging deep breathing and promoting a calm environment
- Administer O2 if patient has a low SPO2
- Encourage patient to sit down straight or slightly leaned forward to promote lung expansion
- Teach pursed-lip breathing to promote an increase in lung ventilation
Monitoring an Asthmatic Patient Post-Treatment
- Monitor SPO2
- Monitor vital signs (heart rate, respiratory rate, temperature, blood pressure)
- Auscultate for possible wheezing on inspiration or expiration and no use of accessory muscles whilst breathing
- Perform PEFR to compare reading with the one taken prior to treatment
- Monitor ABGs-PaO2 (arterial blood gases)
- Monitor for anxiety level
- Monitor for conversational dyspnoea
Below you can find a collection of videos that can help provide a more visual approach to asthma pathophysiology, diagnosis, medical management and nursing care.
Asthma Pathophysiology
Asthma Pathophysiology, Diagnosis, Medical Management and Nursing Care
Spirometry
Peak Expiratory Flow Rate (PEFR)
Expiratory Wheezing Sound – Asthma Pathophysiology
Rhonchi Lung Sound – Asthma Pathophysiology
How to use Metered Dose Inhaler (MDI)
How to use a Metered Dose Inhaler (MDI) with a Spacer
Pursed Lip Breathing Exercises
Oxygen Therapy Delivery Devices
Asthma Nursing Care
Special thanks to the creators of the featured videos on this post, specifically Youtube Channels Alila Medical Media, RegisteredNurseRN, Geeky Medics, EMTprep, UseInhalers Correctly, American Lung Association ,Oxford Medical Education and NURSINGcom.
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