Asthma

Asthma 150 150 Tony Guo

 

Asthma

  • Heterogeneous disease characterized by a combination of clinical manifestations along with reversible expiratory airflow limitation or bronchial hyper-responsiveness 
  • Affects about 18.8 million Americans
  • Women are 62% more likely to have asthma than men
  • Older adults may be undiagnosed

Risk factors and triggers

  • Related to patient (e.g., genetic factors) 
  • Related to environment (e.g., pollen)
  • Male gender is a risk factor in children (but not adults)
  • Obesity is also a risk factor
  • Genetics-inherited component is complex
  • Immune response–hygiene hypothesis
  • Allergens: May be seasonal or year-round depending on exposure to allergen
    • Cockroaches, Furry animals, Fungi, Pollen, Molds

Trigger of Asthma attacks

  • Exercise
    • Exercise-induced asthma (EIA) or exercise-induced bronchospasm (EIB) is induced or exacerbated during physical exertion
      • Occurs after vigorous exercise
      • Pronounced with exposure to cold air
  • Air pollutants
    • Can trigger asthma attacks
      • Cigarette or wood smoke
      • Vehicle exhaust
      • Concentrated pollution
        • Aerosol sprays
        • Oxidants
        • Perfumes
        • Sulfur dioxides
  • Respiratory infections
    • Major precipitating factor of an acute asthma attack
      • Increase Inflammation and hyper-responsiveness of tracheobronchial system
        • Sinusitis, allergic rhinitis
        • Viral upper respiratory tract infection
  • Allergic rhinitis and nasal polyps
    • Large polyps need to be removed 
    • Sinus problems are usually related to inflammation of the mucous membranes
      • Animal dander (e.g., cats, mice, guinea pigs)
      • Cockroaches
      • House dust mite
      • Molds
      • Pollens
  • Drugs and Food additives
    • Asthma triad: Nasal polyps, asthma, and sensitivity to aspirin and NSAIDs
      • Wheezing develops in about 2 hours.
      • Sensitivity to salicylates
        • Found in many foods, beverages, and flavorings
    • β-Adrenergic blockers 
    • ACE inhibitors
    • Food allergies may cause asthma symptoms
      • Rare in adults
      • Oral food challenges
        • Beer, wine, dried fruit, shrimp,
        • processed potatoes
        • Monosodium glutamate
        • Sulfites (bisulfites and metabisulfites)
        • Tartrazine
  • Gastroesophageal reflux disease
    • GERD more common in persons with asthma
      • Reflux may trigger bronchoconstriction as well as cause aspiration
      • Asthma medications may worsen GERD symptoms
  • Emotional stress
    • Psychologic factors can worsen the disease process
      • Extreme emotional expressions 
      • Attacks can trigger panic and anxiety

 

Pathophysiology

  • Primary response is chronic inflammation from exposure to allergens or irritants
    • Leading to airway bronchoconstriction, hyper-responsiveness, and edema of airways
    • Exposure to allergens or irritants initiates inflammatory cascade
  • Inflammatory mediators cause early-phase response
    • Vascular congestion
    • Edema formation
    • Production of thick, tenacious mucus
    • Bronchial muscle spasm
    • Thickening of airway walls
  • Early-phase response
    • As the inflammatory process begins, mast cells (found beneath the basement membrane of the bronchial wall) degranulate and release multiple inflammatory mediators.
      • IgE antibodies are linked to mast cells, and the allergen cross-links the IgE. 
      • Inflammatory mediators such as leukotrienes, histamine, cytokines, prostaglandins, and nitric oxide are released. 
    • Some inflammatory mediators have effects on the 
      • Blood vessels, causing vasodilation and increasing capillary permeability (runny nose)
      • Nerve cells causing itching
      • Smooth muscle cells causing bronchial spasms and airway narrowing
      • Goblet cells causing mucus production
  • Late-phase response
    • Occurs within 4 to 6 hours after initial attack
    • Occurs in about 50% of patients
    • Can be more severe than early phase and can last for 24 hours or longer
    • If airway inflammation is not treated or does not resolve, it may lead to irreversible lung damage
    • Structural changes in the bronchial wall known as remodeling

 

Clinical manifestation

  • Recurrent episodes of wheezing, breathlessness, cough, and tight chest
  • Expiration may be prolonged.
    • Inspiration-expiration ratio of 1:2 to 1:3 or 1:4
    • Bronchospasm, edema, and mucus in bronchioles narrow the airways
    • Air takes longer to move out
  • Most common manifestations
    • Cough
    • Shortness of breath (dyspnea)
    • Wheezing
    • Chest tightness
    • Variable airflow obstruction

 

Complications and classification

  • Mild
    • Dyspnea occurs with activity and patient may feel that he or she “can’t get enough air.”
    • PEF ≥70%
    • Usually treated at home
      • Prompt relief with inhaled SABA such as albuterol (delivered via a nebulizer or MDI with a spacer)
      • Patients instructed to take 2 to 4 puffs albuterol every 20 min three times to gain rapid control of symptoms
      • Occasionally short course of oral corticosteroids is needed.
  • Moderate
    • Dyspnea interferes with or limits usual activities.
    • PEF 40%69%
      • Usually requires office or ED visit
      • Relief is provided with frequent inhaled SABA.
      • Oral systemic corticosteroids. (Symptoms may persist for several days even after corticosteroids are started.)
  • Severe exacerbations
    • Respiratory rate >30/min 
    • Dyspnea at rest, feeling of suffocation
    • Pulse >120/min
    • PEFR is 40% at best
    • Usually seen in ED or hospitalized
      • Partial relief from frequent inhaled SABA
      • Oral systemic corticosteroids. Some symptoms last for >3 days after treatment is begun.
      • Adjunctive therapy: ipratropium, IV magnesium
  • Life-threatening asthma
    • Too dyspneic to speak
    • Perspiring profusely
    • Drowsy/confused
    • PEFR <25%
    • Require hospital care and often admitted to ICU
      • Minimal or no relief from frequent inhaled SABA
      • IV corticosteroids
      • Adjunctive therapy: ipratropium, IV magnesium

 

Diagnostic studies

  • Detailed history and physical exam
  • Spirometry
  • Peak expiratory flow rate (PEFR)
  • Chest x-ray
  • Oximetry
  • Allergy testing
  • Blood levels of eosinophils

Diagnostic Assessment

  • History and physical examination
  • Spirometry, including response to bronchodilator therapy
  • Peak expiratory low rate (PEFR)
  • Chest xray
  • Measurement of oximetry
  • Allergy skin testing (if indicated)
  • Blood level of eosinophils and IgE (if indicated)

Management

Intermittent or Persistent Asthma

  • Identification and avoidance or elimination of triggers
  • Patient and caregiver teaching
  • Drug therapy 
  • Asthma action plan 
  • Desensitization (immunotherapy) if indicated
  • Assess for control (e.g., Asthma Control Test [ACT])*

Acute Exacerbations 

  • SaO2 monitoring
  • ABGs
  • Inhaled β2adrenergic agonists
  • Inhaled anticholinergics
  • O2 by nasal cannula or mask
  • IV or oral corticosteroids
  • IV fluids
  • IV magnesium
  • Intubation and assisted ventilation

 

Interprofessional care

  • The current guidelines focus on 
    • Assessing the severity of the disease at diagnosis and initial treatment and then 
    • Monitoring periodically to control the disease
  • Intermittent and persistent asthma
    • Avoid triggers of acute attacks
    • Pre-medicate before exercising
    • Short-term (rescue or reliever) medication
    • Long-term or controller medication
  • Acute asthma exacerbations
    • Respiratory distress
    • Treatment depends upon severity and response to therapy
      • Classified as mild, moderate, severe, or life-threatening 
      • Management focuses on correcting hypoxemia and improving ventilation
    • O2 given via nasal cannula or mask to achieve a PaO2 of at least 60 mm Hg or O2 saturation greater than 90%
      • Continuous oxygen monitoring with pulse oximetry
    • Bronchodilator treatment
      • Short-acting β2-adrenergic agonists (SABAs)
  • Assessment during acute exacerbation
    • Respiratory and heart rate
    • Use of accessory muscles
    • Percussion and auscultation of lungs
    • PEFR to monitor airflow obstruction
    • ABGs
    • Pulse oximetry
  • Severe and life-threatening exacerbations
    • “Silent chest”
      • Severely diminished breath sounds
      • Absence of wheeze after patient has been wheezing
      • Patient is obviously struggling
      • Life-threatening situation
      • Requires ED and possible ICU
      • IV magnesium sulfate
      • 100% oxygen
      • Hourly or continuous nebulized SABA
      • IV corticosteroids
  • Bronchial thermoplasty
    • Catheter applies heat to reduce muscle mass in the bronchial wall
    • Reverses accumulation of excessive tissue that causes narrowing of airway
  • Drug therapy
    • Three types of anti-inflammatory drugs
      • Corticosteroids (e.g., beclomethasone, budesonide)
        • Suppress inflammatory response
        • Reduce bronchial hyper-responsiveness
        • Decrease mucous production
        • Inhaled form is used in long-term control
        • Systemic form to control exacerbations and manage persistent asthma
        • Oropharyngeal candidiasis, hoarseness, and a dry cough are local side effects of inhaled drug
        • Can be reduced using a spacer or by gargling after each use
      • Leukotriene modifiers or inhibitors (e.g., zafirlukast, montelukast, zileuton)
        • Block action of leukotrienes—potent bronchoconstrictors
        • Have both bronchodilator and antiinflammatory effects 
        • Not indicated for acute attacks
        • Used for prophylactic and maintenance therapy
      • Monoclonal antibody to IgE 
        • Anti-IgE (e.g., Xolair)
          • Decrease in circulating IgE levels
          • Prevents IgE from attaching to mast cells, preventing release of chemical mediators
          • Subcutaneous administration every 2 to 4 weeks
        • β-Adrenergic agonists (SABAs)
          • Examples: albuterol, pirbuterol
          • Effective for relieving acute bronchospasm
          • Onset of action in minutes and duration of 4 to 8 hours
          • Prevent release of inflammatory mediators from mast cells
          • Not for long-term use
        • Methylxanthines (e.g., theophylline)
          • Less effective long-term bronchodilator
          • Alleviates early phase of attacks but has little effect on bronchial hyper-responsiveness
          • Narrow margin of safety
        • Anticholinergic drugs 
          • Block action of acetylcholine
          • Promote bronchodilation
          • Short-acting drugs used for severe acute asthma exacerbation
    • Patient teaching related to drug therapy
      • Correct administration of drugs is a major factor in success 
        • Inhalation of drugs is preferable to avoid systemic side effects
        • MDIs, DPIs, and nebulizers are devices used to inhale medications
        • Using an MDI with a spacer is easier and improves inhalation of the drug
        • DPI (dry powder inhaler) requires less manual dexterity and coordination
          • DPIs are simpler to use than MDIs.
          • The DPI contains dry, powdered medication and is breath-activated. No propellant is used. 
          • Instead an aerosol is created when the patient inhales through a reservoir containing a dose of powder.

 

Nursing management

  • Health promotion
    • Teach patient to identify and avoid known triggers
      • Use dust covers
      • Use scarves or masks for cold air
      • Avoid aspirin and NSAIDs
    • Prompt diagnosis and treatment of upper respiratory infections and sinusitis may prevent asthma exacerbation
    • Fluid intake of 2 to 3 L every day
    • Good nutrition
    • Adequate rest
  • Nursing Assessment
    • Subjective Data
      • Important Health Information
        • Past health history: Allergic rhinitis, sinusitis, or skin allergies.
        • Previous asthma attack and hospitalization or intubation. Symptoms worsened by triggers in the environment. Gastroesophageal reflux disease (GERD). Occupational exposure to chemical irritants (e.g., paints, dust)
        • Medications: Adherence to medication, inhaler technique. Use of antibiotics. Pattern and amount of short-acting β2 –adrenergic agonist used per week. Medications that may precipitate an attack in susceptible asthmatics such as aspirin, nonsteroidal anti-inflammatory drugs, β-adrenergic blockers
      • Functional Health Patterns
        • Health perception–health management: Family history of allergies or asthma. Recent upper respiratory tract or sinus infection 
        • Activity-exercise: Fatigue, decreased or absent exercise tolerance. Dyspnea, cough (especially at night), productive cough with yellow or green sputum or sticky sputum. Chest tightness, feelings of suffocation, air hunger, talking in short sentences or words or phrases, sitting upright to breathe
        • Sleep-rest: Awakened from sleep because of cough or breathing difficulties, insomnia
        • Coping–stress tolerance: Emotional distress, stress in work environment
        • or home
    • Objective Data
      • General
        • Restlessness or exhaustion, confusion, upright or forward-leaning body position
      • Integumentary
        • Diaphoresis, cyanosis (circumoral, nail bed), eczema
      • Respiratory
        • Nasal discharge, nasal polyps, mucosal swelling. Crackles, diminished or absent breath sounds, and wheezes on auscultation. Hyperresonance on percussion. Sputum (thick, white, tenacious), Increased work of breathing with use of accessory muscles. Intercostal and supraclavicular retractions. Tachypnea with hyperventilation. Prolonged expiration
      • Cardiovascular
        • Tachycardia, pulsus paradoxus, jugular venous distention, hypertension or hypotension, premature ventricular contractions
      • Possible Diagnostic Findings
        • Abnormal ABGs during attacks, 
        • Decreased O2 saturation, serum and sputum eosinophilia
        • Increased serum IgE, positive skin tests for allergens, chest x-ray demonstrating hyperinflation with attacks
        • Abnormal pulmonary function tests showing decreased flow rates; FVC, FEV1, PEFR, and FEV1/FVC ratio that improve between attacks and with bronchodilators
  • Nursing diagnoses
    • Ineffective airway clearance related to bronchospasm, excessive mucus production, tenacious secretions, and fatigue
    • Anxiety related to difficulty breathing, perceived or actual loss of control, and fear of suffocation
    • Deficient knowledge related to lack of information and education about asthma and its treatment
  • Planning
    • Minimal symptoms during the day and night 
    • Acceptable activity levels (including exercise and other physical activity)
    • Maintenance of greater than 80% of personal best PEFR
    • Few or no adverse effects of therapy
    • No acute exacerbations of asthma
    • Adequate knowledge to participate in and carry out the plan of care.
  • Nursing implementation
    • Important patient teaching
      • Seek medical attention for bronchospasm or when severe side effects occur
      • Maintain good nutrition
      • Exercise within limits of tolerance
      • Uninterrupted sleep is important
      • Written asthma action plan
      • Measure peak flow at least daily
      • Patients with asthma frequently do not perceive changes in their breathing
    • Peak flow results
      • Green Zone
        • Usually 80% to 100% of personal best
        • Remain on medications
      • Yellow Zone
        • Usually 50% to 80% of personal best
        • Indicates caution
        • Something is triggering asthma. 
      • Red Zone
        • 50% or less of personal best
        • Indicates serious problem
        • Definitive action must be taken with health care provider
  • Evaluation
    • Maintain clear airway with removal of excessive secretions
    • Have normal (for the individual) breath sounds and respiratory rate
    • Report decreased anxiety with increased control of respirations
    • Describe the disease process and treatment regimen
    • Demonstrate correct administration of inhaled drugs
    • Express confidence in ability for long-term management of asthma

 

Cultural considerations: Asthma

  • African Americans and Hispanics have higher rates of poorly controlled asthma and deaths
    • Disparities in socioeconomic status and access to proper health care
    • Cultural beliefs about management of asthma

 

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