Obstructive Lung Disorders

Obstructive Lung Disorders

Airway narrowing → difficulty exhaling (getting air out)

Airway trapping → impaired gas exchange

Obstruction may result from

• Bronchoconstriction

• Airway inflammation

• Excess mucus

• Structural airway changes

• Bronchioles are the major sites of airflow obstruction

Common manifestations

• Wheezing

• Dyspnea

• Cough

• Increased work of breathing

Common disorders

• Asthma

• COPD

• Acute Bronchitis

• Obstructive sleep disorder

Nursing priority: Assess airway, breathing, and oxygenation first

Ventilation

Movement of air into and out of the lungs (V)

Perfusion

Blood flow through pulmonary capillaries available for gas exchange (Q)

Obstructive disease

Airway obstruction → decreased ventilation

V/Q mismatch → impaired gas exchange → hypoxemia

Asthma

• Chronic inflammatory airway disorder

• Causes reversible airflow obstruction

• Trigger exposure

  • Airway inflammation

  • Bronchial smooth muscle constriction (bronchospasm)

  • Increased mucus production

  • Airway narrowing

  • Air trapping during exhalation

• Common triggers

  • Allergens

  • Exercise

  • Respiratory infections

  • Cold air

  • Smoke/environmental irritants

• Long-term effect: Chronic inflammation may lead to airway remodeling

• Pearl: Asthma = bronchospasm + inflammation + mucus

Asthma common manifestations

• Wheezing

• Persistent cough, especially at night

• Chest tightness

• Dyspnea

• Dyspnea with activity

Asthma signs of severe obstruction

• Accessory muscle use/retractions/nasal flaring

• Tripod positioning

• Tachypnea

• Difficulty speaking in complete sentences

• SpO2 less than 80%

• Anxiety/restlessness

Asthma nursing assessment

• Breath sounds

• Respiratory rate

• SpO2

• Work of breathing

• Level of distress

Asthma red flag

• Silent chest = medical emergency

• Minimal/absent wheezing may indicate severe airway obstruction

Asthma diagnostics and monitoring

• Pulmonary function tests

  • REV1: air exhaled in the first second

  • FVC: total forced air exhaled

  • FEV1/FVC: identifies airflow obstruction

• Obstructive pattern

  • decreased FEV1

  • decreased FEV1/FVC

  • Prolonged exhalation/air trapping

• Bronchodilator response

  • Greater reversibility → supports asthma

  • Persistent obstruction → supports COPD

• Peak expiratory flow rate

  • Used for home monitoring

  • Detects worsening obstruction

  • Compare with patient’s personal best

  • Perform 3 attempts → record highest value

• Pearl: A decreasing peak flow may identify worsening asthma before symptoms develop

Assessing asthma severity

• Daytime symptoms

• Nighttime awakenings

• Rescue inhaler use

• Activity limitation

• Exacerbations

Asthma reliever therapy

• ICS-formoterol - anti-inflammatory reliever

• SABA - rapid bronchodilation

Asthma controller therapy

• ICS - foundation of treatment

• LABA - with ICS

• LAMA - add-on therapy

• Leukotriene modifiers - alternative/add-on

• Biologics - severe asthma

Asthma acute exacerbation therapy

• Rapid-acting bronchodilator

• SAMA - add-on for moderate-to-severe exacerbations

• Systemic corticosteroids when indicated (oral or IV)

Inhaled corticosteroids

• MOA: ↓ airway inflammation, ↓ mucus production, prevents asthma exacerbations

• Uses: Foundation of long-term asthma control, used daily for persistent asthma, not for immediate bronchodilation

• ADRs: Thrush, hoarseness, dry mouth, sore throat

• Patient teaching: rinse mouth after each use, use consistently as prescribed, continue even when asymptomatic,

Albuterol

• SABA

• MOA: Stimulates β2 receptors in bronchial smooth muscle

• Rapid bronchodilation → improves airflow

• Used for acute bronchospasm and exercise-induced symptoms

• ADR: tachycardia, tremor, nervousness, palpitations, headache

• Frequent use may indicate poor asthma control

• Monitor HR

Ipratropium

• SAMA

• MOA: Blocks muscarinic receptors → ↓ parasympathetuc bronchoconstriction

• Produces bronchodilation

• Used with SABA during significant acute exacerbations

• ADR: dry mouth, horseness, cough, bitter taste

• Caution with glaucoma or urinary retention

Formoterol

• LABA

• MOA: stimulates β2 receptors → prolonged bronchodilation

• Use: Long-term control; in asthma, use with an ICS

• ADR: tachycardia, palpitations, tremor, headache

• Formoterol: rapid onset → ICS-formoterol may be a reliever

• Never use a LABA alone in asthma

• Monitor HR

Tiotropium

• LAMA

• MOA: Blocks muscarinic receptors → ↓ bronchoconstriction

• Prolonged bronchodilation → ↓ airway resistance

• Use: COPD maintenance; add-on for selected severe asthma

• ADR: dry mouth, hoarseness, urinary retention, worsening glaucoma

• Not a rescue medication

• Monitor anticholinergic effects

Montelukast

• Luekotriene Modifier

• MOA: Blocks leukotrienes → ↓ inflammation/bronchoconstriction

• Route: PO

• Uses: control, exercise-induced symptoms, allergic rhinitis

• ADR: headache, GI upset

• Not for acute attacks

Omalizumab

• Biologics

• MOA: Target specific inflammatory pathways

• Route: SC injection

• Use: selected severe asthma

• ADR: injection-sit/hypersensitivity reactions; monitor for anaphylaxis

Cromolyn

• Mast cell stabilizer

• MOA: prevents release of inflammatory mediators

• Route: inhaled/nebulized

• Use: prevention

• ADRs: cough, throat irritation, bronchospasm

• Less commonly used; not for acute attacks

Theophylline

• Methylxanthine

• MOA: bronchodilation

• Route: PO

• Limited use

• ADRs/toxicity: N/V, tremor, insomnia, tachycardia, severe → dysrhythmias/seizures

• Narrow therapeutic index → monitor levels/interactions

COPD pathophysiology

• Progressive, not fully reversible, airflow limitation

• Includes chronic bronchitis and emphysema

• Chronic inflammation → airway narrowing → air trapping → hyperinflation

• Results in ↑ work of breathing + impaired gas exchange

• Chronic hypoxemia may develop

• Pearl: chronic airflow obstruction + air trapping + difficulty exhaling

COPD risk factors

• Cigarette smoking - most common

• Secondhand smoke

• Air pollution

• Occupational dust/chemicals

• Alpha-1 antitrypsin deficiency

COPD complications

• Respiratory failure

• Pulmonary hypertension → cor pulmonale

• Recurrent respiratory infections

Chronic bronchitis

• Airway inflammation

• ↑ mucus production

• chronic productive cough

• frequent respiratory infections

• wheezing common

• hypoxia develops earlier

• airway/mucus problem

• Pearl: Productive cough greater than 3 months/year for 2 consecutive years. Mucus/airways

Emphysema

• Alveolar destruction

• Loss of elastic recoil

• Severe dyspnea

• Air trapping/hyperinflation

• Barrel chest

• Pursed-lip breathing

• Alveolar problem

• Pearl: Destruction of alveolar wall → decreased surface area for gas exchange. Loss os elastic recoil → air trapping. Increased work of breathing may contribute to weight loss. Alveolar destruction/air trapping

COPD common manifestations

• Chronic cough, dyspnea, wheezing

• Increased sputum production

• Fatgue

• Exercise intolerance

COPD physical findings

• Barrel chest

• Accessory muscle use

• Tripod positioning

• Pursed-lip breathing

• Decreased breath sounds

• Hyperresonance

COPD nursing assessment

• Respiratory effort/work of breathing

• SpO2

• Breath sounds

• Sputum characteristics

COPD diagnostics

• Spirometry - gold standard

  • Post-bronchodilator FEV1/FVC < 0.70 → persistent airflow obstruction

  • FEV1 % predicted → grades airflow limitation

  • Oxygenation & ventilation

  • SpO2: oxygenation

• ETCO2: ventilation

  • Normal: 35-45 mmHg

  • ↑ ETCO2 may indicate hypoventilation/CO2 retention

• ABG: oxygenation + ventilation + acid-base status

• Advanced COPD

  • Decreased PaO2

  • Increased PaCO2

  • +- Respiratory acidosis

• Chest X-ray

  • Hyperinflation

  • Flattened diaphragm

• Additional testing: Alpha-1 antitrypsin testing when indicated

• Pearl: FEV1/FVC identifies obstruction; FEV1 % predicted grades airflow limitation

COPD pharmacologic management

• SABA + SAMA = Relievers

• LABA + LAMA = Daily controllers

• ICS - Used in selected COPD patients as part of combination therapy

• PDE-4 Inhibitor - Severe, chronic bronchitis

Roflumilast

• PDE-4 inhibitor

• MOA: Inhibits PDE-4 → ↓ airway inflammation

• Uses:

  • Severe COPD with chronic bronchitis

  • Reduces exacerbations

  • Not a bronchodilator or rescue medication

• ADRs: Diarrhea, nausea, ↓ appetite, wight loss, anxiety/depression

• ↓ exacerbation - it does not provide immediate bronchodilation

Acute bronchitis

• Pathophysiology:

  • Acute inflammation of the bronchi

  • Causes temporary airflow obstrcution and cough

  • Usually viral and self-limiting

• Causes:

  • Viruses: influenza, RSV, parainfluenza

  • Irritants: smoke, chemicals, pollutants

  • Bacterial causes less common

• Clinical manifestations

  • Persistent cough, typically 10-20 days

  • Sputum +- wheezing

  • Mild fever

  • Fatigue/chest discomfort

• Treatment

  • Rest and hydration

  • Guaifenesin - expectorant

  • Bronchodilator if wheezing

  • Antibiotics only when bacterial infection is suspected

  • Usually viral and doe snot require antibiotcs

Obstructive sleep apnea

• Pathophysiology

  • Repeated upper-airway obstruction during sleep

  • Apnea → hypoxia → sympathetic activation → cardiovascular/metabolic complications

• Risk factors: Obesity/large neck, enlarged tonsils, alcohol/sedatives, smoking, family history

• Manifestations: loud snoring + witness apnea, daytime sleepiness/fatige, morning headache, poor concentration

• Complications: Hypertension, dysrhythmias, CAD/stroke, Type 2 DM

• Treatment: CPAP - first line, weight loss, oral appliances, surgery when indicated

Respiratory stress

• Tachypnea

• ↑ work of breathing

• Accessory muscle use/retractions

• Dyspnea; difficulty speaking

• ↓ SpO2

• Restlessness/anxiety

• Tachycardia

• Pearl: working hard to breath (compensating)

Respiratory failure

• Slowing or irregular respirations

• decreasing respiratory effort/fatigue

• Unable to maintain adequate ventilation/oxygenation

• Altered LOC; confusion, drowsiness

• severe/persistant hypoxemia

• Cyanosis

• Very diminished/absent breath sounds

• Pearl: Tiring and unable to maintain adequate has exchange (compensation no longer sustained)