Respiratory Disorders

Respiratory Disorders

Respiratory disorders represent a high-stakes clinical focus on the DHA nursing exam. Nurses must prioritize interventions based on airway, breathing, and circulation (ABCs), apply strict infection control measures, and manage complex pharmacological therapies. This section reviews Chronic Obstructive Pulmonary Disease (COPD), Asthma, Pneumonia, Tuberculosis (TB), and Pulmonary Embolism (PE).

1. Chronic Obstructive Pulmonary Disease (COPD)

COPD is a progressive, airflow-limiting disease characterized by chronic inflammation of the airways and lung parenchyma. It includes two primary pathological processes, which often coexist:

1. Chronic Bronchitis: Inflammation and hypersecretion of mucus in the bronchi, defined clinically by a productive cough lasting for at least 3 months in 2 consecutive years.
2. Emphysema: Destruction of the alveolar walls leading to permanent enlargement of the air spaces, loss of elastic recoil, and air trapping.

Clinical Presentation

Common signs include progressive exertional dyspnea, a chronic productive cough, barrel chest (increased anteroposterior chest diameter due to hyperinflation), use of accessory muscles for respiration, clubbed fingernails, and pursed-lip breathing (which creates backpressure in the airways, keeping alveoli open during expiration).

Oxygen Therapy and the Hypoxic Drive

In healthy individuals, the respiratory center in the brain responds to elevated carbon dioxide levels (hypercapnia) to stimulate breathing. In chronic COPD patients, the body adapts to chronic hypercapnia, and the respiratory drive becomes driven by low oxygen levels (hypoxic drive).

• DHA Exam Focus: Administering high concentrations of oxygen to a patient with chronic carbon dioxide retention can abolish their stimulus to breathe, leading to carbon dioxide narcosis and respiratory arrest. Always maintain oxygen therapy at low flow rates (typically 1–2 L/min via nasal cannula or 24–28% via Venturi mask) to achieve a target oxygen saturation of 88% to 92%.

Pharmacology

• Bronchodilators: Short-acting beta-agonists (SABA; e.g., Albuterol) for acute relief; long-acting beta-agonists (LABA; e.g., Salmeterol) or long-acting muscarinic antagonists (LAMA; e.g., Tiotropium) for maintenance.
• Corticosteroids: Inhaled (e.g., Fluticasone) for maintenance or systemic (e.g., Prednisolone) for acute exacerbations.
  • Patient Education: Rinsing the mouth with water and spitting it out after using inhaled corticosteroids is vital to prevent oral candidiasis (thrush).

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2. Asthma

Asthma is a chronic inflammatory disorder of the airways characterized by reversible airway hyperresponsiveness, bronchospasm, and mucus hypersecretion in response to specific triggers (e.g., allergens, exercise, cold air, infections).

Clinical Presentation

Wheezing (primarily on expiration), dyspnea, chest tightness, prolonged expiration, and a dry, hacking cough (often worsening at night).

Peak Flow Monitoring

A peak expiratory flow meter measures the maximum speed of expiration. The Peak Expiratory Flow Rate (PEFR) is used to monitor asthma control using a traffic-light zone system based on the patient's personal best:

• Green Zone (80–100% of personal best): Good control. Maintain routine controller medications.
• Yellow Zone (50–79% of personal best): Caution. Indicates an acute exacerbation or worsening control. Administer short-acting rescue bronchodilators as prescribed.
• Red Zone (< 50% of personal best): Medical Emergency. Administer rescue bronchodilator immediately and seek emergency medical care.

Pharmacological Management

• Rescue Medications (Quick Relief): Short-acting beta-agonists (e.g., Albuterol) and anticholinergics (e.g., Ipratropium). These act rapidly to relieve acute bronchospasm.
• Controller Medications (Long-Term Maintenance): Inhaled corticosteroids (e.g., Fluticasone, Budesonide), long-acting beta-agonists (e.g., Salmeterol), and leukotriene receptor antagonists (e.g., Montelukast). These do not treat acute symptoms.
• DHA Exam Alert: In an acute asthma attack, always administer the fast-acting bronchodilator before the inhaled corticosteroid. The bronchodilator opens the airways, allowing the corticosteroid to penetrate deeper into the lung tissues.

Status Asthmaticus

Status asthmaticus is a severe, life-threatening asthma attack that is refractory to conventional treatment (bronchodilators and systemic steroids) and can lead to respiratory failure.

• Critical Emergency Sign: The Silent Chest. If a wheezing patient suddenly develops an absence of wheezing or breath sounds (silent chest) along with altered mental status or cyanosis, it indicates complete airway obstruction and immediate respiratory arrest. The nurse must immediately prepare for endotracheal intubation, mechanical ventilation, and administration of IV magnesium sulfate or epinephrine.

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3. Pneumonia

Pneumonia is an infection of the lung parenchyma that causes inflammation of the alveoli, which fill with exudate, inflammatory cells, and fluid, impairing gas exchange.

Classifications

• Community-Acquired Pneumonia (CAP): Contracted outside of a healthcare setting.
• Hospital-Acquired Pneumonia (HAP): Occurs 48 hours or more after admission and was not incubating at the time of admission. HAP is often caused by multi-drug resistant organisms.

Clinical Presentation and Diagnostics

Fever, chills, productive cough with rust-colored or purulent sputum, pleuritic chest pain (sharp pain on inspiration), tachypnea, tachycardia, and crackles or diminished breath sounds over the affected lobe. In older adults, the classic presentation may be absent; the primary symptom is often an acute change in mental status (confusion, delirium) or hypothermia.

• Diagnostics: Chest X-ray (reveals pulmonary infiltrates or consolidation), elevated white blood cell count (WBC), and sputum culture.
• DHA Exam Priority: Always obtain sputum cultures before administering the first dose of broad-spectrum antibiotics to avoid altering the culture results. However, antibiotic therapy must not be delayed significantly if a culture cannot be obtained promptly.

Nursing Interventions

• Oxygen Therapy: Maintain prescribed oxygen saturation levels.
• Hydration: Encourage fluid intake (up to 2–3 L/day unless contraindicated by heart or renal failure) to thin secretions.
• Incentive Spirometry: Instruct the patient to use the device 10 times every hour while awake (inhaling slowly and deeply) to prevent atelectasis.
• Positioning: Position the patient in Semi-Fowler's to High-Fowler's to optimize chest expansion. For unilateral pneumonia, position the patient with the "good lung down" to optimize ventilation-perfusion (V/Q) matching and improve oxygenation.

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4. Tuberculosis (TB)

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis, an acid-fast bacillus that primarily affects the lungs but can spread to other organs.

Transmission and Infection Control

TB is transmitted via airborne droplets when an infected person coughs, sneezes, speaks, or sings.

• Infection Control Precautions:
  • Place the patient on Airborne Precautions immediately upon suspicion.
  • Assign the patient to a negative-pressure private room (Airborne Infection Isolation Room - AIIR) with at least 6 to 12 air exchanges per hour.
  • Healthcare staff must wear an approved, fit-tested N95 particulate respirator (or Powered Air-Purifying Respirator - PAPR) when entering the room.
  • The patient must wear a standard surgical mask if they must leave the room for essential diagnostic tests.

Clinical Presentation

Progressive fatigue, malaise, anorexia, unexplained weight loss, low-grade afternoon fevers, night sweats, and a persistent cough that may produce mucoid or mucopurulent sputum (hemoptysis in advanced stages).

Screening and Diagnosis

1. Mantoux Tuberculin Skin Test (TST): Purified Protein Derivative (PPD) is injected intradermally. The test is read 48 to 72 hours later. Measure the diameter of induration (palpable, raised, hardened area), NOT erythema (redness).
   • ≥ 5 mm: Positive in HIV-infected individuals, recent contacts of active TB cases, or immunosuppressed patients.
   • ≥ 10 mm: Positive in immigrants from high-prevalence countries, healthcare workers, IV drug users, or residents of high-risk congregate settings.
   • ≥ 15 mm: Positive in individuals with no known risk factors for TB.
2. Acid-Fast Bacilli (AFB) Smear and Culture: The definitive diagnosis for active TB requires a positive sputum culture. The nurse must collect three consecutive early morning sputum specimens on separate days. A patient is considered non-infectious after three consecutive negative AFB smears.

Pharmacological Management (R.I.P.E. Regimen)

Active TB is treated with a combination of four medications for a minimum of 6 months. Adherence is critical to prevent multi-drug resistance; Directly Observed Therapy (DOT) is recommended.

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5. Pulmonary Embolism (PE)

A pulmonary embolism is the occlusion of one or more pulmonary arteries by a thrombus (clot) that originated elsewhere in the body, most commonly from a deep vein thrombosis (DVT) in the lower extremities.

Risk Factors (Virchow's Triad)

1. Venous Stasis: Prolonged immobility, long-distance travel, obesity, paralysis.
2. Hypercoagulability: Malignancy, pregnancy, oral contraceptive use, hormone replacement therapy, genetic coagulation disorders.
3. Endothelial Damage: Trauma, major surgery (especially orthopedic surgery of the hip or knee), central venous catheters.

Clinical Presentation

The onset is typically sudden and acute. Common symptoms include sudden-onset dyspnea, sharp pleuritic chest pain (worse on inspiration), tachypnea, tachycardia, dry cough or hemoptysis, apprehension, syncope, and a low-grade fever. If the clot is massive, signs of right-sided heart failure (JVD) and cardiogenic shock (hypotension, cold clammy skin, altered mental status) will develop.

Diagnostics

• D-Dimer: A blood test measuring fibrin degradation products. High sensitivity but low specificity. A negative D-dimer rules out PE; a positive result indicates clot formation somewhere in the body but requires further testing to confirm PE.
• CT Pulmonary Angiography (CTPA): The gold standard and definitive diagnostic tool for PE. It visualizes the pulmonary vasculature using IV contrast.
• Ventilation-Perfusion (V/Q) Scan: Used for patients who cannot receive IV contrast (e.g., severe renal impairment or contrast allergy).

Nursing and Medical Management

• Oxygen and Stabilization: Administer oxygen immediately, position the client in High-Fowler's, and establish IV access.
• Anticoagulation: Start intravenous Heparin infusion immediately to prevent further clot growth and new clot formation (does not dissolve existing clots).
  • Monitoring: Monitor Activated Partial Thromboplastin Time (aPTT). The therapeutic range is typically 1.5 to 2.5 times the control value (normal control: 25–35 seconds; therapeutic range: 46–70 seconds).
  • Antidote: Keep Protamine Sulfate readily available at the bedside.
• Warfarin Transition: Initiated concurrently with Heparin. Heparin is continued for at least 5 days and until the International Normalized Ratio (INR) is therapeutic (target 2.0 to 3.0) for 24 hours.
  • Antidote: Keep Vitamin K (and Fresh Frozen Plasma) available.
• Thrombolytic Therapy: (e.g., Alteplase) reserved for patients with massive PE, hemodynamic instability, or refractory hypotension. It actively dissolves the clot.
  • Nursing Priority: Monitor for severe bleeding. Contraindicated in patients with active bleeding, recent hemorrhagic stroke, or recent major surgery/trauma.