GAS EXCHANGE

GAS EXCHANGE

Overview of Gas Exchange

  • Definition: Gas exchange is the process by which oxygen is transported to cells and carbon dioxide is transported from cells.

  • Components: Consists of three main processes:

    • Ventilation: The movement of air in and out of the lungs.

    • Perfusion: The flow of blood to the alveoli in the lungs.

    • Transport: The process of oxygen and carbon dioxide moving between the lungs and tissues.

OBJECTIVES

  • Concept: Review the concept of gas exchange.

  • Age-Related Changes: Identify age-related changes in the respiratory system.

  • Diagnostic Tests: Discuss commonly used diagnostic tests for respiratory disorders.

  • Medications: Compare medications used for respiratory conditions.

  • Pathophysiology and Management: Describe the pathophysiology, etiology, signs/symptoms, management, and prevention of:

    • Bronchitis

    • Pneumonia

    • Obstructive Sleep Apnea (OSA)

RESPIRATORY SYSTEM FUNCTIONS

  • Primary Structures:

    • Nostrils: Entry pathway for air.

    • Pharynx: Channels air down the airways.

    • Pleural Membrane: Keeps lungs flexible.

    • Ribs: Protect respiratory organs.

    • Intercostal Muscles: Move ribs during breathing.

    • Diaphragm: Assists in pumping air in and out of the lungs.

    • Lungs: Site for O2-CO2 gas exchange.

    • Nasal Cavity: Purifies and humidifies air.

    • Oral Cavity: Allows for air and food entry.

    • Epiglottis: Prevents food from entering the airways.

    • Larynx: Allows air passage and aids in speech.

    • Trachea: Channels air towards bronchi.

    • Bronchioles: Directs air to alveoli.

    • Alveoli: Primary site for gas exchange.

EFFECTS OF AGING ON THE RESPIRATORY SYSTEM

  • Normal Aging Effects:

    • Increased stiffness of the chest wall

    • Decreased muscle mass

    • Reduced mucociliary clearance

    • Decreased elastic fibers

    • Increased cross-linked collagen

    • Enlarged alveolar ducts and alveoli

    • Overall decreased lung size

NURSING ASSESSMENT AND INTERVENTIONS FOR RESPIRATORY CONDITIONS

  • Key Components of Assessment:

    • Symptom management (Symptom Mx)

    • Knowledge of the disease

    • Identification of risk factors (e.g., smoking)

    • Psychological function assessment

    • Management of comorbidities

    • Exacerbation management

    • Medication and oxygen management

    • Ensure adherence to treatment

    • Discuss advanced care directives and inhaler technique

DIAGNOSTIC TESTS/PROCEDURES

  • Key Diagnostic Tests:

    • Lab Values:

    • CBC (WBC, Hemoglobin & Hematocrit)

    • D-Dimer

    • Pulse Oximetry

    • Nasal/Throat Culture

    • Sputum Analysis

    • Arterial Blood Gas Analysis (ABG)

    • Imaging:

    • Chest Radiograph (X-ray)

    • Computed Tomography (CT scan)

    • Ventilation-Perfusion Scan (V-Q scan)

    • Pulmonary Angiography

    • Procedures:

    • Bronchoscopy

    • Thoracentesis

PHARMACOLOGIC MANAGEMENT OF RESPIRATORY DISORDERS

  • Common Medications Used:

    • Decongestants: Shrink engorged nasal mucous membranes and relieve nasal congestion.

    • Inhaled/Intranasal Corticosteroids: Inhibit inflammatory response in nasal passages.

    • Expectorants: Loosen and thin sputum and bronchial secretions.

    • Antitussives: Suppress the cough reflex (may be opioid or non-opioid).

    • Antibiotics: Destroy bacteria and prevent the spread to treat infections.

    • Inhaled Bronchodilators/Corticosteroids: Decrease airway inflammation and relieve bronchospasm.

NURSING INTERVENTIONS RELATED TO PHARMACOLOGIC MANAGEMENT

  • Assessment: Regularly assess responses to medications.

  • Promotion: Aid in achieving optimal response to treatment.

  • Education: Inform patients about their medications and treatment plans.

BRONCHITIS

  • Definition: An extension of an upper respiratory infection involving the trachea.

  • Causes:

    • Most commonly viral; bacterial and inhalation of physical/chemical agents also implicated.

  • Symptoms:

    • Conditions like cough, nasal congestion, headache, muscle aches, and fatigue.

  • Diagnosis:

    • Based on patient complaints and observable signs/symptoms.

BRONCHITIS TREATMENT

  • Treatment Strategies:

    • Symptomatic treatment: Humidification, nutrition, fluids, and rest.

    • Avoid exposure to smoke and irritants.

    • Use cough suppressants, bronchodilators, and NSAIDs.

    • Antibiotics are indicated only for bacterial infections.

    • Recommend influenza and pneumonia vaccinations.

PNEUMONIA

  • Definition: Extensive inflammation of the lung, characterized by consolidation of lung tissue as it fills with exudate or interstitial inflammation and edema.

  • Etiology:

    • Infectious: Viral, Bacterial, Fungal

    • Non-Infectious: Irritant (inhaled or aspirated)

  • Risk Factors:

    • Age, chronic conditions, immunosuppression, swallowing difficulties, recent respiratory conditions, smoking and alcohol use.

PATHOPHYSIOLOGY OF PNEUMONIA

  • Mechanism:

    • Infectious agent or foreign substance causes aspiration of gastric contents leading to:

    • Inflammation of pulmonary tissue

    • Edema of alveolar membrane

    • Decreased ability of gases to cross edematous alveolar membrane

    • Alveoli fill with exudate from inflammation which prevents air from entering fluid-filled alveoli

    • Results in:

    • Hypoxia and retention of CO2

    • Symptoms such as shortness of breath, fatigue, crackles in lungs, or decreased breath sounds.

SIGNS/SYMPTOMS AND DIAGNOSIS OF PNEUMONIA

  • Signs/Symptoms:

    • Fever, chills, productive cough (rust-colored or blood-tinged), diaphoresis, tachypnea, shortness of breath, chest pain with respirations, fatigue, malaise, loss of appetite, confusion (especially in elders).

  • Diagnosis:

    • Chest X-ray, sputum culture, CBC, pulse oximetry.

TREATMENT OF PNEUMONIA

  • Treatment Approaches:

    • Antibiotics: Administered orally or intravenously based on the causative organism.

    • Symptom management: Includes NSAIDs, bronchodilators.

    • Adjuncts: Barberry root, increased fluids, rest, and oxygen therapy.

NURSE'S ROLE IN MANAGING PNEUMONIA PATIENTS

  • Key Areas of Focus:

    • Assessment of vital signs and pain levels.

    • Monitoring oxygenation and respiratory status.

    • Ensuring adequate nutrition and hydration.

    • Supporting rest and recovery.

    • Preventing secondary infections.

    • Educating about prevention strategies and immunization.

OBSTRUCTIVE SLEEP APNEA (OSA)

  • Pathophysiology: Characterized by recurrent collapse of the pharyngeal airway during sleep resulting in shallow breathing and/or pauses in breathing.

  • Etiology/Risk Factors:

    • Obesity, gender, age, enlarged tonsils/necks, family history, lifestyle habits (e.g., smoking and alcohol abuse).

OSA Details

  • Obstruction Mechanism: In OSA, the pharynx is obstructed by the soft palate and tongue.

  • Symptoms:

    • Snoring (decreased oxygen levels trigger brain to disturb sleep), excessive daytime drowsiness, headaches, irritability, mood swings, sore throat, dry mouth, sexual dysfunction.

  • Diagnosis:

    • Sleep studies and sleep diaries to identify patterns.

  • Treatment:

    • Lifestyle changes, use of Continuous Positive Airway Pressure (CPAP), oral appliances that prevent airway blockage, and surgical implant INSPIRE.

  • Complications of Untreated OSA:

    • Hypertension, myocardial infarction (MI), type 2 diabetes, cerebrovascular accidents (CVA), chronic fatigue.