Gas Exchange PP

Gas Exchange and Oxygenation Overview

  • Presentation adapted from ATI Engage Fundamentals RN Modules.

Learning Objectives

  • Review anatomy and physiology

  • Conduct a cardiopulmonary assessment

  • Understand alterations in ventilation and perfusion

  • Learn about oxygen therapy and its potential complications

  • Identify nursing actions to improve oxygenation

Concept Definition

Oxygenation

  • Definition: The process by which oxygen is transported to cells and carbon dioxide is transported from cells, requiring interaction among the neurologic, respiratory, and cardiovascular systems (Giddens 2021).

Anatomy and Physiology Review

Pulmonary System

  • Ventilation: Movement of air in and out of the lungs.

    • Inhalation: Breathing in.

    • Exhalation: Breathing out.

  • Lungs: Right lung has 3 lobes; left lung has 2 lobes.

  • Gas Exchange: Process that occurs in the alveoli.

  • Atelectasis: Collapse of alveoli reduction oxygenation.

Cardiovascular System

  • Oxygenated blood: Leaves the left ventricle (LV) to circulate throughout the body.

  • SA Node: Functions as the pacemaker of the heart.

Cardiopulmonary Assessment

Health History (Subjective Data)

  • Risk Factors: Diet, exercise, smoking, stress, and environmental exposures.

  • Pertinent History: Document medications and symptoms such as dyspnea, thoracic pain, cough/sputum, and oxygen use.

Physical Examination

  • Inspection: Determine level of consciousness, work of breathing (rate, rhythm & effort), use of accessory muscles, for cyanosis and jugular venous distension (JVD).

  • Palpation: Assess thoracic symmetry, pulses (rate, rhythm & strength), edema, and capillary refill.

  • Percussion: Advanced skill evaluating lung density and borders.

  • Auscultation: Listen for adventitious breath sounds (wheezes, crackles, rhonchi, stridor).

Alterations in Oxygenation

Impaired Gas Exchange

  • Issues may arise at the alveolar level or due to neurologic system dysfunction.

  • Airway Patency: Sputum or inflammation may decrease airway size, impeding gas passage.

  • Respiratory Pattern Changes: Conditions like tachypnea, bradypnea, and apnea.

  • Hypoperfusion: Inadequate blood flow impacting oxygen transport (e.g., myocardial infarction).

  • Multifactorial Issues: Include problems with gas exchange, airway patency, and reference to Arterial Blood Gas (ABG) testing.

Key Terms to Know

  • Hypoxemia: Low levels of oxygen in the blood.

  • Hypoxia: Low oxygenation at the tissue level.

  • Dyspnea on exertion: Difficulty breathing during activity.

  • Tachypnea: Rapid breathing.

  • Bradypnea: Slow breathing.

  • Hyperventilation: Increased rate and/or depth of breathing.

  • Hypoventilation: Decreased rate and/or depth of breathing.

  • Apnea: Temporary cessation of breathing.

  • Retractions: Visible sinking of the chest wall.

  • Cyanosis: Bluish discoloration of the skin indicating low oxygen.

  • FiO2: Fraction of inspired oxygen; Room air = 21% FiO2.

Diagnostic Tests

  • Pulse Oximetry: Measures oxygen saturation noninvasively.

  • Peak Expiratory Flow Rate: Checks airflow and respiratory function.

  • Chest X-ray/CT: Visualizes chest structures.

  • Arterial Blood Gases (ABG): Assesses the levels of oxygen and carbon dioxide.

  • Bronchoscopy: Direct visualization of the airways.

  • Sputum Culture: Tests for infectious agents.

Oxygen Saturation

Pulse Oximetry

  • Noninvasive device measures arterial blood oxygen saturation through a finger, toe or forehead sensor.

  • Detects hypoxemia before clinical symptoms appear; normal levels: 95-100%.

  • Levels < 70% are life-threatening.

Supplemental Oxygen Delivery Devices

Device

Liters Per Minute

FiO2

Nasal Cannula

1-6 LPM

24-44%

Simple Mask

5-8 LPM

40-60%

Venturi Mask

2-10 LPM

24-50%

Non-rebreather Mask

10-15 LPM

100%

CPAP

Continuous pressure

N/A

BiPAP

Bilevel pressure

N/A

Aerosol Mask

Delivers meds via nebulizers

N/A

Hazards of Oxygen

Safety for Home Use

  • No smoking around oxygen.

  • Keep tanks upright and not in confined spaces.

  • Maintain a distance of 5 ft from heat sources.

  • Avoid petroleum products on the face or upper chest (like Vaseline).

  • Keep oxygen tubing no longer than 50 ft.

  • Use 100% cotton bedding if using oxygen overnight.

  • Ensure hands are dry before sanitizing when handling oxygen.

  • Have a fire extinguisher nearby; oxygen supports combustion.

Potential Complications of Oxygen Therapy

  • Oxygen Toxicity: High levels may damage cell membranes leading to alveoli collapse.

  • Fire Risk: Oxygen is highly combustible.

  • Fall Risk: Keep tubing short and neat to minimize tripping hazards.

  • Oxygen Supply: Patients should monitor their oxygen supplies at home.

Nursing Actions

  • Positioning: Utilize upright positioning (High-Fowler’s).

  • Airway Clearance: Encourage deep breathing (using incentive spirometer), maintain hydration to thin secretions, and effective coughing.

  • Ambulation: Promote mobility as tolerated.

  • Suctioning and Chest Physiotherapy (Chest PT): For lung clearance.

  • Breathing Techniques: Instruct on pursed-lip breathing, and provide tracheostomy care and suctioning as needed.

  • Chest Tube Care: Follow protocols for maintenance and care.

Medications to Know

Albuterol

  • Form: Inhaler or nebulizer.

  • Type: Short-acting Beta Agonist (bronchodilator).

  • Function: Relaxes smooth muscle for bronchodilation; used as rescue medication.

  • Common Side Effects: Tachycardia, anxiety.

Corticosteroids (Fluticasone)

  • Form: Nasal spray or pills.

  • Type: Anti-inflammatory; reduces immune response locally.

  • Common Side Effects: Bloody nose, cough, headache.

Leukotriene Receptor Antagonist (Montelukast)

  • Indication: Maintenance for control of respiratory diseases; not a rescue medication.

Current Trends (FYI Only)

  • COVID-19: Triggers immune responses leading to Acute Respiratory Distress Syndrome (ARDS).

  • Current Treatments: Include supportive care such as supplemental oxygen, ventilation, positioning (proning), immunosuppression, vaccines, and antivirals.

Lifespan Considerations

  • Reduced Lung Function: Due to changes in ribcage shape and decreased muscle strength.

  • Decreased Cough Reflex: Increases infection susceptibility.

Key Points

  • Focus on cardiopulmonary assessment, recognizing abnormal breath sounds, identifying alterations in ventilation and perfusion, and understanding diagnostic tests, oxygen therapy, potential complications, and nursing actions to enhance oxygenation.