Nursing 202: Gas Exchange Concepts

Nursing 202: Gas Exchange Study Notes

Concept Overview

  • Gas Exchange: A fundamental physiological process critical for maintaining adequate oxygenation and carbon dioxide elimination in the body.

  • Exemplars of Disorders:

    • Acute Respiratory Failure (ARF)

    • Acute Respiratory Distress Syndrome (ARDS)

  • Instructor: Kelley Becker, DNP, RN

Learning Outcomes

  1. Pathophysiological Basis: Understand the pathophysiological fundamentals of respiratory failure and ARDS.

    • NCLEX: Physiological Integrity

  2. Assessment Findings: Compare assessment findings in clients with respiratory failure vs. those with ARDS, including diagnostic testing and arterial blood gas (ABG) analysis.

    • NCLEX: Physiological Integrity

  3. Nursing Diagnoses: Prioritize nursing diagnoses and collaborative problems for clients with complex oxygenation needs.

    • NCLEX: Safe and Effective Care; Physiological Integrity

  4. Collaborative Management: Outline collaborative management of clients needing intubation and mechanical ventilation.

    • NCLEX: Safety and Infection Control; Psychosocial Integrity; Physiological Integrity

  5. Pharmacologic & Nutritional Therapies: Discuss medications and nutritional therapies for clients with complicated oxygenation needs.

    • NCLEX: Safe and Effective Care; Physiological Integrity

  6. Evidence-Based Nursing Practice: Identify evidence-based practices for the care of clients with advanced oxygenation requirements.

    • NCLEX: Safety and Infection Control; Psychosocial Integrity; Physiological Integrity

  7. Cultural Competence & Support: Integrate cultural competence, psychosocial, and family support into the care of clients with advanced oxygenation needs.

    • NCLEX: Safety and Infection Control; Psychosocial Integrity; Physiological Integrity

  8. Collaborative Care Plan Development: Develop a collaborative care plan for clients with oxygenation alterations, utilizing community resources.

    • NCLEX: Safety and Infection Control; Psychosocial Integrity; Physiological Integrity; Reduction of Risk Potential

Acute Respiratory Failure (ARF) Overview

  • Definition: Rapid deterioration of gas exchange resulting in the inability to remove carbon dioxide (CO2) effectively.

  • Pathophysiology: Classified based on ABG abnormalities.

  • Critical ABG values:

    • PaO2: ≤ 60 mm Hg (hypoxemia)

    • SaO2: < 90%

    • CO2: > 50 mm Hg (hypercapnia/hypercarbia)

    • pH: < 7.35 (acidemia)

    • Reference: Ignatavicius, 2024 pp. 603-604

Respiratory System Anatomy

  • Components:

    • Alveoli

    • Nasal Cavity

    • Pharynx

    • Larynx

    • Trachea

    • Bronchioles

    • Bronchi

    • Lungs

    • Diaphragm

    • Blood (Oxygen Concentration Movement)

    • Gas Exchange Dynamics

Predisposing Factors of ARF

  • Categories:

    • Decreased respiratory drive

    • Chest wall dysfunction

    • Lung dysfunction

    • Massive obesity

    • Sleep apnea

    • Other factors:

    • Pain medications

    • Sedatives

    • Carbon Monoxide (CO) poisoning

Types of Respiratory Failure

  1. Ventilatory Failure:

    • Definition: Mechanical abnormality of lungs/chest wall, impaired diaphragm function, or malfunction in the respiratory center of the brain.

    • Perfusion (Q) is normal, but Ventilation (V) is abnormal.

    • Causes:

    1. Physical lung/chest wall abnormalities

    2. Defect in the respiratory control center

    3. Poor respiratory muscle function

  2. Oxygenation Failure:

    • Occurs due to

      • Lack of perfusion to pulmonary capillary bed (e.g., pulmonary embolism)

      • Conditions that alter gas exchange medium (e.g., pulmonary edema, pneumonia)

Implications of Inadequate Ventilation & Oxygenation

  • Seen in diseases like asthma, emphysema, and cystic fibrosis

  • Diseased lung tissue can cause oxygen failure leading to respiratory muscle fatigue and ventilatory failure.

  • Combined failure leads to more profound hypoxemia than either alone.

Clinical Symptoms of ARF

Initial Symptoms

  • Impaired Oxygenation: Early signs of tissue hypoxia

  • Dyspnea (DOE): Hallmark sign of respiratory failure

  • Orthopnea

  • Hypercapnia: Elevated CO2 levels

  • Tachypnea: Increased respiratory rate

  • Restlessness and/or combative behavior

  • Fatigue

  • Headache

  • Air hunger

  • Tachycardia

  • Hypertension

Worsening Symptoms

  • Hypoxemia: Symptoms may escalate to confusion, lethargy, disorientation, and delirium.

  • Coma

  • Decreased breath sounds

  • Use of accessory muscles for breathing

  • Diaphoresis

  • Cool, clammy skin

  • Dysrhythmias

  • Inability to speak without pausing for breath

  • Cyanosis: A late sign

  • Possible respiratory arrest

Diagnostic Studies for ARF

  • ABGs: Assess blood gas levels

  • Continuous Pulse Oximetry: Monitor oxygen saturation continuously

  • Chest X-Ray (CXR): Visual confirmation of lung involvement

  • Complete Blood Count (CBC): To check for infections or other issues

  • Cultures: Identify any infective agents

  • V/Q Scan: Assess ventilation and perfusion in lungs

  • Pulmonary Angiography: Detailed vascular imaging of lung structures

Collaborative Treatment for ARF

  • Goals:

    • Identify and correct underlying causes

    • Ensure adequate gas exchange

    • Improve ventilation and oxygenation

    • Conserve energy; allow the client to rest adequately by providing a quiet environment

  • Measures:

    • Maintain and establish a clear airway

    • Administer O2 as prescribed

    • Monitor ABGs and oxygen saturation

    • Mobilize secretions effectively through methods such as:

    • Coughing and deep breathing (C/DB)

    • Incentive Spirometry (IS)

    • Hydration and humidification

    • Chest physiotherapy

    • Suctioning as needed

    • Regular repositioning (at least every 2 hours) for comfort

    • Ensure proper positioning to facilitate breathing

    • Monitor breath sounds regularly

Advanced Collaborative Care

  • Ventilation Techniques:

    • Noninvasive positive pressure ventilation

    • Intubation with mechanical ventilation

  • Supportive Therapy:

    • Manage underlying causes of respiratory failure

    • Maintain adequate cardiac output and hemoglobin levels

  • Nutritional Therapy:

    • Enteral feeding (tube feeding)

    • Parenteral nutrition (TPN)

Medication Administration for ARF

  • Bronchodilators: e.g., Albuterol, Proventil, Aminophylline

  • Corticosteroids: e.g., Solu-Medrol for airway inflammation

  • Diuretics: e.g., Furosemide (Lasix) for pulmonary congestion

  • Antibiotics: Treat any infections present

  • Anxiolytics: Manage anxiety, if it arises, using appropriate agents

  • IV Fluids and blood products: Improve overall cardiac output and oxygen-carrying capacity

Complications Associated with ARF

  • Actual and Potential Complications:

    • Ineffective airway clearance

    • Ineffective breathing patterns

    • Risk for fluid volume deficit

    • Anxiety

    • Impaired gas exchange

    • Imbalanced nutrition

    • Potential complications:

    • Respiratory failure/arrest due to decreased oxygen saturation

    • Cardiopulmonary arrest due to respiratory rate dropping below 6

    • Pneumonia related to decreased mobility and inability to C/DB

Nursing Interventions for ARF

  • Monitoring:

    • Airway, oxygen levels, pulse oximetry, and oxygen saturation

    • C/DB to clear secretions

    • Patient positioning for optimal breathing

    • Monitor ABGs and breath sounds (BS)

    • Implement comfort measures to reduce oxygen demand and anxiety

    • Address nutritional needs and hydration status

Client Goals for ARF Recovery

  • Objectives:

    • Adequate oxygenation and ventilation

    • Effective gas exchange as evidenced by:

    • ABGs returning to baseline levels

    • Effective breathing patterns, cough, and airway clearance

    • Breath sounds returning to baseline (no dyspnea)

    • Increased comfort and reduced anxiety

    • Adequate nutritional status

    • Avoidance of complications like ARDS

Client Education for ARF

  • Prevention Education:

    • Coughing and breathing techniques (C/DB and IS)

    • Recognize early signs and symptoms of respiratory failure

Acute Respiratory Distress Syndrome (ARDS) Overview

  • Definition: A form of acute respiratory failure with high mortality risk characterized as follows:

    • Persistent hypoxemia even with 100% oxygen (refractory hypoxemia)

    • Decreased pulmonary compliance

    • Dyspnea

    • Non-cardiac associated bilateral pulmonary edema

    • Dense pulmonary infiltrates visible on X-ray (ground-glass appearance)

    • Reference: Iggy, 2024 pp. 605-606

Pathophysiology of ARDS

  • Overview:

    • Marked by a sudden and progressive inflammatory process

    • Involves diffuse alveolar damage and lung capillary damage (atelectasis)

    • Leads to lung tissue inflammation, bilateral pulmonary edema, and increased capillary permeability

    • Results in severe hypoxemia and decreased lung compliance, with metabolic acidosis

Causes of ARDS

Direct Lung Injury

  • Infections/Pneumonia

  • Aspiration of gastric contents

  • Chest trauma

  • Rib fractures, pneumothorax

  • Emboli

  • Inhaled toxic agents (e.g., CO poisoning)

  • Near drowning incidents

  • Oxygen toxicity

  • Lung Radiation

Indirect Lung Injury

  • Sepsis

  • Massive trauma

  • Pancreatitis

  • Anaphylaxis

  • Major bleeding

  • Disseminated intravascular coagulation (DIC)

  • Burn injury

  • Pulmonary edema

  • Drug overdose

  • Shock

Phases of ARDS

Initial Inflammatory Response

  • Damage to the alveolar-capillary membrane leading to fluid leakage into the interstitial space, causing atelectasis.

Severe Ventilation/Perfusion (V/Q) Mismatch

  • Leads to collapse of alveoli, surfactant dysfunction, and decreased lung compliance, resulting in shunting blood past alveoli without gas exchange.

Progression Event

  • Dense and fibrotic lungs develop with significantly reduced surface area, leading to increased pulmonary vascular resistance and pulmonary hypertension.

Clinical Symptoms of ARDS

  • Rapid Onset:

    • Dyspnea and tachypnea (earliest sign is tachypnea)

    • PaO2 < 60 mm Hg despite oxygen supplementation (refractory hypoxemia)

    • Change in mental status (restlessness/anxiety)

    • Crackles indicative of noncardiogenic pulmonary edema

    • Tachycardia

    • Diaphoresis

    • Peripheral cyanosis and pallor

    • Accessory muscle use and air hunger

Hallmark Signs of ARDS

  • Progressive refractory hypoxemia despite increased oxygen levels

  • Severe dyspnea and tachypnea

  • Notable mental status changes

  • Visual inclusions on CXR (check for infiltrates)

  • Decreased lung compliance coupled with low oxygen saturation levels

Diagnostic Tests for ARDS

  • ABGs: Evaluated initially for mild hypoxemia and respiratory alkalosis, progressing to hypercapnia and severe hypoxemia as condition worsens.

    • Notable results include: PaO2 < 60 mm Hg

  • CXR: Initially showing extensive infiltrates noting pulmonary edema, later looks like "white-out" or "white lung" signs.

Collaborative Care for ARDS

  • Goals:

    • Identify and treat the underlying cause as a priority

    • Employ mechanical ventilation with Endotracheal Tube (ETT) or tracheostomy where needed

    • Implement Positive End-Expiratory Pressure (PEEP) to prevent/treat atelectasis

    • Lower target: PaO2 > 60; O2 sat > 90%

    • Utilize sedatives to keep the patient comfortable

Medication Protocol in ARDS

  • Administer medications as directed including:

    • Sedation/analgesia/anti-anxiety agents

    • Stress ulcer prophylaxis

    • DVT prophylaxis

    • Corticosteroids

    • Vasopressors (e.g., dopamine)

    • Diuretics as needed

    • IV fluids for hydration support

    • Antibiotics for treating infections

Oxygenation and Ventilation Strategies in ARDS

  • Procedures:

    • Cough, deep breathe and help clear secretions

    • Proper positioning (HOB semi-Fowler's 15-45 degrees or prone)

    • Continuous nursing assessments of ABGs, oxygen saturation, breath sounds, and respiratory rate

  • Nutritional Support:

    • Daily caloric needs of 35-45 cal/kg/day via TPN or enteral nutrition

The Importance of Positioning in ARDS

  • Prone Positioning:

    • Enhances patient oxygenation and improves PaO2 and SaO2 levels

    • Mobilizes secretions and reduces fluid accumulation in airways

  • Semi-Fowler's Position:

    • Promotes oxygenation through increased chest expansion, easing the breathing process

Potential Complications of ARDS

  • Infection (e.g., catheter-related, nosocomial pneumonia/VAP, sepsis)

  • Cardiac Issues (dysrhythmias, reduced cardiac output)

  • Respiratory Complications (pneumothorax, emboli, pulmonary fibrosis)

  • GI Complications (ileus, stress ulcers, hemorrhage)

  • Hematological Issues (anemia, DIC, thromboembolism)

  • Acute renal failure

Client & Family Education for ARDS

  • Encourage positivity and keeping family members informed

  • Emphasize participation in medical decision-making

  • Suggest journaling and discussing positive memories to foster mental well-being

  • Highlight the necessity for family self-care

  • Inform about the potential for flashbacks and that maximal respiratory function may take around 6 months to return

Plan of Care for ARDS Patient Scenario

Assessment

  • Signs of hypoxemia despite 60% mask:

    • Dyspnea, tachypnea, tachycardia, restlessness, anxiety, diaphoresis, and decreased oxygen saturation.

Collaborative Interventions

  • Intubate and mechanical ventilation as required.

    • Monitor and protect the airway, ensure perfusion and adequate fluid volume without overload.

    • Use IV drugs for cardiac output enhancement (e.g., Dobutrex, Primacor, vasopressors)

    • Maintain HOB elevation and foley placement for drainage

Anxiety Management

  • Facilitate relaxation techniques and provide diversional activities

Post-Ventilation Care

  • Post-weaning medications including bronchodilators (e.g., Albuterol) for ongoing respiratory management

Sample Clinical Questions

  1. What clinical manifestations does the patient have to support the diagnosis of ARDS?

    • Hallmark sign of increasing hypoxemia despite oxygen therapy

    • Symptoms include SOB, tachypnea, tachycardia, restlessness, and crackles on chest examination.

  2. What would be the possible causes?

    • Surgical trauma, bleeding, and sepsis from bowel perforation

  3. What are potential complications?

    • Emboli, catheter-associated UTI, and pneumonia or VAP if on mechanical ventilation.

  4. What nursing interventions would you perform?

    • Comprehensive assessment, maintain infection control, perform C/DB and incentive spirometry techniques, allow patient to rest adequately, and prepare for potential intubation.

  5. Develop a plan of care for this ARDS patient.

    • Include monitoring objectives, interventions for intubation, sedation protocols, and strategies to maintain airway patency and reduce anxiety.