Nursing 202: Gas Exchange and ARDS

Nursing 202 Study Notes

Concept: Gas Exchange

Exemplars:

  • Acute Respiratory Failure (ARF)

  • Acute Respiratory Distress Syndrome (ARDS)
    Instructor: Kelley Becker, DNP, RN

Learning Outcomes

  1. Relate pathophysiological basis for respiratory failure & ARDS

    • NCLEX: Physiological Integrity

  2. Compare assessment findings identified in clients with respiratory failure vs. ARDS including diagnostic testing & ABG analysis

    • NCLEX: Physiological Integrity

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

    • NCLEX: Safe and Effective Care and Physiological Integrity

  4. Describe the collaborative management of clients requiring intubation & mechanical ventilation

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

  5. Discuss pharmacologic and nutritional therapies for clients with complex oxygenation needs

    • NCLEX: Safe and Effective Care and Physiological Integrity

  6. Identify evidence-based nursing practice for care of clients with advanced oxygenation needs

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

  7. Integrate cultural competence, psychosocial and family support in providing care for clients with advanced oxygenation needs

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

  8. Develop a collaborative plan of care for clients with alteration in oxygenation, utilizing community resources for facilitating transition from one level of care to another

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

Acute Respiratory Failure (ARF)

  • Definition: Sudden deterioration of gas exchange leading to inability to eliminate CO2.

  • Pathophysiology: Classified based on ABG abnormalities, manifested by critical values of:

    • ↓ PaO2 ≤ 60 mm Hg (hypoxemia)

    • SaO2 < 90%

    • CO2 > 50 mm Hg (hypercapnia/hypercarbia)

    • pH < 7.35 (acidemia)

    • (Source: Ignatavicius, 2024 pp. 603-604)

Respiratory System Components

  • Key Structures:

    • Alveoli

    • Nasal Cavity

    • Pharynx

    • Larynx

    • Trachea

    • Bronchioles

    • Bronchi

    • Diaphragm

    • High oxygen (O2) concentration and movement of O2 and carbon dioxide (CO2) concentration

ARF Predisposing Factors

  • Decreased respiratory drive

  • Dysfunction of chest wall

  • Dysfunction of lungs

  • Massive obesity

  • Sleep apnea

  • Additional causes: Pain medications, sedatives, Carbon Monoxide (CO) poisoning

Types of ARF

  1. Ventilatory Failure:

    • Due to mechanical abnormality of lungs or chest wall, impaired muscle function (e.g., diaphragm), or malfunction in the respiratory center of the brain.

    • Normal perfusion (Q) but abnormal ventilation (V).

    • Causes include physical lung or chest wall problems, a defect in respiratory control centers in the brain, or poor function of respiratory muscles.

  2. Oxygenation Failure:

    • Results from lack of perfusion to the pulmonary capillary bed (e.g., pulmonary embolism) or conditions altering the gas exchange medium (pulmonary edema, pneumonia).

Pathophysiological Implications

  • Inadequate ventilation and oxygenation may occur in patients with diseased lungs (e.g., asthma, emphysema, cystic fibrosis), ultimately leading to respiratory muscle fatigue and ventilatory failure.

  • Combined failures lead to more severe hypoxemia than either failure alone.

Clinical Symptoms of ARF

  • Initial Symptoms:

    • Impaired oxygenation due to early signs of tissue hypoxia

    • Dyspnea (DOE) - hallmark sign of respiratory failure

    • Orthopnea

    • Hypercapnia (high CO2)

    • Tachypnea

    • Restlessness/Combative behavior

    • Fatigue

    • Headache

    • Air hunger

    • Tachycardia

    • Hypertension

  • Worsening Symptoms:

    • Confusion/Lethargy

    • Disorientation and delirium

    • Coma

    • Decreased breath sounds (BS)

    • Accessory muscle use

    • Diaphoresis, cool clammy skin

    • Dysrhythmias

    • Inability to speak without pausing to breathe

    • Cyanosis (late stage)

    • Possible respiratory arrest

Diagnostic Studies for ARF

  • Arterial Blood Gases (ABGs)

  • Continuous Pulse Oximetry

  • Chest X-ray (CXR)

  • Complete Blood Count (CBC)

  • Cultures

  • Ventilation/Perfusion (V/Q) Scan

  • Pulmonary Angiography

Collaborative Treatment and Nursing Interventions

  • Identify and correct underlying cause.

  • Ensure adequate gas exchange and improve ventilation and oxygenation.

  • Conserve energy for breathing by allowing patient to rest - recommended practices include:

    • Quiet environment

    • Uninterrupted rest

    • Position maintenance every 2 hours

  • Airway Management:

    • Establish and maintain airway

    • Administer oxygen as ordered

    • Monitor ABGs and O2 saturations (using pulse oximetry)

    • Mobilize secretions through:

      • Effective coughing/deep breathing (C/DB)

      • Incentive spirometry (IS)

      • Hydration/Humidification

      • Chest physiotherapy

      • Suctioning as needed

Supportive Therapies

  • Mechanical Ventilation:

    • Noninvasive positive pressure ventilation

    • Intubation with mechanical ventilation

  • Nutritional therapy:

    • Enteral (tube feeding)

    • Parenteral (total parenteral nutrition - TPN)

Medication Administration

  • Bronchodilators:

    • Albuterol/Proventil/Aminophylline

  • Corticosteroids:

    • Solu-medrol to relieve airway inflammation

  • Diuretics:

    • Furosemide (Lasix) to relieve pulmonary congestion

  • Antibiotics:

    • To treat infections

  • Anti-anxiety Agents:

    • For anxiety reduction

  • Maintain/improve cardiac output using IV fluids (Normal Saline - NS, Dopamine)

  • Adequate hemoglobin and hematocrit through blood products

Complications for ARF

  • Ineffective airway clearance related to poor respiratory function

  • Ineffective breathing patterns

  • Risk for fluid volume deficit

  • Anxiety

  • Impaired gas exchange

  • Imbalanced nutrition

  • Potential Complications:

    • Respiratory failure/arrest related to decreased O2 saturation

    • Cardiopulmonary arrest related to respiratory rate < 6

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

Nursing Interventions

  • Monitor oxygen levels, pulse oximetry, and oxygen saturations

  • Assist with effective coughing/deep breathing (C/DB)

  • Clear secretions as needed

  • Positioning for comfort

  • Monitor ABGs and breath sounds

  • Provide comfort measures to reduce O2 demand and anxiety

  • Address nutritional needs and hydration status

Client Goals

  • Achieve adequate oxygenation

  • Ensure adequate ventilation

  • Ensure adequate gas exchange, as evidenced by:

    • ABGs returning to baseline

    • Effective breathing patterns and successful cough/airway clearance

    • Breath sounds returning to baseline (absence of dyspnea)

    • Increased comfort and reduced anxiety

    • Adequate nutritional status

    • Avoid complications such as ARDS

Client Education

  • Focus on prevention strategies

    • C/DB practice

    • Use of Incentive Spirometry (IS)

    • Early recognition of signs/symptoms of respiratory failure

Acute Respiratory Distress Syndrome (ARDS)

  • Mortality Rate: High

  • Defining Features:

    • Hypoxemia that persists even when giving 100% oxygen (refractory hypoxemia)

    • Decreased pulmonary compliance

    • Dyspnea

    • Non-cardiac associated bilateral pulmonary edema

    • Densities on chest X-rays presenting a ground-glass appearance

    • (Source: Iggy, 2024 pp. 605-606)

Pathophysiology of ARDS

  • Characterized by sudden and progressive inflammatory process

    • Diffuse alveolar damage

    • Lung capillary damage leading to atelectasis

    • Lung tissue inflammation with bilateral pulmonary edema

    • Increasing bilateral infiltrates and capillary permeability

    • Resulting in severe hypoxemia and decreased lung compliance

    • Metabolic acidosis may occur

Causes of ARDS

  1. Direct Lung Injury:

    • Infections/Pneumonia

    • Aspiration of gastric contents

    • Chest trauma (e.g., rib fractures, pneumothorax)

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

    • Near drowning

    • Oxygen toxicity

    • Lung radiation

  2. Indirect Lung Injury:

    • Sepsis

    • Massive trauma

    • Pancreatitis

    • Anaphylaxis

    • Bleeding/disseminated intravascular coagulopathy (DIC)

    • Burn injury

    • Pulmonary edema

    • Drug overdose

    • Shock

Phases of ARDS

  1. Inflammatory Response:

    • Damage to alveolar capillary membrane

    • Fluid leakage into alveolar interstitial space

    • Atelectasis occurs as a result

  2. Severe Ventilation/Perfusion (V/Q) Mismatch:

    • Alveoli collapse

    • Surfactant dysfunction increases risk for atelectasis

    • Airways narrow leading to decreased lung compliance

    • Blood is shunted past alveoli with no ventilation occurring

  3. Progression:

    • Lungs become dense and fibrotic

    • Surface area for gas exchange is greatly reduced

    • Increased pulmonary vascular resistance leading to pulmonary hypertension

    • Results in stiff lung mechanics

Clinical Symptoms of ARDS

  • Rapid onset dyspnea and tachypnea with an increased respiratory rate (earliest indicator identified)

  • Refractory hypoxemia defined as PaO2 decrease to 60 mm Hg despite oxygen administration

  • Changes in mental status: Restlessness and anxiety

  • Bilateral crackles reflecting pulmonary edema

  • Additional manifestations:

    • Tachycardia

    • Diaphoresis

    • Peripheral cyanosis

    • Pallor

    • Use of accessory muscles, representing air hunger

Hallmark Signs of ARDS

  • Progressive refractory hypoxemia despite increased administration of O2

  • Shortness of breath (SOB) and severe dyspnea

  • Tachypnea and increased changes in mental status

  • Infiltrates observed on chest X-ray indicating fluid presence

  • Reduced lung compliance and decrease in O2 saturation

Diagnostic Tests for ARDS

  • Arterial Blood Gases (ABGs) display initial mild hypoxemia with respiratory alkalosis; progression indicates hypercapnia and severe hypoxemia

  • Chest X-ray findings will evolve from extensive infiltrates to pulmonary edema and may depict a “white-out” or “white lung” appearance

Collaborative Care for ARDS

  • Primary Goal: Identify and treat the underlying cause of ARDS

  • Implement mechanical ventilation using an Endotracheal Tube (ETT) or tracheostomy

  • Use Positive End-Expiratory Pressure (PEEP) to prevent or treat atelectasis with goals for PaO2 > 60 mm and O2 saturation > 90%

  • Administer medications as prescribed, including:

    • Sedation, analgesia, anxiolytics

    • Stress ulcer prophylaxis

    • DVT prophylaxis

    • Corticosteroids

    • Vasopressors (e.g., Dopamine)

    • Diuretics

    • Antibiotics as necessary

Positioning in ARDS

  • Prone Positioning: Improves oxygenation, increasing PaO2 and SaO2 levels

  • Assists in mobilizing secretions and reducing atelectatic risks

  • Raising the head of the bed (Semi-Fowler's position) to promote chest expansion and ease breathing

Potential Complications of ARDS

  • Infections: Catheter-related, nosocomial pneumonia or VAP

  • Cardiac Issues: Dysrhythmias and decreased cardiac output

  • Respiratory Complications: Pneumothorax, emboli, pulmonary fibrosis

  • GI Issues: Ileus, stress ulcers, or hemorrhage

  • Hematologic Issues: Anemia, DIC, thromboembolism

  • Acute Renal Failure: Monitor hydration and urine output

  • Risk for multiple organ dysfunction syndrome

Client & Family Education for ARDS

  • Emphasize the importance of remaining positive and keeping family informed

  • Encourage keeping a journal and participating actively in medical decision-making

  • Discuss enjoyable moments and the importance of self-care for family members

  • NOTE: Advise family about the possibility of flashbacks during recovery and that maximal respiratory function may take about 6 months to return

Nursing Problems and Potential Complications regarding ARDS

  • Production of sepsis, respiratory failure/arrest, cardiopulmonary arrest, and death

  • Addressing anxiety, impaired gas exchange, and imbalanced nutrition

Plan of Care Scenario

  • Case Study Patient: Ms. Respirs post-emergency surgery with observable symptoms of ARDS after significant blood loss.

  • Key indicators include:

    • Vital signs: Orthopnea, diffuse abdominal pain, cool moist skin, respiratory rate of 28, oxygen saturation of 88%, crackles observed bilaterally, hypotension (BP 100/60), and elevated temperature of 101.2°F.

  • Recent diagnostic results reflect ABG readings and chest X-ray findings indicating potential ARDS.

Potential questions regarding plan of care:

  1. Clinical Manifestations Supporting Diagnosis of ARDS:

    • Increasing hypoxemia despite 60% O2 mask administration

    • Notable SOB, tachypnea, tachycardia

    • Exhibiting restlessness, anxiety, and diaphoresis

    • Decreased O2 saturation and bilateral crackles observed

    • Chest X-ray demonstrating infiltrates

  2. Possible Causes:

    • Surgery-related bleeding, trauma, hypovolemia, sepsis

  3. Potential Complications:

    • Emboli, catheter-associated UTI, respiratory arrest, pneumonia, sepsis, DIC, hypovolemic shock, nosocomial infection, and acute renal failure

  4. Interventions to Perform:

    • Complete head-to-toe assessment

    • Infection control precautions

    • Positioning (elevated head, encouragement of C/DB, incentive spirometry, turning every 2 hours)

    • Allowing the client to rest, providing personal care, preparing for intubation/ventilation, and ensuring oral care

  5. Overall Plan of Care Development:

    • Focus on collaborative interventions and monitoring, recognizing hypoxemia and associated symptoms.

    • Preparing for intubation and mechanical ventilation if necessary while optimizing fluid administration and drug interventions for improving cardiac perfusion.

Management Post-Ventilator Weaning

  • Enhancing medication delivery via metered inhalers (MDI) or systemic administration post-ventilator support.

  • Ensure minimal self-care efforts during recovery to reduce energy expenditure.

Practice Questions Examples

  • Assessment finding indicative of impaired gas exchange?

    • Given options include oxygen saturation drops, heart rate changes, and respiratory rate changes for possible identification of issues.

  • Education for discharged ARDS patients.

    • Emphasize expected timeframes for recovery and functional returns post-ARDS.

  • Knowledge assessment from new nurses.

    • Statement validations of awareness regarding ARDS with criteria for understanding:

      • Correct comprehension of pathophysiology or misattribution based on other pulmonary disorders for teaching.

  • Determining risk associated with potential ARDS candidates and their prognosis.

  • Identifying meaningful chest X-ray findings reflective of ARDS developments.