Module 9: Gas Exchange - Week 11

Module Overview and Curriculum Scope

• Course identification: Keysville NSG $106$.
• Curricular placement: Module $9$, scheduled for Week $11$.
• Core concept focus: Gas Exchange, encompassing physiological mechanisms, diagnostic specimen collection, airway management interventions, therapeutic modalities, and nursing clinical skills.

Gas Exchange Clinical Exemplars

• Artificial Airways and Oxygen Delivery Equipment:
  • Clinical implementation and management of devices designed to maintain airway patency.
  • Delivery systems utilized for supplemental oxygen administration across varying concentrations and flow rates.
• Cough, Deep Breathing, and Incentive Spirometry:
  • Non-pharmacological respiratory care interventions designed to promote lung expansion.
  • Pulmonary hygiene techniques aimed at clearing airway secretions and preventing atelectasis.
• Sputum Collection:
  • Diagnostic specimen procurement procedures to identify pulmonary pathogens, cellular components, or systemic abnormalities.
  • Ensuring proper collection timing, handling, sterility, and contamination avoidance.
• Suctioning Modalities:
  • Oral suctioning: Clearance of secretions from the oral cavity and oropharynx.
  • Tracheal suctioning: Direct aspiration of secretions from an established artificial tracheal airway.
  • Naso-tracheal suctioning: Insertion of a suction catheter through the nares into the trachea to clear secretions in non-intubated patients lacking effective cough clearance.

Core Learning Objectives

• Physiological Process of Blood Gas Exchange and Transport:
  • Summarize the mechanics of pulmonary ventilation: The physical movement of air into and out of the lungs (inspiration and expiration).
  • Define and calculate fractions of inhaled oxygen ($FiO_2$): The percentage or concentration of oxygen delivered to and inhaled by the patient (ranging from ambient room air at approximately $21\%$ up to $100\%$ supplemental oxygen).
  • Oxygen delivery measurement: Clinical metrics, flow rates (in $L/min$), and delivery monitoring via pulse oximetry ($SpO_2$) and arterial blood gas analysis ($PaO_2$, $PaCO_2$, $pH$, $HCO_3^-$).
  • Perfusion: The flow of blood through pulmonary and systemic capillary beds available for alveolar-capillary diffusion.
  • Transport: The binding, carrying, and cellular delivery of oxygen and carbon dioxide via hemoglobin throughout the systemic circulation.
• Gas Exchange Risk Factors:
  • Identification of intrinsic risk factors: Age-related physiological changes (infants, elderly), pre-existing chronic cardiopulmonary disease (COPD, asthma, heart failure), neuromuscular impairment, immunosuppression, and smoking history.
  • Identification of extrinsic risk factors: Environmental pollutants, occupational airborne toxins, prolonged immobility, surgical interventions involving general anesthesia, and artificial airway placement.
• Prevention Strategies for Alterations in Gas Exchange:
  • Primary prevention: Smoking cessation, immunizations (influenza, pneumococcal), infection control practices, and environmental hazard reduction.
  • Secondary prevention: Early ambulation, scheduled pulmonary hygiene, frequent repositioning, and routine clinical screening.
• Patient Education on Deep Breathing and Coughing Techniques:
  • Controlled diaphragmatic breathing instruction to optimize alveolar ventilation.
  • Effective coughing protocols (cascade cough, huff cough) to mobilize secretions from distal airways to central airways without causing airway collapse or patient exhaustion.
  • Splinting techniques for postoperative surgical incisions (e.g., thoracic or abdominal) to minimize pain during exertion.
• Incentive Spirometry Client Education:
  • Proper procedural education on sustained maximal inspiration (SMI) using an incentive spirometer.
  • Goal setting, frequency of performance ($10$ breaths per hour while awake), mouth seal technique, slow continuous inhalation, breath-hold duration ($3$ to $5$ seconds), and tracking visual markers.
• Indications and Contraindications for Oxygen Therapy:
  • Clinical indications: Documented arterial hypoxemia ($PaO_2 < 60\,mmHg$ or $SpO_2 < 90\%$), acute myocardial infarction, severe trauma, respiratory distress, and shock.
  • Contraindications and precautions: Cautious titration in patients with chronic hypercapnic respiratory failure (such as end-stage COPD relying on hypoxic drive), oxygen toxicity risks associated with prolonged high concentrations ($FiO_2 > 50\%$ over extended durations), combustion and fire hazards, and carbon dioxide narcosis.
• Upper Airway and Tracheal/Endotracheal Suctioning Procedures:
  • Demonstration of aseptic technique and sterile barrier maintenance.
  • Selection of appropriately sized suction catheters and setting negative pressure ranges.
  • Patient pre-oxygenation (hyperoxygenation) prior to catheter introduction.
  • Safe catheter insertion without applying suction, intermittent suctioning during withdrawal, duration limits per pass (typically under $10$ to $15$ seconds), and monitoring patient physiological tolerance.

Detailed Topic Outline

• Cough and Deep Breathing:
  • Mechanics of deep inhalation expanding lower lung lobes and opening collapsed alveoli.
  • Mobilization and expulsion of tracheobronchial secretions.
• Incentive Spirometry Use:
  • Device calibration, mechanical operation, and physiological benefits.
  • Prevention and reversal of micro-atelectasis in postoperative and bedridden patients.
• Oxygen Delivery Equipment:
  • Low-flow delivery systems: Nasal cannula, simple face mask, partial rebreather mask, non-rebreather mask.
  • High-flow delivery systems: Venturi mask (precise $FiO_2$ delivery), high-flow nasal cannula systems.
  • Humidification requirements for flows exceeding $4\,L/min$ to preserve mucosal integrity.
• Artificial Airways:
  • Types of artificial airways: Oropharyngeal airways (OPA), nasopharyngeal airways (NPA, nasal trumpet), endotracheal tubes (ET tubes), and tracheostomy tubes.
  • Indications, sizing, placement techniques, securing mechanisms, and routine stoma or airway care.
• Airway Suctioning Demonstration:
  • Upper airway suctioning: Yankauer/tonsil-tip suctioning of oral secretions.
  • Endotracheal and tracheal suctioning: In-line (closed) suction systems versus open sterile suction technique.
  • Assessment criteria before, during, and after suctioning (heart rate, rhythm, oxygen saturation, breath sounds).
• Specimen Collection:
  • Protocols for obtaining sterile or clean-catch sputum specimens.
  • Suction-trap collection for patients unable to spontaneously expectorate.
  • Laboratory requisitions: Sputum culture and sensitivity (C&S), acid-fast bacilli (AFB), and cytology.

Curricular Reading Assignments

• Assigned textbook chapter: Fundamentals Chapter $40$: Oxygenation and Perfusion.
• Required reading focus:
  • In-depth exploration of cardiopulmonary anatomy and physiology.
  • Clinical assessment of oxygenation status and tissue perfusion.
  • Nursing diagnoses related to impaired gas exchange, ineffective airway clearance, and ineffective breathing patterns.
  • Nursing interventions and collaborative management of respiratory dysfunction.