What are key concepts to teach medical students about the respiratory system in a 5-10 minute session?

Key Respiratory System Concepts for a 5-10 Minute Teaching Session

For an effective 5-10 minute teaching session on the respiratory system, focus on oxygen delivery principles and airway management techniques as these directly impact patient morbidity and mortality.

Oxygen Delivery Principles

• Understand that oxygen is the most commonly prescribed drug in hospitals, with delivery affected by flow rate, device characteristics, and patient's respiratory pattern 1
• For acutely breathless patients without risk of hypercapnic respiratory failure who have saturations below 85%, start with a reservoir mask at 15 L/min 2
• Target oxygen saturation of 94-98% for most patients, but adjust to 88-92% for patients with COPD or at risk of hypercapnic respiratory failure 2
• Recognize that high-flow nasal oxygen (HFNO) at 30-70 L/min can be considered as an alternative to reservoir mask treatment in patients with acute respiratory failure without hypercapnia 2

Airway Management Techniques

• Emphasize the importance of preoxygenation before induction of anesthesia to delay onset of hypoxia 2

• Teach optimal preoxygenation techniques including:

  • Tight-fitting facemask with circuit capable of delivering CPAP 2
  • Application of nasal oxygen throughout airway management 2
  • Use of 5-10 cm H₂O CPAP if oxygenation is impaired 2

• Demonstrate the two-handed, two-person bag-mask technique with VE-grip to improve seal, particularly in obese patients 2

Physiological Concepts

• Explain that the respiratory system exchanges oxygen and carbon dioxide between circulating blood and external environment through complex transport phenomena 3
• Discuss how respiratory acidosis develops from disorders affecting gas exchange, chest wall/respiratory muscles, or inhibition of the medullary respiratory center 4
• Highlight that respiratory alkalosis (primary hypocapnia) is caused by disorders that increase alveolar ventilation, defined by PaCO₂ <35 mmHg 4

Monitoring Parameters

• Teach the importance of monitoring:
  • SpO₂ in all ventilated patients 2
  • End-tidal CO₂ in all ventilated patients 2
  • Arterial PO₂ in moderate-to-severe disease 2
  • pH, lactate and central venous saturation in moderate-to-severe disease 2

Common Pitfalls to Avoid

• Avoid using high concentration oxygen unnecessarily in patients with acute coronary syndromes as it may increase infarct size 2
• Be cautious with oxygen therapy in patients with paraquat poisoning or bleomycin lung injury as supplemental oxygen may be harmful 2
• Don't delay intubation when non-invasive ventilation is failing; delay leads to profound hypoxemia during intubation 2
• Recognize that the F₁O₂ delivered by low-flow devices decreases significantly when respiratory rate increases (as in respiratory failure) 1