AS11.1-2 | Oxygen Delivery Devices and Oxygen Therapy Principles — Summary & Reflection

KEY TAKEAWAYS

Oxygen delivery devices are classified as fixed-performance (Venturi mask, HFNC) or variable-performance (nasal cannula, simple mask, NRM). The nasal cannula delivers approximately 24–44% FiO₂ at 1–6 L/min; the simple face mask delivers 40–60% at 5–10 L/min (minimum 5 L/min to prevent CO₂ re-breathing); the Venturi mask delivers discrete fixed FiO₂ values (24%, 28%, 35%, 40%, 60%) using colour-coded Bernoulli-principle adaptors; and the NRM delivers 60–90% FiO₂ at 10–15 L/min using a reservoir bag and one-way valves. Oxygen therapy must be prescribed with a specific target SpO₂ — 88–92% in COPD, ≥94% in most adults. Monitoring requires continuous pulse oximetry and ABG where CO₂ retention is a risk. Key hazards are hyperoxia-induced hypercapnia in COPD, absorption atelectasis, pulmonary oxygen toxicity, and fire risk. Device selection is driven by the severity of hypoxaemia, the need for FiO₂ precision, and the patient's clinical context.

REFLECT

Consider a busy night shift in which three consecutive patients each need oxygen: a 65-year-old with COPD, a 40-year-old with severe community-acquired pneumonia, and a 25-year-old postoperative patient recovering from an appendicectomy. For each, articulate which device you would choose, what flow rate or adaptor colour you would set, what target SpO₂ you would prescribe, and which monitoring parameter you would check at 30 minutes. What would prompt you to escalate to the next device tier for each patient? Practising this reasoning before you encounter these patients in clinical postings will make your choices automatic when seconds matter.