Oxygen therapy Flashcards
What is the O2 flow rate in a nasal canula?
- 1-6 L/min
- In practice, rarely give > 4 L/min, because O2 is not humidified; giving such high flow can dry out nasopharyngeal mucous membrane, which increases pain and discomfort
What is the FiO2 in a nasal canula?
FiO2: 24-40%
FiO2 is variable (depending on the patient’s breathing pattern) and cannot be fixed
What is the peak flow rate in a nasal canula?
~ 15 L/min
Large fraction of inspired volume is drawn from room air
What are the advantages of a nasal canula?
Comfortable for patient (if < 4 L/min)
Can eat simultaneously
What are the disadvantages of a nasal canula?
Low performance device (i.e. not accurate in providing a fixed FiO2)
What is the O2 flow rate in a standard face mask?
O2 flow rate: 5-10 L/min
What is the FiO2 in a standard face mask?
FiO2: 35-60% (but variable depending on patient’s breathing pattern, cannot be fixed)
What is the advantage of a standard face mask?
Higher FiO2 than nasal cannula (owing to reservoir volume)
What is the disadvantage of a standard face mask?
Variable performance, depending on patient’s ventilatory depends
Cannot eat simultaneously
What is the O2 flow rate in a partial rebreathing mask?
O2 flow rate: 10-15 L/min
What is the FiO2 in a partial rebreathing mask?
FiO2: 40-70%
What is the FiO2 in a non rebreathing mask?
60-80%
Theoretically able to achieve FiO2 of 100%, but fails to do so due to leaks around the mask
What is the advantage of a venturi mask?
Able to deliver a constant, fixed FiO2 (especially for lower levels, e.g. 24%) – important in COPD patients who are depending on hypoxic drive to breathe, and a high FiO2 will induce apnoea
What are the disadvantages of a venturi mask?
Unable to deliver high FiO2 (max. approx. 50%)
