O2 Therapy Basics

Question 1

On HFNC; what does flow provide compared to FiO2?

Answer 1

Flow = rate of O2/air mixture is delivered to patient. Higher flows ensure better oxygenation and CO2 washout in the upper airways.

• Can provide pseudo peep, but its unreliable
• Flow can reduce WOB
• Prevents entrainment of room air Higher flows can stablize O2 saturations bc each breath is ensured to have the same O2 per breath taken in w/o dilution from air entrainment

Question 2

Weaning approach for HFNC (airvo/optiflow)?

Answer 2

Wean FiO2 first, than flow second

Question 3

why do HFNC devices entrain less ambient air than regular high flow nasal cannula?

Answer 3

1. Higher flow rates match/exceed Pt inspiratory demand
2. Larger prongs create better seal
3. Reduction in nasal dead space
4. Provide dynamic PEEP
5. Minimal room air dilution at higher flow rates

Question 4

Why is it important to match or exceed pt inspiratory demand on HFNC?

Answer 4

Reduces the need for Pt to pull in additional room air during inhalation, ensuring a consistent FiO2