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

Question 5

Hypoxia and CO2 Effects on systemic vasculature?

Answer 5

• Hypoxia results in vasodilation in systemic vasculature
• High CO2 results in vasodilation of systemic vasculature

Question 6

Hypoxia and CO2 effects on pulmonary vasculature?

Answer 6

• Hypoxia results in pulmonary vasoconstriction
• High CO2 results in pulmonary vasodilation (severe can cause constriction tho, pay attention to other signs)

Question 7

Hypoxia and CO2 effects on neurological vasculature?

Answer 7

• Hypoxia results in neurological vasodilation
• High CO2 results in vasodilation

Question 8

Why does hypoxia result in pulmonary vasoconstriction?

Answer 8

In regions with low O2 (causing hypoxia) the lungs will constrict to shunt blood to well ventilated areas and optimize external gas exchange

Question 9

Why does high CO2 result in vasodilation?

Answer 9

The body wants to eliminate CO2 by increasing blood flow to regions with higher CO2 via vasodilation

• severe can cause constriction tho, pay attention to other signs

Question 10

Indications for hyperbaric therapy

Answer 10

1. Carbon monoxide poisoning
2. Decompression syndrome
3. Hemorrhagic cystitis
4. Air embolism
5. Osteoradionecrosis of the jaw
6. Radiation proctitis
7. Non healing diabetic foot
   wounds
8. Osteomyelitis
9. Graft/flap ischemia
10. Acute sensory hearing loss
11. Dental surgery post significant radiation exposure
12. Radiation related disorders of the skin and subcutaneous
    tissue
13. Chronic non diabetic wounds/peripheral vascular disease wounds