AMP 24: Oxygen Therapy (old) Flashcards
What is the definition of hypoxemia?
PaO2 < 80 mm Hg
List 5 causes for hypoxemia
- Hypoventilation
- ventilation/perfusion (V/Q) mismatch
- low inspired oxygen
- diffusion-barrier impairment
- right-to-left extrapulmonary blood shunting
How close to the nose or mouth should flow-by oxygen be placed?
2-4 cm
What FiO2 can be achieved with flow-by O2 supplementation at 2 L/min?
29.5 to 48% FiO2
What FiO2 can be achieved with mask O2 supplementation?
50-60% at 0.5 L/min - need higher rate for loose fitting face masks (2-5 L/min)
What FiO2 can be achieved with nasal cannula O2 supplementation?
FiO2 of 40-65% at a flow rate of 50-100 mL/kg/min
What decreases the FiO2 in an animal with nasal cannula O2 supplementation?
open mouth breathing or panting
What are contraindications for nasal insufflation catheters?
- nasal mass
- epistaxis
- nasal fracture
- rhinitis
After how long can O2 supplementation at 100% FiO2 lead to oxygen toxicity?
>12 hours
If the animal suffers from oxygen toxicity or is at high risk for oxygen toxicity, but decreasing or discontinuing supplemental O2 leads to persistent hypoxemia, what is the next step?
mechanical ventilation will be required to reduce FiO2 while hopefully maintaining adequate oxygenation
How does airway obstruction lead to atalactasis
Eventually all gas diffuses into blood, leaving the alveoli empty ⇒ alveolar collapse
Why does oxygen supplementation increase the risk for atalactasis/airway collapse
at some point all gas diffuses into blood = absorption atalactasis, but some gases take longer than others ⇒ nitrogen does not readily diffuse ⇒ absorption atalactasis takes long to develop
O2 supplementation ⇒ O2 replaces nitrogen ⇒ O2 more readily diffuses ⇒ fastened absorption atalactasis
