What happens when the tissues run short of oxygen, and how much giving oxygen helps each kind of shortage. The four-way classification of hypoxia is the heart of the chapter. Examiners ask for it most, often as a long essay with a note on 100% O₂ therapy, and as short notes on anemic and stagnant hypoxia.
Topics, in the book’s order
- Hypoxia · pp. 950–952 · asked 11 times
- Oxygen therapy · pp. 952–953
When you’ve read them: Quiz 110 · Hypoxia and Oxygen Therapy, 15 questions.
After this chapter you should be able to
- define hypoxia
- classify hypoxia and explain the mechanism behind each type
- list the effects of hypoxia on the body
- name the ways oxygen is given
- explain, type by type, why O₂ therapy helps some kinds of hypoxia more than others
- list the complications of prolonged oxygen therapy
Viva checklist
- Definition of hypoxia, and the four types
- Which type has a low PaO₂, and which a high venous PO₂
- Causes of hypoxic hypoxia, and what “respiratory hypoxia” means
- Alveolar PO₂ after a rapid climb to 3000 m
- Why CO poisoning is anemic hypoxia; how much more strongly CO binds Hb than O₂ does
- Why mild anemia is tolerated at rest but not in exercise
- The other names for stagnant hypoxia, and where it is seen
- How cyanide causes hypoxia, and how it is treated
- Effects of hypoxia on cells (HIFs) and on the brain (15 s, 4–5 min)
- Methods of O₂ therapy, and why a nasal cannula for a patient on hypoxic drive
- Why O₂ cannot correct hypoxia due to A-V shunts
- Hyperbaric O₂: what it is, the numbers behind it, its main use
- Effects of 100% O₂ on the CNS, lungs and special senses
- The mechanism of O₂ toxicity