Oxygenation


ABG's can tell us some important things about the body's oxygenation. Every living cell in the body needs oxygen. Hemoglobin binds and then releases O2 in response to physiologic conditions.


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PaO2 measures the total oxygen in the blood
True
False

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The carboxyhemoglobin molecule carries the same amount of oxygen as oxyhemoglobin.
True
False

How and when do body tissues become hypoxic?
 Problem Ventilation Circulatory (perfusion)
 Mechanism Too little oxygen reaches the alveoli Too little blood reaches the alveoli
Examples
  • pneumonia

  • bronchospasm

  • heart failure
  • pulmonary embolism

Points to remember:

  1. PaO2 is oxygen dissolved in plasma, not total O2.
  2. SaO2 is saturated hemoglobin minus HbCO and MetHb.
  3. Ventilation does not equal oxygenation.
  4. A shunt is normal alveolar O2, but low blood O2.

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Tissue hypoxia can result from either a ventilation or a circulatory problem.
True
False

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