January 12, 2016 - Hypoxemia and Gas Transport (UNFINISHED)

Question 1

Oxygen in the Blood

Answer 1

98% is bound to hemoglobin

2% is dissolved in plasma

Question 2

Oxygen Dissociation Curve

Answer 2

Shifting the curve to the right will cause a lower hemoglobin affinity, causing it to unload easier and have an increased uptake of oxygen in the tissue. Things that will cause this right shift are an increase in temperature, an increase in CO2, an increase in acid.

Shifting the curve to the left will cause an increased hemoglobin affinity, leading to less oxygen unloading and a decrease of oxygen uptake at the tissue.

Question 3

Carbon Monoxide

Answer 3

Binds to hemoglobin with a 240x greater affinity than oxygen.

Shifts the oxygen dissociation curve to the left.

Because of this, oxygen cannot bind and your tissues become hypoperfused and can lead to death.

Oxygen saturation meters cannot tell the difference between oxygen and carbon monoxide bound hemoglobin, so it is possible for a patient to show 99% oxygen saturation and then die from lack of oxygen.

Question 4

Arterial and Alveolar PaCO₂

Answer 4

They are essentially the same.

CO₂ diffuses through tissue 20x faster than O₂.

Question 5

Arterial Hypoxemia

Answer 5

Low partial pressure of oxygen in the arterial blood.

Question 6

Mechanisms that Lead to Arterial Hypoxemia

Answer 6

1. Low inspired oxygen
2. Hypoventilation
3. Diffusion limitation
4. Shunt
5. V/Q mismatch