Introduction to blood gas transport

Question 1

Oxygen transport capacity, normal adult

Answer 1

20 ml/100 ml blood

Question 2

Oxygen content (CaO2) equation, in ml/100ml blood

Answer 2

CaO2 = [Hb (g Hb/100ml blood) x 1.34 (ml O2/g Hb) x SaO2 (%)] + PaO2 x 0.003

Question 3

Distribution of dissoved vs Hb-bound oxygen

Answer 3

2 vs 98%

Question 4

Percent saturation equation

Answer 4

SaO2 = oxygen bound to Hb/oxygen carrying capacity of Hb x 100%

Question 5

Plateau region of oxyHb curve

Answer 5

reached at PO2 ~ 60 mmHg (97-100% sat)

Question 6

Bohr’s effect

Answer 6

increase in CO2, acidity shifts the dissociation curve to the right, promoting dissociation of O2

Question 7

Factors that shift oxyHB curve to the right

Answer 7

increase in CO2
decrease pH
increase T
increase 2,3 DPG (byproduct of anaerobic metabolism of glucose in RBC)

Question 8

Factors that shift oxyHb curve to the left

Answer 8

CO poisoning (200x affinity)

Question 9

Hb in cyanosis

Answer 9

> 5 g Hb/100 mL unbound to oxygen

Question 10

Distribution of dissolved vs. bicarbonate CO2 vs carbamino proteins

Answer 10

5-10 vs 60 vs 30%

Question 11

Chloride shift

Answer 11

movement of Cl- out of plasma into RBC to allow HCO3- to diffuse into plasma

Question 12

H+ and bicarbonate

Answer 12

bicarbonate diffuses out

H+ cannot diffuse, binds Hb –> reduced affinity for O2 (Bohr’s effect)

Question 13

CO2 dissociation curve

Answer 13

straight line function in the range of normal PaCO2

Question 14

Haldane effect

Answer 14

high PO2 shifts CO2 dissociation curve down (allows blood to load more CO2 with low O2)
deoxyHg binds H+, assists with loading CO2
deoxyHg combines with CO2 to form carbamino compounds

Question 15

Normal Hb amount

Answer 15

15 g Hb / 100 ml blood

Question 16

Normal oxygen carrying capacity of Hb

Answer 16

1.34 ml Hb / g Hb