O2, CO2

Question 1

How much hemoglobin is there in 100ml of blood?

Answer 1

12-15mg

Question 2

Why is CO dangerous?

Answer 2

Higher affinity for hemogloblin than O2

Alters biding affinity of hemoglobin to O2

Question 3

How do you treat CO poisoning?

Answer 3

Treatment with high O2

Question 4

What is the Bohr effect?

Answer 4

CO2/H+ are affecting the affinity of hemoglobin for O2

Question 5

What is the Haldane effect?

Answer 5

O2 is affecting the affinity of hemoglobin for CO2/H+

Question 6

What factors impact diffusion according to Fick’s law?

Answer 6

Proportional to:
Surface Area
Partial pressure difference
Solubility of the gas and molecular weight
Small thickness of tissue

Question 7

In the capillaries, O2 uptake depends on diffusion or blood flow?

Answer 7

Blood flow

Question 8

In the capillaries, CO uptake depends on diffusion or blood flow?

Answer 8

Diffusion

Question 9

We can measure for some disease with CO diffusing capacities (DLCO). High DLCO can be indicative of what?

Answer 9

Increased pulmonary capillary blood volume
Pulmonary hemorrhage
Polycythemia
Asthma

Question 10

We can measure for some disease with CO diffusing capacities (DLCO). Low DLCO can be indicative of what?

Answer 10

Emphysema
Interstitial lung disease
Pulmonary vascular disease
Anemia

Question 11

What is hypoxemia? What is hypoxia?

Answer 11

Low PaO2
Hypoxemia is low O2 in arterial blood
Hypoxia is low O2 at the tissue level

Question 12

What are the causes of hypoxemia (5 elements)?

Answer 12

Decreased PiO2
Hypoventilation
V/Q (ventilation/perfusion) mismatch
Shunt
Diffusion limitation

Question 13

Does physiological dead space cause hypoxemia?

Answer 13

NO

Question 14

What is shunt?

Answer 14

Perfusion, but no ventilation

Question 15

What is dead space?

Answer 15

Ventilation, but no perfusion

Question 16

What is pulmonary shunt? Give some disease examples.

Answer 16

Extreme form of V/Q mismatch, caused by shunt.

Disease: pulmonary edema, consolidation, atelectasis, airway obstruction

Question 17

What is extrapulmonary shunting? Give some disease examples.

Answer 17

V/Q mismatch resulting from the blood bypassing the pulmonary circulation altogether.
Disease: ductus arteriosus, heart septal defects, thebesian veins

Question 18

How can you calculate the physiological dead space?

Answer 18

Using the Bohr method: the more dead space, the more deluded the expired CO2

Question 19

You find that the patient has hypoxemia, but his (A-a)O2 difference is normal. What could be the causes of hypoxemia?

Answer 19

Hyperventilation

Altitude

Question 20

You find that the patient has hypoxemia, but his (A-a)O2 difference is increased. Further, the patient is responsive to breathing 100% oxygen. What could be the cause of hypoxemia?

Answer 20

Low V/Q ratio

Question 21

You find that the patient has hypoxemia, but his (A-a)O2 difference is increased. Further, the patient is not so responsive to breathing 100% oxygen. What could be the causes of hypoxemia?

Answer 21

Shunt