Gas Transport

Question 1

PATM = 760 mmHg = ?

Answer 1

N2: 597 (78.6%)
O2: 158.4 (20.84%)
CO2: 0.3 (0.04%)
H2O: 3.8 (0.5%)

Question 2

O2 in free solution

Answer 2

PO2 x solubility of O2 in plasma (0.003)

Question 3

What is the PO2 in arterial blood and venous blood?

Answer 3

Arterial: 100 mmHg

Venous: 40 mmHg

Question 4

What is the formula for O2 bound to Hgb?

Answer 4

[hgb] x (O2 binding capacity at 100% saturation (1.34)) x (%saturation)

For arterial blood: 15 g hb(.97)= 19.5

Question 5

What is the formula for O2 content?

Answer 5

O2 in free solution + O2 bound to Hgb

Arterial: 0.3 + 19.5

Question 6

Patient arrives at ER with CO poisoning. Is her PO2 increased?

Answer 6

NO: CO required to cause poisoning is low enough that it doesn’t alter the amount of oxygen dissolved in plasma. Hypoxia, no cyanosis.

Question 7

How do you determine P50?

Answer 7

PO2 at 50% Hgb saturation.

Used to indicate affinity of O2 for Hb.

⬆️P50 = right shift in curve

Question 8

How is CO2 produced by tissue metabolism carried in blood (3)?

Answer 8

1. Bicarbonate (70%)
2. Carbamino-Hgb (23%)
3. Dissolved CO2 (7%)