Gas Exchange and Hypoxemia Flashcards Preview

Week 6: Pneumonia and Cough > Gas Exchange and Hypoxemia > Flashcards

Flashcards in Gas Exchange and Hypoxemia Deck (12):
1

Respiratory membrane

The wall of the alveoli, the interstitium, and the wall of the capillary

2

How does CO2 influence bicarbonate serum levels?

More CO2 absorbed = higher serum bicarb levels

3

3 ways CO2 is transported

As bicarb (70%)
Bound to hemoglobin (23%)
Diffused in plasma (7%)

4

Haldane effect

Oxygenated Hb less able to pick up CO2

5

Partial pressure of
1. O2
2. CO2
leaving and entering the lung

1. 100mmHg, 40 mmHg
2. 40 mmHg, 47 mmHg

6

Dead space alveolus

Blocked capillary
V/Q = infinity
Still completely ventilated

7

Shunt alveolus

No fresh gas is delivered to blood (blocked airway)
V/Q = 0

8

Effect of
1. Fraction of O2
2. Arterial CO2
on PAO2

1. High fraction = increased PAO2
2. High PaCO2 = low PAO2

9

Hemoglobin saturation values when PaO2 is at
1. 40
2. 60
3. 90

1. 60%
2. 90%
3. 97%

10

Most clinically important cause of hypoxemia

VQ mistmatch
Seen in pneumonia, heart failure, pulmonary emboli

11

5 causes of hypoexmia (in order of commonality)

1. VQ mismatch
2. Hypoventilation
3. Right-to-left shunt
4. Thickened diffusion barrier
5. Low inspired ppO2

12

Hypoxemia is when PaO2 drops to...

Under 60 mmHg