Exam 6: Arterial Blood Gas Analysis

Question 1

What is blood gas analysis?

Answer 1

The direct measurement of oxygen and carbon dioxide dissolved in blood

Question 2

What can you get from an arterial sample?

Answer 2

Oxygenation (lung function)

Question 3

What is arterial blood gas analysis the gold standard for?

Answer 3

Evaluating both oxygenation and ventilation

Question 4

Is there a physical exam parameter that can evaluate oxygenation and ventilation?

Answer 4

No

Question 5

What is hypoxemia?

Answer 5

Deficient oxygenation of the blood

Question 6

What is the PaO2 of absolute hypoxemia?

Answer 6

Less than 80 mmHg

Question 7

Where can you get an arterial blood sample?

Answer 7

Dorsal pedal

Question 8

What are the possible sampling errors?

Answer 8

AVERT
Air
Venous sampling
Excessive anticoagulant
Rate of metabolism
Temperature

Question 9

What are all gases subject to?

Answer 9

Atmospheric pressure

Question 10

What is Dalton’s Law of Partial pressure?

Answer 10

Total pressure of a gas is equal to the sum of its individual components

Question 11

What happens to oxygen as altitude increases?

Answer 11

Less is available for gas exchange

Question 12

Any pathophysiologic process that disrupts normal lung function will cause hypoxemia via what?

Answer 12

Venous admixture

Question 13

What are the 3 causes of hypoxemia?

Answer 13

Low FIO2
Hypoventilation
Venous admixture

Question 14

What is the PaO2 with hypoxemia? SpO2?

Answer 14

Less than 80 mmHg

Less than 95%

Question 15

What is the PaO2 when oxygen is needed? SpO2?

Answer 15

Less than 70 mmHg

Less than 93%

Question 16

What is the PaO2 with severe hypoxemia? SpO2?

Answer 16

Less than 60 mmHg

Less than 90%

Question 17

What are the 3 reasons that indicate ventilator support outside of anesthesia?

Answer 17

PaO2 is less than 60 mmHg despite oxygen supplementation
PaCO2 is more than 60 mmHg despite supportive therapies
Respiratory fatigue or impending failure

Question 18

Describe the rule of 120

Answer 18

If PaO2 + PaCO2 is more than 120 mmHg, hypoventilation alone is causing the hypoxemia
If PaO2 + PaCO2 is less than 120 mmHg, venous admixture is also present