More Nitty gritty facts on exam 1

Question 1

What causes Hypercapnia

Answer 1

Hypoventilation

Question 2

Why do diffusion limitations not cause hypercapnia?

Answer 2

CO2 diffuses much faster than O2 – diffusion limitations will cause lethal hypoxemia before significant hypercapnia

Question 3

What is the outcome of right to left shunts?

Answer 3

Hypoxemia

Question 4

What are the 3 ways to affect oxygen consumption?

Answer 4

1. Inc CaO2: not an option, only can do this by inc Hb (blood doping)
2. Dec CvO2: extract more O2 from blood (exercise)
3. Inc CO: inc SV or HR (exercise)

Question 5

What are some respiratory conditions that limit oxygen consumption?

Answer 5

1. Inadequate O2 in Inspired Air – high altitude
2. Inadequate alveolar ventilation
3. Pulmonary diffusion limitation
4. Right to Left Shunts

Question 6

Why are R-L shunts dangerous?

Answer 6

They don’t remove CO2 and can’t acquire oxygen; Causing hypoxemia

Question 7

Discuss the Ventilation-Perfusion Mismatch

Answer 7

Excessive blood flow for the amount of oxygen ventilation. Normal especially in upright position

Question 8

Discuss the effects of gravity on Ventilation

Answer 8

Superior (apical) alveoli are more distended than inferior (basal) alveoli
Inferior alveoli increase in size more than superior alveoli w/ inspiration

Question 9

How does ventilation change as you go down the lung?

Answer 9

It increases; to have V-Q matching, pulmonary blood flow would have to inc from superior to inferior w/in the lung

Question 10

Discuss the effects of gravity on perfusion?

Answer 10

Pulmonary vessels are more distended in the inferior (basal) regions of the lung than in the superior (apical) regions
Resistance is lowered inferiorly, causing inc blood flow inferiorly

Question 11

How does the body compensate for the ventilation-perfusion mismatch?

Answer 11

Hypoxic vasoconstriction; Blood flow is limited to poorly ventilated regions of the lungs

Question 12

What are some non-respiratory conditions that limit oxygen consumption?

Answer 12

1. Abnormal oxygen carrying capacity

2. Inability to increase CO

Question 13

Discuss Anemia and Polycythemia in oxygen consumption

Answer 13

Anemia = low [Hb, DOES NOT cause decreased Hb saturation or hypoxemia]

Polycythemia = high [Hb], DOES NOT cause increased Hb saturation or hyperoxemia

Question 14

How does breathing in oxygen enriched air help pts?

Answer 14

1. Increases oxygen in inspired air (PiO2)

2. Increases alveolar and arterial oxygen.

Question 15

Which pts would oxygen enriched air be helpful in ?

Answer 15

1. Hypoventilated pts
2. Diffusion limitations
3. V-Q mismatches
4. CO poisoning

Question 16

What does oxygen enriched air not help with?

Answer 16

Does not CORRECT hypoventilation, hypercapnia, or respiratory acidosis