Lung lecture 3

Question 1

Because lungs go downhill after age 20, what is considered normal PaO2 for elderly person?

Answer 1

~80 mmHg

Question 2

Normal pulmonary interstitial pressure (Pis)

Answer 2

-8 mmHg

higher than systemic d/t lymphatics + negative thoracic pressure

Question 3

Normal interstitial osmotic pressure (πis)

Answer 3

14mmHg (about double systemic)

Question 4

Normal pulmonary capillary pressure (Pc)

Answer 4

7mmHg

Question 5

Normal blood oncotic pressure (πpl)

Answer 5

28 mmHg

Question 6

Increasing ventilation without increasing blood flow will _____ O2 and _____ CO2

Answer 6

increase O2 and decrease CO2

Question 7

Increasing blood flow while keeping ventilation the same will _____ PAO2 and _____ PACO2

Answer 7

decrease O2, increase CO2

Question 8

Normal minute ventilation (VT)

Answer 8

6L/min

Question 9

Equation for minute ventilation

Answer 9

V̇T= VE= VT x BPM
tidal volume x breaths per min

Question 10

Physiologic deadspace vs. alveolar dead space

Answer 10

P= both normal anatomical plus alveolar dead space

A= deadspace within the lung.

abnormal, airflow and gas to alveoli but no perfusion (ex = PE)

some decrease is expected with age

Question 11

Overtime, positive pressure ventilation can ______ alveolar dead space

Answer 11

increase

Question 12

Normal minute deadspace ventilation

Answer 12

1.8L/min

Question 13

Normal Alveolar minute ventilation

Answer 13

4.2L/min

Question 14

If alveolar deadspace increases, what is done to compensate

Answer 14

increase ventilation

Question 15

Net filtration in pulmonary capillaries

Answer 15

1 mmHg

Question 16

Which factors favor filtration

Answer 16

Pc, Pis, πis

Question 17

which factors oppose filtration

Answer 17

blood oncotic pressure (πpl)

Question 18

Pulmonary edema doesn’t become a problem until left atrial pressure reaches

Answer 18

~23 mmHg

Question 19

What starling factor changes in ARDS, oxygen toxicity, and inhaled toxins that increase pulmonary edema

Answer 19

increased capillary permeability (Kf)

Question 20

Which starling factor changes from inc. LA pressure from MI or mitral stenosis that increases pulmonary edema

Answer 20

increased capillary hydrostatic pressure (Pc)

Question 21

Which starling factor changes due to rapid evacuation of pneumothorax or hemothorax that increases pulmonary edema

Answer 21

decreased interstitial hydrostatic pressure (Pis)

Question 22

Which starling factor changes due to protein starvation, dilution of blood from IV fluids, proteinuria that increase pulmonary edema

Answer 22

decreased colloid osmotic pressure (πpl)

Question 23

At FRC, pleural pressures are ____ at the base of the lung, and ____ at the apex of the lung

Answer 23

-1.5 cmH2O, -8.5 cmH2O

Question 24

At FRC, the alveoli at the apex of the lung are ___% full

Answer 24

60%

Question 25

At FRC, the alveoli at the base of the lung are ___% full

Answer 25

25%

Question 26

At FRC, the alveoli at the base of the lung are _____ compliant than the alveoli at the apex

Answer 26

more

Question 27

At RV, the alveoli at the base of the lung are _____ compliant than the alveoli at the apex

Answer 27

less

Question 28

At RV, the alveoli at the base of the lung are ___% full

Answer 28

20%

Question 29

At RV, the alveoli at the apex of the lung are ___% full

Answer 29

30%

Question 30

At RV, pleural pressures are ____ at the base of the lung, and ____ at the apex of the lung

Answer 30

+4.8 cmH2O, -2.2 cmH2O

Question 31

Lung compliance under GA is similar to when the lung volume is at ____

Answer 31

RV

Question 32

Transpulmonary pressures at RV

Answer 32

apex: 2.2 cmH2O base: -4.8 cmH2O

Question 33

Transpulmonary pressures at FRC

Answer 33

apex: 8.5 cmH2O base: 1.5 cmH2O

Question 34

At RV, the lung fills up from ____ to ____ during inspiration

Answer 34

top to bottom

Question 35

Are lungs more compliant during inspiration or expiration?

Answer 35

Expiration

Question 36

V/Q matching occurs because of what?

Answer 36

Pleural pressure gradient - more neg at top, more pos at base Transpulmonary pressure higher at top and lower at base

Question 37

Alveoli at the top of the lung are ____ than the alveoli at the base of the lung

Answer 37

larger - less compliant

Question 38

Where are the 2 smooth muscles that change lung ventilation and perfusion?

Answer 38

- pulmonary BV smooth muscle upstream of capillaries - airway smooth muscle

Question 39

Lower alveolar PO2 causes upstream

Answer 39

vasoconstriction - hypoxic pulmonary vasoconstriction (HPV)

Question 40

Increased alveolar PCO2 causes upstream

Answer 40

vasoconstriction

Question 41

How do volatiles affect HPV? How is this mediated?

Answer 41

Turns off this compensatory mechanism - vasodilation Supplemental oxygen

Question 42

Why do airways constrict when PAO2 is high?

Answer 42

To prevent alveolar dead space ventilation

Question 43

How do lung volumes change when supine?

Answer 43

FRC decreased to 2 L ERV reduced and IRV expands

Question 44

Basic spirometry can measure what?

Answer 44

Tidal volume, ERV, IRV, and vital capacity