Exam 2 Lecture 12 (3-9-23) Do-over Pulmonary Lecture, Spirometry, V/Q Matching

Question 1

What could be causing the slow slope of the inspiration curve (black dashed line)?

Answer 1

If we have a lack of surfactant, it becomes difficult to put air into the lungs. And what happens when we get down to very low lung volume, usually our surfactant level decreases. And the longer the lung is collapsed or at very low lung volumes, the lower our surfactant concentrations go.

Question 2

The surfactant that floats around in our alveolar fluids typically has a _______ shelf life.

Answer 2

short

Question 3

What are type II alveolar cells?

Answer 3

Alveolar cells that produce surfactant

Question 4

What are type I alveolar cells?

Answer 4

These cells are thin and cover a lot of surface area on the alveoli. They are responsible for gas exchange.

Question 5

During normal breathing, inspiration will generate negative alveolar pressure. What effect will this cause on the surfactants lining the alveoli?

Answer 5

The negative alveolar pressure will cause the surfactant to be knocked loose. This will cause the lungs to replace the lost surfactant.

If the lungs are deflated and don’t have enough negative alveolar pressure, less surfactant will be knocked loose and replaced.

Question 6

In terms of the proportions that make up the elastic recoil of a healthy lung.
_______ of recoil is based on the connective tissue of the lungs.
________ of recoil is based on surface tension.

What will happen to the surface tensions if the lungs lack surfactant?

Answer 6

one-third (connective tissue)
two-thrid (surface tension)

If the lungs lack surfactant, surface tension will play an even larger role in elastic recoil (increased proportion). This will also make it very difficult to fill the alveoli with air.

Question 7

Does positive pressure ventilation affect that process of replacing surfactant?

Answer 7

Yes.

Question 8

Does positive pressure ventilation affect that process of replacing surfactant?

Answer 8

Yes.

Alveolar pressure has to be negative to normally jar some surfactant loose. Breathing on an artificial ventilator is not the same as somebody who’s breathing on their own. With long term vent use, lungs usually start to misbehave.

(52:00)

Question 9

For this graph, why does it require less transpulmonary pressure to fill the lungs up with saline than with air?

Answer 9

The saline filled lungs has a greatly reduce level of surface tension due to a decrease in air-water interface. All the air has been massaged out of the lungs before it was fill with saline. This results in a more compliant lung. (54:00)

Question 10

Compare the hysteresis of the saline filled lung with air filled lung in this graph.

Answer 10

There is no hysteresis with saline filled lung. The lung behaves the same during inspiration vs expiration. For the air filled lung, there is less compliance during inspiration and more compliance during expiration.

Question 11

What cell in the alveolus non-selectively engulfs and destroy pathogens and surfactants?

Answer 11

Alveolar Macrophage (60:00)

Question 12

What is the function of spirometry?

What is the limitation simple spirometry?

Answer 12

Spirometry can measures air movement in and out of the patient.

Spirometry can not measure RV or any capacities that involve RV such as FRC and TLC. (73:00)

Question 13

What indicator is used as a diagnostic measurement of FRC?

How does it work?

Answer 13

Helium (The system usually contains about 10% He)

The test starts with a known concentration of Helium and known volume in the deluxe spirometer system. The patient then takes a few normal breaths in the spirometer to allow Helium to diffuse to the lungs. This will result in a new concentration of He, which can be used to calculate FRC.

(Refer to min 81:00 for math)

Question 14

What were the inert noble gases mentioned in this lecture?

Answer 14

He, Ne, Ar, Kr, Xe, and Rn

Question 15

What is the second leading cause of lung cancer in the US?

Answer 15

Radon

Question 16

What part of the house is more likely to be exposed to Radon?

Answer 16

Radon can pass from the soil to the air in a gaseous form and enter your home. Because your basement is below ground, it’s the first room that radon gas will reach as it rises from the soil to the air. Therefore, the concentration of radon gas in your basement will likely be higher than in any other room of your house.

Question 17

Surface tension is ____________ to elastic recoil.

Answer 17

proportional

Question 18

Surfactant Metabolism: After synthesis in ER and alterations in the Golgi Apparatus, surfactant is packed in multivesicular bodies and stored in the ____________ of type II alveolar cells.

Answer 18

Lamellar Bodies (96:30 and Lange)

Question 19

What is normal alveolar ventilation (VA)?

What is normal perfusion to the lungs?

What is the normal V/Q ration?

Answer 19

VA= 4.2 L/min

Q= 5 L/min

4.2:5 = 0.84 *
“V/Q ratio about 0.8”- Dr. Schmidt

Question 20

Which alveolus depicts normal V/Q matching?

Answer 20

Alveolus A is normal.
PAO2 = 100 mmHg
PACO2 = 40 mmHg

Question 21

Which alveolus depicts airway obstruction? What could be an example of this?

What would gas conditions in the alveolus be equal to?

Answer 21

Alveolus B is depicting airway obstruction. Marble stuck in the mainstem bronchus .

Gas conditions in the alveolus should be equal to mixed venous blood.
PAO2 = 40 mmHg
PACO2 = 45 mmHg

Question 22

Which alveolus depicts blood flow obstruction? What could be an example of this?

What would gas conditions in the alveolus be equal to?

Answer 22

Alveolus C is depicting blood flow obstruction. Pulmonary Embolus.

Gas condition in the alveolus should be equal to inspired gas.
PAO2 = 150 mmHg
PACO2 = 0 mmHg

Question 23

Which alveolus wil have a V/Q ratio of zero?

Answer 23

Alveolus B will have a V/Q of zero.
There will be normal perfusion, but no ventilation.

Question 24

What will be the V/Q ratio of Alveolus C?

Answer 24

If there is normal ventilation, but no perfusion. V/Q ratio comes up as an “ERROR” on the calculator, because the ratio is pretty much infinity. (103:00)

Question 25

What parts of the lung will have a higher V/Q ratio?

What parts of the lugn will have a lower V/Q ratio?

Answer 25

Apex portion of the lung will have a higher than average V/Q ratio.

Base portion of the lung will have a lower than average V/Q ratio. Despite the fact that there is higher perfusion and ventilation at the base of the lung. The V/Q ratio is lower.

(104:00)

Question 26

What will the PO2 and PCO2 look like during expiration if air is coming from the base of lung?

What about if air is expired form the apex of the lung?

Answer 26

Air expired from the base of the lung will have a lower V/Q ratio. PO2 will be lower than normal, PCO2 will be higher than normal.

Air expired from the apex of the lung will have a higher V/Q ratio. PO2 will be higher than normal, PCO2 will be lower than normal.

(105:00)

Question 27

How does age effect V/Q matching?

Answer 27

A young person will have good V/Q matching. As an individual age ventilation rate decreases, thus decreasing the V/Q ratio of the individual.

Question 28

What is used to prevent the lungs from collapsing during anesthesia?

Answer 28

Positive End Expiratory Pressure

Question 29

What is the downside of using too much PEEP (in regards to the heart)?

Answer 29

Overloading the right side of the heart.

Question 30

How does the lung collapse during general anesthesia?

Answer 30

When the patient is supine, there is already a decrease of FRC. With the addition of anesthesia and muscle relaxants there is an even greater loss of volume that can result in sub-residual volume. (112:00)

Question 31

Higher lung volumes correlates with _________ airway resistance.

Answer 31

Lower

As air enters the lungs the alveolus gets larger, but the airways also get larger. A wider airway gives us lower airway resistance. (114:00)

Question 32

What will happen to our airways if we increase our thoracic pressure?

Answer 32

Increasing our thoracic pressure (more positive) will make the airways more narrow, thus increasing resistance.