Week 10 Possibly Important Parameters

Question 1

Normally, how much air after full inhalation can be exhaled in 1 second (FEV1)?

What happens if there is an increase in compliance?

Answer 1

80%

With increased compliance, it takes longer to exhale 80% (same thing happens with increased resistance)

Question 2

What is the formula and values for alveolar pressure in normal inhalation?

Answer 2

Alveolar pressure (0 mmHg) = elastic recoil pressure (5 mmHg) + pleural pressure (-5 mmHg).

Question 3

What are the values for alveolar pressure during full inhalation?

Answer 3

P_alveolar (0 mmHg) = P_elastic (30 mmHg) + P_pleural (-30 mmHg)

Question 4

What are the values for alveolar pressure during maximum exhalation?

What is the flow rate?

Answer 4

P_alveolar (90 mmHg) = P_elastic (30 mmHg) + P_pleural (60 mmHg)

Flow = 15 L/sec

Question 5

How do you calculate the end pressure point (EPP), and what is it?

What is the normal value for the EPP?

Answer 5

This is point when the pressure inside the bronchial system and pleural space are equal

EPP = pleural pressure / alveolar pressure

= 60 / 90 = 0.67

Question 6

What are the values of alveolar pressure with maximum exhalation of a person with emphysema (increased compliance)?

What is their equal pressure point (EPP)?

Answer 6

P_alveolar (75 mmHg) = P_elastic (15 mmHg) + P_pleural (60 mmHg)

EPP = 60/75 = 0.8, which can lead to the dynamic airway compression effect

Question 7

What is the normal O2 partial pressure of inhaled air?

CO2 partial pressure?

Answer 7

O2 = 150-160 mmHg

CO2 = 0.3 (approximately 0)

Question 8

What is the normal O2 partial pressure of the alveoli?

CO2 partial pressure?

Answer 8

O2 = 100 mmHg

CO2 = 40 mmHg

Question 9

What is the normal O2 partial pressure of arteries?

CO2 partial pressure?

Answer 9

O2 = 95 mmHg (notice the slight drop from alveoli!)

CO2 = 40 mmHg

Question 10

What is the normal O2 partial pressure of veins?

CO2 partial pressure?

Answer 10

O2 = 40 mmHg

CO2 = 46 mmHg

Question 11

What is the normal O2 partial pressure of exhaled air?

CO2 partial pressure?

(wasnt stressed in lecture, but potentially important)

Answer 11

O2 = 116 mmHg

CO2 = 32 mmHg

Question 12

What is the normal tidal volume, in reference to its components of dead space volume and alveolar volume?

Answer 12

Tidal volume (500 mL) = dead space (150mL) + alveolar (350 mL)

Question 13

What is the tidal volume ventilation, in reference to its dead space ventilation and alveolar space ventilation?

Answer 13

tidal volume ventilation (7 L) = dead space ventilation (2.1 L) + alveolar ventilation (4.9 L)

you get this by multiplying the normal tidal volume (500 mL) by the normal respiratory rate of 14 breaths / minute

the alveolar ventilation (~5 L) is very important

Question 14

How much CO2 is normally produced when resting?

Answer 14

210 mL / min

Question 15

What is the normal alveolar pCO2, and what results if you go under or over this number?

Answer 15

~40 mmHg pCO2

Below this number = hyperventilation (because you’re breathing off too much CO2)

Above this number = hypoventilation (because you aren’t breathing off enough CO2)

Question 16

How much CO2 can be ventilated out during mild exercise?

Answer 16

750 mL/min

Question 17

What is the blood pressure of the pulmonary arteries?

the MAP?

Answer 17

24/9 mmHg

MAP = 14 mmHg

Question 18

What is the pressure of the driving force in the pulmonary blood circuit, and how do you calculate it?

Answer 18

6 mmHg

because the mean arterial pressure of pulmonary arteries (14) minus the pressure of the left atrium (8) = 6 mmHg

Question 19

What is the cardiac output of the pulmonary circulation?

Answer 19

5.5 L/min, just like the systemic circuit

Question 20

Low pO2 (hypoxia) leads to mean pulmonary artery pressures in what range?

Answer 20

higher than normal! > 14 mmHg

this is opposite from the effects of hypoxia in the systemic circulation. hypoxia causes systemic vasodilation to allow better perfusion to tissues, whereas pulmonary circulation is vasoconstricted to create resistance and slow down flow to allow O2 into alveoli better

Question 21

What are the differences in pleural pressure at the basis versus the apex of the lung?

Answer 21

Basis: -10 cm H2O

Apex: -2 cm H2O