Ventilation Flashcards Preview

Apex 1 - 2 Respiratory II: Physiology (24) > Ventilation > Flashcards

Flashcards in Ventilation Deck (26)
Loading flashcards...
1

What is the primary determinant of carbon dioxide elimination?

Study on!!!

2

The process of exchanging gas between the atmosphere and the lungs is called:

Ventilation

3

Ventilation supports the acquisition of ----- to support aerobic metabolism

Oxygen

4

Ventilation supports the removal of ----- the waste product of aerobic metabolism

 

CO2

5

A tidal volume (Vt) contains one volume of gas in the -------- zone and another in the ------- zone.

Conducting zone and another in the

Respiratory zone

6

Gas that does not participate in gas exchange is called:

Dead space (Vd)

7

Dead space (Vd) normally approximately ----- mL/kg or -------- mL in a 70 kg patient.

2 mL/kg or 150 mL in a 70 kg patient

8

When the patient exhales, which gas is removed first?

Dead space gas

9

Any condition that ----- dead space (Vd) makes it more difficult to eliminate expiratory gases from the lungs

"increases"

10

Increased Vd ----- the PaC02-EtCO2 gradient

'widens"

11

Increased Vd widens the PaC02-EtCO2 gradient and causes ----- retention

CO2 retention

12

The amount of air in a single breath multiplied by the number of breaths per minute is called:

Minute ventilation (VE)

13

How is Minute Ventilation (VE) calculated?

Minute Ventilation = Tidal volume x Resp.Rate

or

VE  =  Vt  x RR

14

If a patient has a Vt of 500 mL with a rate of 10 b/m, then his VE=?

VE= 500 mL x 10 b/ min = 5000 mL/min

15

Which value removes anatomic dead space gas from the minute ventilation equation and therefore only measures the fraction of VE that is available for gas exchange?

Alveolar ventilation (VA)

16

How is Alveolar ventilation (VA) calculated?

Alveolar Ventilation = (Tidal Volume - Anatomic Dead Space) x Respiratory Rate

VA = (Vt - Vd) x RR

17

If a patient has a Vt of 500 ml with a rate of 10 b/m, then his VE= 500 ml x 10 b/ min = 5000 ml/min.

If the same patient has 150 ml of dead space, then his alveolar ventilation is:

(500 - 150) x 10 = 3,500 ml/min

18

Another way to conceptualize VA is to relate it to

PaC02

19

How does VA relate to CO2 production?

VA is directly proportional to carbon dioxide production

20

How does VA relate to PaCO2?

VA is inversely proportional to PaC02

21

How is Alveolar Ventilation (VA) calculated based on CO2 production and paCO2?

VA = (CO2 production / PaCO2)

22

What is the primary determinant of carbon dioxide elimination?

Alveolar ventilation

VA = (Vt - Vd) x RR

23

Alveolar ventilation (NOT minute ventilation) determines the rate of removal of carbon dioxide from the body. Let's examine why...

Shall we!!!?

24

Minute ventilation (VE) = ?

Minute ventilation = Tidal volume x Respiratory rate

VE = Vt x RR

But not all this participates in gas exchange

This doesn't take Dead space (Vd) into account

25

References:

 

Hall . Guyton and Hall Textbook of Medical Physiology. 12th ed. 2011. p. 471 -472 . Stoelting . Pharmacology and Physiology in Anesthetic Practice. 4th ed. 2006 . p. 778.

26

Alveolar ventilation (VA) = ?

Alveolar ventilation = (Tidal volume - Dead space) x Respiratory rate

VA = (Vt - Vd) x RR

The key here is to recognize that dead space doesn't contribute to gas exchange, so only the fraction of the tidal volume that reaches the respiratory zone contributes to gas exchange