Module 4 Gas Exchange

Question 1

Two types of external respiration?

Answer 1

Pulmonary ventilation (breathing)

Pulmonary gas exchange

Question 2

2 aspects of Internal transport of gases? (hint internal respiration)

Answer 2

Via Blood:
-Systemic tissue gas exchange
-cellular respiration

Question 3

Where is O2 and CO2 exchanged?

Answer 3

Alveolar-capillary membrane

Question 4

What is considered effective ventilation?

Answer 4

when the bodies needs for O2 uptake are met, AND CO2 removal.

Alternatively as well:
(low consumption of O2 and low production of CO2)

Question 5

Why is ventilation not entirely efficient?

Answer 5

Dead space.

Question 6

Dead space is a portion of inspired air wasted with each breath.

What are 3 types of deadspace?

Answer 6

Anatomic dead space (VDanat)

Alveolar dead space (VDalv)

Physiological dead space (VDphy)

Question 7

Anatomic Dead Space

Answer 7

Gas left in the conducting airways; Does not patriciate in gas exchange.

(oropharynx, trachea, and airways)

Question 8

Alveolar Dead Space

Answer 8

Alveoli that are ventilated but have no perfusion; No Gas exchange.

(alveoli are ventilated but not perfused)

Question 9

Physiologic Dead Space

Answer 9

The sum of anatomic and alveolar dead space

Question 10

How do you calculate ventilation?

Answer 10

Probably just understand it. Don’t worry about this one too much.

Question 11

Tidal Volume

Answer 11

Volume of air that is inhaled/exhaled from the lungs normally (without effort)

Question 12

Minute Ventilation

Answer 12

Total volume moving in or out of the lungs per minute

Question 13

Efficiency of ventilation depends what?

Answer 13

The volume of fresh gas reaching the alveoli.

Question 14

What factors produce alveolar ventilation?

Answer 14

Breathing frequency and alveolar volume per breath

Question 15

Why is alveolar ventilation always less than minute ventilation?

Answer 15

Dead space (VDphy)

Question 16

Calculate VA (add solutions later)

Answer 16

Worse case scenario
- check google docs for solutions.

Question 17

what is “Vd.Vt”?

Answer 17

Ratio of physiologic dead space over tidal volume.

Question 18

What could cause an increase in VdVT

Answer 18

-Pulmonary embolism
-thrombosis

-vascular obliteration (kinking/clamping of pulmonary artery during surgery)

Status asthmaticus: long-lasting and severe asthma

Question 19

Normal Vd.VT range?

Answer 19

30-40%

Question 20

Generally, what could you say Physiologic dead space could result from?

Answer 20

Shunt

Low ventilation/perfusion (V/Q)

TLDR: if minute ventilation can’t be increased

Question 21

How much does dead space increase for intubated patients?

Answer 21

50%

Question 22

Complete the reaction/path for Dead Space: for every given minute ventilation, the ____ the deadspace, the ____ the CO2 elimnation.

Answer 22

For any given minute ventilation, the GREATER the dead space, and the POORER the CO2 elimnation

Question 23

Why does dead space increase for intubated patients?

Answer 23

increases in ventilated patients is due to positive pressure.

Question 24

What is Vd, Va, MV, and Vd/Vt?

Answer 24

Vd = dead space

Va = alveolar volume

Vd/Vt = how much is going into dead space

MV = min volume/ventilation

Question 25

What is a normal range for Vd/Vt?

Answer 25

30-40%

Question 26

Do equal pressure points limit inspiration flow?

Answer 26

No.

(needs confirmation)
Equal pressure points only happen during expiration

Question 27

What is VQ, and what is its normal range?

Answer 27

V/Q is the amount of air that reaches your lungs divided by the amount of blood flow in the capillaries in your lungs.

Normal Range = 0.8

Question 28

What constant (number) is used for dead space?
-Important-

Answer 28

2.5ml/kg

You have to multiply 2.5 by IBW to get Vd