Functional Residual Capacity Flashcards Preview

Apex 1 - 2 Respiratory II: Physiology (24) > Functional Residual Capacity > Flashcards

Flashcards in Functional Residual Capacity Deck (31)
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1

The volume of air in the lungs at end-expiration is known as:

Functional residual capacity (FRC)

2

Functional Residual Capacity =

FRC

=

Residual volume + Expiratory reserve volume

3

The normal FRC in mL/kg is:

35 mL/kg

4

At FRC, the inward elastic recoil of the lungs is balanced by the outward elastic recoil of the chest wall - this is called:

Static equilibrium

5

True or False

Diaphragmatic tone and position also affect FRC

True

Diaphragmatic tone and position also affect FRC

6

The reservoir of oxygen that prevents hypoxemia during apnea is known as:

 

FRC

7

FRC can be measured indirectly by

Nitrogen washout

Helium wash-in

Body Plet-Hysmo-graphy

8

FRC cannot be measured with spirometry, because

Residual volume (RV) cannot be exhaled

and

RV is a component of the FRC

9

How do Conditions that reduce FRC affect outward lung expansion

Reduce outward lung expansion

10

How do Conditions that reduce FRC affect lung compliance?

Reduce lung compliance

11

When FRC is reduced, which lung zone increases?

Zone III (intrapulmonary shunt)

12

How does General Anesthesia decrease FRC?

Diaphragm shifts cephalad ~ 4 cm as a result of decreased inspiratory muscle tone and increased expiratory muscle tone

13

Why does Diaphragm shift cephalad with General anesthesia?

 

Decreased inspiratory muscle tone
and

Increased expiratory muscle tone

14

How does Obesity decrease FRC?

Decreased chest  wall compliance

Increased airway collapsibility

15

How does pregnancy decrease FRC?

Diaphragm shifts cephalad

(as a result of the gravid uterus)

Decreased Chest wall compliance

16

Why is FRC decreased in Neonates?

Fewer alveoli -->  Decreased lung compliance

Cartilaginous rib cage that is prone to collapse

17

Why is FRC increased with Advanced age?

Decreased elastic lung Tissue --> Air trapping

--> Increased RV --> Increased FRC

 

18

Why do position changes alter FRC?

Changes in the position of the diaphragm
 

19

How does gravity affect FRC?

 

Gravity alters the

Distribution of pulmonary blood flow

20

Which positions decrease FRC?

Supine

Lithotomy

Trendelenburg

 


 

21

Which positions increase FRC?

Prone (COVI-19 patients)

Sitting

22

Which position slightly increases FRC or does affect it by much?

Lateral

23

How does Paralysis decrease FRC?

Diaphragm moves cephalad

--> Decreased lung volumes

24

How does Inadequate Anesthesia decrease FRC?

Straining

--> Forceful expiration

--> Decreased lung volumes

25

How do Excessive IV fluids decrease FRC?

Fluid accumulation

(in the dependent lung favors zone 3)

26

How does High FiO2 decrease FRC?

Absorption atelectasis

--> Conversion of low V/Q unit

--> Shunt unit

27

Conditions that Reduced Pulmonary Compliance and lead to a decrease in FRC include:

Acute lung injury

Pulmonary edema

Pulmonary fibrosis

Atelectasis

Pleural effusion

28

How does Obstructive Lung Disease increase FRC?

Air trapping

--> Inc. RV --> Inc. FRC

29

How does PEEP increase FRC?

Recruits collapsed alveoli

Partially overcomes effects of GA

Dec. venous admixture --> Pa02

30

How do Sigh breaths increase FRC?

Recruit collapsed alveoli