Dead Space and Vd/Vt Flashcards Preview

Apex 1 - 2 Respiratory II: Physiology (24) > Dead Space and Vd/Vt > Flashcards

Flashcards in Dead Space and Vd/Vt Deck (65)
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1

Which conditions will MOST likely increase the PaCO2 to EtCO2 gradient? (Select 3.)

Study on!!!

2

Air confined to the conducting airways is called:

Anatomic Dead space (Vd)

3

Examples of Anatomic Dead space (Vd):

Nose/mouth --> Terminal bronchioles

4

Alveoli that are ventilated but not perfused constitute ----- Dead Space

Alveolar Dead Space (Vd)

5

A ----- pulmonary blood flow creates Alveolar Dead Space (Vd)

"reduced"

6

Anatomic Vd + Alveolar Vd = ----- Dead Space (Vd)

Physiologic Dead Space (Vd)

7

Example of Physiologic Dead Space (Vd)

Variable

8

Dead space (Vd) added by equipment is known as:

Apparatus Dead Space (Vd)

9

Apparatus or equipment that contribute to Apparatus Dead Space (Vd) include:

Face mask

Heat moisture exchanger

10

The fraction of the tidal volume that contributes to dead space is determined by the ----- to ----- ratio

Dead Space to Tidal Volume Ratio

(Vd/Vt ratio)

11

Dead Space to Tidal Volume Ratio (Vd/Vt) is affected by factors that alter Dead space and the ------- relationship

V/Q relationship

12

In the spontaneously ventilating 70 kg patient, we assume that dead space is ---- mL/kg or ---- mL.

2 mL/kg or 150 mL

13

In the spontaneously ventilating 70 kg patient, we assume that Vt is ----- mL

Vt = 450 mL

14

In the spontaneously ventilating patient, we assume that dead space is 2 ml/kg or 150 ml in a 70 kg patient.

Therefore Vd/Vt  =   

Vd/Vt  =   150 ml/450 ml   = 0.33

15

Mechanical ventilation ----- alveolar pressure

 

 

"increases"

 

 

16

Mechanical ventilation increases alveolar pressure, which ----- ventilation relative to perfusion

 

 

"increases"

17

Mechanical ventilation increases alveolar pressure, which increases ventilation relative to perfusion. This explains why Vd/Vt increases to --- or --- %  with mechanical ventilation

 

0.50 or 50%

18

Anything that increases the Vd/Vt ratio ----- dead space (Vd)
 

"increases"

 

19

Anything that increases the Vd/Vt ratio increases dead space (Vd) and by extension -----  alveolar ventilation

"reduces"

(Recall that alveolar ventilation [VA = (Vt - Vd) x RR])

20

The most common cause of increased Vd/Vt under general anesthesia is a ----- Cardiac output

"reduced"

21

If the EtC02 acutely decreases, you should first rule out ----- before considering other causes of increased dead space

A. Hypotension

B. Hypertension

Hypotension

22

When thinking about Vd, consider how things change the volume of the conducting airway relative to pulmonary blood flow. For example, an LMA reduces Vd because it -----  much of the anatomic Vd between the mouth to the glottis

"Bypasses"

23

When thinking about Vd, consider how things change the volume of the conducting airway relative to pulmonary blood flow. For example, Atropine increases Vd, because its ----- action increases the volume of the conducting airway

Bronchodilator action

24

When thinking about Vd, consider how things change the volume of the conducting airway relative to pulmonary blood flow. For example, Neck extension increases Vd, because it opens the hypopharynx and ----- its volume

"increases"

25

Airway pieces of equipment that increase Vd:

Facemask

HME

PPV

26

Airway pieces of equipment that decrease Vd:

ETT

LMA

Tracheostomy

27

Drugs that increase Vd:

Anticholinergics (bronchodilation)

28

Age group with increased Vd:

Old age

29

Neck position that increases Vd:

Neck Extension

30

Neck position that decreases Vd:

Neck Flexion