Deck 5: Ventilation and Ventilatory Control Tests

Question 1

Which of the following tests requires a variable CO₂ scrubbing device in the breathing circuit?

A) Dead space determination
B) Closed-circuit O₂ response test
C) Closed-circuit CO₂ response test
D) Open-circuit CO₂ response test

Answer 1

B

Question 2

When preparing for a CO₂ response test,the technologist should fill the rebreathing bag with which of the following concentrations?

A) Oxygen 21%,CO₂ 7%,Balance N₂
B) Oxygen 90%,CO₂ 10%
C) Oxygen 93%,CO₂ 7%
D) Oxygen 21%,CO₂ 10%,Balance N₂

Answer 2

C

Question 3

Which of the following parameters should be measured to assess the adequacy of the output of the respiratory centers?

A) PaCO₂
B) PaO₂
C) V_D/V_T
D) P₁₀₀

Answer 3

D

Question 4

A subject has the following data recorded during a rebreathing O₂ (hypoxic)response test: These findings are consistent with which of the following?

A) A normal ventilatory response to hypoxemia
B) A blunted ventilatory response to hypoxemia
C) An improperly calibrated pneumotachometer
D) A malfunctioning end-tidal CO₂ analyzer

Question 5

A subject has the following results after 4.0 minutes of a CO₂ rebreathing test: These findings are consistent with which of the following?

A) Normal lung function
B) Obesity-hypoventilation syndrome
C) Chronic asthma
D) Interstitial pulmonary fibrosis

Question 6

All of the following are end-of-test criteria for a CO₂ response except:

A) Test duration of 4 minutes
B) PETCO₂ $\geq$ 9%
C) Patient intolerance
D) End-tidal CO₂ $\geq$ 75 mm Hg

Question 7

What is the subject's tidal volume (V_T)?

A) 493 ml (BTPS)
B) 577 ml (BTPS)
C) 1011 ml (BTPS)
D) 2292 ml (BTPS)

Question 8

A subject performing a closed-circuit hypoxic response test abruptly stops the test and complains of dizziness.This is most likely because of:

A) Inadequate scrubbing of CO₂
B) Failure to maintain eucapnia
C) Incomplete gas mixing in the circuit
D) Excessive resistance in the circuit

Question 9

Exhaled gas is collected for 5 minutes;the mixed expired PCO₂ is measured.Blood gases are drawn during the last minute of gas collection,and the following data are recorded: What is this subject's V_D/V_T ratio?

A) 0.75
B) 0.33
C) 0.25
D) 0.11

Question 10

A subject has the following results after 4 minutes of a CO₂ rebreathing test: These findings are consistent with a ventilatory response that is:

A) Markedly reduced
B) Slightly reduced
C) Normal
D) Extremely high

Question 11

Sodium hydroxide crystals (Sodasorb)are used to scrub CO₂ from a rebreathing circuit.What is the color these crystals change to when they are fully depleted?

A) Violet
B) Blue
C) Red
D) White

Question 12

A subject's tidal breathing is measured at 720 ml,with a respiratory rate of 12.Assuming a dead space of 150 ml,what is the subject's alveolar volume? Temperature 19 $\degree$ C BTPS conversion factor 1.111

A) 7.60 L
B) 6.84 L
C) 8.64 L
D) 9.60 L

Question 13

What is the subject's V_D/V_T%?

A) 15%
B) 25%
C) 33%
D) 40%

Question 14

A circuit is set up to perform a CO₂ rebreathing response test.The reservoir bag in the circuit should contain which of the following?

A) Room air
B) 3% CO₂ in air
C) 7% CO₂ in O₂
D) 100% O₂

Question 15

What is the calculated V_D/V_T ratio,given the following variables?

A) 10.7%
B) 9.6%
C) 12%
D) 15%

Question 16

A subject has the following data recorded during a rebreathing CO₂ response test: These findings are consistent with:

A) A decreased ventilatory response
B) A normal ventilatory response
C) An improperly calibrated pneumotachometer
D) A malfunctioning end-tidal CO₂ analyzer

Question 17

A patient with COPD has the following data recorded: What is this subject's V_T?

A) 0.42 L (BTPS)
B) 0.33 L (BTPS)
C) 0.23 L (BTPS)
D) 0.14 L (BTPS)

Question 18

The V_D/V_T ratio may be estimated noninvasively by measuring which of the following?

A) V_T and mixed expired PCO₂
B) Mixed expired PCO₂ and end-tidal PCO₂
C) End-tidal PCO₂ and V_T
D) Arterial PCO₂ and mixed expired PCO₂

Question 19

Which of the following statements best describes the measurement P₁₀₀ or P_0.1?

A) Pressure measure at 100 mm Hg during CO₂ response test
B) Occlusion pressure measured at 10 msec during a hypoxic challenge test
C) Pressure measured at 100 msec during a CO₂ response test
D) The oxygen saturation level at which the partial pressure of oxygen is 100 mm Hg

Question 20

P₁₀₀ is the:

A) Ventilation in liters per minute when the patient is breathing 100% O₂
B) PETCO₂ when the subject is breathing 100 L/min
C) Pressure developed during the first 100 msec of an occluded breath
D) Mean alveolar pressure extrapolated to a respiratory rate of 100/min

Question 21

The high altitude simulation test is used to predict hypoxemia in individuals:

A) Climbing mountains to 2000 ft
B) Climbing mountains to 4000 ft
C) Flying at 6000 ft
D) Flying at 8000 ft

Question 22

The diagram shows the graphic data from a CO₂ response test.On the basis of the gross change,what physiologic response do these data represent?

A) Blunted CO₂ response
B) 3.5 L/min/mm Hg
C) Normal response
D) 0.5 L/min/mm Hg

Question 23

All of the following would cause an increased V_D/V_T ratio except:

A) Exercise
B) COPD
C) Pulmonary hypertension
D) Pulmonary embolism

Question 24

What formula can you use to estimate dead space?

A) 1 ml per pound of ideal body weight
B) 2 ml per pound of ideal body weight
C) 1 ml per kg of ideal body weight
D) 5 ml per kg of ideal body weight