Question 1

If a patient has a tidal volume of 450 mL, what is the approximate alveolar volume?&#10;A) 100 mL&#10;B) 150 mL&#10;C) 200 mL&#10;D) 300 mL&#10;

Accepted Answer

For example, if a normal 150 lb adult has a V_T of 500 mL and V_D/V_T equals 0.33, then 33% of the V_T is dead space; the remaining 67% of the V_T must be alveolar volume.

Question 2

What is the partial pressure of carbon dioxide in atmospheric air?&#10;A) 0.228 mm Hg&#10;B) 159 mm Hg&#10;C) 47 mm Hg&#10;D) 149 mm Hg&#10;

Accepted Answer

The partial pressure of carbon dioxide (PCO₂) is calculated as follows: PCO₂ = 0.0003 ´ 760 mm Hg = 0.228 mm Hg

Question 3

V_E is the product of which of the following parameters? A) V_T and V_C B) V_D and f C) V_T and f D) V_D and V_T

Accepted Answer

Regardless of the measuring method, V_E is the product of V_T and breathing frequency (f) per minute (V_E = V_T x f). For example, if V_T is 500 mL and breathing frequency is 12 breaths per minute, V_E is calculated as follows: V_E = 500 mL x 12/minV_E = 6000 mL/min or 6.0 L/minV_Eis easy to measure but is not extremely useful in evaluating the amount of ventilation that participates in respiration at the alveolar level.

Question 4

Normally, approximately what percentage of the V_E is dead-space ventilation? A) 5% to 10% B) 15% to 20% C) 20% to 30% D) 30% to 40%

Accepted Answer

Dead-space ventilation constitutes approximately 30% to 40% of the V_E.

Question 5

What is the approximate amount of anatomical dead space in normal adults?&#10;A) 1 mL/pound IBW&#10;B) 2 mL/pound IBW&#10;C) 3 mL/pound IBW&#10;D) 4 mL/pound IBW&#10;

Accepted Answer

V_Danat is related to lung size; in normal adults, anatomical dead space is approximately 1 mL per pound of ideal body weight.

Question 6

Which of the following gases is utilized in the measurement of V_Danat? A) Carbon dioxide B) Oxygen C) Nitrogen D) Carbogen

Accepted Answer

V_Danat is the volume exhaled that results from the sharp rise in N₂%.

Question 7

Which of the following terms defines the conducting airways from the mouth and nose down to and including terminal bronchioles?&#10;A) Physiological dead space&#10;B) Anatomical dead space&#10;C) Anatomical tidal volume&#10;D) Gas exchange units&#10;

Accepted Answer

The conducting airways from the mouth and nose down to and including terminal bronchioles constitute the anatomical dead space (V_Danat).

Question 8

Which of the following determine the PCO₂ of alveolar gas and thus the PCO₂ of the blood leaving the lung?
I.Metabolic CO₂ production per minute
II.VA
III.CO₂ rate of elimination
IV.pH

A) I, II, III
B) II, III
C) I, II, III, IV
D) II, III, IV

Accepted Answer

The balance between metabolic CO₂ production per minute (VCO₂) and its rate of elimination (VA) determines the PCO₂ of alveolar gas and thus the PCO₂ of the blood leaving the lung.

Question 9

What is the amount of CO₂ produced under normal resting conditions? A) 50 mL B) 100 mL C) 150 mL D) 200 mL

Accepted Answer

Under normal resting conditions, the body produces approximately 200 mL of CO₂ each minute and alveolar ventilation is approximately 4 L/min.

Question 10

If a VA of 5 L/min produces a P_ACO₂ of 40 mm Hg, a VA of 10 L/min will produce what level of PACO₂? A) 80 mm Hg B) 40 mm Hg C) 20 mm Hg D) 10 mm Hg

Accepted Answer

P_ACO₂ is inversely related to VA; if VA is reduced by half, P_ACO₂doubles. If VA doubles, P_ACO₂ (and P_aCO₂) is reduced by half. For example, if a VA of 5 L/min produces a P_ACO₂ of 40 mm Hg, a VA of 10 L/min produces a P_ACO₂of 20 mm Hg.

Question 11

A 55-year-old woman is admitted to the hospital in obvious respiratory distress.Her increased rate and depth of breathing have raised her minute ventilation from 10 to 15 L/min.Arterial blood gases show a normal P_aCO₂ of 40 mm Hg.It seems odd that this woman, with a minute ventilation this great, has a normal P_aCO₂.What is the explanation for this?

A) There is an increase in alveolar ventilation.
B) This change in minute ventilation has little impact on the PaCO2; therefore, P_aCO₂ is normal.
C) This patient's dead space has decreased.
D) A normal P_aCO₂ associated with high minute ventilation indicates that much of this patient's ventilation is not in contact with blood flow.

Accepted Answer

The answer of A 55-year-old woman is admitted to the...

Question 12

Normally, approximately what percentage of the inspired VT remains in conducting airways, never reaching alveoli?&#10;A) 5% to 10%&#10;B) 15% to 20%&#10;C) 20% to 30%&#10;D) 30% to 40%&#10;

Accepted Answer

The answer of Normally, approximately what percentage of the inspired...

Question 13

What is the partial pressure of water vapor at 37&#176;C and 100% relative humidity (RH)?&#10;A) 0.228 mm Hg&#10;B) 159 mm Hg&#10;C) 47 mm Hg&#10;D) 149 mm Hg&#10;

Accepted Answer

The answer of What is the partial pressure of water...

Question 14

What is the partial pressure of oxygen in atmospheric air?&#10;A) 0.228 mm Hg&#10;B) 159 mm Hg&#10;C) 47 mm Hg&#10;D) 149 mm Hg&#10;

Accepted Answer

The answer of What is the partial pressure of oxygen...

Question 15

What is the partial pressure of oxygen in the lung's airways?&#10;A) 0.228 mm Hg&#10;B) 159 mm Hg&#10;C) 47 mm Hg&#10;D) 149 mm Hg&#10;

Accepted Answer

The answer of What is the partial pressure of oxygen...

Question 16

What happens to anatomical dead space if a patient is mechanically ventilated through a tracheostomy tube?&#10;A) It is reduced.&#10;B) It is increased.&#10;C) It is unchanged if the cuff is inflated.&#10;D) It is unchanged if fenestration has been done.&#10;

Accepted Answer

The answer of What happens to anatomical dead space if...

Question 17

Which technique allows a more precise measurement of V_Danat? A) Dubowitz B) Ballard's C) Boyle's D) Fowler

Accepted Answer

The answer of Which technique allows a more precise measurement...

Question 18

The end-tidal PCO₂ is a reflection of which of the following? A) Mixed-expired PCO₂ B) Mixed-inspired PCO₂ C) Alveolar gas composition D) Arterial gas composition

Accepted Answer

The answer of The end-tidal PCO₂ is a reflection of...

Question 19

Which of the following terms describes the rise in P_aCO₂ above normal? A) Normal ventilation B) Hypocapnia C) Hypercapnia D) Acidosis

Accepted Answer

The answer of Which of the following terms describes the...

Question 20

Which of the following are characteristics of the anatomical dead space?
I.It changes when a part of a lung is surgically removed.
II.It increases when an artificial airway bypasses the upper airway.
III.It increases during deep inspiration.
IV.It increases with emphysema.

A) I, IV
B) II, III, IV
C) I, II, III, IV
D) II, IV

Accepted Answer

The answer of Which of the following are characteristics of...

Question 21

Which of the following breathing patterns is a common signal of respiratory distress and possible ventilatory failure?&#10;A) Rapid, shallow breathing&#10;B) Tachypnea&#10;C) Bradypnea&#10;D) Dyspnea&#10;

Accepted Answer

The answer of Which of the following breathing patterns is...

Question 22

Gas exchange can be maintained with tidal volumes smaller than dead space and high frequencies.What type of ventilation can accomplish this?&#10;A) Rapid, shallow, spontaneous breathing&#10;B) High-frequency ventilation&#10;C) Hyperventilation&#10;D) Dead space ventilation&#10;

Accepted Answer

The answer of Gas exchange can be maintained with tidal...

Question 23

Which of the following breathing patterns is the most efficient in improving alveolar ventilation?&#10;A) Rapid, shallow breathing&#10;B) Rapid, deep breathing&#10;C) Slow, deep breathing&#10;D) Slow, shallow breathing&#10;

Accepted Answer

The answer of Which of the following breathing patterns is...

Deck 4: Ventilation