Deck 1: Principles of Mechanical Ventilation

Question 1

Airway resistance is an important concept in mechanical ventilation, because when the airway radius is reduced by 50% airflow resistance increases by:

A) 2 times.
B) 4 times.
C) 8 times.
D) 16 times.

Answer 1

D

Question 2

For mechanically ventilated patients, pressure support ventilation (PSV) is useful to compensate for the increased work of breathing due to:

A) airflow resistance.
B) compliance.
C) respiratory muscle fatigue.
D) ventilation/perfusion mismatch.

Answer 2

A

Question 3

What does the pressure gradient (ΔP) represent in the compliance (C = ∆V/∆P) and airway resistance (R = ΔP/V̇) equations?

A) Peak inspiratory pressure
B) Oxygen consumption
C) Work of breathing
D) Metabolic rate

Answer 3

C

Question 4

Ventilatory failure develops when the patient's minute alveolar ventilation cannot keep up with the:

A) oxygen consumption.
B) carbon dioxide production.
C) acid-base balance.
D) pulmonary perfusion.

Question 5

During mechanical ventilation, one method to evaluate compliance change is to use the:

A) volume-time waveform.
B) pressure-time waveform.
C) pressure-volume waveform.
D) flow-volume waveform.

Question 6

A decrease of the peak inspiratory pressure-plateau pressure (PIP-P_plat) gradient implies that the

A) airflow resistance has increased.
B) airflow resistance has decreased.
C) total compliance has increased.
D) total compliance has decreased.

Question 7

During volume-controlled ventilation, a patient's plateau pressure has been increasing over the past 3 hours. This is indicative of:

A) increasing airflow resistance.
B) decreasing airflow resistance.
C) increasing compliance.
D) decreasing compliance.

Question 8

During volume-controlled ventilation, a patient's peak inspiratory pressure has been increasing over the past 8 hours. What is the cause of this change?

A) Increasing airflow resistance or decreasing compliance
B) Decreasing airflow resistance or increasing compliance
C) Increasing airflow resistance
D) Decreasing compliance

Question 9

During mechanical ventilation, the flow is paused momentarily at end inspiration. This maneuver is done to:

A) evaluate a patient's lung compliance.
B) evaluate a patient's airway resistance.
C) obtain the peak inspiratory pressure.
D) obtain the dynamic compliance.

Question 10

The equation corrected tidal volume/(peak inspiratory pressure − PEEP) is used to calculate the patient's:

A) static compliance.
B) dynamic compliance.
C) airway resistance.
D) transpulmonary pressure.

Question 11

A higher than normal lung compliance is often seen in patients with:

A) tension pneumothorax.
B) acute respiratory distress syndrome.
C) emphysema.
D) atelectasis.

Question 12

Which of the following pressure changes is consistent with atelectasis?

A) Increase in P_plat, increase in PIP
B) Decrease in P_plat, decrease in PIP
C) No change in P_plat, increase in PIP
D) No change in P_plat, decrease in PIP

Question 13

Which of the following pressure changes correlates with acute bronchospasm?

A) Increase in P_plat, decrease in PIP
B) No change in P_plat, increase in PIP
C) No change in P_plat, decrease in PIP
D) Decrease in P_plat, no change in PIP

Question 14

A mechanically ventilated patient has shown significant clinical improvement. The lung consolidation and bronchospasm are almost completely resolved. Which of the following demonstrates the patient's improvement?

A) Decrease in P_plat, large decrease in PIP
B) No change in P_plat, decrease in PIP
C) Increase in P_plat, large increase in PIP
D) Decrease in P_plat, increase in PIP

Question 15

A rapid shallow breathing pattern leads to V̇/Q̇ mismatch due to a(n):

A) decrease in lung compliance.
B) increase in airflow resistance.
C) decrease in cardiac output.
D) increase in dead space ventilation.

Question 16

Hypoventilation is a condition that results in a(n):

A) decrease in pH.
B) decrease in PaO₂.
C) increase in PaCO₂.
D) increase in cardiac output.

Question 17

Refractory hypoxemia is usually caused by:

A) intrapulmonary shunting.
B) hypoventilation.
C) cardiac arrest.
D) dead space ventilation.

Question 18

Which of the following factors at the alveolocapillary membrane affect the gas diffusion rate?

A) Capillary flow, surface area, gas pressure gradient
B) Thickness, capillary flow, surface area
C) Thickness, surface area, gas pressure gradient
D) Thickness, capillary flow, surface area, gas pressure gradient

Question 19

A patient arrives at the emergency department with complaint of shortness of breath. She also shows cyanosis, diminished sensorium, bradycardia, and hypotension. Based on this information, the patient is most likely to have:

A) a mental disorder.
B) hypoxia.
C) hyperventilation.
D) COPD.

Question 20

Gas exchange abnormalities may be caused by which of the following conditions?

A) V̇/Q̇ mismatch, diffusion defects, shunting
B) V̇/Q̇ mismatch, hypoventilation, diffusion defects, shunting
C) Hypoventilation, diffusion defects, shunting
D) V̇/Q̇ mismatch, hypoventilation, shunting

Question 21

Conditions leading to mechanical ventilation may include all of the following except:

A) excessive ventilatory workload.
B) gas exchange abnormalities.
C) eucapnic respiratory drive.
D) failure of the ventilatory pump.