Question 1

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

Accepted Answer

Airway resistance is inversely proportional to the fourth power of the radius (Poiseuille's Law). Therefore, if the radius is reduced by 50%, the resistance increases by 16 times (2^4).

Question 2

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

Accepted Answer

PSV helps reduce the work of breathing by providing additional pressure during inspiration, which compensates for increased airflow resistance.

Question 3

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

Accepted Answer

The pressure gradient (ΔP) in the compliance and airway resistance equations represents the work of breathing, as it is the pressure difference driving airflow and volume changes in the respiratory system.

Question 4

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

Accepted Answer

Ventilatory failure occurs when the respiratory system cannot eliminate carbon dioxide at a rate that matches its production, leading to hypercapnia.

Question 5

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

Accepted Answer

The pressure-volume waveform is used to evaluate compliance changes during mechanical ventilation, as it directly relates pressure to volume, allowing for assessment of lung compliance.

Question 6

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

Accepted Answer

A decrease in the PIP-P_plat gradient indicates a decrease in airflow resistance, as this gradient reflects the resistance to airflow in the airways.

Question 7

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

Accepted Answer

An increasing plateau pressure during volume-controlled ventilation suggests decreasing lung compliance, as the pressure needed to maintain the same volume increases when the lungs become stiffer.

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?

Accepted Answer

An increase in peak inspiratory pressure during volume-controlled ventilation can be due to either increasing airflow resistance (e.g., due to bronchospasm, secretions, or kinked tubing) or decreasing lung compliance (e.g., due to pulmonary edema, pneumothorax, or atelectasis).

Question 9

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

Accepted Answer

Pausing the flow at end inspiration allows for the measurement of plateau pressure, which is used to calculate static lung compliance, thereby evaluating a patient's lung compliance.

Question 10

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

Accepted Answer

Dynamic compliance is calculated using the corrected tidal volume divided by the difference between peak inspiratory pressure and PEEP.

Question 11

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

Accepted Answer

Emphysema is characterized by the destruction of alveolar walls, leading to increased lung compliance as the lungs become more distensible.

Question 12

Which of the following pressure changes is consistent with atelectasis?

Accepted Answer

Atelectasis leads to decreased lung compliance, which results in an increase in both plateau pressure (P_plat) and peak inspiratory pressure (PIP) due to the lungs being stiffer and harder to inflate.

Question 13

Which of the following pressure changes correlates with acute bronchospasm?

Accepted Answer

Acute bronchospasm increases airway resistance, leading to an increase in peak inspiratory pressure (PIP) while plateau pressure (P_plat) remains unchanged.

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?

Accepted Answer

P_plat is the plateau pressure, which is the pressure in the alveoli at the end of inspiration. PIP is the peak inspiratory pressure, which is the highest pressure in the alveoli during inspiration. As the patient's lung consolidation and bronchospasm resolve, the resistance to airflow decreases. This allows the alveoli to fill more easily, which decreases P_plat. The decrease in resistance also allows the ventilator to deliver the same volume of air with a lower PIP.

Question 15

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

Accepted Answer

Rapid shallow breathing increases dead space ventilation, leading to a V̇/Q̇ mismatch as more ventilation goes to areas of the lung that do not participate in gas exchange.

Question 16

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

Accepted Answer

Hypoventilation is a condition in which the rate of ventilation is inadequate to meet the metabolic demands of the body. This results in an increase in PaCO2, which is a measure of the partial pressure of carbon dioxide in the blood.

Question 17

Refractory hypoxemia is usually caused by:

Accepted Answer

Refractory hypoxemia is often due to intrapulmonary shunting, where blood bypasses ventilated alveoli, leading to poor oxygenation despite increased oxygen delivery.

Question 18

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

Accepted Answer

The gas diffusion rate across the alveolocapillary membrane is influenced by the thickness of the membrane, the surface area available for diffusion, the gas pressure gradient, and the capillary blood flow.

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:

Accepted Answer

The symptoms of shortness of breath, cyanosis, diminished sensorium, bradycardia, and hypotension are indicative of hypoxia, which is a deficiency in the amount of oxygen reaching the tissues.

Question 20

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

Accepted Answer

Gas exchange abnormalities can be caused by V̇/Q̇ mismatch, hypoventilation, diffusion defects, and shunting. These factors can impair the ability of the lungs to properly exchange oxygen and carbon dioxide.

Quiz 1: Principles of Mechanical Ventilation

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

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

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

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

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

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

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

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?

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

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

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

Which of the following pressure changes is consistent with atelectasis?

Which of the following pressure changes correlates with acute bronchospasm?

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

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

Refractory hypoxemia is usually caused by:

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

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:

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

Quiz 1: Principles of Mechanical Ventilation

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

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

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

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

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

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

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

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?

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

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

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

Which of the following pressure changes is consistent with atelectasis?

Which of the following pressure changes correlates with acute bronchospasm?

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

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

Refractory hypoxemia is usually caused by:

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

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:

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

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