Question 1

You are using a ventilator circuit that has a tubing compliance of 3 mL/cmH₂O. The peak pressure is 30 cmH₂O, and the measured exhaled volume is 760 mL. What is the corrected volume?

Accepted Answer

The answer of You are using a ventilator circuit that...

Question 2

The pathology of your patient changes such that more secretions are produced and bronchospasm occurs. Airway caliber decreases by one-half. What happens to airway resistance?

Accepted Answer

According to Poiseuille's law, airway resistance is inversely proportional to the fourth power of the radius (or diameter) of the airway. Therefore, if the airway caliber decreases by one-half, the resistance increases by 2^4, which equals 16 times.

Question 3

Resistance is defined as:

Accepted Answer

Resistance in a physical context, especially in fluid dynamics and electrical circuits, is defined as the opposition to flow. In the case of electrical circuits, it's the opposition to the flow of electric current, and in fluid dynamics, it's the opposition to the flow of fluids. The formula given in option C, pressure divided by flow, aligns with the definition of resistance in contexts such as blood flow through vessels, where resistance is calculated as the pressure difference across the vessel divided by the flow rate of blood through it.

Question 4

Compliance is defined as:

Accepted Answer

Compliance is the ability of a structure to expand or contract in response to changes in volume. It is defined as the change in volume divided by the change in pressure. Therefore, the correct answer is B, which is volume divided by pressure.

Question 5

Which of the following modes of ventilation maintains spontaneous breathing?

Accepted Answer

The answer of Which of the following modes of ventilation...

Question 6

During pressure control, which of the following variables are set by the clinician?
I. Volume
II.Pressure
III.Flow
IV.Inspiratory time

Accepted Answer

The answer of During pressure control, which of the following...

Question 7

Which of the following are considered drive mechanisms:
I. pistons
II. bellows
III. compressors
IV. pneumatic circuits

Accepted Answer

Drive mechanisms are systems or devices that convert energy into mechanical motion to perform work. Pistons, bellows, and compressors are direct examples of devices that can create motion or force, making them drive mechanisms. Pneumatic circuits, which use compressed air to transmit and control energy, also qualify as they are integral in driving various mechanical systems, hence all options are considered drive mechanisms.

Question 8

The diaphragm is responsible for what percentage of the thoracic volume increase during inspiration?

Accepted Answer

The diaphragm is responsible for about 75% of the thoracic volume increase during inspiration, as it contracts and moves downward, enlarging the chest cavity and allowing the lungs to expand.

Question 9

The load required that a mechanical ventilator must overcome includes which of the following: I.	Elastic properties of the lungs
II.	Resistance properties of the lung
III.	The compliance of the lung

Accepted Answer

The load required that a mechanical ventilator must overcome includes all three options listed: elastic properties of the lungs, resistance properties of the lung, and the compliance of the lung. Therefore, choice D, "I, II, and III only" is the best answer.

Question 10

The primary difference between pressure support and CPAP is:

Accepted Answer

Pressure support provides a set pressure that augments spontaneous breaths, while CPAP maintains a constant pressure throughout inspiration and expiration. CPAP does not provide pressure support during inspiration only and does not allow the clinician to set a rate. Although CPAP does allow the clinician to set a baseline pressure, this is not the primary difference between the two modes.

Question 11

A mode of ventilation in which two CPAP levels are set and the patient may breathe spontaneously from both CPAP levels is termed:

Accepted Answer

Airway Pressure Release Ventilation (APRV) is a mode of ventilation that allows two levels of CPAP, enabling spontaneous breathing at both levels.

Question 12

During normal quiet ventilation, pleural pressures change by approximately:

Accepted Answer

During normal quiet ventilation, pleural pressures change by approximately 3 - 6 cmH2O.

Question 13

Which of the following is/are the primary muscle(s) of ventilation? 
I.	Diaphragm
II.	External intercostals
III.	Scalene
IV.	Pectoralis major

Accepted Answer

The answer of Which of the following is/are the primary...

Question 14

During volume control, which of the following variables are set by the clinician?
I. Volume
II.Pressure
III.Flow
IV.Inspiratory time

Accepted Answer

Volume and inspiratory time are set by the clinician during volume control.

Question 15

The pressure difference between the mouth and alveoli is termed the:

Accepted Answer

Transairway pressure is the pressure difference between the mouth and the alveoli, reflecting the resistance air must overcome to enter or leave the lungs.

Question 16

You are using a ventilator circuit that has a tubing compliance of 4 mL/cmH₂O. The peak pressure is 30 cmH₂O, and the measured exhaled volume is 760 mL. What is the corrected volume?

Accepted Answer

The answer of You are using a ventilator circuit that...

Question 17

The pressure difference between the alveoli and the pleural space is termed the:

Accepted Answer

The pressure difference between the alveoli and the pleural space is known as transpulmonary pressure. It is important for maintaining lung recoil and expansion during respiration.

Quiz 7: Mechanical Ventilator Theory and Classification

You are using a ventilator circuit that has a tubing compliance of 3 mL/cmH2O. The peak pressure is 30 cmH2O, and the measured exhaled volume is 760 mL. What is the corrected volume?

The pathology of your patient changes such that more secretions are produced and bronchospasm occurs. Airway caliber decreases by one-half. What happens to airway resistance?

Resistance is defined as:

Compliance is defined as:

Which of the following modes of ventilation maintains spontaneous breathing?

During pressure control, which of the following variables are set by the clinician? I. Volume II.Pressure III.Flow IV.Inspiratory time

Which of the following are considered drive mechanisms: I. pistons II. bellows III. compressors IV. pneumatic circuits

The diaphragm is responsible for what percentage of the thoracic volume increase during inspiration?

The load required that a mechanical ventilator must overcome includes which of the following: I. Elastic properties of the lungs II. Resistance properties of the lung III. The compliance of the lung