Deck 1: Basic Terms and Concepts of Mechanical Ventilation

Question 1

An increase in peak inspiratory pressure (PIP)without an increase in plateau pressure (Pₚₗₐₜₑₐᵤ)is associated with which of the following?

A) Increase in static compliance (Cs)
B) Decrease in static compliance (Cs)
C) Increase in airway resistance
D) Decrease in airway resistance

Answer 1

C
The PIP represents the amount of pressure needed to overcome both elastance and airway resistance.The Pₚₗₐₜₑₐᵤ is the amount of pressure required to overcome elastance alone.Since the Pₚₗₐₜₑₐᵤ has remained constant in this situation,the static compliance is unchanged.The difference between the PIP and the Pₚₗₐₜₑₐᵤ is the transairway pressure (Pᴛᴀ)and represents the pressure required to overcome the airway resistance.If Pᴛᴀ increases,the airway resistance is also increasing,when the gas flow rate remains the same.

Question 2

Plateau pressure (Pₚₗₐₜₑₐᵤ)is measured during which phase of the ventilatory cycle?

A) Inspiration
B) End-inspiration
C) Expiration
D) End-expiration

Answer 2

B
The calculation of compliance requires the measurement of the plateau pressure.This pressure measurement is made during no-flow conditions.The airway pressure (Pₐw)is measured at end-inspiration.The inspiratory pressure is taken when the pressure reaches its maximum during a delivered mechanical breath.The pressure that occurs during expiration is a dynamic measurement and drops during expiration.The pressure reading at end-expiration is the baseline pressure; this reading is either at zero (atmospheric pressure)or at above atmospheric pressure (PEEP).

Question 3

The respiratory therapist should expect which of the following findings while ventilating a patient with acute respiratory distress syndrome (ARDS)?

A) An elevated plateau pressure (Pₚₗₐₜₑₐᵤ)
B) A decreased elastic resistance
C) A low peak inspiratory pressure (PIP)
D) A large transairway pressure (Pᴛᴀ) gradient

Answer 3

A
ARDS is a pathological condition that is associated with a reduction in lung compliance.The formula for static compliance (Cs)utilizes the measured plateau pressure (Pₚₗₐₜₑₐᵤ)in its denominator (CS = Vᴛ /(Pₚₗₐₜₑₐᵤ - EEP).Therefore,with a consistent exhaled tidal volume (Vᴛ),an elevated Pₚₗₐₜₑₐᵤ will decrease Cₛ

Question 4

The values below pertain to a patient who is being mechanically ventilated with a measured exhaled tidal volume (Vᴛ)of 700 mL.

Analysis of this data points to which of the following conclusions?

A) Airway resistance is increasing.
B) Airway resistance is decreasing.
C) Lung compliance is increasing.
D) Lung compliance is decreasing.

Question 5

Based upon the following patient information,calculate the patient's static lung compliance: exhaled tidal volume (Vᴛ)is 675 mL,peak inspiratory pressure (PIP)is 28 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)is 8 cm H₂O,and PEEP is set at 5 cm H₂O.

A) 0.02 L/cm H₂O
B) 0.03 L/cm H₂O
C) 0.22 L/cm H₂O
D) 0.34 L/cm H₂O

Question 6

The formula used for the calculation of static compliance (Cs)is which of the following?

A) (Peak inspiratory pressure (PIP) - EEP)/tidal volume (Vᴛ)
B) (Plateau pressure (Pₚₗₐₜₑₐᵤ) - EEP)/tidal volume (Vᴛ)
C) Tidal volume/(plateau pressure - EEP)
D) Tidal volume/(peak pressure (PIP) - plateau pressure (Pₚₗₐₜₑₐᵤ))

Question 7

Calculate airway resistance (Rₐᴡ)for a ventilator patient,in cm H₂O/L/sec,when the peak inspiratory pressure (PIP)is 50 cm H₂O,the plateau pressure (Pₚₗₐₜₑₐᵤ)is 15 cm H₂O,and the set flow rate is 60 L/min.

A) 0.58Rₐᴡ
B) 1.2Rₐᴡ
C) 35Rₐᴡ
D) 50Rₐᴡ

Question 8

The body's mechanism for conducting air in and out of the lungs is known as which of the following?

A) External respiration
B) Internal respiration
C) Spontaneous ventilation
D) Mechanical ventilation

Question 9

Which of the following are involved in external respiration?

A) Red blood cells and body cells
B) Scalenes and trapezius muscles
C) Alveoli and pulmonary capillaries
D) External oblique and transverse abdominal muscles

Question 10

The graph that shows intrapleural pressure changes during normal spontaneous breathing is depicted by which of the following?

A)
B)
C)
D)

Question 11

A patient receiving mechanical ventilation has an exhaled tidal volume (Vᴛ)of 500 mL and a positive end expiratory pressure setting (PEEP)of 5 cm H₂O.Patient-ventilator system checks reveal the following data:

The respiratory therapist should recommend which of the following for this patient?
1)Tracheobronchial suctioning
2)Increase in the set tidal volume
3)Beta adrenergic bronchodilator therapy
4)Increase positive end expiratory pressure

A) 1 and 3 only
B) 2 and 4 only
C) 1, 2, and 3 only
D) 2, 3, and 4 only

Question 12

The patient-ventilator data over the past few hours demonstrates an increased peak inspiratory pressure (PIP)with a constant transairway pressure (Pᴛᴀ).The respiratory therapist should conclude which of the following?

A) Static compliance (Cₛ)has increased.
B) Static compliance (Cₛ)has decreased.
C) Airway resistance (Rₐᴡ) has increased.
D) Airway resistance (Rₐᴡ) has decreased.

Question 13

Which of the following conditions causes pulmonary compliance to increase?

A) Asthma
B) Kyphoscoliosis
C) Emphysema
D) Acute respiratory distress syndrome (ARDS)

Question 14

Calculate the pressure required to achieve a tidal volume of 400 mL for an intubated patient with a respiratory system compliance of 15 mL/cm H₂O.

A) 6 cm H₂O
B) 26.7 cm H₂O
C) 37.5 cm H₂O
D) 41.5 cm H₂O

Question 15

During spontaneous inspiration alveolar pressure (PA)is about: ________________.

A) -1 cm H₂O
B) +1 cm H₂O
C) 0 cm H₂O
D) 5 cm H₂O

Question 16

The pressure required to maintain alveolar inflation is known as which of the following?

A) Transairway pressure (Pᴛᴀ)
B) Transthoracic pressure (Pᴛᴛ)
C) Transrespiratory pressure ( Pᴛʀ)
D) Transpulmonary pressure (Pʟ)

Question 17

Calculate the effective static compliance (Cs)given the following information about a patient receiving mechanical ventilation: peak inspiratory pressure (PIP)is 56 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)is 40 cm H₂O,exhaled tidal volume (Vᴛ)is 650 mL,and positive end expiratory pressure (PEEP)is 10 cm H₂O.

A) 14.1 mL/cm H₂O
B) 16.3 mL/cm H₂O
C) 21.7 mL/cm H₂O
D) 40.6 mL/cm H₂O

Question 18

The term used to describe the tendency of a structure to return to its original form after being stretched or acted on by an outside force is which of the following?

A) Elastance
B) Compliance
C) Viscous resistance
D) Distending pressure

Question 19

The condition that is associated with an increase in airway resistance is which of the following?

A) Pulmonary edema
B) Bronchospasm
C) Fibrosis
D) Ascites

Question 20

Calculate the pressure needed to overcome airway resistance during positive-pressure ventilation when the proximal airway pressure (PAw)is 35 cm H₂O and the alveolar pressure (PA)is 5 cm H₂O.

A) 7 cm H₂O
B) 30 cm H₂O
C) 40 cm H₂O
D) 175 cm H₂O

Question 21

Air accidentally trapped in the lungs due to mechanical ventilation is known as which of the following?

A) Plateau pressure (Pₚₗₐₜₑₐᵤ)
B) Functional residual capacity (FRC)
C) Extrinsic positive end expiratory pressure (extrinsic PEEP)
D) Intrinsic positive end expiratory pressure (intrinsic PEEP)

Question 22

Calculate the static compliance (Cs),in mL/cm H₂O,when PIP is 26 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)is 19 cm H₂O,baseline pressure is 5 cm H₂O,and exhaled tidal volume (Vᴛ)is 425 mL.

A) 16
B) 20
C) 22
D) 30

Question 23

Calculate the inspiratory time necessary to ensure 98% of the volume is delivered to a patient with a Cs = 40 mL/cm H₂O and the Rₐᴡ = 1 cm H₂O/(L/sec).

A) 0.04 second
B) 0.16 second
C) 1.6 second
D) 4.0 seconds

Question 24

Which of the following statements best defines elastance?

A) Ability of a structure to stretch.
B) Ability of a structure to return to its natural shape after stretching.
C) Ability of a structure to stretch and remain in that position.
D) Ability of a structure to fill and empty during static conditions.

Question 25

The statement that describes the alveolus shown in Figure 1-1 is which of the following?

1)Requires more time to fill than a normal alveolus.
2)Fills more quickly than a normal alveolus.
3)Requires more volume to fill than a normal alveolus.
4)More pressure is needed to achieve a normal volume.

A) 1 and 3 only
B) 2 and 4 only
C) 2 and 3 only
D) 1, 3, and 4

Question 26

Use this figure to compute the static compliance for an intubated patient with an inspiratory flow rate set at 70 L/min.

A) 0.2 cm H₂O/(L/sec)
B) 11.7 cm H₂O/(L/sec)
C) 16.7 cm H₂O/(L/sec)
D) 20 cm H₂O/(L/sec)

Question 27

Compute the inspiratory time necessary to ensure 100% of the volume is delivered to an intubated patient with a Cs = 60 mL/cm H₂O and the Rₐᴡ = 6 cm H₂O/(L/sec).

A) 0.36 second
B) 0.5 second
C) 1.4 second
D) 1.8 second

Question 28

What type of ventilator increases transpulmonary pressure (Pʟ)by mimicking the normal mechanism for inspiration?

A) Positive-pressure ventilation (PPV)
B) Negative-pressure ventilation (NPV)
C) High frequency oscillatory ventilation (HFOV)
D) High frequency positive-pressure ventilation (HFPPV)

Question 29

The transairway pressure (Pᴛᴀ)shown in this figure is which of the following?

A) 5 cm H₂O
B) 10 cm H₂O
C) 20 cm H₂O
D) 30 cm H₂O

Question 30

Evaluate the combinations of compliance and resistance and select the combination that will cause the lungs to empty slowest.

A) CS = 0.05 L/cm H₂O Rₐᴡ= 2 cm H₂O/(L/sec)
B) CS = 0.05 L/cm H₂O Rₐᴡ= 6 cm H₂O/(L/sec)
C) CS = 0.03 L/cm H₂O Rₐᴡ= 5 cm H₂O/(L/sec)
D) CS = 0.03 L/cm H₂O Rₐᴡ= 8 cm H₂O/(L/sec)

Question 31

The ventilator that functions most physiologically uses which of the following?

A) Open loop
B) Double circuit
C) Positive pressure
D) Negative pressure

Question 32

Use this figure to compute the static compliance (Cs)for an intubated patient with an exhaled tidal volume (Vᴛ)of 500 mL.

A) 14 mL/cm H₂O
B) 20 mL/cm H₂O
C) 33 mL/cm H₂O
D) 50 mL/cm H₂O

Question 33

Calculate the static compliance (Cs),in mL/cm H₂O,when PIP is 47 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)is 27 cm H₂O,baseline pressure is 10 cm H₂O,and exhaled tidal volume (Vᴛ)is 725 mL.

A) 43 CS
B) 36 CS
C) 20 CS
D) 0.065 CS

Question 34

How many time constants are necessary for 95% of the tidal volume (Vᴛ)to be delivered from a mechanical ventilator?

A) 1
B) 2
C) 3
D) 4

Question 35

Calculate airway resistance (Rₐᴡ)for a ventilator patient,in cm H₂O/L/sec,with the following information: Peak inspiratory pressure (PIP)is 20 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)is 15 cm H₂O,PEEP is 5 cm H₂O,and set flow rate is 50 L/min.

A) 5Rₐᴡ
B) 6Rₐᴡ
C) 10Rₐᴡ
D) 15Rₐᴡ

Question 36

Evaluate the combinations of compliance and resistance and select the combination that will cause the lungs to fill fastest.

A) Cs = 0.1 L/cm H₂O Rₐᴡ= 1 cm H₂O/(L/sec)
B) Cs = 0.1 L/cm H₂O Rₐᴡ= 10 cm H₂O/(L/sec)
C) Cs = 0.03 L/cm H₂O Rₐᴡ= 1 cm H₂O/(L/sec)
D) Cs = 0.03 L/cm H₂O Rₐᴡ= 10 cm H₂O/(L/sec)