Deck 45: Mechanical Ventilators

Question 1

The volume waveform generated by a ventilator remains the same against changing lung mechanics. Which of the following parameters might this device be controlling?
1) Volume
2) Flow
3) Pressure

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

Answer 1

A

Question 2

Which of the following equations best describes the pressure (P) necessary to drive gas into the airway and inflate the lungs?

A) P = (Elastance . Volume) + (Resistance . Flow)
B) P = (Elastance - Volume) + (Resistance ÷ Flow)
C) P = (Volume + Compliance) + (Resistance ÷ Flow)
D) P = (Volume ÷ Compliance) - (Resistance . Flow)

Answer 2

P = (Elastance . Volume) + (Resistance . Flow)

Question 3

According to the equation of motion of the respiratory system, a ventilator can control which of the following variables?
1) Volume
2) Resistance
3) Pressure
4) Flow

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

Answer 3

D

Question 4

A ventilator's pressure waveform changes when a patient's lung mechanics change, but its volume waveform remains the same. The device does not directly control the delivered volume. What is this ventilator?

A) Volume controller
B) Pressure controller
C) Time controller
D) Flow controller

Question 5

Which of the following are characteristics of a ventilator that function as a true volume controller?
1) Its pressure waveform changes with changes in lung mechanics.
2) It measures and uses volume to control the volume waveform.
3) Its volume waveform stays constant with changes in lung mechanics.

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

Question 6

If the pressure waveform of a ventilator remains the same when a patient's lung mechanics change, then what is the ventilator?

A) Volume controller
B) Pressure controller
C) Time controller
D) Flow controller

Question 7

During mechanical ventilation, what variable causes a breath to end?

A) Limit
B) Cycle
C) Trigger
D) Baseline

Question 8

Which of the following major categories of ventilator function are useful in classifying ventilators?
1) Control system
2) Power transmission and conversion
3) Output
4) Input

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

Question 9

Types of output control valves used in modern ventilators include which of the following?
1) Pneumatic diaphragm valve
2) Proportional valve
3) Electromagnetic poppet or plunger
4) Linear screw valve

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

Question 10

Which of the following ventilators is controlled by fluidic logic systems?

A) Siemens Servo 300
B) Bio-Med MVP-10
C) Bird 8400ST
D) Bear 1000

Question 11

During volume control ventilation, the clinician has control over which of the following?
1) Pressure waveform
2) Volume waveform
3) Flow waveform

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

Question 12

Primary drive mechanisms used by modern ventilators include which of the following?
1) Compressed gas or reducing valve
2) Hydraulic or fluidic compressor
3) Electrical motor or compressor

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

Question 13

During mechanical ventilation, what variable causes a breath to begin?

A) Limit
B) Cycle
C) Trigger
D) Baseline

Question 14

A complete ventilatory cycle or breath consists of which of the following phases?
1) Expiration
2) Initiation of inspiration
3) Inspiration
4) End of inspiration

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

Question 15

Which of the following are true of the relationship between flow and volume?
1) Volume is the integral of flow.
2) Volume is the derivative of flow.
3) Flow is the derivative of volume.

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

Question 16

For which of the following uses might you consider the use of a purely pneumatically powered ventilator?
1) As a backup to electrically powered ventilators
2) When electrical device cannot be used (e.g., magnetic resonance imaging)
3) During certain types of patient transport

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

Question 17

A ventilator can derive its input power from which of the following sources?
1) Alternating current (AC) electricity
2) Battery
3) Pneumatic

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

Question 18

How would a ventilatory support device that uses pressure regulators, needle valves, and balloon valves to regulate most or all of the parameters of ventilation be classified?

A) Mechanically controlled
B) Electronically controlled
C) Fluidically controlled
D) Pneumatically controlled

Question 19

Which of the following types of ventilators would you select for use during an MRI procedure?
1) Electronically controlled
2) Pneumatically controlled
3) Fluidically controlled
4) Electrically controlled

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

Question 20

The respiratory therapist has been called to transport a patient from the emergency department to obtain a CT scan. Which of the following types of ventilator should the therapist chose to transport the patient?

A) Electric
B) Apneuistic
C) Pneumatic
D) Electronic

Question 21

In which of the following modes inspiration ends when flow decays to some preset value?

A) Intermittent mandatory ventilation
B) Pressure support ventilation
C) Continuous mandatory ventilation
D) Airway pressure release ventilation

Question 22

A physician requests that you switch from pressure-triggering a patient to flow-triggering. Which of the following new settings would be appropriate?

A) Base flow = 0 L/min; trigger at 2 L/min
B) Base flow = 10 L/min; trigger at -2 cm H₂O
C) Base flow = 10 L/min; trigger at 2 L/min
D) Base flow = 0 L/min; trigger at 10 cm H₂O

Question 23

A patient receiving time-triggered continuous mechanical ventilation at a preset rate of 10/min stops breathing. Which of the following will occur?

A) The high-pressure limit alarm will sound (if properly set).
B) The patient will continue to receive 10 breaths/min.
C) The low tidal volume (V_T) alarm will sound (if properly set).
D) Ventilation will drop to zero and the apnea alarm will sound.

Question 24

Compared to using pressure as the trigger variable, what is the major advantage of flow-triggering?

A) Decreased work of breathing
B) Improved minute ventilation (V_E)
C) Decreased physiologic dead space
D) Improved arterial oxygenation

Question 25

To describe what happens during the expiratory phase of mechanical ventilation, you must know the value of which variable?

A) Limit
B) Cycle
C) Trigger
D) Baseline

Question 26

When using pressure as the trigger variable, where do you typically set the trigger level?

A) 0.5 to 1.5 cm H₂O below the baseline expiratory pressure
B) 0.5 to 1.5 cm H₂O above the baseline expiratory pressure
C) 2.0 to 3.5 cm H₂O below the baseline expiratory pressure
D) 2.0 to 3.5 cm H₂O above the baseline expiratory pressure

Question 27

When you adjust the pressure drop necessary to trigger a breath on a ventilator, what are you adjusting on the machine?

A) Sensitivity
B) Pressure limit
C) Mode setting
D) Positive end expiratory pressure (PEEP) level

Question 28

Pure time-triggered ventilation is the same as what type of ventilation?

A) Assist
B) Intermittent mandatory ventilation
C) Assist and control
D) Proportional assist

Question 29

A volume-cycled ventilator has a rate knob for setting the controlled frequency of breathing. If this control is set to 12/min, which of the following other settings will determine the inspiratory and expiratory times?
1) FiO₂
2) Flow
3) Volume

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

Question 30

What parameter serves as the baseline variable on all modern ventilators?

A) Pressure
B) Flow
C) Time
D) Volume

Question 31

Flow serves as a limit variable whenever a ventilator controls what?

A) Pressure
B) Flow
C) Time
D) Volume

Question 32

You observe that a ventilator reaches a preset pressure early in inspiration but holds it for a specific time, after which inspiration ends. What mode of ventilatory support is in force?

A) Time cycled
B) Pressure limited
C) Pressure cycled
D) Volume limited

Question 33

Which of the following is false about the application of flow triggering on a mechanical ventilator?

A) The ventilator measures both input and output flow.
B) Between patient breaths, input flow exceeds output flow.
C) A relative drop in output flow triggers the machine to turn on.
D) Gas flows continuously through the ventilator circuit.

Question 34

If a patient initiates a ventilator breath, the trigger variable could be which of the following?
1) Pressure
2) Flow
3) Time
4) Volume

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

Question 35

Which of the following parameters can serve as the cycle variable during ventilatory support?
1) Volume
2) Pressure
3) Flow
4) Time

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

Question 36

A volume-cycled ventilator provides gas under positive pressure during inspiration until what point?

A) The patient receives a preselected volume of gas.
B) An adjustable, preselected airway pressure is reached.
C) The inspiratory time equals or exceeds the expiratory time.
D) A preselected volume of gas is expelled from the device.

Question 37

What ventilatory variable reaches and maintains a preset level before inspiration ends?

A) Limit
B) Cycle
C) Trigger
D) Baseline

Question 38

If a ventilator, not the patient, initiates a breath, what is the trigger variable?

A) Time
B) Pressure
C) Flow
D) Volume

Question 39

A time-cycled constant flow generator is set up with a flow of 35 L/min and an inspiratory time of 1.7 sec. What is the approximate V_T?

A) 750 ml (0.75 L)
B) 1000 ml (1.00 L)
C) 1900 ml (1.90 L)
D) 1200 ml (1.20 L)

Question 40

What is the name of a breath where a patient is able to change the inspiratory time?

A) Patient cycled
B) Patient triggered
C) Machine triggered
D) Machine cycled

Question 41

What is the mode of ventilatory support in which patient's inspiratory efforts are augmented with a set amount of positive airway pressure?

A) Intermittent mandatory ventilation
B) Continuous mandatory ventilation (CMV)
C) Pressure support ventilation (PSV)
D) Positive end expiratory pressure (PEEP)

Question 42

Mean airway pressure is highest with what waveform?

A) Rectangular flow
B) Rectangular pressure
C) Ascending ramp flow
D) Sinusoidal flow

Question 43

During volume-targeted ventilation, which of the following settings determine the machine-delivered minute volume?
1) Volume
2) Flow
3) Rate

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

Question 44

During volume-targeted ventilation, which of the following settings determine I:E ratio?
1) Volume
2) Flow
3) Rate

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

Question 45

Which of the following ventilator control systems are considered closed loop?
1) Orientation based
2) Servo
3) Adaptive
4) Optimal

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

Question 46

A patient is receiving continuous mandatory ventilation in the control mode at a rate of 15/min. The expiratory time is 2.9 sec. What is the inspiratory time?

A) 1.1 sec
B) 1.3 sec
C) 1.5 sec
D) 1.7 sec

Question 47

Which of the closed-loop controllers is used by all ventilators?

A) Set point
B) Auto set point
C) Adaptive
D) Servo

Question 48

Which of the following provides clinicians with measured or calculated date related to ventilatory support over time?

A) Waveforms
B) Trends
C) Compliance
D) Minute ventilation

Question 49

While observing a patient receiving ventilatory support, you notice that all delivered breaths are initiated or terminated by the machine. Which of the following modes of ventilatory support is in force?

A) Intermittent mandatory ventilation
B) Partial ventilatory support
C) Continuous mandatory ventilation
D) Continuous spontaneous ventilation

Question 50

While observing a patient receiving ventilatory support, you notice that some delivered breaths are begun or ended by the machine, whereas others are begun and ended by the patient. Which of the following modes of ventilatory support is in force?

A) Intermittent mandatory ventilation (IMV)
B) Pressure support ventilation
C) Continuous mandatory ventilation (CMV)
D) Airway pressure release ventilation

Question 51

During volume-targeted ventilation, which of the following settings determine the inspiratory time?
1) Volume
2) Flow
3) Rate

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

Question 52

During volume-targeted ventilation, which of the following settings determine the expiratory time?
1) Volume
2) Flow
3) Rate

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

Question 53

During mechanical ventilation, a mandatory breath is defined as one that is:

A) initiated or terminated by the machine.
B) initiated and terminated by the machine.
C) initiated and terminated by the patient.
D) begun according to a preset time interval.

Question 54

What is the primary physiological effect of positive end expiratory pressure (PEEP)?

A) Increase the functional residual capacity (FRC).
B) Increase the inspiratory reserve volume (IRV).
C) Decrease the compliance of the lung (C_L).
D) Increase the length of expiration.

Question 55

A patient receiving continuous mandatory ventilation in the control mode has an inspiratory time of 1.5 sec and an expiratory time of 2.5 sec. What is the frequency of breathing?

A) 10/min
B) 12/min
C) 15/min
D) 18/min

Question 56

What is the application of pressure above atmospheric at the airway throughout expiration during mechanical ventilation?

A) Positive end expiratory pressure (PEEP)
B) Pressure support ventilation
C) Continuous mandatory ventilation (CMV)
D) Continuous positive airway pressure (CPAP)

Question 57

Which of the following modes is a good example of adaptive control?

A) Intermittent mandatory ventilation
B) Airway pressure release ventilation
C) Continuous mandatory ventilation (CMV)
D) Pressure-regulated volume control (PRVC)

Question 58

During mechanical ventilation, a spontaneous breath is defined as one that:

A) initiated and terminated by the machine.
B) begun by the patient and ended by the machine.
C) initiated and terminated by the patient.
D) begun by the machine and ended by the patient.

Question 59

A mode that allows spontaneously breathing patients to breathe at a positive-pressure level, but drops briefly to a reduced pressure level for CO₂ elimination during each breathing cycle is also known as:

A) intermittent mandatory ventilation.
B) airway pressure release ventilation.
C) continuous mandatory ventilation (CMV).
D) continuous spontaneous ventilation.

Question 60

During volume-targeted ventilation, which of the following setting(s) determine(s) the total cycle time?
1) Volume
2) Flow
3) Rate

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

Question 61

In which of the following situations is volume-controlled ventilation sometimes used?
1) When a precise PaCO₂ has to be maintained (some closed-head injuries)
2) When more even distribution of ventilation is required
3) When ventilating patients with severe, refractory hypoxemia
4) When ventilating patients with unstable or changing ventilatory drives

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

Question 62

During pressure-targeted ventilation, which of the following setting(s) determine(s) V_T?
1) Pressure difference
2) Inspiratory time
3) Time constant

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

Question 63

A patient is receiving continuous mandatory ventilation in the control mode at a rate of 10/min. The inspiratory time control is set at 25%. What is the I:E ratio?

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

Question 64

A patient is receiving continuous mandatory ventilation through a constant flow generator in the control mode at a rate of 20/min with a V_T of 750 ml. The inspiratory time is 1 sec. What is the flow?

A) 15 L/min
B) 30 L/min
C) 45 L/min
D) 60 L/min

Question 65

Which of the following is the primary parameter used to alter the breath size in pressure controlled?

A) Positive inspiratory pressure (PIP)-positive end expiratory pressure (PEEP)
B) Continuous positive airway pressure (CPAP)
C) Tidal volume
D) Flow

Question 66

A patient is receiving continuous mandatory ventilation in the control mode at a rate of 20/min. The inspiratory time is 0.75 sec. What is the percentage inspiratory time?

A) 20%
B) 25%
C) 30%
D) 33%

Question 67

A patient is receiving continuous mandatory ventilation in the control mode at a rate of 12/min. The inspiratory time control is set at 33%. What is the expiratory time?

A) 1.65 sec
B) 2.45 sec
C) 3.35 sec
D) 3.85 sec

Question 68

In which of the following situations is pressure-controlled ventilation sometimes used?
1) When a precise PaCO₂ has to be maintained (some closed-head injuries)
2) When more even distribution of ventilation is required
3) When ventilating patients with severe, refractory hypoxemia
4) When tidal volume in unstable due to leaks

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

Question 69

A patient is receiving continuous mandatory ventilation in the control mode at a rate of 15/min. The inspiratory time is 0.8 sec. What is the expiratory time?

A) 3.2 sec
B) 2.8 sec
C) 2.4 sec
D) 4.2 sec

Question 70

A patient is receiving continuous mandatory ventilation in the control mode at a rate of 10/min. The inspiratory time control is set at 40%. What is the inspiratory time?

A) 1.60 sec
B) 1.85 sec
C) 2.40 sec
D) 3.50 sec