Deck 46: Physiology of Ventilatory Support

Question 1

Which of the following conditions may require higher initial respiratory rates?
1) Metabolic alkalosis
2) ARDS
3) Increased intracranial pressure
4) Metabolic acidosis

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

Answer 1

D

Question 2

Administration of positive end expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) is associated with which of the following benefits?
1) Helps maintain open alveoli.
2) Helps with alveoli stability.
3) Helps maintain fluid-filled alveoli open.
4) Ensures surfactant-depleted alveoli remain closed.

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

Answer 2

B

Question 3

In which of the following types of ventilation is alveolar expansion during inspiration due to a decrease in pleural pressure?
1) Positive-pressure ventilation (PPV)
2) Negative-pressure ventilation (NPV)
3) Spontaneous ventilation

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

Answer 3

C

Question 4

In which of the following modes of ventilatory support would the patient's work of breathing be greatest?

A) Continuous positive airway pressure (CPAP)
B) Pressure-supported ventilation (PSV)
C) Intermittent mandatory ventilation (IMV)
D) Continuous mandatory ventilation (CMV)

Question 5

The volume delivered by a pressure-limited ventilator will decrease under which of the following conditions?
1) The patient's lung or thoracic (chest wall) compliance falls.
2) Airway resistance rises (inspiratory time <3 times the time constant).
3) The patient tenses the respiratory muscles during inspiration.
4) Airway resistance rises (inspiratory time >3 times the time constant).

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

Question 6

Which of the following is the recommended tidal volume for mechanical ventilation in a patient with ARDS who is in acute respiratory failure?

A) 4 to 8 ml/kg
B) 3 to 5 ml/kg
C) 6 to 10 ml/kg
D) 10 to 12 ml/kg

Question 7

Which of the following strategies are useful in the management of shunt?
1) Positive end expiratory pressure
2) Permissive hypercapnia
3) Control of membrane permeability

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

Question 8

Which of the following statements are true about negative-pressure ventilation (NPV)?
1) NPV is similar to spontaneous breathing.
2) Airway (mouth) pressure during NPV is zero.
3) Expiration during NPV is by passive recoil.
4) NPV decreases pressure at the body surface.

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

Question 9

Which of the following is considered a normal spontaneous tidal volume?

A) 3 to 5 ml/kg
B) 5 to 7 ml/kg
C) 7 to 9 ml/kg
D) 10 to 12 ml/kg

Question 10

Which of the following occur in pressure-limited modes of ventilation?
1) The volume delivered at a given pressure must decrease as compliance falls.
2) The inspiratory flow varies with patient effort and lung mechanics.
3) Active effort by the patient against inspiration will decrease delivered volume.
4) The volume delivered at a given pressure must increase as Raw rises.

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

Question 11

Mean airway pressures can be increased by which of the following factors?
1) Increasing the inspiratory time
2) Increasing compliance
3) Increasing level of PEEP
4) Changing from a square to a decelerating ramp waveform

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

Question 12

During pressure-targeted modes of ventilatory support, the volume delivered depends on which of the following?
1) Set pressure limit
2) Patient lung mechanics
3) Patient effort

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

Question 13

In which of the following types of ventilation is alveolar expansion during inspiration due to an increase in alveolar pressure?
1) Negative-pressure ventilation
2) Positive-pressure ventilation
3) Spontaneous ventilation

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

Question 14

Which of the following is the consequence of decreased resistance or compliance?

A) It takes more time to fill the alveoli.
B) It takes more time to empty the alveoli.
C) It takes less time to fill and more time to empty the alveoli.
D) It takes less time to fill and empty the alveoli.

Question 15

Which of the following occur with positive-pressure ventilation (PPV)?
1) During inspiration, pleural pressure decreases.
2) During inspiration, pressure in the alveoli increases.
3) The pressure gradients of normal breathing are reversed.
4) During inspiration, alveolar pressure exceeds pleural pressure.

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

Question 16

Which of the following is the explanation for the increased ratio when excessive positive end expiratory pressure (PEEP) is used?

A) Diversion of blood from ventilated alveoli to hypoventilated alveoli
B) Diversion of blood from hypoventilated alveoli to ventilated alveoli
C) Shunt-like effect
D) Hyperexpansion

Question 17

During pressure-controlled continuous mandatory ventilation, when the patient's lung compliance increases, which of the following will occur?

A) The tidal volume will increase.
B) The FRC will increase.
C) The peak airway pressure will increase.
D) The inspiratory time will decrease.

Question 18

Which of the following are considered safe settings for a recruitment maneuver?
1) Pressures up to 50 cm H₂O
2) Pressures up to 35 cm H₂O
3) Pressures applied for 5 to 10 min
4) Pressures applied for 1 to 3 min

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

Question 19

Which of the following conditions is associated with a lack of response to increased FiO₂ in patients receiving positive-pressure ventilation?

A) Dead space
B) Shunt
C) Hypoxemia
D) Hypoventilation

Question 20

In which of the following types of ventilation can pleural pressure become positive during inspiration?
1) Positive-pressure ventilation
2) Spontaneous ventilation
3) Negative-pressure ventilation

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

Question 21

In which of the following modes of ventilatory support would the patient's work of breathing be least?

A) Continuous positive airway pressure (CPAP)
B) Pressure-supported ventilation (PSV)
C) Intermittent mandatory ventilation (IMV)
D) Continuous mandatory ventilation (CMV)

Question 22

Which level of plateau pressure increases the likelihood of causing lung injury?

A) Greater than 15 cm H₂O
B) Greater than 25 cm H₂O
C) Greater than 28 cm H₂O
D) Greater than 32 cm H₂O

Question 23

Volume-controlled (VC) modes of mechanical ventilation include which of the following?
1) VC continuous mandatory ventilation
2) VC intermittent mandatory ventilation
3) Volume-assured, pressure-controlled
4) Bilevel positive airway pressure

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

Question 24

What are some key causes of patient-ventilator asynchrony and increased work of breathing during pressure-triggered volume-controlled continuous mandatory ventilation?
1) Improper trigger setting
2) Insufficient inspiratory flow
3) High peak airway pressures

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

Question 25

Inspection of the airway pressure waveform of a patient receiving volume-controlled continuous mandatory ventilation assist-control with constant flow reveals a large dip or drop in pressure at the beginning of inspiration. Which of the following problems is most likely?

A) The trigger setting is improper.
B) The inspiratory flow is inadequate.
C) The set volume is too large.
D) The pressure limit is too low.

Question 26

To prevent muscle fatigue or atrophy, the level of PSV should be adjusted to achieve what work load?

A) 0 J/L
B) 0.6 to 0.8 J/L
C) 0 to 0.5 J/L
D) Greater than 0.8 J/L

Question 27

Which of the following modes of ventilatory support would result in the highest mean airway pressure?

A) Volume-controlled intermittent mandatory ventilation
B) (Volume-controlled intermittent mandatory ventilation) + pressure-supported ventilation
C) Pressure-controlled intermittent mandatory ventilation
D) Volume-controlled continuous mandatory ventilation

Question 28

Compared with a square wave flow pattern, a decelerating flow waveform has which of the following potential benefits?
1) Reduced peak pressure
2) Improved cardiac output
3) Less inspiratory work
4) Decreased volume of dead space-to-tidal volume ratio (V_D/V_T)

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

Question 29

When bedside work of breathing measures are unavailable, you should adjust the level of pressure-supported ventilation (PSV) to which of the following breathing patterns? Spontaneous Rate V_T

A) 20 breaths/min 6 ml/kg
B) 27 breaths/min 9 ml/kg
C) 22 breaths/min 4 ml/kg
D) 10 breaths/min 9 ml/kg

Question 30

Which of the following is a benefit of high inspiratory flows during positive-pressure ventilation?

A) Improved gas exchange
B) Higher peak pressures
C) Reduced air trapping
D) Higher work of breathing

Question 31

During volume-controlled continuous mandatory ventilation, should either compliance decrease or airway resistance (Raw) increase, what will happen?

A) The peak airway pressure will decrease.
B) The inspiratory flow will increase.
C) The peak airway pressure will increase.
D) The inspiratory time will decrease.

Question 32

Contraindications for using positive end expiratory pressure (PEEP) in conjunction with mechanical ventilation include which of the following?
1) Untreated bronchopleural fistula
2) Chronic airway obstruction
3) Untreated pneumothorax

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

Question 33

Physiological effects of adding a volume-limited inflation hold to mandatory breaths include which of the following?
1) Decreased PaCO₂
2) Increased inspiratory time
3) Decreased V_D/V_T
4) Longer expiratory times

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

Question 34

Beneficial physiological effects of positive end expiratory pressure (PEEP) include which of the following?
1) Increased PaO₂ for given FiO₂
2) Increased lung compliance (C_L)
3) Decreased shunt fraction
4) Increased functional residual capacity

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

Question 35

Which of the following modes of support provides all of the patient's minute ventilation (V_E) as mandatory volume-controlled (VC) breaths?

A) VC continuous mandatory ventilation
B) VC intermittent mandatory ventilation
C) Pressure-supported ventilation
D) Continuous positive airway pressure

Question 36

In which of the following patients is positive end expiratory pressure (PEEP) most indicated? FiO₂ PaO₂

A) 0.3 80 mm Hg
B) 0.5 80 mm Hg
C) 0.3 50 mm Hg
D) 0.5 50 mm Hg

Question 37

Primary indications for using positive end expiratory pressure (PEEP) in conjunction with mechanical ventilation include which of the following?
1) When dynamic hyperinflation occurs in chronic obstructive pulmonary disease (COPD) patients.
2) When the imposed work of breathing is excessive.
3) When acute lung injury causes refractory hypoxemia.

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

Question 38

All of the following factors would tend to increase mean airway pressure except:

A) short inspiratory times.
B) increased mandatory breaths.
C) increased levels of positive inspiratory pressure (PIP).
D) increased levels of positive end expiratory pressure (PEEP).

Question 39

The volume of gas actually delivered to a patient by most positive-pressure ventilation is always less than that expelled from the machine. Which of the following factors help to explain this finding?
1) Gas compression under pressure
2) Presence of built-in leaks
3) Expansion of the ventilator circuitry

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

Question 40

Detrimental effects of positive end expiratory pressure (PEEP) include which of the following?
1) Increased incidence of barotrauma
2) Decreased venous return or cardiac output
3) Increased pulmonary vascular resistance
4) Increased C_L

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

Question 41

Which of the following modes of ventilatory support combines the advantages of pressure-controlled and volume-controlled ventilation?

A) Volume-assured pressure-supported ventilation
B) Pressure-supported ventilation
C) Bilevel positive airway pressure
D) Airway pressure-release ventilation

Question 42

What spontaneous pressure-controlled breath mode allows separate regulation of the inspiratory and expiratory pressures?

A) Bilevel positive airway pressure
B) Continuous positive airway pressure
C) Pressure-supported ventilation
D) Pressure-controlled intermittent mandatory ventilation

Question 43

A patient switched from pressure-controlled continuous mandatory ventilation (CMV) with positive end expiratory pressure (PEEP) to pressure-controlled inverse ratio ventilation (PC-IRV) shows a good improvement in PaO₂ but a decrease in tissue oxygenation. Which of the following best explains this observation?

A) High mean pressures caused by PC-IRV decreased pulmonary blood flow.
B) Intrinsic PEEP caused by PC-IRV resulted in increased alveolar recruitment.
C) High mean pressures caused by PC-IRV decreased cardiac output.
D) Intrinsic PEEP caused by PC-IRV compressed the pulmonary capillaries.

Question 44

Which of the following parameters are set when volume-supported ventilation (VSV) is used?
1) Tidal volume
2) Maximum peak pressure
3) Positive end expiratory pressure (PEEP)
4) Flow

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

Question 45

For patients with respiratory insufficiency, pressure-supported ventilation (PSV) has all of the following advantages over spontaneous breathing except:

A) decreased respiratory rate.
B) increased V_T.
C) decreased O₂ consumption.
D) increased muscle activity.

Question 46

What are some primary uses for pressure-supported ventilation (PSV)?
1) Recruiting collapsed alveoli and improving oxygenation
2) Augmenting patient's spontaneous V_T
3) Overcoming the imposed work of breathing

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

Question 47

In which mode of ventilatory support does the patient breathe spontaneously at an elevated airway pressure, with short, intermittent decreases in pressure to a lower level?

A) Volume-assured pressure-supported ventilation
B) Pressure-controlled inverse ratio ventilation
C) Bilevel positive airway pressure
D) Airway pressure-release ventilation

Question 48

Which of the following modes of ventilatory support is used to help decrease airway and alveolar pressures?

A) Pressure-controlled continuous mandatory ventilation
B) Pressure-controlled intermittent mandatory ventilation
C) Volume-controlled continuous mandatory ventilation
D) Volume-assured pressure-supported ventilation

Question 49

During volume-assured pressure-supported ventilation, the breath will be pressure-limited under what conditions?

A) The delivered tidal volume (V_T) is greater than the preset minimum V_T.
B) The patient's lung or thoracic compliance decreases from the baseline.
C) The delivered V_T is less than the preset minimum V_T.
D) The patient's Raw increases from baseline.

Question 50

Bilevel positive airway pressure (BiPAP) is used for which of the following purposes?
1) Nocturnal ventilatory support of chronic disease patients
2) Preventing intubation of patients with acute exacerbations of chronic obstructive pulmonary disease (COPD)
3) Treatment of obstructive sleep apnea (OSA) in the home
4) Providing ventilatory support for patients with status asthmaticus

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

Question 51

Which of the following variables determine the level of support achieved with adaptive support ventilation?
1) Patient effort
2) Elastance
3) Resistance of the endotracheal tube

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

Question 52

After accounting for the compressed volume loss on a stable adult patient receiving volume-controlled continuous mandatory ventilation at a preset volume of 500 ml, you still note a 150-ml difference between the expected and the actual delivered volume. Which of the following is most likely causing this problem?

A) Gas absorption across the alveolar membrane
B) Increase in the respiratory quotient
C) Bronchopleural fistula or pneumothorax
D) Leak in the patient-ventilator system

Question 53

What mode of pressure-controlled ventilation is designed to prevent alveoli with short-time constants from collapsing, thereby improving oxygenation?

A) Pressure-controlled inverse ratio ventilation
B) Pressure-controlled intermittent mandatory ventilation
C) Volume-assured pressure-supported ventilation
D) Bilevel positive airway pressure

Question 54

During volume-assured pressure-supported ventilation, if the desired V_T is not reached or exceeded at the preset pressure support level, what happens?

A) Flow continues at a constant rate until the desired volume is achieved.
B) The breath terminates when a predetermined low flow is achieved.
C) Flow decreases exponentially until the desired volume is achieved.
D) Flow increases linearly until the desired volume is achieved.

Question 55

Which of the following variables determine the level of support achieved with proportional assist ventilation?
1) Patient effort
2) Elastance
3) Resistance

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

Question 56

Which of the following variables determine the level of support achieved with adaptive support ventilation?
1) Patient effort
2) Flow
3) Time constant

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

Question 57

Which of the following is considered an acceptable tidal volume for mechanical ventilation?

A) 3 to 5 ml/kg
B) 5 to 7 ml/kg
C) 4 to 8 ml/kg
D) 8 to 10 ml/kg

Question 58

What are some physiological advantages of volume-assured pressure-supported ventilation?
1) Improved patient-ventilator synchrony
2) Increased pressure-time product
3) Decreased work of breathing

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

Question 59

Which of the following are true about continuous positive airway pressure (CPAP)?
1) It maintains alveoli at greater inflation volumes.
2) It holds airway pressure essentially constant.
3) It provides the pressure gradient needed for ventilation.
4) It has side effects similar to those of positive pressure ventilation.

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

Question 60

What does pressure-supported ventilation consist of?

A) Patient-triggered, pressure-limited, and flow-cycled breaths
B) Machine-triggered, pressure-limited, and flow-cycled breaths
C) Patient-triggered, pressure-limited, and time-cycled breaths
D) Machine-triggered, flow-limited, and pressure-cycled breaths

Question 61

Which of the following lung units would be most prone to air-trapping?

A) One with high resistance and low compliance
B) One with low resistance and low compliance
C) One with normal resistance and low compliance
D) One with high resistance and high compliance

Question 62

Ventricular dysfunction occurs in patients receiving positive-pressure ventilation for which of the following reasons?
1) Hypovolemia
2) Excessive tidal volume
3) Receiving more than optimal positive end expiratory pressure (PEEP)
4) Hypervolemia

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

Question 63

Which of the following gastrointestinal conditions are commonly associated with long-term positive-pressure ventilation (PPV)?
1) Bleeding
2) Ulceration
3) Diarrhea

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

Question 64

Types of damage associated with pulmonary barotrauma include which of the following?
1) Pneumoconiosis
2) Pneumomediastinum
3) Pneumothorax
4) Subcutaneous emphysema

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

Question 65

Moderate rises in pleural pressure during positive-pressure ventilation have a minimal effect on cardiac output in normal subjects. What are some reasons for this lack of effect?
1) Compensatory dilation of the large arteries
2) Compensatory increase in venomotor tone
3) Compensatory increase in the cardiac rate

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

Question 66

Potential effects of hyperventilation on the central nervous system include which of the following?
1) Increased O₂ consumption
2) Increased cerebral vascular resistance (CVR)
3) Increased intracranial pressure (ICP)

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

Question 67

What factors contribute to the development of auto-positive end expiratory pressure (PEEP)?
1) High expiratory Raw
2) High inspiratory flows
3) Inadequate expiratory time

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

Question 68

A patient receiving long-term positive-pressure ventilation support exhibits a progressive weight gain and a reduction in the hematocrit. Which of the following is the most likely cause of this problem?

A) Pulmonary hemorrhage
B) Water retention
C) Hypovolemia
D) Hyponatremia

Question 69

Physical assessment indicating the presence of a tension pneumothorax includes which of the following?
1) Unequal chest excursion
2) Hyperresonance upon chest percussion
3) Absent breath sounds
4) Loud breath sounds

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

Question 70

Which of the following are potential effects of positive-pressure ventilation on the cardiovascular system?
1) Decreased venous return
2) Decreased cranial perfusion pressures
3) Increased pulmonary blood flow
4) Decreased ventricular stroke volume

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

Question 71

Which of the following mechanisms explains the impaired renal function seen in patients receiving ventilatory support with positive pressure?
1) Decreased secretion of aldosterone
2) Decreased intravascular volume
3) Increased secretion of vasopressin

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

Question 72

Positive-pressure ventilation (PPV) can reduce urinary output by how much?

A) 10% to 20%
B) 30% to 50%
C) 60% to 70%
D) 80% to 90%

Question 73

Which of the following mechanisms explains the hepatic dysfunction in patients receiving positive-pressure ventilation (PPV)?

A) Decreased hepatic blood flow
B) Increased portal venous pressure
C) Hepatic congestion
D) Increased bilirubin conjugation

Question 74

Which of the following is the best explanation for the decreased levels of atrial natriuretic hormone commonly observed among patients receiving positive-pressure ventilation?

A) Stimulation of the pulmonary stretch receptors
B) Inhibition of posterior pituitary function
C) Inhibition of the cortex of the adrenal gland
D) Decreased right atrial transmural pressure

Question 75

Assuming a constant rate of breathing, which of the following inspiratory-to-expiratory (I:E) ratio would tend to most greatly impair a patient's systemic diastolic pressure?

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

Question 76

What is traumatic injury to lung tissue caused by excessive pressure called?

A) Pulmonary barotrauma
B) Pulmonary hemorrhage
C) Pulmonary infarction
D) Pulmonary embolism

Question 77

Which of the following terms describes the lung injury associated with the release of prostanoids?

A) Biotrauma
B) Barotrauma
C) Volutrauma
D) Atelectrauma

Question 78

What factor primarily determines the effect of positive-pressure ventilation (PPV) on the cardiac output?

A) Peak airway pressure
B) Mean pleural pressure
C) CO₂
D) Expiratory time

Question 79

Hyperventilation should generally be avoided during mechanical ventilatory support. Exceptions to this rule include:
1) Trying to calm an agitated patient.
2) Failure of other methods to reduce intracranial pressure.
3) Hypokalemia causing cardiac arrhythmias.

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

Question 80

Which of the following terms describe the lung injury associated with the use of low tidal volumes?

A) Biotrauma
B) Barotrauma
C) Volutrauma
D) Atelectrauma