Mechanical Ventilation

Question 1

What are the 5 basic ventilator settings?

Answer 1

Mode, Tidal Volume (TV), Respiratory Rate (RR), FiO2, PEEP

Question 2

What is tidal volume (TV)?

Answer 2

Volume of air moved in or out of lungs with each breath.

Question 3

How is tidal volume determined?

Answer 3

Based on predicted ideal body weight (based on height).

Question 4

What is the formula for predicted body weight in males?

Answer 4

50 + 2.3 × (height in inches – 60)

Question 5

What is the formula for predicted body weight in females?

Answer 5

45.5 + 2.3 × (height in inches – 60)

Question 6

What is the normal range for tidal volume setting?

Answer 6

6–8 cc/kg of ideal body weight.

Question 7

What is the normal respiratory rate (RR) setting?

Answer 7

10–14 breaths per minute.

Question 8

What does MV (minute ventilation) equal?

Answer 8

TV × RR

Question 9

What is normal minute ventilation (MV)?

Answer 9

4–6 L/min

Question 10

What is FiO₂?

Answer 10

Fraction or percentage of oxygen delivered to the patient.

Question 11

What is a common initial setting for FiO₂?

Answer 11

1.0

Question 12

What are the goals for titrating FiO₂?

Answer 12

PaO₂ > 60 mmHg or O₂ saturation > 90%

Question 13

What is PEEP?

Answer 13

Positive End-Expiratory Pressure – maintains airway pressure during expiration.

Question 14

What is extrinsic PEEP?

Answer 14

PEEP applied by the ventilator.

Question 15

How is PEEP measured?

Answer 15

In cm H₂O.

Question 16

How does PEEP treat respiratory illness?

Answer 16

Prevents alveolar collapse, improves alveolar recruitment for gas exchange.

Question 17

What is the difference between PEEP and CPAP?

Answer 17

PEEP is delivered via endotracheal tube, CPAP via face mask for non-intubated patients.

Question 18

How is lung compliance assessed?

Answer 18

Via peak and plateau pressures.

Question 19

What is lung compliance?

Answer 19

Lungs ability to stretch or expand.

Question 20

How is gas exchange assessed?

Answer 20

Via ABG: pH, PaCO2, PaO2.

Question 21

What settings are adjusted for ventilation issues (PaCO₂)?

Answer 21

RR or TV.

Question 22

What settings are adjusted for oxygenation issues (PaO₂)?

Answer 22

FiO₂ or PEEP.

Question 23

What does an ABG with pH 7.28, PaCO₂ 55, PaO₂ 100 indicate?

Answer 23

Respiratory acidosis with adequate oxygenation.

Question 24

How should you respond to respiratory acidosis?

Answer 24

Increase RR (first-line), or optionally increase TV.

Question 25

What does an ABG with pH 7.4, PaCO₂ 40, PaO₂ 40 indicate?

Answer 25

Hypoxemia with adequate ventilation.

Question 26

How should you respond to hypoxemia?

Answer 26

Increase FiO₂, optionally increase PEEP.

Question 27

What is end-tidal CO₂ (ETCO₂)?

Answer 27

Partial pressure of CO₂ in exhaled gas.

Question 28

When is ETCO₂ not reliable?

Answer 28

Impaired pulmonary blood flow. ARDS, cardiac arrest, or PE.

Question 29

What does SpO₂ of 90% correlate to?

Answer 29

PaO₂ of approximately 60 mmHg.

Question 30

What are the three main types of ventilator modes?

Answer 30

Controlled, Hybrid, Spontaneous.

Question 31

What are volume control modes?

Answer 31

Modes where tidal volume is set.

Question 32

What are pressure control modes?

Answer 32

Modes where inspiratory pressure is set.

Question 33

What is ACVC mode?

Answer 33

Assist Control Volume Control – full TV delivered on all breaths.

Question 34

What is SIMVVC mode?

Answer 34

Synchronized Intermittent Mandatory Ventilation – full TV on mandatory breaths, variable on spontaneous.

Question 35

What additional setting is used in SIMVVC?

Answer 35

Pressure support.

Question 36

What is ACPC mode?

Answer 36

Assist Control Pressure Control – breaths delivered at fixed inspiratory pressure (on top of PEEP).

Question 37

What is SIMVPC mode?

Answer 37

SIMV with pressure control – fixed pressure for mandatory breaths, variable pressure for spontaneous due to pressure support. TV is variable on spontaneous breaths.

Question 38

In volume control modes, what is controlled?

Answer 38

Tidal volume.

Question 39

In pressure control modes, what is controlled?

Answer 39

Airway pressure (inspiratory pressure).

Question 40

Which variable is unknown in volume control modes?

Answer 40

Airway pressure.

Question 41

Which variable is unknown in pressure control modes?

Answer 41

Tidal volume.

Question 42

Why is volume control often preferred?

Answer 42

Consistent tidal volume delivery.

Question 43

What can change tidal volume in pressure control?

Answer 43

Changes in lung compliance.

Question 44

What is PSV?

Answer 44

Pressure Support Ventilation – spontaneous mode, patient initiates breaths.

Question 45

What settings are set in PSV?

Answer 45

Pressure support, PEEP, FiO₂.

Question 46

Who cannot be on PSV?

Answer 46

Paralyzed or apneic patients. Requires drive to breathe.

Question 47

What is an SBT?

Answer 47

Spontaneous Breathing Trial – assesses extubation readiness.

Question 48

What are typical SBT settings?

Answer 48

PS 5–7 with PEEP 5, FiO₂ 40–50%.

Question 49

What is assessed during a spontaneous breathing trial?

Answer 49

MV, TV achieved, Gas exchange, Vital Signs.

Question 50

What criteria must be met for extubation?

Answer 50

protects airway, manageable secretions, maintain adequate O₂/ventilation, resolved underlying issue.