Ventilator

Question 1

Ventilators are cycled from inspiration to expiration or
from expiration to inspiration through one of what four
variables?

Answer 1

1. Volume 2. Pressure 3. Time 4. Flow
   Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
   Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
   2011: 55.

Question 2

What is the result of using a PEEP valve on a

spontaneously breathing patient?

Answer 2

There is an increased work of breathing
Dorsch JA, Dorsch SE. Understanding Anesthesia Equipment.
5th ed. Philadelphia, PA: Lippincott Williams and Wilkins, 2008:
201.

Question 3

Are PEEP valves unidirectional or bidirectional flow

valves?

Answer 3

They may be unidirectional or bidirectional. PEEP is only
produced when gas flows in the correct direction through the valve.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 59.

Question 4

If a unidirectional PEEP valve is incorrectly placed on
the inspiratory limb opposing gas flow, what is the
result?

Answer 4

An obstruction occurs resulting in the patient not being ventilated.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 58.

Question 5

If a unidirectional PEEP valve is incorrectly placed on
the expiratory limb opposing gas flow, what is the
result?

Answer 5

Severe barotrauma can occur
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 58.

Question 6

If a bidirectional PEEP valve is misplaced on either
limb of the system opposing gas flow, what is the
result?

Answer 6

There will be no obstruction, but no PEEP will be delivered to the
patient.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 58.

Question 7

What is the most common mode of ventilation?

Answer 7

Volume controlled ventilation
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 55

Question 8

Describe volume controlled ventilation

Answer 8

In volume controlled ventilation, the ventilator controls the
inspiratory flow and delivers a preset tidal volume with each
breath. Tidal volume and inspiratory flow are constant, however
the airway pressure required to deliver the preset volume varies
depending on the patient’s resistance and compliance.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 57.

Question 9

Does peak inspiratory pressure remain constant during

volume controlled ventilation?

Answer 9

No.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 57.

Question 10

Describe pressure controlled ventilation

Answer 10

With pressure controlled ventilation, there is a target gas delivery
pressure established. Tidal volume varies from breath to breath
depending upon the patient’s resistance and compliance. At the
beginning of inspiration, the ventilator rapidly increases the
pressure to the determined level and maintains that pressure until
the beginning of exhalation.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 56.
Dorsch JA, Dorsch SE. Understanding Anesthesia Equipment.
5th ed. Philadelphia, PA: Lippincott Williams and Wilkins, 2008:
317.

Question 11

During pressure controlled ventilation, if airway
resistance increases, or compliance decreases, what
happens to the patient’s tidal volume?

Answer 11

The tidal volume decreases.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 174.

Question 12

How does PEEP (Positive End Expiratory Pressure)

improve oxygenation?

Answer 12

1. Decreases the physiological shunt 2. Prevents alveoli from
   collapsing 3. Restores the functional residual capacity.
   Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
   Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
   2011: 57.

Question 13

When is inspiratory gas flow the highest during

pressure controlled ventilation?

Answer 13

At the beginning of inspiration. Inspiratory flow accelerates rapidly
at the beginning of inspiration to attempt to reach the target set
pressure. Once this pressure is achieved, flow rapidly decreases.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 57.

Question 14

Where on the anesthesia machine is a detachable

PEEP valve placed?

Answer 14

PEEP valves are placed on the expiratory limb of the breathing
system. Most modern ventilators have built-in PEEP valves,
however.
Sandberg WS, Urman RD, Ehrenfield JM. The MGH Textbook of
Anesthetic Equipment. Philadelphia, PA: Elsevier Saunders;
2011: 58.