Mechanical Ventilation Modes

Question 1

What is mechanical ventilation?

Answer 1

Medical term for artificial ventilation using mechanical means to assist or replace spontaneous breathing.

Question 2

What device is commonly used for mechanical ventilation?

Answer 2

A ventilator or a bag valve mask (manually by a healthcare professional).

Question 3

When is mechanical ventilation considered invasive?

Answer 3

When it involves instruments inside the trachea (e.g. endotracheal tube) or through the skin (e.g. tracheostomy tube).

Question 4

What is non-invasive ventilation?

Answer 4

Ventilation using face or nasal masks in selected conscious patients.

Question 5

What are the two main types of mechanical ventilation?

Answer 5

Positive pressure ventilation and negative pressure ventilation.

Question 6

How does positive pressure ventilation work?

Answer 6

Air is pushed into the lungs through the airways.

Question 7

How does negative pressure ventilation work?

Answer 7

Air is drawn into the lungs by stimulating movement of the chest.

Question 8

What is Continuous Mandatory Ventilation (CMV) ventilator mode?

Answer 8

Breaths delivered at preset intervals regardless of patient effort; mainly for paralyzed or apneic patients.

Question 9

Why has CMV been replaced by Assist-Control (A/C) mode?

Answer 9

A/C mode functions like CMV in apneic patients but is better tolerated in those with respiratory effort.

Question 10

What is Assist-Control ventilation?

Answer 10

Ventilator delivers preset breaths in coordination with respiratory effort of the patient. With each inspiratory effort ventilator delivers full assisted Tv. Spontaneous breathing between A/C breaths is not allowed.

Question 11

How is A/C better than CMV?

Answer 11

It is better tolerated in patients with intact respiratory effort.

Question 12

What is Intermittent Mandatory Ventilation (IMV)?

Answer 12

Preset breaths are delivered, but spontaneous breathing is allowed between them.

Question 13

Why has IMV been replaced by SIMV?

Answer 13

SIMV synchronizes with the patient’s effort to reduce barotrauma and breath stacking.

Question 14

What is Synchronous Intermittent Mandatory Ventilation (SIMV)?

Answer 14

Preset breaths are delivered in sync with patient effort; spontaneous breaths are allowed.

Question 15

What is the main benefit of SIMV over IMV?

Answer 15

Synchronization limits barotrauma and breath stacking.

Question 16

What is one disadvantage of SIMV?

Answer 16

Increased work of breathing.

Question 17

How can increased work of breathing in SIMV be mitigated?

Answer 17

By adding pressure support on top of spontaneous breaths.