Ventilator settings

Question 1

What do these modes of ventilation stand for?
A/C
CMV
PSV
PCV
SIMV
VCV

Answer 1

A/C - Assist control
CMV - Controlled mechanical ventilation or continuous mandatory ventilation
PSV - Pressure support ventilation
PCV - Pressure control ventilation
SIMV - Synchronized intermittent mandatory ventilation
VCV - Volume controlled ventilation

Question 2

When considering volume -targeted modes, explain volume constant.

Answer 2

Guarantees volume at expense of letting airway

pressure vary

Question 3

When considering volume -targeted modes, explain when inspiration terminates.

Answer 3

Terminates when preset Vt delivered

Question 4

When considering volume -targeted modes, explain what would inhibit the preset Vt from being delivered?

Answer 4

a specified pressure limit is exceeded (upper airway pressure alarm is set) or patient’s cuff or ventilator tubing has air leaks that cause a decrease in Vt
delivered

Question 5

When considering volume -targeted modes, explain peak airway pressure.

Answer 5

Variable; determined by changes in airway
resistance, lung compliance, or extrapulmonary factors. The peak airway pressure increases as needed to deliver prescribed Vt

Question 6

When considering volume -targeted modes, explain inspiratory flow rate.

Answer 6

Fixed; if patient inspires faster or more vigorously, work of breathing increases; clinician needs to promptly correct airway resistance and/or lung compliance problems, readjust flow-rate setting higher to match inspiratory demands

Question 7

When considering pressure-targeted modes, explain volume variable

Answer 7

Guarantees pressure at expense of letting Vt vary

Question 8

When considering pressure-targeted modes, explain when Inspiration terminates

Answer 8

Terminates when preset pressure reached

Question 9

When considering pressure-targeted modes, explain the preset pressure delivered

Answer 9

Volume is variable and determined by

set pressure level, airway resistance, and lung compliance factors, specified time or flow cycling criteria

Question 10

When considering pressure-targeted modes, explain peak airway pressures

Answer 10

Fixed; determined by set pressure level; volume delivered is variable and decreases with increased airway resistance, decreased lung compliance, or extrapulmonary factors

Question 11

When considering pressure-targeted modes, explain inspiratory flow rate

Answer 11

Variable; if patient inspires faster or more vigorously, variable flow rate may match change in inspiratory
demand or may be insufficient; clinician needs to promptly correct airway resistance and/or lung compliance problems, may need to readjust pressure support, inspiratory, expiratory time settings