Mechanical Ventilation Terminology
A. Power
1. The power source used by the ventilator to achieve either positive or negative pressure is provided by electrical power, pneumatic (gas), or a
combination of the two.
B. Inspiratory Phase Variables that Determine Inspiration - Types of Breaths
1. Three main types of mechanical ventilation breaths.
a. Mandatory - those that are started (triggered), controlled (limited), and ended (cycled) by the ventilator. Ventilator does all the work of
breathing.
b. Assisted - those that are started (triggered) by the patient and controlled (limited) and ended (cycled) by the ventilator.
c. Spontaneous - those that are started, controlled and ended by the patient. The amount of volume and/or pressure delivered is based on
patient demand and not by a pre-selected amount set on the ventilator.
C. Trigger Variable - Begins Inspiration
1. The mechanism used by the ventilator to end exhalation and begin inspiration is the triggering mechanism (trigger variable).
D. Limit Variable - Limits Inspiratory Factors
1. A limiting variable or a limiting parameter is the maximum value a variable (pressure, volume, flow or time) can attain during inspiration. This
limits the variable during inspiration only. lt does not end the inspiratory phase.
2. Example: Ventilating an infant with time-cycled, pressure limited ventilation, inspiration ends due to time, but PIP is limited at a pre-set level.
E. Gycling Variable - Termination of the Inspiratory Phase
1. Pressure cycled - Inspiration ends when a pre-set pressure is reached.
2. Volume cycled - Inspiration ends when a pre-set volume is delivered.
3. Time cycled - Inspiration_ends when a pre-set time has been met.
4. Flow cycled - Inspiration ends when flow decreases to a pre-set level.
5. Manual cycled - the operator or patient stops inspiration.
F. Expiratory Phase
1. The period between inspirations.
2. During mechanical ventilation, when inspiratory flow ends, the expiratory valve opens, and expiratory flow beg ins.
1. The power source used by the ventilator to achieve either positive or negative pressure is provided by electrical power, pneumatic (gas), or a
combination of the two.
B. Inspiratory Phase Variables that Determine Inspiration - Types of Breaths
1. Three main types of mechanical ventilation breaths.
a. Mandatory - those that are started (triggered), controlled (limited), and ended (cycled) by the ventilator. Ventilator does all the work of
breathing.
b. Assisted - those that are started (triggered) by the patient and controlled (limited) and ended (cycled) by the ventilator.
c. Spontaneous - those that are started, controlled and ended by the patient. The amount of volume and/or pressure delivered is based on
patient demand and not by a pre-selected amount set on the ventilator.
C. Trigger Variable - Begins Inspiration
1. The mechanism used by the ventilator to end exhalation and begin inspiration is the triggering mechanism (trigger variable).
D. Limit Variable - Limits Inspiratory Factors
1. A limiting variable or a limiting parameter is the maximum value a variable (pressure, volume, flow or time) can attain during inspiration. This
limits the variable during inspiration only. lt does not end the inspiratory phase.
2. Example: Ventilating an infant with time-cycled, pressure limited ventilation, inspiration ends due to time, but PIP is limited at a pre-set level.
E. Gycling Variable - Termination of the Inspiratory Phase
1. Pressure cycled - Inspiration ends when a pre-set pressure is reached.
2. Volume cycled - Inspiration ends when a pre-set volume is delivered.
3. Time cycled - Inspiration_ends when a pre-set time has been met.
4. Flow cycled - Inspiration ends when flow decreases to a pre-set level.
5. Manual cycled - the operator or patient stops inspiration.
F. Expiratory Phase
1. The period between inspirations.
2. During mechanical ventilation, when inspiratory flow ends, the expiratory valve opens, and expiratory flow beg ins.