Assist/Control Mode; Definition; Available Breath Types; Description - GE iVent 201 Series User's Reference Manual

ASSIST/CONTROL MODE

DEFINITION

Assist/Control (A/C) mode combines two traditional modes of ventilation: Assisted
Ventilation and Control Mechanical Ventilation (CMV). Unlike a pure Control
Ventilation mode, a patient may breathe more frequently than the set respiratory
rate by producing inspiratory efforts sufficient to trigger a mandatory assist
breath prior to the end of CMV breath cycle.

AVAILABLE BREATH TYPES




All breath types may be either pressure control or volume control.

DESCRIPTION

Figure 170 demonstrates how breaths are delivered in this mode.
At the beginning of the breath cycle (event a), the ventilator delivers a ventilator
breath. After the ventilator breath is delivered, the patient does not attempt to
trigger an assist breath. The ventilator then waits for the normal breath period
(60/bpm) to elapse and delivers another ventilator breath (event b). An insufficient
inspiratory effort (event c) has no effect on the normal delivery of mandatory
ventilator breaths. After delivering the third ventilator breath (event d), patient
effort reduces the airway pressure below PEEP (pressure triggering) or generates
initial inspiratory flow (flow triggering) by an amount equal to or greater than the
operator-selected value for sensitivity (event e). Therefore, an assist breath is
initiated (event f). This resets the breath cycle, thus breath rate is increased. If the
Mandatory ventilator breath
Mandatory assist breath
Manual breath
Figure 170: Breath Pattern in Assist/Control Mode
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Appendix E: Ventilation Modes