B- Assist Control Mode - BIO-MED DEVICES Crossvent-2i+ Operation & Service Manual

VII. T H E O R Y O F O P E R A T I O N - C O N T .

B- ASSIST CONTROL MODE

In this mode the Crossvent-2i+ will function either as an assist or controller. If the patient is inspiring, the ventilator will
sense flow past the pneumotach with Flow Trigger being used and this will initiate an assisted inspiration. If the patient fails
to breathe, the ventilator will continue to give controlled breaths at the backup rate set by the main RATE setting.
Inspiration may be initiated by either a patient inspiratory effort or, in the absence of that, the backup setting. At the start of
inspiration, gas flows to the patient at the flow rate established by the FLOW control, for the duration of the inspiratory
time. Simultaneously, the exhalation valve is pressurized to the PIP level. The maximum pressure attainable is established by
the PIP control on the front of the ventilator. At the end of the inspiratory time, the patient gas flow is terminated and zero
or PEEP pressure is applied to the exhalation valve. This allows the pressure in the patient circuit to fall only to the PEEP
level.
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