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Functions and Parameters of the Vivo 40
Vivo 40 clinician’s manual
Doc. 003886 En-Us A-1e
4.5 The PSV Mode (Pressure Support Ventilation)
In the PSV mode, the patient normally controls both the inspiration through
the inspiratory trigger, and the exhalation by the expiratory trigger.
Inspiration is started when either the patient triggers a breath (if the trigger is
activated), or when the breath rate setting initiates an inspiration. The ventilator
tries to reach and maintain the set pressure until the expiration starts.
Inspiration stops and an exhalation starts in three cases:
• The inspiration flow has dropped to the value set for expiratory trigger.
• The limit for the high-pressure alarm is reached.
• The inspiration time is longer than the limit for maximal inspiration time or
when inspiration time reaches 3 seconds.
The set IPAP pressure is used as a target pressure. If the flow is decreased to the
expiratory trigger level before the set IPAP is reached the expiration starts.
The figure below shows how the pressure and the expiratory trigger settings
control the ventilator’s function in the PSV mode.
The following settings have been used: Pressure 20 cmH
2
O, exp. trigger 8.
Pressure
cmH
2
O
Pressure
setting
Max. delivered pressure
Max. flow
seconds
seconds
Insp. time PSV
Exp. Trig.
setting
Flow
Flow has dropped
to set Exp. Trig.
New breath
is triggered
Patient
exhales
IPAP
EPAP
