Instructions for use Oxylog 3000 plus SW 1.n 155
Description
VC-SIMV
Volume Controlled - Synchronized Intermittent
Mandatory Ventilation
VC-SIMV provides a combination of mandatory
ventilation and spontaneous breathing. It enables
the patient to breathe spontaneously, with the
mechanical mandatory breaths providing minimum
ventilation. The minimum ventilation is controlled
via the two set values for the tidal volume VT and
the respiratory rate RR and is determined from the
product of VT × RR.
The mandatory ventilation pattern results from the
ventilation parameters of the tidal volume VT,
respiratory rate RR, ventilation time ratio I:E or
inspiratory time Ti and plateau time Tplat. To
prevent the mandatory breath from being applied
during spontaneous expiration, the flow trigger of
the ventilator ensures that the breath is triggered in
synchrony with the patient's spontaneous
inspiratory effort within a fixed time window during
expiration.
The trigger window has a duration of 5 seconds. If
the expiratory time is less than 5 seconds, the
trigger window covers the entire expiratory time
minus a minimum expiratory time of 500 ms.
Since the synchronization of the mandatory breath
reduces the spontaneous breathing time, which
would result in an undesirable increase in
respiratory rate, Oxylog 3000 plus prolongs the
spontaneous breathing time of the subsequent
breath by the difference ΔT - thus preventing an
increase in SIMV frequency. The respiratory rate
RR remains constant.
The respiratory rate RR and tidal volume VT set the
minimum ventilation – as in VC-CMV and VC-AC.
During the spontaneous breathing phases, the
patient can be assisted with pressure by Pressure
Support PS.
Generally the number of mandatory breaths is
reduced in the course of weaning the patient off
ventilation. This increases the spontaneous
breathing time, so that the required total minute
volume MV is increasingly supplied by
spontaneous breathing.
042
Paw
PEEP
t
Spontaneous
breathing time
Spontaneous
breathing time + T
Trigger
window
Synchronized
mandatory
ventilation stroke
Unsynchronized
mandatory
ventilation stroke
T
i
Set mandatory
cycle time
Set mandatory
cycle time
1
RR
1
RR
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