Principles of operation
226 Instructions for use Savina 300 SW 5.n
VC-SIMV
Volume Control-Synchronized Intermittent
Mandatory Ventilation
Intermittent, triggered, volume-controlled
ventilation, allowing spontaneous breathing during
the expiratory phase
Volume-controlled ventilation
The tidal volume of the mandatory breaths is
determined by the volume VT. The pressure rise is
determined by the flow acceleration FlowAcc. The
number of mandatory breaths is determined by the
respiratory rate RR.
If the flow acceleration is so high that the set tidal
volume is already reached before the set
inspiratory time T
i has fully elapsed, an inspiratory
pause occurs. The inspiratory pause can be
identified as the plateau P
plat in the waveform
Paw (t).
If the inspiratory pause time Plateau is deactivated,
Savina 300 immediately switches to expiration as
soon as the set tidal volume VT is applied.
When the Pressure limitation ventilation function
is activated, the P
max therapy control is active. The
set tidal volume VT is maintained and pressure
peaks are avoided.
During spontaneous breathing on PEEP level, the
patient can be supported with PS.
Synchronization
The mandatory breaths can be triggered by the
patient's inspiratory effort on PEEP level.
A mandatory breath can only be triggered within a
"trigger window" by the flow trigger in synchrony
with the patient's inspiration. This prevents the
breath being applied during expiration.
The trigger window has a maximum duration of
5 seconds. For expiratory times shorter than
5 seconds, the trigger window covers the entire
expiratory time minus a refractory period of 500 ms
for the previous expiration.
Synchronization of the mandatory breath reduces
the expiratory time. Savina 300 prolongs the
subsequent expiratory time or spontaneous
breathing time by the missing time T. Th i s
prevents an increase of the mandatory respiratory
rate.
The number of mandatory breaths is determined by
the respiratory rate RR.
207
Paw
PEEP
t
T
i
RR
1
FlowAcc
Trigger window
Unsynchronized
mandatory breath
Synchronized
mandatory breath
Spontaneous
breathing time
Spontaneous
breathing time + T
RR
1
P
plat
Tplat
Pmax