Principles of Operation
118
Instructions for Use Oxylog 2000 plus SW 1.n
Ventilation modes
VC-CMV
Volume-Constant Mandatory Ventilation stroke
The ventilation pattern is specified by the settings
for tidal volume VT, respiratory rate RR, ventilation
time ratio I:E and PEEP.
At the end of the flow phase, the expiration valve
remains closed until the end of the inspiration time
Ti. This phase, the inspiratory pause, can be identi-
fied as the plateau Pplat.
VC-AC
Assisted ventilation with continuous positive airway
pressure.
The mandatory ventilation stroke begins when the
patient reaches an inspiratory flow corresponding
at least to the set flow trigger.
The current ventilation respiratory rate may be
greater than the set respiratory rate for the same
trigger.
VC-SIMV
Synchronized Intermittent Mandatory Ventilation
Combination of mandatory ventilation and sponta-
neous breathing
VC-SIMV enables the patient to breathe
spontaneously in regular prescribed cycles, with
the mechanical mandatory ventilation strokes
providing a minimum ventilation during the
remaining cycles.
The minimum ventilation is controlled by the two set
values of the tidal volume VT and respiratory rate
RR and is determined from the product of VT x RR.
The ventilation pattern results from the ventilation
parameters of the tidal volume VT, respiratory rate
RR and inspiration time Ti.
To prevent the mandatory ventilation stroke from
being applied during spontaneous expiration, the
flow trigger of the ventilator ensures that the venti-
lation stroke is triggered in synchrony with the
patient's spontaneous inspiratory effort within a
"trigger window".
The trigger window is 5 seconds long. If the
expiration times are less than 5 seconds, the
trigger window covers the entire expiration time
minus a minimum expiration time of 500 ms.
041
Paw
Flow
Ti Te
T=
P
plat
1
t
t
PEEP
without plateauwith plateau
RR
Tplat%
042
Paw
PEEP
t
Spontaneous
breathing time
Spontaneous
breathing time + T
Trigger
window
Synchronized
mandatory
ventilation stroke
Unsynchronized
mandatory
ventilation stroke
Ti
Set mandatory
cycle time
Set mandatory
cycle time
1
RR
1
RR
To Next Page
Loading...
