Treaton MV200, User Manual

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4.9 Setting of the type of inspiration trigger
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4.9 Setting of the type of inspiration trigger
The ventilator has two types of inspiration triggers - flow and pressure.
The trigger is intended for activation of the inspiration process when it detects patient’s attempts
to spontaneous breathing. Flow trigger is triggered, if it detects that inspiratory flow of the pa-
tient is greater than the threshold value. The pressure trigger is started when pressure drop in
the circuit caused by inhalation of the patient is greater than the threshold value.
Trigger flow is preferable because it usually allows the patient to breathe with less effort. An ad-
ditional criterion of flow triggering is the excess of the inspiration volume of 25 ml that provides
triggering at the slow spontaneous breaths.
Enter the main menu of device to set type of the inspiration trigger (see it. 4.6). This automati-
cally sets the correct sensitivity parameter Ftrig or Ptrig, which is displayed in the right window
of the set parameters area (Figure 4.4, position 13).
Designation of
parameter
Description of parameter Values
Ftrig Flow trigger sensitivity:
- child mode
- adult mode
0.5 …10 lpm
1…20 lpm
with step of 0.5 lpm*
Ptrig Pressure trigger sensitivity 0.5 …20 cmH
2
O
with step of 0.5 cmH
2
O
* - in the range up to 3.0 lpm –with step of 0.1 lpm
The sensitivity of the trigger is a parameter that determines the minimum value of the patient's
respiratory effort required to run the spontaneous inspiration support algorithm.
In the NIV mode flow trigger is not used because its operation is impossible in the presence
of leak. The algorithm of the inspiratory trigger in NIV has two simultaneous criteria:
•
The first one is similar to the pressure trigger of other modes (Ptrig is limited to 10 cmH
2
O).
•
The second one is unique for the NIV and applies only in the NIV mode. The ventilator com-
pares the flow of the patient with the same flow but delayed for 0.3 seconds. This operation
is performed by control microprocessor of the ventilator.
If the difference between the flows reachs 10 lpm, device makes a decision about detection of
spontaneous inspiration. This criterion is not susceptible to leakage and allows the device to
work reliably at unpressurized breathing circuit (mask).
An additional criterion of activation of the inspiratory trigger is excess of the inspiratory volume
of 25 ml. That allows the triggering at the slow spontaneous breaths.
In the CMV / VCV, CMV / PCV and PCV-VG modes, the flow and pressure triggers can be dis-
abled (has Off position).
Do not set high trigger sensitivity of 1 - 2 lpm (1 cmH
2
O) without necessity. It
can cause false triggering because of different kinds of noise of auto trigger-
ing.