Trigger Response - Dräger Medical NeoFlow Addendum To Operating Instructions

Theory of Operation – Special Features of Neonatal Ventilation

Trigger Response

Trigger Response
In neonatal mode, Evita detects a patient's spontaneous
XL
breathing using the neonatal flow sensor proximal to the
patient. When spontaneous inspiration is detected, a
synchronized, mechanical, and pressure controlled breath, or
a pressure support breath is triggered according to the
selected mode of ventilation.
In order to avoid incorrect triggering due to leak flows, Evita
not only takes into account the flow signal from the neonatal
flow sensor (Flow ) but also the calculated leak flow
insp
(MV ). For this purpose, the leak flow is referenced to the
Leak
momentary pressure level (P
Flow = Flow
Patient, insp insp
Flow : Patient flow
Patient
Flow : Inspiratory flow, without correction for leak
insp
MV : Leakage minute volume – mean leakage flow,
Leak
averaged over inspiration and expiration
P : Airway pressure at the Y-piece
AW
P : Average airway pressure at the Y-piece
mean
Spontaneous inspiration is only detected if the corrected
measured value of the neonatal flow sensor exceeds the set
flow trigger threshold. The trigger threshold covers a range
from 0.3 L/min to 15 L/min, but only the range from 0.3 L/min
to 3 L/min is recommended for neonatal ventilation.
The trigger threshold should be set so that self-triggering is
just avoided.
If the neonatal flow sensor in neonatal mode is defective,
Evita can no longer detect attempts at spontaneous
XL
inspiration, and therefore cannot trigger a ventilator breath.
42
):
AW
– MV * P / P
Leak AW mean
XL