EvitaXL

Ventilation Modes
ASB
ASB
Assisted Spontaneous Breathing
Pressure support for insufficient spontaneous breathing.
The function of the machine in assisting insufficient spontaneous
breathing is similar to that of the anaesthetist who manually
assists and monitors the patient's spontaneous breathing
by feeling the breathing bag.
The machine takes over part of the inhalation function, with the
patient maintaining control of spontaneous breathing.
The CPAP system supplies the spontaneously breathing
patient with the breathing gas, even if the inspiration effort
is weak.
The pressure support of the ASB system is started:
— when the spontaneous inspiration flow reaches the set
value of the Flowtrigger,
or at the latest
— when the spontaneous inspired volume exceeds 25 mL
(12 mL in paediatric mode).
The machine then produces an increase in pressure up to the
preselected ASB pressure PASB, which is adjustable to the
breathing requirement of the patient.
The time for this pressure increase is adjustable from
64 milliseconds to 2 seconds.
With a rapid increase in pressure, EvitaXL supports the
patient's insufficient spontaneous breathing with a high peak
flow.
With a slow increase in pressure, EvitaXL begins gently with a
low inspiratory flow. The patient must increase his/her breathing
effort.
With the patient adjusted pressure increase and ASB pressure
PASB the patient defines via his/her breathing activity the
required inspiration flow, which can rise in 8 ms to 2 L/s.
ASB is terminated:
— when the inspiration flow returns to zero during phase I, i.e.
when the patient exhales or fights the ventilator, or
— when the inspiration flow in phase II falls below a certain
ratio of the maximum value previously supplied:for adult
ventilation: 25 % Insp. Flow
for paediatric ventilation: 25 % Insp. Flow
or
— at the latest after 4 seconds (1.5 seconds in paediatric ventilation)
if the two other criteria have not come into operation.
If this time criterion occurs three times in succession,
EvitaXL gives an alarm and warns of a possible leak in the
ventilation system.
216 Instructions for Use EvitaXL
PAW
Insp.
Flow
PASB
CPAP
Start of inspiration
Phase
I II
max. 4 s
End of inspiration
Prescribed ideal
airway pressure
t
25 % Insp. Flow for adults
25 % Insp. Flow for paediatrics
t
021