Maquet Servo ventilator 900 C, Руководство по обслуживанию

Страница: 31 / 55

31
= Not valid for SV 900 E
= Not valid for SV 900 D
Electronic unit – Timing
End insp. indicator (PC board no 5)
In all modes which include spontaneous breathing.
(PRESS SUPPORT, SIMV and SIMV + PRESS. SUPPORT
and CPAP the moment when the spontaneous inspiration
is about to stop is normally determined in this stage (a
START EXP. SPONT signal is generated).
Criteria no 1. for this is when the measured flow drops
below 25% (V22:2/R53. R76) of the PEAK FLOW during
the same inspiration (V16:1/C13) if the PEAK INSP. FLOW
is higher than 0.1 l/second.
Closed inspiratory valve and a pressure increase of
+3 cm H
2
O will also result in a STARTEXP SPONT. signal
to INSP. TIME & EXP. TIME GENERATOR (criteria no 2).
This signal makes INSP. TIME end even if the peak insp.
flow is lower than 0.1 l/s.
See table on page 32.
Man. vent. timing (PC board no 7)
This stage receives the AIRWAY PRESURE (I) signal from
the inspiratory pressure transducer. This signal goes to the
comparator (V1d:12, 13, 14) which controls the manual
ventilation EXP. TIME., and to (V1c:10, 9, 8), which controls
the manual ventilation INSP. TIME.
The INSPIRATION TIME in this case, means the time
during which the manual breathing bag will be filled.
This will start when the pressure drops below
approximately 2 cm H
2
O and it will stop when the
pressure rises above approximately 4 cm H
2
O
(comparator V1c).
The expiration will take place if the pressure
drops below approximately 4 cm H
2
O and will stop
if the pressure rises above approximately 6 cm H
2
O
(comparator V1d).