Instructions for use Babylog 8000 plus SW 5.n
161
Principles of operation
Additional settings for ventilation
Volume Guarantee (VG)
The mandatory mechanical breaths are volume
controlled with the additional setting
VG
. The
device regulates the inspiratory plateau pressure
automatically in order to apply the selected tidal
volume. Changes in the mechanical properties of
the respiratory system are compensated. The tidal
volume of the mandatory breaths remains
constant.
Volume Guarantee can be used in the
SIPPV
,
SIMV
, or
PSV
ventilation modes. The following
diagram provides an example of the
SIMV
ventilation mode with Volume Guarantee.
The advantage in contrast to time-cycled,
pressure-limited ventilation is that changes in the
resistance or compliance of the respiratory system
have no impact on the tidal volume. If, for example,
compliance increases, the inspiratory pressure
decreases automatically. Conversely, the pressure
increases as compliance decreases, but only until
the selected pressure limitation
Pinsp
.
Fluctuations in spontaneous breathing are also
compensated. The stronger the patient breathes,
the less pressure the ventilator applies. Thus, with
Volume Guarantee, the device always ventilates
with the right pressure required for the tidal volume
desired. The pressure load on the lungs is limited
to the extent absolutely necessary.
Without Volume Guarantee, the user must adjust
the inspiratory pressure to reach the tidal volume
desired.
Regulation works in the range from
PEEP
to
Pinsp
. The user determines the maximum
pressure the device may apply via
Pinsp
.
In the following situations, the regulator cannot
reach the target volume:
–
Pinsp
is insufficient.
– The inspiratory pressure pattern has no
plateau because the flow is too low or
TI
is too
short.
In both cases, the device displays an alarm
message if the actual tidal volume remains below
90 % of the target volume.
When the PEEP is set to <2.5 mbar (2.5 cmH
2
O),
additional ventilation and patient monitoring must
be used because disconnection or extubation
cannot be reliably detected by the integrated
pressure monitoring system, and an alarm cannot
be triggered, see page 12.
Regulation is stepwise from spontaneous breath to
spontaneous breath. The expiratory tidal volume
(A) is measured, then compared to the target
volume and a new plateau pressure is calculated
for the next spontaneous breath. After a change to
the target volume, the inspiratory pressure
required for this is reached after approx. 7 breaths.
21
174
Paw
Pinsp
PEEP
TI
Flow
t
A