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14.1.7 Parameter Memory
The user should be aware that the ventilator will
remember user parameter settings when switching
between modes, except when switching between a
ventilatory mode and Ventilation Off. When
switching from a ventilatory mode to Ventilation Off
and then back to a ventilatory mode the ventilator
resets all parameters to the default values. Though
when the setting is remembered between ventilatory
modes the parameter title may change. An example
is the CPAP parameter in CPAP mode becomes the
PEEP parameter in CMV mode.
14.1.8 BPM or Backup, Measured and Set
Parameters
The user needs to be made aware that the BPM Tot
in the lung mechanics and measurement panel is
updated every 2 seconds, so it may not correspond
immediately with the set value which is for breaths
in one minute.
14.1.9 Tidal Volume Parameter Resolution
The tidal volume parameter control has three
different resolutions.
From 2ml to 10ml the parameter increments in
0.2ml steps (Fine resolution).
From 10ml to 100ml the parameter increments in
1ml steps (Standard resolution).
From 100ml to 200ml the parameter increments in
5ml steps (Coarse resolution).
14.1.10 Displayed O
2
%
If at any time the user believes that the O
2
% reading
has drifted, the user should re-calibrate the oxygen
sensor. The oxygen sensor can be calibrated from
the services panel. (See ’10.6 Services Panel’ on
page 38)
14.1.11 HFO mode, Mean & Delta P Parameters
In HFO Only mode the set values for Mean and
Delta P are not displayed in the parameter control,
only the measured values are displayed. The Mean
and Delta P controls do not show the precise set
values, because they should not be used as a guide
for the resulting proximal pressure. The Mean and
Delta P readings are affected by the dynamic lung
characteristics.
14.1.12 HFO variable I:E ratio
The variable I:E ratio allows the user to increase the
expiratory phase in proportion to the inspiratory
phase by the indicated ratio 1:2 or 1:3.
14.1.13 HFO Mean compensation
HFO Mean compensation only functions in HFO
Only mode.
HFO Mean compensation reduces the inadvertent
mean resulting from larger Delta P or higher
frequencies.
HFO Mean compensation uses feedback from the
measured HFO mean to control the set mean.
The ventilator looks at the measured mean and the
set mean and moves the HFO waveform (up or
down), back to the set mean. The compensation is
limited to 10mbar of the set mean, beyond the
10mbar compensation threshold the ventilator will
allow the mean to increase.
Example A Example B
Set Mean of 10mbar Set Mean of 10mbar
Measured mean 12mbar Measured mean
24mbar
Mean pressure reduced Mean pressure reduced
by 2mbar by 10mbar (Maximum)
Displayed mean 10mbar Displayed mean
14mbar
The ventilator uses a feedback system to
compensate the Mean pressure, and the user may
find that the HFO mean may undulate slightly. There
is the facility to switch the mean compensation OFF.
The HFO mean compensation can only be turned
ON or OFF when the ventilator is in “Ventilation
Off” mode.
Warning: Inappropriate changes in the I:E
ratio may result in a reduction of the volume
for each HFO pulse and the subsequent
minute volume delivered to the patient.
Secondary monitoring of TcPO
2
may be
required.
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