Tafonius
Auxiliary Mode Operating Manual
Printed: 28/Feb/11
Page 9 of 15
DOCA4956
displays any error or warning messages. The battery information shows the actual voltages
of the two batteries used in
Tafonius
and whether or not they are being charged When
there are no warning or error messages, the name
TAFONIUS
is displayed.
2) Piston Graphic and Information
Area 2 shows a representation of the piston. The dark area shows the volume of gas in the
piston and the numerical value at the top of the list to the right gives the amount in litres.
See the photo on the front cover as the piston in the photo above is at the bottom with 0.0
litres under it. The piston position and volume is constantly updated and shows the position
of the piston at all times. Two asterix (* *) will appear at the top of the piston area whenever
the Dump Valve, an electric pop-off valve, is open.
Below the volume display in litres are three settings that are not otherwise always display on
the screen.
MWPL
The Maximum Working Pressure Limit in cmH
2
O is generally seen above the right most
control knob used to set its value however it will not be displayed there when using the
Assist Mode. The MWPL is set as a high pressure safety limit the value of which is
continuously compared to the breathing system pressure.
Tafonius
is a volume or time
cycled ventilator so the MWPL does NOT set how high the pressure will go but if the
pressure should reach the set level the machine will alarm and immediately, terminate
inspiration and switch to the expiratory phase of the breathing cycle.
ASSIST
The ASSIST function is a mechanism that detects a patient’s efforts to breathe then gives
an assisted breath if that effort meets or exceeds a user set minimum level. The value next
to the text
ASST
is the level of inspiratory flow, in liters per minute, the patient must
generate or exceed to trigger and assisted breath.
In STANDBY mode
In STANDBY, spontaneous breathing, mode this effort level can be set but is not active until
the IPPV/RUN button is pushed. To use the ASSIST function, press the ASSIST button
once, the ASSIST button will flash slowly and the MWPL legend on the auxiliary screen will
be replaced with the text “SENS” for sensitivity followed by a value e.g. 60 LPM. This value
of 60 litres per minute is the inspiratory flow rate that the patient must meet or exceed in
order to trigger the next IPPV stroke. This will not happen unless the ventilator is in IPPV
mode. Pressing the RUN/IPPV button will cause the IPPV button to be lit and the ASSIST
button will then remain lit continuously.
In IPPV mode
Alternatively the ASSIST mode can be chosen when the patient is receiving IPPV. In this
case the ASSIST mode will be lit continuously to show that the ASSIST mode is active. In
this state the ventilator is waiting for an effort from the patient. If this effort level is not met
within the time required for 3 breath cycles based on the set RR a mandatory breath is
given. If the patient triggers a breath then the timing of the mandatory breath is reset. In
either case, the delivered breath will be based on the set TV and I-time. Pressing the
RUN/IPPV button will return the ventilator to spontaneous mode and cancel the ASSIST
function.
This is a new feature and we currently have no guidelines on values to set. The software
offers a range of between 1 LPM and 200 LPM as trigger values. We would welcome
feedback on the settings found useful or normal in practice.
3) Resultant Ventilation values
Area 3 shows the values that result from the settings of the independent variables Tidal
Volume, Respiratory Rate and Inspiratory Time. The dependent variables displayed in this
area are Minute Volume (MV) in liters per minute (lpm), Inspiratory Flow Rate (IF) in lpm, I:E
