Blease 8500 Installation guide

8500 Ventilator Training Manual
1
Blease
8500
Anaesthesia Ventilator
Training Manual
Part Number: 129TM000
Issue 3
0120

8500 Ventilator Training Manual
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Read this manual before servicing the 8500
Ventilator

8500 Ventilator Training Manual
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Contents
1. Mode Descriptions for the 8500
2. Test Procedures
Adjustment and Calibration Document 129AC000
Checklist and Calibration Record Document 129TC000
Final Test Procedure Document 129TP000
3. Circuit Diagrams
Interconnection Diagrams
8500 Electrical Interconnection
6500/8500 Pneumatic system Diagram
Display
Blease Display Interface 10100190
Pressure Interface
Pressure Interface 10110088
BAV Controller
BAV Controller Type 2 Alarms 10110077
BAV Controller Type 2 Analogue 10110077
BAV Controller Type 2 Connect 10110077
BAV Controller Type 2 CPU 1010077
BAV Controller Type 2 I/O Circuits 10110077
BAV Controller Type 2 Memory 10110077
BAV Controller Type 2 PWM 10110077
Power Supply
BAV Power Supply 101CD076

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The Blease 8500 ventilator must only be serviced by Qualified Service Personnel.
The contents of this manual are not binding. If any significant difference is found between
the product and this manual please contact Blease Medical Equipment Limited for further
information. To ensure correct functioning, the equipment must be serviced at regular in-
tervals.
Blease Medical Equipment Limited recommends that the machine should be serviced at
intervals not exceeding three months. Qualified Service Personnel and genuine spare
parts should be used for all servicing and repairs. Blease Medical Equipment Limited will
not otherwise assume responsibility for the materials used, the work performed or any pos-
sible consequences of the same.
In communication with Blease Medical Equipment Limited, quote the model and serial
number of the equipment, with the approximate date of purchase. If the unit is being re-
turned for repair, indicate the nature of the fault or the work you require to be carried out.
Contact:
Blease Medical Equipment Limited
Beech House
Chiltern Court
Asheridge Road
Chesham
Buckinghamshire
HP5 2PX
England
Tel: [phone]
Fax: [phone]
www.blease.com
[email protected]

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2
MODE Descriptions for the 8500s
PEEP
Control Panel
The Control panel has a permanent display of measured PEEP and a button to actuate
the setting of the desired value.
The display box will have the heading “PEEP” and show the “SET” value.
The default is that PEEP will be at the minimum setting ie. the residual that is < 2 cmH2O
caused by the bellows assembly. In this default condition or if the Set value is subse-
quently set below 3 cmH2O the set value display will show as “OFF”.
The method of control is that the user will rotate the Trak Wheel until the desired display is
highlighted, press the Trak Wheel and then increase the set value by rotating the Trak
Wheel until the desired value is reached, this is then accepted by a further press of the
Trak Wheel.
The range of set values will be 3 to 20 cmH2O. An alarm will be implemented to indicate
to the user that the set value has not been maintained. The alarm will activate at ± 50 %
of the set value.
The activation of a set value will be made by pressing the Trak Wheel. If this is not
done no change will be made and the previous value will be reset after a time out
period. This is to apply to all controls.
The implication of PEEP on other alarms is that the Pressure and cycle alarms will be
PEEP referenced, the pressure Limit will be absolute. ie. Referenced to atmosphere
Control System
For the control system to effect PEEP two functions will need to be activated :-
1. During the expiration phase of the breathing cycle or continuously in Spontaneous
mode the flow control valve will pass 10 LPM of diving gas.
2. A pulse width modulator will control the power to the coil of a PEEP valve. This
valve is a voice coil actuator working as a variable spring applying a force to a disc
that impinges on a seat. The implication being that the valve is closed until the gas
pressure exceeds the actuator force.
The control processor will monitor the PEEP value and modify the PWM setting to main-
tain the desired value.

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Future Improvements
In the 8500s ventilator there is a monitor that measures the fresh gas flow of the anaes-
thetic machine. The 10 LPM gas flow from the Flow valves in 1 above is an arbitrary fig-
ure that has been arrived at empirically. This flow can be reduced substantially at low fresh
gas flow rates. It only requires high drive gas flows with high fresh gas flows to maintain
PEEP. This could obviously save gas which would be helpful when using cylinders for sup-
ply.
Volume Control ventilation (CMV)
Volume Control ventilation is a mechanical mode that delivers a tidal volume set by the
user into the patient tubing. This delivered volume is to be independent of the compression
losses in the absorber, bellows and associated tubing. It will also be independent of any
small leaks that may be present. Fresh gas flowing into the breathing system will not
cause a permanent change in the delivered volume. If a change in fresh gas flow rate oc-
curs during ventilation the ventilator will re-adjust the delivered tidal volume to be correct
within the next 4 breaths.
8500s Ventilator Fresh Gas and Compliance Compensation
Fresh Gas
Fresh gas flow adds to the delivered Tidal Volume during the inspiratory period. To com-
pensate for this, a reduction in the delivered volume needs to be made. This reduction is :-
FG Flow rateml / M x Insp Time (sec)
60
Take FG = 5 LPM TV 600 ml 10 BPM I:E 1:2.0
5000 x 2 seconds = 166 ml
60
New Effective TV is now 600 -166 = 434 ml
Compliance
The effect of the gas being compressed in the dead space within the breathing system is to
reduce the Volume (TV) that is delivered to the patient. In an ideal ventilator the Set TV
would the volume of gas that is delivered to the patients lungs. This can only be partly
achieved because the anatomy of the patient is unknown, what can be done is the set TV
can be made to be accurately delivered from the catheter mount. Thus reducing set TV er-
rors to a minimum.

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To calculate the effect of Breathing System compliance on the delivered TV it is necessary
to measure what the capacity or compliance of the system is (Cs). This can only be done
by some form of pre-use check procedure. In essence it is necessary to have the ability to
first of all select “Compliance Compensation” from a menu. It is then necessary to lead the
user through the process of measuring the dead space within the particular breathing sys-
tem for that period of use. It is obvious that should the system be re-configured the test
will need to be repeated.
A possible process is to allow the ventilator to prompt the user to :-
1. Reduce the FG flow to minimum (but Allow for it as above)
2. Occlude the catheter mount. This can be a 15 mm male taper on the gas machine.
3. The ventilator then delivers a breath to pressurize the system to 10 cmH2O.
4. The ventilator records the volume required to achieve this pressure and verifies that
a leak is not present.
The dead space is now calculated as follows :-
Volume in ml = Dead space compliance Cs
Pressure
This figure is stored until the ventilator is switched off or a re-test is asked for by the user.
The ventilator is then set to use on a patient and when the ventilation is stable measure
the total compliance of system and patient Ct. An adjustment can the be made to the TV
that will be increased to compensate for the lost volume due to compression within the
breathing system. :-
Increase in TV = Set TV x1 + Cs = new TV
Ct-Cs
eg.
System test Measurement using 200 ml gave 25 cmH2O pressure rise.
80 ml =Cs=8
10 cmH2O
Running the ventilator on a patient with a set 500 ml TV gave 20 cmH2O peak pressure .
500 ml =Ct=25
20 cmH2O
So to calculate the TV increase :-
500 x 1 + 8 =735 ml
25 -8

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So 735 ml is the actual ventilator output into the breathing circuit to give 500 mL at the
catheter mount.
This figure would have to be recalculated in the light of any fresh gas flow change as
above but would just be a variation on the 735 ml figure.
Pressure Control ventilation (PCV)
Pressure control ventilation is a time cycled mode where the ventilator strives to produce
the user set inspiration pressure for the inspiratory period. To accomplish this goal, the in-
spiratory flow rate and pressure are set by the user. To do this, the control that is used for
the Set TV function will be reasigned as “I Flow” and calibrated in LPM. The pressure
Limit control becomes the “Set Pressure” control. This allows the user to define the deliv-
ered wave form. The default pressure will be 30 cmH2O in both Adult and Paediatric
modes.
Inspiratory Pause
A function that is “Inspiratory Pause” is to be implemented. This option will be available in
volume and PCV mode such that a pause of 25% of the inspiratory time is used as a Pla-
teau before starting the expiratory phase. This means the expiratory time is reduced by
the plateau time. If at all possible the pause or plateau time should be made variable from
5 to 60 %. The x % should be displayed on the second row up of the display.
Sigh
Sigh is a function that can be selected in volume or Pressure ventilation the effect is that
every 50 breaths the delivered breath is increased by 15 %. The selection of this function
will be displayed as an extension to the main mode display under the bar graph.
Spontaneous or PSV
Spontaneous is a mode that is equivalent to the machine being in standby with all moni-
toring enabled. This allows a patient to breath at their own rate and volume with the venti-
lator being able to display the monitored parameters and actuate alarms. At this level the
Breathing rate would be a monitored parameter, it should follow the same pattern as other
features in that it will display the monitored value in large characters and show Pressure
Support Ventilation “PSV” as the mode.
Pressure Support
When a patient is taking a “Spontaneous Breath” from an anaesthetic system the work of
breathing is higher than normal. To overcome this it is desirable for the ventilator to be
able to assist the spontaneous breath. The assistance is provided by the ventilator sens-
ing the negative pressure caused by the “Patient Attempt” to breath and initiating flow
from the ventilator. This flow is continued to the point where the breathing circuit pressure
has reached a set value. ie. Pressure Support. To implement this action the user needs
to be able to set first the trigger threshold in the range -1 to -10 cmH2O and secondly the
Support Pressure 0 to 30 cmH2O both referenced to the PEEP level.

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It will also be necessary to define an inspiratory time in which the pressure support is deliv-
ered. In this case the breathing rate and tidal volume are not relevant. The Inspiratory
flow rate will be a fixed value of 40 LPM in Adult and 30 LPM in Paediatric.
The detection of a “Patient Attempt” will be carried out by the control system to aid
the speed of support. A patient attempt will be indicated on screen by the negative
excursion of the pressure wave form being green rather than blue for the positive
phase.
SIMV
This mode is Synchronised Intermittent Mandatory Ventilation. This is an extension of the
spontaneous mode in so far as the patient can take breaths on demand with pressure sup-
port but some mandatory breaths are included. To achieve this it is necessary to set a
tidal volume, a breathing rate and all of the features described above for pressure support.
To simplify things a little the inspiratory flow rate can be assumed from the TV / Inspiratory
Time set values.
The patient attempt or trigger signal will be used to synchronise the mandatory breaths to
the patients breathing pattern and initiate the pressure supported spontaneous breaths.
Thus allowing the patient to establish the breathing rate.
In this way a patient could be breathing at say 12 BPM with the settings such that 4
breaths of say 500 ml are mandatory and 8 breaths are taken spontaneously with pressure
support of up to 30 cmH2O above the PEEP level.
The ventilator will monitor all of the breaths, display the parameters TV / BPM / I:E and in-
dicate the patient attempt by showing negative excursions of the graph in RED. The set
breathing rate and measured rate will be displayed, the Set Inspiratory time and I:E ratio
will be displayed in the appropriate window.
A means of preventing hyperventilation will be implemented such that any change in
breathing rate is only allowed to take place slowly.
The method of inflating the patient's lungs and the operation of the valves and the gas
flows in the SIMV mode are the same as for the CMV mode.
The main difference between this mode and CMV is that a facility is provided for synchro-
nising the mechanical breaths given by the ventilator to the patient's own respiratory ef-
forts (spontaneous breaths).
If the patient fails to make any effort, then SIMV will default to ventilation functionally iden-
tical to CMV at the set SIMV rate.
The routine within the ventilator that detects the Patient Trigger is used to detect the in-
stant a patient starts to inhale and is thus ready for a synchronised breath to be given by
the ventilator. Whether a breath is spontaneous or mandatory depends on where it occurs
in the SIMV cycle.

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This can be explained as follows :-
1. The frequency control sets up an internal clock tick in the ventilator. The time be-
tween clock ticks is the Set breathing period and is equal to a time in seconds of
60/frequency in BPM. ie. 4 BPM = 1 tick every 15 seconds
With no patient triggers detected, the ventilator will deliver a mechanical breath at
the start of each respiratory period on the clock tick.
2. Preceding each clock tick is a time window in which the ventilator will be looking
for a patient trigger. If a trigger occurs within the window the patient will be given a
synchronised mechanical breath. If it occurs outside the window it will be a sponta-
neous or Pressure Supported spontaneous breath depending on the ventilator set-
ting.
In practical use of the SIMV mode, the ventilator should first be set at an adequate
RATE, TIDAL VOLUME, I:E RATIO, PEEP and PRESSURE LIMIT for controlled
ventilation, say 600 ml, 12 BPM and 1.5 secs for an adult patient. When patient
trigger signals are being displayed regularly the mandatory rate can be reduced
and the total breathing rate will be controlled by the patient. If this rate is inade-
quate the the low MV or Rate alarm will be activated.

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Vol Rate I:E Press Limit Vol Alm
Lo / Hi Press Alm Lo / Hi
Adult 500 ml 12 1:2.0 50 4 / 10 4 / 55
Paed 150 ml 20 1:2.0 40 1 / 6 4 / 45
Vol Rate Insp
TIME Press Limit Vol Alm
Lo / Hi Press Alm Lo / Hi
Adult 500 ml 12 1.5 50 4 / 10 4 / 55
Paed 150 ml 20 1.5 40 1 / 6 4 / 45
Support
Pressure Rate Alm
Lo / Hi Vol Alm Lo / Hi Press Alm Lo / Hi
Adult 10 5 / 25 4 / 10 4 / 50
Paed 10 10 / 35 1 / 6 4 / 40
Mode Sigh Pause Press SuppPEEP MV Alm Rate Alm Press Alm
CMV üü üü üü üü üü
Spont üü üü üü üü üü üü
SIMV üü üü üü üü üü üü
PCV üü üü üü üü üü
CMV Defaults at start up
Matrix of Modes, Facilities and Alarms
Spontaneous Defaults at start up
SIMV Defaults at start up

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Insp
Flow Insp TIME Support Pressure Press Limit Rate Alm
Lo / Hi Vol Alm Lo / Hi Press Alm Lo / Hi
Adult 30L 1.5 10 50 5 / 25 4 / 10 4 / 55
Paed 20L 1.5 10 40 10 / 35 1 / 6 4 / 45
Insp
Flow Ventilation Pressure Rate Press Alm
Lo / Hi
Adult 30L 30 12 4 / 50
Paed 20L 20 20 4 / 40
Spontaneous with Pressure Support Defaults at start up
Pressure Control Ventilation Defaults at start up
Default for all Modes is “PEEP off” in PCV the maximum PEEP available will be limited to
6 cmH2O.
If PEEP is set, the default “PEEP Alarm” will be ± 50 % in the range 0 to 30 cmH2O
The Rate or BPM alarm is to be the set value ± 50 % or in SIMV mode Lo 10 hi 20 BPM.

Blease Test Procedure
Title: 8500 Adjustment & Calibration Document No:129AC000 Sheet 1of 12
Issue 123456
Change Note No n/a 3724 3829 3487 3866 3935
Originator JLB JLB JLB JLB JLB JLB
Checked DB RHC RHC RHC RHC
Date Nov 00 Dec 00 June 01 July 01 28/08/01
BLEASE QUALITY DOCUMENT
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1.0 OBJECTIVES
To set up and calibrate the Blease 8500 Anaesthesia Ventilator. A final test (129TP000) must
also be followed to obtain a set of calibration results.
2.0 SCOPE
This test document is applied to new manufactured units before burn-in and after warm up,
and/or when any repairs have been completed on the ventilator.
This procedure is only valid for software versions 8.20 and 8.60 onwards.
3.0 OVERVIEW
The following procedure describes the adjustments and checks necessary to calibrate the
ventilator and set all the pre-set controls to achieve the specified performance. Inability to
make these adjustments, or failure to meet the specification, after these adjustments have been
made, must be considered a fault.
The procedure given in section 4 is written so that minimum adjustment of controls and test
equipment is done between each test. This means that any particular test assumes all previous
tests have been set up IN THE SEQUENCE STATED and passed. If this is not done, invalid
results may be taken.
4.0 ADJUSTMENT AND CALIBRATION
All quoted test parameter values and tolerances are absolute with no allowance made for test
equipment errors unless otherwise stated in the text. At appropriate points during this
procedure the route card should be updated to reflect the key stages of calibration.

Blease Test Procedure
Title: 8500 Adjustment & Calibration Document No:129AC000 Sheet 2of 12
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4.1 Test Apparatus
4.2 Initial Checks
4.3 Reference Voltage and Electrical Supplies
4.4 BAV Controller PCB
4.5 Display Interface PCB
4.6 Main Pneumatic Regulator Calibration
4.7 Calibration
4.8 Flow Control Set-up
4.9 Zero Offset Connection
4.10 Pressure Sensor Gain
4.11 Delivered TV Calibration
4.12 Hardware Pressure Overload Backup
4.13 Fresh Gas Flow Sensor Calibration
4.14 Saving Data and Printer Check
4.15 O2Monitor Calibration
4.16 PEEP Calibration
4.17 Font Panel Calibration Adjustment
4.18 Parameter Checking
4.19 Assembly Completion and burn in
4.1 Test Apparatus
•Digital Voltmeter to measure the 4v reference supply.
•Timeter RT-200 Calibration Analyser with following options fitted: RT-201 Control
Module, RT-202 Press Module, RT-203 Flow Module, or another calibrated calibration
analyser with the required functionality.
•IBM PC (compatible) ANSI terminal emulator running on serial interface. 9600 baud,
8-data bits, 1 start bit and 1 stop bit.
•Digital storage scope or chart recorder for monitoring drive gas flow waveform.
•Ventilator programming cable (12600015). For programming and diagnostics through
calibration port.
•Front Panel programming lead (12600016).
•Miscellaneous 17mm/22mm pneumatic tubes.
•O2sensor simulator. (68A –68D)
•20 ± 1 L compliance. (C20), 5 ±0.25 L compliance
•20 ± 2 cmH2O /L/s resistance. (R20)

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4.2 Initial Checks
BAV Controller Board 10110077
Check all links are fitted correctly and securely.
•JP2 link pins1&2
•JP5 link pins 2&3
•GND & AGND
•No links to be fitted to JP1 & JP3
PSU Board 10100076
•LK2 and LK3 on PSU board both have links fitted.
Display Interface Board 10100190
•Ensure J15 has pins 3 & 4 linked
BAV Interface Board 10110075
4.3 Reference Voltage and Electrical Supplies
With nominal mains input applied, switch ventilator ON in standby mode.
Check the following voltages are correct before proceeding any further:
•+24V Valve supply PSU TP6 = +25.0 ±2.0V
•+25V unregulated PSU TP2 = +26.5 ±3.0V
•Battery voltage PSU TP4 = +14.0 ±0.8V
•A-5V analogue supply CPU-5VA = -4.20 ±0.3V
•A+5V analogue supply CPU+5VA = +5.0 ±0.25V
•ALM+5V alarm supply PSU TP7 = +5.0 ±0.25V
•D+5V logic supply CPU 5V = +5.0 ±0.25V
•+6V main supply PSU TP3 = +6.05 ±0.3V
•+4VREF CPU 4V REF =+4000±60mV
4.4 BAV Controller PCB
To program the controller board connect the ventilator serial cable (12600015) between the
calibration port connector on the back panel of the 8500 & a PC. Run the flash for front and back
flash programming utility on the PC under windows & download the latest BAV.ABS opcode
file.

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4.5 Display Interface PCB
First time program
Ensure that JP2 has a link fitted & JP1 has a link fitted between pins 1 & 2, prior to switch on.
Connect a serial cable (12600016) between J10 & a PC & run the Hitachi flash programming
utility to load the H8/3048 microcontroller.
Select connect from the command menu, select BOOT mode and then OK to load the boot
kernel.
Once the kernel has been downloaded select program for the command menu, the
LOAD386.A20 absolute opcode file will be loaded.
Switch off 8500 remove the link on JP2 & move the link on JP1 to between pins 2 & 3.
Switch on the 8500 and run the flash for front and back program, select the A20 absolute opcode
file, followed by open to download the file.
After the first time programming of the display interface board, ensure JP1 has a link between
pins 2 & 3 and JP2 has no link fitted.
Re-program
Connect the ventilator serial cable (12600015) between the calibration port connector on the
back panel of the 8500 & a PC.
Run the flash for front and back utility under windows on the PC; select the A20 absolute
opcode file, followed by open to download the file.
Enter the save menu on the 8500, select configuration, and enter the password PRAAA in the
set-up menu.
Select re-program
4.6 Main Pneumatic Regulator Calibration
Remove the plug from the side of the pneumatic block and connect a pressure gauge to this port.
Select adult mode.
Using a DVM check that JP4 is open.
Connect gas supply.
Adjust the supply pressure to 35 psi/37 PSI Max
JP4 should now be closed.
The pressure switch should be adjusted so that as the supply gas is reduced, to between 35 & 37
PSI, the switch opens (on JP4).
Check the switch is reset by the time the supply pressure is raised in excess of 2 PSI beyond the
stated alarm pressure.
Note: to run the Blease Medical Test I/O Diagnostics connect the ventilator serial cable between
the recorder output connector on the back panel of the 8500 & a PC. Run Hyper Terminal on the
PC using the stored 8500 HT settings file.

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Press CTRL+E on the PC followed by the up cursor key. Page through the diagnostics using the
TAB key & scroll through using the UP/DOWN cursor keys.
Select Blow off valve ref. Pressure. Set a flow of 1 LPM, the flow rate can be adjusted using
the Tidal Volume control.
Set main regulator output pressure = 34.0 ± 0.5 PSI while ventilator is in standby mode.
Turn ventilator off and remove gas supply.
Remove pressure gauge and replace plug.
4.7 Calibration
Initial Calibration
Prior to calibrating the unit ensure that the switch, encoder and all the membrane key switches
perform their expected functions.
Note: to run the Blease Medical Test I/O Diagnostics connect the ventilator serial cable between
the recorder output connector on the back panel of the 8500 & a PC. Run Hyper Terminal on the
PC using the stored 8500 HT settings file.
Press CTRL+E on the PC followed by the up cursor key. Page through the diagnostics using the
TAB key & scroll through using the UP/DOWN cursor keys.
On page 1 set gas to that specified by the model number, use right cursor, set gas convert to
Norm.
Adjust RV2 on the Interface board for –50 mV +/-10 mV at FGZ test pin.
Select Patient airway pressure zero, to cal press Space Bar
Select Drive gas pressure zero, to cal press Space Bar
Select Flow gas pressure zero field
Adjust RV3 on the Interface board for a Flow gas pressure zero adjustment parameter of 600 ±
5, press spacebar to update display. When achieved press Space Bar to save.
Select Patient Flow Pressure Zero.

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Adjust RV1 on the Interface board for 0V +/-10mV at PFZ test pin.
Press Space Bar to save.
Press Ctrl+U to save zeros.
Leak Test and Absorber Switching
Absorber switching
The function of this will have been checked during compliance compensation and the
presence of an absorber will have been displayed.
Fresh gas leak test
Connect spirometry tubing 10110089 from TJ92 to the fresh gas connections on the rear of the
ventilator. Each side of the circuit is checked by pressurising it to 80 mmHg and checking that
the pressure is maintained.
Patient Flow transducer leak test
Connect spirometry tubing 10110089 from TJ92 to the patient connections on the rear of the
ventilator. Each side of the circuit is checked by pressurising it to 80 mmHg and checking that
the pressure is maintained.
Drive Flow Sensor Leak Test
Note: to run the Blease Medical Test I/O Diagnostics connect the ventilator serial cable between
the recorder output connector on the back panel of the 8500 & a PC. Run Hyper Terminal on the
PC using the stored 8500 HT settings file.
Press CTRL+E on the PC followed by the up cursor key. Page through the diagnostics using the
TAB key & scroll through using the UP/DOWN cursor keys.
Tee in to the drive gas outlet the pressure monitor and then block the flow sensor outlet.
Select Blow off valve ref. pressure. With the flow sensor outlet blocked the internal pressure
will build up until the Blow off valve operates.
Using an oscilloscope monitor the voltage at test point DF on the BAV Interface Board
10110099 this voltage will remain stable whilst the monitored pressure is stable if there are no
leaks.
Once this test is complete restart the ventilator by pressing CTRL + E.
Run the ventilator for 3 hours on default settings, but with BPM set to 30.

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Fine calibration
Ensure that unit is in cal standby.
Note: to run the Blease Medical Test I/O Diagnostics connect the ventilator serial cable between
the calibration port connector on the back panel of the 8500 & a PC. Run HyperTerminal on the
PC using the stored 8500 settings file.
Press CTRL+E on the PC followed by the up cursor key. Page through the diagnostics using
the TAB key & scroll through using the UP/DOWN cursor keys.
On page 1 set gas to that specified by the model number, use right cursor, set gas convert to
Norm.
4.8 Flow Control Set-up
Connect Gas supply, Flow sensor, Fresh gas sensor and Mains power supply to the rear of the
ventilator.
With no fresh gas supply and the flow sensor disconnected from the test lung, select the
relevant fields; on the flowmeter, watch peak flow on constant not peak.
Select Flow valve just off ref. value.
Press space bar to start auto-find. A series of dots will appear in the value field. Once the lowest
achievable flow has been discerned, the relevant value will replace the dots.
Select Min flow available (use right cursor) enter peak value from the monitor.
Select Flow valve on full ref. value.
Press space bar to start auto-find. A series of dots will appear in the value field. Once the highest
achievable flow has been discerned, the relevant value will replace the dots.
Select Max flow available (use right cursor) enter peak value from the monitor.
Press Ctrl+U to save flows.
4.9 Zero Offset Correction
Select Patient airway pressure zero, to cal press Space Bar
Select Drive gas pressure zero, to cal press Space Bar
Select Flow gas pressure zero field
Adjust RV3 on the Interface board for a Flow gas pressure zero adjustment parameter of 600 ± 5,
press spacebar to update display. When achieved press Space Bar to save.
Select Patient Flow Pressure Zero.
Adjust RV1 on the Interface board for 0V +/-5mV at PFZ test pin.
Press Space Bar to save.
Select Fresh gas flow zero.
Adjust RV2 on the Interface board for -50mV +/-5mV at FGZ test pin.
Press Space Bar to save
Press Ctrl+U to save zeros.

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4.10 Pressure Sensor Gain
Wind both pots fully anti-clockwise on PEEP control board.
Select Blow off valve ref. Pressure. Set a flow of 1 LPM, the flow rate can be adjusted using
the Tidal Volume control.
Tee in to the drive gas outlet the pressure monitor and then block the flow sensor outlet. With
the flow sensor outlet blocked the internal pressure will build up until the Blow off valve
operates. The pressure will then stabilise at this point, shown on the pressure monitor, this
should be 75 ± 3 cmH2O.
If the reading is other then 75 +/-3 cmH2O then adjust the valve.
Select Patient airway pressure gain.
When measured patient airway pressure reaches set value press the Space bar to set gain value.
Select Drive gas pressure gain.
When measured patient airway pressure reaches set value press the Space bar to set gain value.
Press Ctrl+U to save values.
4.11 Delivered TV Calibration
With the flow sensor connected to the test lung (C20 compliance & R20 resistance) via the high
flow port on the monitor, check the default values are set to; TV =500ml, rate = 12 BPM and
Ratio 1:2.0.
Change mode from cal. standby to cal. mode. By pressing STBY/ON switch.
Select Flow gas pressure gain for a delivered output volume of 470ml TV. Adjust the tidal
volume setting until 470ml is monitored, on the external monitor, not the 8500.
Press space bar to save.
Press Ctrl+U to save values.
Select patient flow inspired gain for a delivered output volume of 500ml TV. Adjust the tidal
volume setting until 500ml is monitored, on the external monitor, not the 8500.
Press space bar to save.
DO NOT move the cursor from patient flow inspired gain until the displayed EtidalV value HAS
GONE RED (on third breath) then returned to black.
Select patient flow expired gain, press space bar to set.
Press Ctrl+U to save values.
Change mode from cal. mode to cal. Standby, using STBY key.
4.12 Hardware Pressure Overload Backup
Put the ventilator in cal mode standby. All settings should be at default. Move the cursor to
Sensor Calibration at the top of diagnostics page 1.
With a C5 compliance connected to the drive gas outlet. Put the ventilator into run mode and