Digitimer DS7A User manual

Digitimer
Constant Current Stimulator
DS7A (including DS7AH)
OPERATOR’S MAN AL
0120
The DS7A/DS7AH has been Listed for human use
in Europe, USA, Canada and other Countries.
Caution: Federal la restricts this device to sale by or on the order of a physician.
‘Digitimer’ is a registered Trade Mark of Digitimer Limited

Operator's Manual DS7A - Constant Current Stimulator
Product Registration
Please take time out to register your ne product.
Details are included in the General Information Chapter
You can even do it online at:-
.digitimer.com/register
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Operator's Manual DS7A - Constant Current Stimulator
The Digitimer DS7A & DS7AH Constant Current Stimulator
NOTE: Where “DS7A” is ritten is this manual, details apply to the DS7A and DS7AH
unless noted other ise.
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This page is left intentionally blank to provide an insertion place of any changes subsequent to the printing
of this document.
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Operator's Manual DS7A - Constant Current Stimulator
Warning & Caution
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WARNING
For Patient and Operator safety, this manual
should be fully read and understood before use
of this product.
CA TION
Please note that here
“Percutaneous Stimulation”
is referred to in this document, it means
“Electrical Stimulation Through the Skin”
and NOT the use of Needle electrodes.

Operator's Manual DS7A - Constant Current Stimulator
Contact Addresses
Manufactured by: Digitimer Limited
37 Hyde ay
Wel yn Garden City
Hertfordshire
AL7 3BE
UK
Telephone:- (UK) 01707 328347 (Int.) [phone]
Fax:- (UK) 01707 373153 (Int.) [phone]
E-mail:- [email protected] or
[email protected]
Website:- .digitimer.com
Main Representatives:
SA MEPs, LLC
One East Bro ard Blvd.
Suite 700
Fort Lauderdale, FL 33301
Tel: [phone]
Fax: [phone]
E-mail: [email protected]
Japan Miyuki Giken Co. Ltd
Hongo Daiya Building 6F
18-14, 3-Chome, Hongo
Bunkyo-ku
Tokyo 113-0033
Tel : [phone]
Fax : [phone]
E-mail: [email protected]
Germany Helmut Wehking
Vertrieb MedicalProducts
Neuberg 1-b
D-65193 Wiesbaden
Tel: [phone]
Fax: [phone]
E-mail: helmut ehking@ ehking-med.de
Please contact Digitimer for Representatives in other countries.
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Operator's Manual DS7A - Constant Current Stimulator
Purchase Information
A record of salient information, on this page, ill aid the Operator should this information become necessary
in the future.
Date of Purchase: ____________________________________________________________
Dealer: ____________________________________________________________
Dealers Tel. Number: ____________________________________________________________
Dealers Fax Number: ____________________________________________________________
Dealers e-mail address: ____________________________________________________________
Contact name at Dealer:____________________________________________________________
Serial Number of Unit: ____________________________________________________________
Other Notes: ____________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
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Operator's Manual DS7A - Constant Current Stimulator
Product Registration
Why Register your purchase?
Digitimer Limited periodically offers enhancements and updates to our products. Without product
registration, users of our products may miss out on announcements of important enhancements to the
products that they are using.
Digitimer Limited does not make our customer list available to anyone else. Any information that you
provide to us is strictly confidential.
How to Register your purchase
Product registration can be accomplished in t o ays. You may fill out and mail in the product
registration/ arranty card supplied ith each Digitimer Limited product. You may also register on-line at
our www.digitimer.com/register eb page.
Product announcement mailing list
Digitimer Limited has e-mailing lists hich e use as our primary outlet for announcements of ne products,
product enhancements and product updates. We strongly recommend that all users of our products sign up
for the list that is most appropriate to their area of interest. E-mail is kept to a minimum and list
membership is kept in the strictest confidence. Only Digitimer Limited can send mail to members of our e-
mailing lists.
You may join the DS7A mailing list through our www.digitimer.com/register eb page.
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For a speedy response to all your questions no and in the future, please take time out to
register your ne DS7A Stimulator at www.digitimer.com/register no !
Product registration permits us to quickly advise you of any safety matters or ne product
information.
A point of contact for all questions regarding the DS7A is www.digitimer.com/support.
The site’s contents are no gro ing rapidly, so please bookmark it so that you visit it
regularly to check out the ne items.

Operator's Manual DS7A - Constant Current Stimulator
Table of Contents
Warning & Caution...............................................................................................5
Contact Addresses................................................................................................6
Purchase Information..........................................................................................7
Product Registration............................................................................................8
Why Register your purchase?..............................................................................8
Ho to Register your purchase...........................................................................8
Product announcement mailing list......................................................................8
E Declaration of Conformity............................................................................12
FDA – Indications for se..................................................................................13
Equipment Description.......................................................................................14
Regulatory Statements......................................................................................14
EN 60601-1:2006 + A1:2013 Classifications.......................................................14
Environmental..................................................................................................14
Cleaning, Maintenance & Servicing...................................................................14
npacking your DS7A Stimulator......................................................................15
Accessories.........................................................................................................15
Precautions & Warnings....................................................................................15
Product Intended sage....................................................................................18
Indications for se.............................................................................................18
Explanation of Symbols sed on DS7A..............................................................19
Front Panel Controls..........................................................................................21
Notes on Front Panel Controls.................................................................22
Rear Panel Controls...........................................................................................23
Insertion of DS7A Stimulus Output Connector..................................................24
Installation & Initial Check................................................................................25
Stimulus Control................................................................................................26
'Pulse Duration' control.....................................................................................26
'Pulse Polarity' control.......................................................................................26
'Normal' Polarity.....................................................................................26
'Reverse' Polarity....................................................................................26
'Alternating' Polarity................................................................................26
“Too-fast” Warning and Cut-out...............................................................26
'Current max.' control and 'x1/x10' Range s itch...............................................26
'Volts max.' control...........................................................................................27
'Out of Compliance' indicator............................................................................27
Maximum Stimulus Repetition Rates................................................................28
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Operator's Manual DS7A - Constant Current Stimulator
Trigger Out Pulse Duration................................................................................28
Specifications.....................................................................................................30
Stimulus Output......................................................................................30
Trigger...................................................................................................30
Indicators...............................................................................................30
External Fuses........................................................................................31
Internal Fuses........................................................................................31
Dimensions............................................................................................31
Temperature..........................................................................................31
Other.....................................................................................................31
Stimulating Electrodes.......................................................................................32
Mains Connection...............................................................................................33
Mains Plug connections...........................................................................33
Mains Plug fuse......................................................................................33
Mains Voltage Selector............................................................................33
Trigger Polarity..................................................................................................34
Input trigger...........................................................................................34
Output trigger........................................................................................34
Explanation of Symbols sed on Accessories....................................................35
D185-HB1...........................................................................................................36
D185-HB4...........................................................................................................37
D185-TCx - Trigger Cables.................................................................................38
D185-FS1...........................................................................................................39
Connection of DS7A to an EMG System.............................................................40
Introduction.....................................................................................................40
Modes.............................................................................................................40
DS7A - Trigger-Out.................................................................................40
DS7A - Trigger-In...................................................................................40
Setting up the EMG system...............................................................................41
Artefact Rejection.............................................................................................41
Making Trigger Connections to the DS7A...........................................................42
Symbols used in connection ith the Trigger.....................................................42
Description of socket function...........................................................................42
Electrical characteristics of Triggers...................................................................43
Trigger pulse to output stimulus relationship......................................................43
Bibliography.......................................................................................................44
Appendix 1 .. DS7A Modification Record Status................................................46
Ne Instruments.............................................................................................46
Units that have been modified after first delivery...............................................46
The Modifications made....................................................................................46
Appendix 2 .. DS7AH - High Output Current......................................................48
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Operator's Manual DS7A - Constant Current Stimulator
Performance Differences over standard DS7A...........................................48
Safety Considerations..............................................................................48
Appendix 3 .. Operational Tests.........................................................................49
Appendix 4 .. Recurrent Testing of the DS7A....................................................50
Test Procedure.......................................................................................50
Visual Inspection....................................................................................50
Electrical Tests.......................................................................................51
Functional Test.......................................................................................51
Evaluation, Documentation and Preparation for Normal Use......................51
Appendix 5 .. Guidance & Declarations on Electromagnetic Compatibility.......52
Appendix 6 .. Guidance on system integration..................................................56
Warranty Information........................................................................................57
Limited Warranty....................................................................................57
Obtaining Warranty Service.....................................................................57
Product change or discontinuation...........................................................57
Please send any comments regarding this product or manual (omissions, amendments, deletions, problems,
adverse events, etc.) by fax or e-mail, to Digitimer at address in this manual.
Thank you
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Operator's Manual DS7A - Constant Current Stimulator
E Declaration of Conformity
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Operator's Manual DS7A - Constant Current Stimulator
FDA – Indications for se
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Operator's Manual DS7A - Constant Current Stimulator
Equipment Description
This manual is to be used as a reference for operators of the Digitimer DS7A Stimulator.
The Digitimer Stimulator model DS7A provides constant current high voltage pulses of brief duration for
percutaneous stimulation during investigation of the electrical activity of nerve and muscle tissue. The
output current is continuously variable over the range 0 to 100 milliamps, from a source voltage
continuously variable from less than 100 volts to 400 volts, to meet the requirements of human pathological
cases. Short pulse durations have been made available to minimise any discomfort to the subject. The
pulse duration range can be varied from 50 microseconds to 2 milliseconds in six steps. The DS7A no
incorporates a stimulus polarity control hich allo s the operator to select bet een normal, reverse and
alternating polarity modes. A specially designed isolated output stage maintains a square (current) pulse
shape hile minimising stimulus artefacts.
The DS7A is mounted in a non-conductive, flame retardant, free standing case and is mains po ered.
For higher voltages the Digitimer Stimulator model D185 is suggested.
The stimulator accepts an external electrical trigger pulse input and triggers on the factory set edge at
approximately +2.6 Volts. Alternatively a foot s itch may be connected to a socket on the rear panel or the
front panel push button pressed. A TTL compatible Trigger output is provided at a BNC socket at the rear
panel - this can be factory set to have a positive or negative active state.
Regulatory Statements
EN 60601-1:2006 + A1:2013 Classifications
This equipment is CLASS I ith TYPE BF Applied Parts.
This equipment is NOT sealed against any ingress of ater and is therefore IPX0.
This equipment is NOT intended to be used sterile. If it is necessary to remove contamination from the
surface of the equipment, an alcohol moistened cloth may be used. Sterilisation of any electrodes should be
performed according to the recommendations from their manufacturer.
This equipment must NOT be used in the presence of flammable anaesthetic gases.
This equipment is rated for CONTINUOUS operation.
Environmental
This unit does not produce any aste.
As ith all electronic devices, at the end of its life it should be disposed of by a registered aste contractor
ho is made a are of its nature.
Cleaning, Maintenance & Servicing
If the stimulator requires cleaning, it should be unplugged from the mains po er supply and iped ith a
damp cloth.
This equipment does not require any regular maintenance but Digitimer recommends that the DS7A is
returned to the factory for inspection and re-testing every 2 years. Please contact us for a reference number
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Operator's Manual DS7A - Constant Current Stimulator
and instructions before despatching the unit.
For on-site testing, a guide to recurrent testing procedures is given in Appendix 4 of this document.
Before each use - The case and all leads should be inspected for any damage. The equipment (or the lead)
should be sent for repair if any damage is found.
For all servicing requirements please contact Digitimer, ho can advice on best course of action.
Digitimer also offer to supply a service manual (chargeable) to fully qualified, and certified, service repair
centres.
npacking your DS7A Stimulator
Your DS7A Stimulator as delivered in a carton hich as carefully designed to protect the DS7A case
against damage in shipment. It ould be advisable to keep the carton in case you need to relocate or
return your DS7A some time in the future.
Accessories
The follo ing items should have been packed ith you DS7A Stimulator:
1 x Po er Cord, 110 V or 230 V type, depending on your location;
1 x DS7A Stimulator Operator’s Manual.
1 x Safety Certificate for the unit.
If any of these are missing, please contact your Distributor, or Digitimer Limited, immediately.
The follo ing items are optional purchases:
Headboxes (patient connection, extension leads):
D185-HB1 Electrode Connection Headbox ith a 5 pairs of DIN 42 802-1 1.5 mm
“TouchProof” sockets that are colour coded to the original sockets- 4.5m
D185-HB4 Electrode Connection Headbox ith a pair (2) of DIN 42 802-1 1.5 mm
“TouchProof” sockets that are colour coded to the original sockets - 4.5m
Trigger Cables:
D185-TC1 Trigger Cable (BNC - 3.5mm) - 1.5m
D185-TC2 Trigger Cable (BNC - SMB) - 1.5m
D185-TC3 Trigger Cable (BNC - BNC) - 1m
Foot switches:
D185-FS1 Foot s itch to IP68
Fuller details and usage is contained in the Accessories section later in this manual.
Precautions & Warnings
a) Read Manual Carefully
Study this Operator's Manual before using the DS7A Stimulator.
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Operator's Manual DS7A - Constant Current Stimulator
Continued...
b) Explosion and Fire.
The DS7A must not be used in an explosive atmosphere or in the presence of flammable anaesthetic
gases.
c) High voltages
Dangerous voltages are present ithin this unit. Do not remove covers, and refer servicing to
qualified personnel.
d) Damage
The DS7A and/or any accessories must not be used if there are any signs of external damage.
e) Moisture
The DS7A and/or any accessories must not be used if any parts are damp or et.
f) Input/Output Connectors
Only equipment that complies ith EN(IEC) 60601 (Medical Equipment), EN(IEC) 60950 (IT
Equipment) or EN(IEC) 61010 (Laboratory Equipment) should be connected to the input/output
connectors. See Appendix 6 for guidance on choice of equipment and system integration.
g) Electrical Interference
This unit has been fully tested for EMC conformity of Medical Devices. This unit should NOT be used
near radio transmitters. If any "strange" behaviour of the unit is noted, discontinue use immediately
and refer to qualified EMC engineer. Refer to Appendix 5 for further information.
h) Electrical Stimulation Safety
The safety considerations involved in electrical stimulation for motor evoked potentials have been
revie ed by Agne and McCreery (1987) and by Barker et al (1988). These papers are listed in the
appendices of this manual and should be fully read.
i) Electronic Implants
Understand that this unit may not be appropriate for use on patients ith cardiac pacemakers or
electronic implants.
j) Do NOT use transthoracically
Only use this Stimulator on one limb at a time. Do NOT use transthoracically. Doing so could
influence the rhythm of the heart.
k) Do NOT stimulate over the carotid sinus nerves, neck and mouth
Stimulation should not be applied over carotid sinus nerves, particularly in patients ith a kno n
sensitivity to the carotid sinus reflex. Severe spasm of the laryngeal and pharyngeal muscles may
occur and the contractions may be strong enough to close the air ay or cause difficulty in
breathing.
l) Needle Electrodes
Please note that here “Percutaneous Stimulation” is referred to in this document, it means
“Electrical Stimulation Through the Skin” and NOT the use of Needle electrodes.
The use of Needle Electrodes is NOT recommended, due to the possibility of high current densities
at stimulation sites.
m) Electrode Isolation
The follo ing generally applies to the use of nerve and muscle stimulators, and especially those
designed for percutaneous use. See, for example, the section on Safety of Apparatus in Guld et al,
19701. It is essential for safety that the connections from the stimulator to the subject are isolated
1 Guld, C., Rosenfalk, A., and Willison, R. G. (1970), Technical factors in recording electrical activity of
muscle and nerve in man. Electroenceph. Clin. Neurophysiol., 28:399- 13
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Operator's Manual DS7A - Constant Current Stimulator
from earth/ground, and this means that a earth/ground connection must not be made to either
terminal on the stimulator or to either stimulating electrode. Similarly, it is undesirable to place an
earth/ground electrode on the patient close to one of the stimulating electrodes. It is also important
that an unintentional path to earth/ground should not be introduced by attempts to monitor the
stimulating current (see belo ), or in any other ay. As an instance of such dangers, it is likely that
hen using the DS7A Stimulator ith recording apparatus, it ill be necessary to have an
earth/ground electrode on the subject some here in the vicinity of the recording electrodes. If a
second earth/ground connection as to be made to one of the stimulating electrodes, current could
flo bet een the other stimulating electrode and the recording earth/ground electrode. Since the
recording site ould be some distance from the stimulating site, structures other than those
bet een the stimulating electrodes, e.g. the heart, might be reached by the unintended spread of
current via the recording earth/ground electrode. It is important, therefore, that the output
terminals of the DS7A Stimulator should be connected only to the stimulating electrodes
and to nothing else. Attempts to measure the stimulus current, by inserting a resistor into one
stimulating lead and using an oscilloscope to measure the voltage drop across the resistor, are likely
to violate the rule of not connecting a path to earth/ground to either side of the stimulator output.
The safe ay to monitor the stimulating current (should this be necessary) is by means of a suitable
(Medical grade) current transformer, preferably of the clip on type, hich can be clipped over one of
the stimulator output leads.
n) “Output Enable”
An operational protocol should be established hereby the “Output Enable” s itch of the DS7A is
only s itched to “ON / enabled” hen delivery of a stimulus is specifically required.
o) Simultaneous Connection of Equipment
Simultaneous connection of a patient to the DS7A and high frequency surgical equipment may result
in burns at the site of stimulation and possible damage to the stimulator.
p) DS7A and Therapy Equipment
Operation of the DS7A in close proximity (e.g. 1m) to a short ave or micro ave therapy equipment
may produce instability in the stimulator output.
q) DS7A and MRI scanners
The DS7A is not suitable for use in close proximity to extreme magnetic fields, such as those
generated by MRI scanners.
r) DS7A and Defibrillators
The DS7A is not classified as being defibrillator proof
s) Modification
WARNING - Do NOT modify this equipment ithout authorization of the manufacturer.
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Operator's Manual DS7A - Constant Current Stimulator
Product Intended sage
The Digitimer DS7A Stimulator is intended for use as sho n in the “Indications for Use” section that follo s.
It is intended to be used by persons trained in its use. Users are expected to be able to properly operate
the DS7A Stimulator and associated instruments.
The DS7A Stimulator is not intended for use in life support situations, or in situations here improper
operation or failure of the DS7A Stimulator can result in personal injury to user or patient.
Digitimer Limited makes no representation that the design, implementation, testing or manufacture of the
DS7A Stimulator meet more than reasonable standards for use as a medical product.
As stated in the Digitimer Limited Warranty Statement, supplied ith each product, “Digitimer Limited
Expressly disclaims all arranties to buyer except the limited arranty set forth therein, including ithout
limitation to any and all implied arranties of merchantability and fitness for a particular purpose.”
Indications for se
The Digitimer DS7A and DS7AH are stimulators intended for use during neurological monitoring and
assessment in a clinical environment
They are intended for use by trained personnel either competent to apply appropriate stimuli or under the
supervision and instruction of one ho is.
This is from our FDA application for registration of the product.
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Operator's Manual DS7A - Constant Current Stimulator
Explanation of Symbols sed on DS7A
The majority of these symbols comply ith and are documented in ISO 15223: 2012.
Front Panel
Output Enabled ith s itch in
this position
Plus; positive connection of
connection to patient (Anode)
Output Disabled ith s itch
in this position
Minus; negative connection of
connection to patient (Cathode)
!
Caution, consult
accompanying documents
Type BF applied part
Output (stimulus connection
to patient)
"Start Process"
Manual Trigger Button
mA
Output Stimulus.
strength in mA.
Vmax
Output Stimulus.
Adjustment for maximum Voltage of
stimulus.
Consult operator
documentation (this manual)
before use of this equipment.
µs
Output Stimulus.
Stimulus, in µs.
Output pulses are set to
positive (normal) polarity.
Output pulses are set to negative
(reverse) polarity.
Output pulses are set to
alternating polarity.
Trigger frequency is too fast i.e.
>100Hz. This only applies in
alternating polarity mode.
Off (po er) - Indicates OFF
position of Mains Po er
s itch
On (po er) - Indicates ON position of
Mains Po er s itch
Off (po er) - Indicates OFF
position of Mains Po er
s itch
On (po er) - Indicates ON position of
Mains Po er s itch
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Operator's Manual DS7A - Constant Current Stimulator
Rear Panel
Equipotentiality Connector
Digitimer have declared that this
equipment complies ith the Medical
Device Directive under the supervision
of Notified Body 0120 (SGS UK Ltd.)
0120
Trigger Input - signal input connector.
Positive going pulse required Output - signal output connector.
Active "high" square ave
pulse produced
Foot s itch connector.
Note: Only connect to other Medical
Equipment.
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