MS324C*
Low Volt AC Stimulator
User's Guide
Amrex
®
electrotherapy equipment
a division of Amrex-Zetron, Inc.
*Federal law (USA) restricts this device to sale by or on the order of a licensed practitioner licensed by the law of the state in which
he practices to use or order the use of this device.
MS324C User's Guide
Low Volt AC Stimulator
Revised June 2008
Copyright © Amrex-Zetron, Inc. 1995. All rights reserved.
Printed in the United States of America
The following are registered or trademarked by Amrex:
Amrex®
SynchroSonic®
Flextrode®
AMREX® electrotherapy equipment
a division of Amrex-Zetron, Inc.
641 East Walnut Street
Carson, California 90746
(310) 527-6868
Toll Free Customer Service (800) 221-9069
Fax (310) 366-7343
E-Mail: amrex@amrex-zetron.com
Web Site: http://www.amrex-zetron.com
Thank you. . .
for selecting the Amrex MS324C Low Volt AC Stimulator. We believe that you will
find this instrument to be versatile, dependable and user friendly. The MS324C is
designed for the application of low volt ac muscle stimulation. The Amrex MS324C
Low Volt AC Stimulator is a dual-channel, four-pad, low voltage ­electrical muscle
stimulator that produces pulsation, tetanize, surge and reciprocal output. The
­electrical muscle ­stimulation may be applied separately or may be combined with
ultrasound ­simultaneously through the ultrasound ­transducer using an ­external
Amrex SynchroSonic® U/50.
Your MS324C has been manufactured by a group of dedicated, highly trained
employees who exemplify the sixty-year Amrex tradition of manufacturing
­therapeutic equipment of the highest quality while supporting you with prompt,
courteous customer service.
Upon receipt of your MS324C, verify your accessories against the enclosed check
list. Promptly return the postage paid Registration Card to Amrex. Save the ­original
shipping carton and all packing materials.
Please carefully review this User’s Guide prior to operating the Amrex MS324C
Low Volt AC Stimulator. Should you have questions regarding your new ­purchase,
or need assistance, telephone Amrex Technical Services at (800) 221-9069.
i
Limited Warranty
Amrex-Zetron, Inc. (Manufacturer) warrants each instrument it manufactures to be free from
defects in material and workmanship under normal use and service for a period of two (2) years
from the date of purchase. This two-year warranty extends only to the original purchaser and shall
not apply to batteries, fuses, accessories or any instrument which has been subjected to misuse,
neglect, accident or abnormal conditions of operation.
The Manufacturer's obligation under this warranty is limited to repairing or replacing, at the
Manufacturer's option, any instrument returned to the factory within two (2) years from the date
of purchase. If the Manufacturer determines that the product fails to conform to this warranty
due to misuse, alteration or abnormal condition of operation, including evidence that nonauthorized personnel have attempted to repair the device, the instrument will be repaired at customer's
expense. This warranty is exclusive and in lieu of all other warranties, expressed or implied,
including but not limited to any other warranty of merchantability or fitness for any particular
purpose. Manufacturer shall not be liable for any special, incidental or consequential damages,
whether in contract, tort or otherwise.
Service and Shipping Information
Amrex Technical Services has a representative to assist you should your equipment require service
or repair. It is necessary to obtain a Return Merchandise Authorization (RMA) number before returning equipment to the factory for warranty repair. Call our representative toll free (800) 221-9069.
Damage, resulting from repairs made outside the factory, is not covered under the warranty.
To maintain original design specifications, your Amrex muscle stimulator must be calibrated
and safety tested on an annual basis. Amrex strongly recommends that servicing be referred
to
the factory. Call toll free (800) 221-9069.
Save the original shipping carton and all packing materials to safely return Amrex equipment
to the factory for service, repair, annual calibration, electrical and mechanical safety check. All
accessories, including the ac line cord, must be included with the returned instrument. The
­customer is responsible for all freight charges. The Manufacturer shall assume NO responsibility
for ­damage in transit.
ii
Contraindications—Warnings—Precautions
THIS INSTRUMENT OPERATES ON 150/230 VOLTS AC, 50/60 Hz. (unless otherwise indicated on
the unit) AND MUST BE PROPERLY GROUNDED FOR SAFETY. The three wire power cord with
"hospital grade" plug should be connected to a GROUNDED AC wall receptacle. It is the personal
responsibility and obligation of the user to insure that this instrument is properly connected to the
AC POWER source before use.
Warning–Risk of burns and fire. DO NOT use near conductive
­material such as metal bed parts or innerspring mattresses. Renew
electrode cables upon evidence of deterioration. Use of controls,
­adjustment, or performance of procedures, other than those ­specified
herein, may result in hazardous exposure to electrical energy.
Important
AMREX Intensity Reset Circuit: The Amrex Low Volt AC Stimulator incorporates a unique
safety reset function as part of the intensity controls. This is to prevent any sudden or inadvertent
stimulation output to the patient in the event that:
• The Low Volt AC Intensity controls are not set to the 0/Reset position enabling the
audible/
tactile "clicks" at power on.
• The ac power is interrupted during treatment.
• The treatment period has ended.
• The Patient Treatment Stop Switch is activated.
The Low Volt AC Intensity controls must be returned to the 0/Reset position enabling the audible/
tactile "clicks", a treatment time selected, and the Start Timer control pressed before stimulation
output can be activated.
When the Amrex Low Volt AC Stimulator safety reset function is initiated, ­stimulator ­output will
be discontinued immediately, the Reset Intensities indicator light will flash and an audible signal
will be emitted from the generator. The Intensity controls must be returned to the 0/Reset position,
enabling the audible/tactile "clicks", ­a treatment time selected, and the Start Timer control pressed
before stimulator output can be ­activated.
Note: The generator will default to factory settings unless the treatment period has ended
without interruption or the Patient Treatment Stop Switch has been activated.
Patient "Treatment Stop" Switch: When the patient "Treatment Stop" switch is activated, ­stimulator
­output will be discontinued immediately. The Reset Intensities indicator light will flash and an
audible signal will be emitted from the generator. ­Stimulator output cannot be resumed until the
Low Volt AC Intensity controls for Channel A and Channel B are returned to the 0/Reset position
enabling the audible/tactile "clicks" which will turn off the Reset ­Intensities ­indicator light, a
treatment time selected, and the Start Timer control pressed. NOW the stimulator output can be
activated.
Note: All generator settings are maintained except the treatment time which reverts to the
­factory default setting of fifteen minutes.
iii
Electrical Muscle Stimulation—Contraindications
• Contraindicated for patients with cardiac demand pacemakers.
• Should not be used on cancer patients.
Electrical Muscle Stimulation—Warnings
• Long term effects of chronic electrical stimulation are unknown.
• Safety has not been established for the use of electrical muscle stimulation during
­pregnancy.
• Adequate precautions should be taken in the case of persons with suspected heart
­problems.
• Adequate precautions should be taken in the case of persons with suspected or diagnosed
epilepsy.
• Do not stimulate over the carotid sinus nerves, especially in patients with a known ­sensitivity
to the carotid sinus reflex.
• Severe spasm of the laryngeal and pharyngeal muscles may occur when the electrodes are
positioned over the neck or mouth. The contractions may be strong enough to close the
airway or cause difficulty in breathing.
• Electrical muscle stimulators should not be applied transcerebrally.
• Electrical muscle stimulators should not be used over swollen, infected or inflamed areas
or skin eruptions.
• Caution should be used in the transthoracic application of electrical muscle stimulators in
that the introduction of electrical current into the heart may cause arrhythmias.
• Electrical muscle stimulators should be kept out of the reach of children.
Electrical Muscle Stimulation—Precautions
Precautions should be observed:
• When there is a tendency to hemorrhage following acute trauma or fracture.
• Following recent surgical procedures when muscle contraction may disrupt the healing
process.
• Over the menstruating uterus.
• Where sensory nerve damage is present by a loss of normal skin sensation.
Some patients may experience skin irritation or hypersensitivity due to the electrical
­stimulation or the conductive medium. The irritation can usually be reduced by use of an
alternate conductive medium or alternate electrode placement.
Skin irritation and burns beneath the electrodes have been reported with the use of­­­electrical
muscle stimulators.
iv
Table of Contents
Part 1
Overview...................................................................................................................................1
Part 2
Power/Timer Section................................................................................................................5
Part 3
Low Volt AC Stimulator Modality.......................................................................................9
Part 4
MS324C General Operation and Application Procedures...............................................19
General Operation........................................................................................................................19
Application of Electrical Muscle Stimulation...........................................................................23
Adverse Effects - Shortwave Diathermy Interference.............................................................24
Electrical Muscle Stimulation—Indications .............................................................................25
Electrical Muscle Stimulation—Contraindications .................................................................25
Electrical Muscle Stimulation—Warnings.................................................................................25
Electrical Muscle Stimulation—Precautions.............................................................................26
Appendix A
Specifications.........................................................................................................................27
Appendix B
References................................................................................................................................29
v
vi
Part 4
AMREX
MS324C General Operation and
Application Procedures
General Operation
1. Prepare MS324C unit for treatment. First locate the red Power Control in
the lower left corner of the cover panel. Check that the red Power Control is
in the Off (raised) position. Second, locate the Main Power Switch at the
back panel next to the power plug socket. Make sure the On/Off switch is in
the Off ("0" Zero) position.
2. Reduce both Channel A Intensity control and Channel B Intensity control to
the 0/Reset position. An audible/tactile "click" will indicate that the knobs
are turned all the way to zero positions.
3. Connect the "Treatment Stop" Switch to the Treatment Stop Jack.
4. Connect the medical grade power cord to the MS324C's ac receptacle and
plug the "Hospital Grade" connector to a properly grounded 115/230Vac,
50/60Hz power outlet.
5. Set the Main Power Switch, located on the back panel, to the On ("1" One)
position.
6. Prepare the pad electrodes and apply them to the patient. The pad electrodes
may be held in place by means of retention straps or weight bags.
Important: It is the personal responsibility and obligation of the user to verify
that patient leads and pad electrodes show no evidence of deterioration prior
to patient application. When such evidence exists, replace the patient leads
and/or pad electrodes. Never sharply bend or twist the patient leads. Loose
connections or broken patient leads can cause poor conductance and possible
discomfort to the patient. Should the patient complain of low stimulation
output, no output, or sudden, irregular increases in output, immediately
discontinue treatment. Check for the following:
• Secure patient lead connections
MS324C User's Guide
19
Part 4
• Proper pad electrode contact with the patient
• Low Volt ac stimulator pad electrode wear or lack of cleanliness
6. Hand the Patient Treatment Stop Switch to the patient and explain its function.
Note: When the Patient Treatment Stop Switch button is pressed during
treatment, stimulator output will be discontinued immediately.
• The Channel A On indicator light and Channel B On indicator light
are no longer illuminated.
• The Reset Intensities indicator light flashes and an audible signal is
emitted from the generator.
Stimulator output cannot be resumed until the Low Volt AC Intensity controls
for Channel A Intensity and Channel B Intensity are returned to the O/Reset
position, enabling the audible/tactile "clicks", which will turn off the Reset
Intensities indicator light, a treatment time selected, and the Start Timer control
pressed. All generator settings are maintained except the treatment time
which reverts to the factory setting of fifteen minutes.
7. Depress the red Power Control. The generator will self-test. All indicators
will illuminate. An audible signal will be emitted and the generator will
default to factory settings of:
• Timer display 15 minutes
• Output Mode selection Continuous mode
• Pulse Rate display 80 pulses per second
• Surge On display inoperable in Continuous mode
• Ramping display inoperable in Continuous mode
• Surge Off display inoperable in Continuous mode
Note: If the Intensity controls are not in the 0/Reset position, the generator
will emit a sequence of audible signals and the Reset Intensities indicator light
will flash. Channel A Intensity and Channel B Intensity controls must be returned
to the 0/Reset position, enabling the audible/tactile "clicks", to return to factory
default settings.
8. Select the desired output pulse frequency (pps) using the Pulse Rate controls.
To adjust the pulse rate selection in one pulse per second increments, press
and release. For rapid adjustment, press and hold until the desired pluse
rate setting is reached. The pulse rate selected will be indicated on the Pulse
Rate digital display.
20
MS324C User's Guide
MS324C General Operation and Application Procedures
Note: The output pulse rate selection can be changed at any time during
treatment.
9. Set the treatment duration using the Timer controls.
Note: To adjust in one minute increments, press and release. For rapid
adjustment, press and hold until the desired treatment duration setting is
reached. The treatment duration will be indicated on the Timer digital display.
Treatment duration may be reduced or increased during the treatment period.
10. Press the Start Timer control to activate the treatment timer. A flashing decimal
point on the Timer digital display indicates timer countdown in 1 minute
increments.
11. Verify the Output Mode selection is set at Continuous.
Note: Press and release the Mode control until the Continuous output mode
is selected. The continuous mode indicator light will illuminate when the
Continuous output mode is selected. The output mode selection can be
changed at any time during treatment.
Note: Always set the Channel A Intensity and Channel B Intensity levels
while in the Continuous output mode.
12. Slowly increase the low volt ac intensity control(s) for Channel A Intensity
and/or Channel B Intensity to the desired output levels.
Note: The output levels can be changed at any time during treatment
duration.
13. Select an alternate output pulse frequency (pps) using the Pulse Rate controls,
if so desired. The pulse rate selected will be indicated on the Pulse Rate digital
display.
Note: To adjust the pulse rate selection in one pulse per second increments,
press and release. For rapid adjustment, press and hold until the desired
pluse rate setting is reached.
14. Select an alternate Output Mode, Surge or Reciprocal, and adjust the Surge
On, Ramping, Surge Off controls if so desired.
Note: Press and release the Mode control until the Surge or Reciprocal output
mode is selected. The Output Mode indicator light array will indicate the
output mode selected.
Note: To adjust the Surge On, Ramping, and Surge Off controls in one second
increments, press and release. For rapid adjustment, press and hold until
the desired treatment duration settings are reached.
MS324C User's Guide
21
Part 4
15. Set either Surge Output Mode or Reciprocal Output Mode. Adjust the Ramping
to the desired level.
Note: Ramping time cannot be set at greater that half of the Surge-On time.
If the user reduces the Surge-On time to less the twice of the Ramping setting
time, the Ramping time will self-adjust to half of the new Surge-On setting
time automatically.
Note: THE PROGRAMMING PROCEDURES WILL LIMIT the maximum
Surge-On time to be set less than that of Surge-Off time minus one second in
the Recrporcal Output Mode. For accommodatie the limitation, the user
must first increase the Surge-Off time in order to adjust up the previous
maximum Surge-On setting time.
16.When treatment is completed, stimulator output will be discontinued
immediately.
• The treatment duration reduces to 00 as indicated
on the Timer digital display
• The Reset Intensities indicator light flashes and the
generator emits an audible signal
The Channel A Intensity and Channel B Intensity controls must be returned to
the 0/Reset position, enabling the audible/tactile "clicks", which will turn
off the Reset Intensities indicator light and the audible signal. All generator
settings are maintained except the treatment time which reverts to the factory
setting of fifteen minutes. Thoroughly clean the pad(s) with warm water
and dispose of the used cloth cover(s).
22
MS324C User's Guide
Appendix A
Specifications
Input Power Requirements
Electrical Stimulator continued
Line Voltage .............. 115/230 Vac, 50/60 Hz
Modality Treatment Range ................ minutes
Continuous mode treatment ....... 1 - 99 min
(15 min default)
Surge mode treatment ................. 1 - 99 min
(15 min default)
Reciprocal mode treatment ......... 1 - 99 min
(15 min default)
Current ................................................... < 1.0 A
Line Leakage ...................................... < 100 μA
Electrical Stimulator
Waveform ............... asymmetrical alternating
current (no load)
+V
0
t
-V
Output Voltage .... 110 V peak into 1K ohm load
36 V peak into 100 ohm load
Output Intensity ..... 90 μC maximum charge
per pulse into 100 ohm load
Pulse Width ............................................. 250 μs
at 50% V maximum
Frequency Range ............... pulses per second
Continuous Mode ........................ 1 to 99 pps
(80 Hz default)
Surge Mode .................................. 1 to 99 pps
(80 Hz default)
Reciprocal Mode .......................... 1 to 99 pps
(80 Hz default)
Timer (minutes) ............................... 1 - 99 min
(15 min default)
MS324C User's Guide
Surge Duration settings ...................... seconds
Surge ramp
Surge On
Surge Off
0.5 s
1.0 s - 25 s
1.0 s - 25 s
1.0 s
2.0 s - 25 s
1.0 s - 25 s
2.0 s
4.0 s - 25 s
1.0 s - 25 s
3.0 s
6.0 s - 25 s
1.0 s - 25 s
4.0 s
8.0 s - 25 s
1.0 s - 25 s
5.0 s
10.0 s - 25 s
1.0 s - 25 s
6.0 s
12.0 s - 25 s
1.0 s - 25 s
7.0 s
14.0 s - 25 s
1.0 s - 25 s
8.0 s
16.0 s - 25 s
1.0 s - 25 s
9.0 s
18.0 s - 25 s
1.0 s - 25 s
1.0 s
5.0 s
2.0 s
(------- d e f a u l t s e t t i n g s -------)
Reciprocal Duration settings ............. seconds
Recip ramp
Recip On
Recip Off
0.5 s
1.0 s - 24 s
2.0 s - 25 s
1.0 s
2.0 s - 24 s
3.0 s - 25 s
2.0 s
4.0 s - 24 s
5.0 s - 25 s
3.0 s
6.0 s - 24 s
7.0 s - 25 s
4.0 s
8.0 s - 24 s
9.0 s - 25 s
5.0 s
10.0 s - 24 s
11.0 s - 25 s
6.0 s
12.0 s - 24 s
13.0 s - 25 s
7.0 s
14.0 s - 24 s
15.0 s - 25 s
8.0 s
16.0 s - 24 s
17.0 s - 25 s
9.0 s
18.0 s - 24 s
19.0 s - 25 s
1.0 s
5.0 s
7.0 s
(------- d e f a u l t s e t t i n g s -------)
27
Appendix A
Instrument
Service and Shipping Information
Overall Dimensions................ 10" W x 11½" D
x 4½" H
Amrex Technical Services has a representative
to assist you should your equipment require
service or repair. It is necessary to obtain a
Return Merchandise Authorization (RMA)
number before returning equipment to the
factory for warranty repair. Call our
representative toll free (800) 221-9069. Damage,
resulting from repairs made outside the factory,
is not covered under the warranty.
Weight .................................................. 4.25 Lbs
Shipping Weight ................................. 10.5 Lbs
Cleaning Instructions
1. Disconnect the power supply.
2. Use mild soap with a lightly moistened
cloth.
3. Air dry before using.
To maintain original design specifications, your
Amrex stimulator must be calibrated and safety
tested on an annual basis. Amrex strongly
recommends that servicing be referred to the
factory. Call toll free (800) 221-9069.
Save the original shipping carton and all
packing materials to safely return Amrex
equipment to the factory for service; repair;
annual calibration, electrical and mechanical
safety check. All accessories, including the ac
line cord, must be included with the returned
instrument. The customer is responsible for all
freight charges. The Manufacturer shall assume
NO responsibility for damage in transit.
28
MS324C User's Guide
Appendix B
References
Alon, G. High Voltage Stimulation (High Voltage Pulsating Direct Current). Chattanooga
Corporation, Chattanooga, Tennessee, 1984.
Currier, D.P. and R.M. Nelson. Clinical Electrotherapy. Appleton and Lange, Norwalk,
Connecticut, 1986.
Dyson, M. “Mechanisms Involved in Therapeutic Ultrasound”. Physiotherapy,
March, Vol.73.3, pp.116-120, 1987.
Jaskoviak, P.A. and R.C. Schafer. Applied Physiotherapy. ACA Press, Arlington,
Virginia, 1986.
Kahn, J. “Iontophoresis and Ultrasound for Post Surgical TMJ Trismus and
Paresthesia”. Physical Therapy, March 1980, 60:3.
Kahn, Joseph. Principles and Practice of Electrotherapy. Churchill Livingstone, New
York, 1987.
Kleinkort, J.A. and F. Wood. “Phonophoresis with 1% Versus 10% Hydrocortisone”.
Physical Therapy, 55:1320-1324, 1975.
Kottke, F.J., G.K. Stillwell and J.F. Lehman, ed. Krusen’s Handbook of Physical Medicine
and Rehabilitation. W.B. Saunders Co., Philadelphia, 1982.
Michlovitz, S.L. and S.L. Wolf, ed. Thermal Agents in Rehabilitation. F.A. Davis Co.,
Philadelphia, 1986.
Nix, W.A. and G. Vrbova. Electrical Stimulation and Neuromuscular Disorders.
Springer-Verlag, Berlin, West Germany, 1986.
Nyborg, W.L. and M.C. Ziskin, ed. Biological Effects of Ultrasound. Vol. 16 of Clinics
in Diagnostic Ultrasound. Churchill Livingstone, New York, 1985.
Peat, Malcolm, ed. Current Physical Therapy. B.C. Decher, Inc., Philadelphia,
Pennsylvania, 1988.
MS324C User's Guide
29
Appendix B
30
MS324C User's Guide