EMS COMBINATION 850 User manual

COMBINATION 850
MODEL 90
Electro-Medical Supplies (Greenham) Limited,
Wantage,
Oxfordshire OX12 7AD,
England.
Telephone :[phone]
Fax :[phone]

Record of Amendments
Combination850 Model 90
ISSUE COMMENTS DATE
1 Initial Issue 01-06-99
2 Corrections 19-10-99
This manual provides the necessary information for the installation and
operation of the Combination 850 Unit.
These instructions must be studied before putting the unit into operation.
The information contained in this manual is subject to change without notice.
No part of this manual may be photocopied, reproduced or translated into
another language without the prior written consent of Electro-Medical Supplies
(Greenham) Ltd.
General Information
COMBINATION 850 2 ISSUE 2

EC Declaration of Conformity
Electro-Medical Supplies (Greenham) Ltd
LimboroughRoad
Wantage
Oxfordshire
OX12 7AD
United Kingdom
Declares that the followingmedicaldevice is in conformity with
the essential requirements and provisions of Council Directive
93/42/EEC and is subject to the procedure set out in Annex 2
of Directive 93/42/EEC under the supervisionof Notified Body
Number 0120, SGS Yarsley International CertificationServices.
Product Name Combination 850
Model Number 90
Signature
Position Technical Director
Date 20 August 1999
COMBINATION 850 3 ISSUE 2

Contents
PAGE
Title 1
General Information 2
Record of Amendments 2
Declaration of Conformity to 93/42/EEC 3
Contents 4
Warranty 5
Introduction 6
Precautions 10
Contraindications - Ultrasound 11
Contraindications - Interferential 12
Technical Specification 13
Controls and Markings 18
Installation 24
Operating Instructions 25
Interferential Electrodes 35
Maintenance 36
COMBINATION 850 4 ISSUE 2

This Electro-Medical Supplies (Greenham) Ltd., (hereinafter called the
company) product is warranted against defects in materials and workmanship
for a period of two years from the date of shipment. The Company will at its
option, repair or replace components which prove to be defective during the
warranty period, provided that the repairs or replacements are carried out by the
Company or its approved agents.
The Company will consider itself responsible for the effects on safety, reliability
and performance of the product:-
Should the product be returned to the Company for repair it must be sent
carriage paid.
Consumable items, for example, electrodes, electrode covers and batteries, are
excluded from the above warranty.
only if assembly operations, re-adjustments, modifications or repairs
are carried out by persons authorised by it,
only if the product is used in accordance with the instructions for use,
only if the electrical installation of the relevant room complies with
the appropriate national requirements.
Warranty
COMBINATION 850 5 ISSUE 2

Introduction
Ultrasound
Sound is mechanical vibration. The human ear responds to these vibrations in
the range 20 Hz to 20 kHz. Sound above 20 kHz is called ultrasound.
Therapeutic ultrasound is sound in the range 500 kHz to 5 MHz.
Sound waves are produced by some disturbance in a material medium causing
the particles or molecules of the medium to vibrate. For this reason sound will
not pass through a vacuum. If the vibration is continuous and regular a constant
tone or frequency is produced. The vibration or sound wave propagates through
the medium as particles in the medium pass on their vibration to neighbouring
particles and series of compressions and rarefactions are produced in the
direction of travel of the wave. Therefore, sound waves are longitudinal waves.
Direction of wave motion
compression
Mean
compression compressionrarefaction rarefaction
The diagram shows a sound wave travelling from left to right. The vertical bars
represent thin slices of the medium which are displaced to form areas of
compression and rarefaction. The sinewave represents their displacement
relative to their mean position. The distance over which the vibration repeats
itself is called the wavelength. The number of complete vibrations in one
second is called the frequency of the sound wave. The velocity of sound in the
medium is given by:
One wavelength
Velocity = frequency x wavelength
Sound will travel faster through media where the molecules are closer together
and so the velocity is higher in solids than in liquids, and higher in liquids than
in gasses.
COMBINATION 850 6 ISSUE 2

For example, the velocity of sound in stainless steel is approximately 5800 m/s,
in water 1500 m/s and in air only 330 m/s.
As the sound wave passes through the medium, causing molecules to vibrate,
some of the energy in the wave is converted from kinetic energy to heat. For a
collimated sonic beam the intensity, power per unit area, therefore, decreases
exponentially with the distance travelled. The attenuation of the beam is also
dependent upon the frequency of the sound. In solids the attenuation is
proportional to frequency whereas in liquids the attenuation is proportional to
the square of the frequency.
The usual method of specifying the degree of attenuation of ultrasound in
different media is by the half depth. The half depth is the distance the
ultrasound must travel through the medium for its intensity to be reduced to one
half of its original value. Many attempts have been made to measure the
attenuation in various types of tissue with varying results. It is perhaps more
important to remember which types of tissue have the highest absorption and
which the lowest. With the lowest absorption first the order is, fat, muscle, skin,
tendon, cartilage and bone. For soft tissue the half depth is around 50 mm at 1
MHz and 15 mm at 3 MHz.
It is also important to remember that where there is a change in medium or
tissue type there will be both reflection and refraction of the ultrasound beam.
In particular, there is almost 100% reflection at the interface of a solid or liquid
to air at therapeutic ultrasound frequencies. Any air bubbles in coupling
medium will therefore reduce the effective intensity of the ultrasound. Also
bone reflects a high percentage of incident ultrasound. It is important, therefore,
when applying ultrasound to keep the transducer orthogonal to the surface of
the treatment area, to keep the ultrasound transducer moving and to use a good
coupling medium to avoid unwanted reflections and locally high intensities.
Interferential Therapy
The Combination 850 Unit generates medium frequency currents used for 2 and
4-pole interferential therapy.
Prior to the introduction of interferential therapy in the mid 1950s, low
frequency stimulation was used for pain relief, muscle re-education etc. These
currents, however, have the disadvantage that normal human skin has a
relatively high impedance at such frequencies. In order to overcome the skin
impedance a larger voltage has to be used to achieve the desired current,
resulting in a more uncomfortable treatment for the patient.
COMBINATION 850 7 ISSUE 2

In addition, the penetration depth of these currents is poor and in part is limited
by the discomfort to the patient.
Interferential therapy overcomes the problem of skin impedance. At 50 Hz
(faradic current) the impedance for a 100 cm2of skin is approximately 3000
ohms. At 4000 Hz (medium frequency) the skin impedance of the same area is
around 50 ohms. This means that a much lower voltage signal can be used to
produce the desired current, resulting in less skin sensation and a more
comfortable treatment. This medium frequency is, however, well outside of the
normal biological frequency range (0.1 to 250 Hz). In order to produce the
required stimulation, two medium frequencies are used. A constant frequency
of, say, 4000 Hz is applied to one pair of electrodes and a slightly different
frequency of say 3900 Hz is applied to the other pair. These two frequencies
’interfere’to produce an amplitude modulated medium frequency (beat
frequency) in the tissue. The tissue responds to the cyclic rise and fall in the
current intensity. It is the amplitude modulation frequency (AMF) that is within
the normal biological frequency range and not the medium frequency (carrier).
Combination Therapy
In general terms, combination therapy involves the simultaneous application of
ultrasound with an electrical stimulation therapy. In Europe, diadynamic
currents are frequently used, but in the UK, ultrasound is most often combined
with two-pole interferential therapy.
By combining ultrasound with interferential therapy, the advantages and effects
of each treatment modality can be realised - but lower intensities are used to
achieve the effect. The accommodation effects that normally accompany
interferential therapy are reduced (or even eliminated).
The main advantages of such a combination are said to be:-
é
in localising lesions (especially chronic) ie. diagnostic use.
é
in ensuring accurate localisation of ultrasound treatment to provide
increased accuracy / effectiveness in treating deeper lesions.
é in treating trigger points.
COMBINATION 850 8 ISSUE 2

Possible Explanations
It would appear that by applying ultrasound to peripheral nerves, their threshold
to stimulation is reduced, thus making them more sensitive or excitable. It is
likely that this effect is brought about by the alteration of the ion pump activity,
predominantly Na+and K+, but also Ca++. By altering the transport of these
ions across the cell membrane, the resting potential will be altered and in this
case, it would seem that it results in a reduced threshold for depolarisation.
It is reasonable to expect this situation to exist in other tissues (apart from
nerve) although no direct evidence has been noted to date.
When interferential therapy is applied simultaneously with ultrasound through
the same tissues, a reduced intensity is required in order to achieve the same
physiological / therapeutic effects when compared with interferential therapy in
isolation. This can easily be demonstrated by turning off the ultrasound
component whilst continuing with the interferential therapy. The patient very
soon becomes aware of a much reduced sensation / effect, which can be restored
by restarting the ultrasound.
In addition, the simultaneous application of ultrasound with interferential
therapy minimises the accommodation phenomenon normally associated with
electrical stimulation of the peripheral nerves.
The combination of ultrasound with interferential therapy appears to give rise to
less adverse treatment effects than are associated with the combination of
ultrasound with diadynamic currents, or other electrical stimulations. It has also
been suggested that a greater effective treatment depth can be achieved with
ultrasound - interferential therapy combination.
Unlike routine interferential therapy, the intensity of the electrical stimulation
in combination therapy may need to be REDUCED during treatment, probably
due to the continued effect of the ultrasound on the nerve membrane threshold.
In summary, by combining the two treatment modalities, none of the individual
effects of the treatments are lost, but the benefit is that lower treatment
intensities can be used to achieve the same results, and there are additional
benefits in terms of diagnosis and treatment times.
COMBINATION 850 9 ISSUE 2

Precautions
Interferential Therapy
Interferential therapy is a safe and effective modality. The therapist must,
however, be aware of the following precautions and potential hazards.
Simultaneous connection of a patient to high frequency surgical equipment may
result in burns at the site of the stimulator electrodes and possible damage to
the stimulator itself.
Operation in close proximity (less than 1 metre) to shortwave or microwave
therapy equipment may produce instability in the stimulator output.
Consideration must be given to the current densities for any electrode used with
the Combination 850 Unit. Current densities greater than 2 mA rms/cm2are not
recommended because of the risk of an interferential burn. The small size EMS
conductive rubber electrodes (NC3052B 70 x 50 mm) have an area of 35 cm2
and should, therefore, only be used with output currents up to 100 mA peak (
70 mA rms). All other standard EMS conductive rubber electrodes may be used
up to the maximum output of the unit without exceeding this figure. When
using other electrodes, the maximum safe output current should be assessed
before use. First estimate the effective contact area of the electrode in square
cm, and then apply the following formula:-
Maximum peak output current (mA) = Area of electrode (cm2) x 2.8
The factor of 2.8 is the maximum recommended rms output current multiplied
by the ratio of the peak current to the rms current for a sinusoidal waveform.
The output display on the Combination 850 control panel shows the peak output
current in mA. For sinusoidal currents the rms current is approximately 70% of
the peak value.
Patients with implanted electronic devices (eg cardiac pacemaker) should not be
subjected to stimulation unless specialist medical opinion has first been
obtained.
COMBINATION 850 10 ISSUE 2

Contraindications- Ultrasound
Tumoursas ultrasound affects tissue repair and could therefore encourage
growth
Infections, due the risk of spreading the infection
Pregnancy, treatment over the pregnant uterus as ultrasound could affect
rapidly dividing cells
Radiotherapy, sites that have received radiotherapy treatment during the last
six months
Thrombosis and impaired circulation.
Areas of impaired sensation
Haemorrhage, due to the risk of increased bleeding, including recently
controlled bleeding and haematoma.
Haemophilia
Implanted devices such as cardiac pacemakers should be avoided due to the
possibility of affecting their operation. Also some plastics used in replacement
surgery may be affected by absorption of ultrasound energy. Metal implants may
lead to reflections, and as a precaution low doses of ultrasound should be used
near these.
Extreme care should be taken when treating areas near the eye because of the
danger of damage to the retina.
Similarly, extreme care should be taken near the ears and reproductive organs.
COMBINATION 850 11 ISSUE 2

There are comparatively few absolute contraindications to interferential therapy.
Acute Sepsis, due to the risk of spreading infection.
Tumours,due to the risk of increased growth or metastatic activity.
Pregnancy, do not treat the lower abdomen, back or pelvis.
Menstruation, do not treat lower back or abdomen due to risk of increased
bleeding or pain.
Cardiac conditions, do not treat the chest area or near the cervical ganglion.
Cardiac pacemakers, especially demand type, or any other implanted
electronic device.
Febrile conditions
Large open wounds in treatment area
Dermatological conditions in treatment area
Thrombosis
Hypersensitivity or fear of electrical treatments
Any patient who cannot understand the nature of the treatment, for
example, young children, very old or senile patients who cannot report back
adequately or understand the potential dangers. This may apply equally to
persons who do not speak the same language as the therapist.
Severe hypotension/hypertension, do not treat in the region of the lower
cervical spine.
If in doubt the patient’s physician should be consulted.
Electrodes should never be placed so that the applied current crosses the
chest.
Contraindications- Interferential
COMBINATION 850 12 ISSUE 2

Technical Specification
General
Power Input 100-240 Vac 50/60 Hz
Battery Internal Rechargeable (NiMh)
Classification (EN60601-1) Class 1, Type BF
Mains Fuses 2 x T630 mA (5 x 20 mm)
Size (height x width x depth) 100 x 240 x 210 mm (including handle)
Weight 2.2 kg
Treatment Programs 16 user-defined set-ups
Ultrasound
Frequency 1.1 MHz ±5% and 3.3 MHz ±5%
Maximum Intensity 2 W/cm2
Maximum Output Power 10 W (Mains operation only)
Output Modes CW and pulsed 1:1, 1:2, 1:4 and 1:9
Pulse Duration 2 ms
Treatment Timer 0 to 20 minutes (treatment linked)
Contact Monitor Light on transducer
Large Ultrasound Transducer
ERA 5 cm2
BNR <6
Beam Type Collimating
Small Ultrasound Transducer
ERA 0.5 cm2
BNR <6
Beam Type Collimating
Transducers for use with the Combination 850 are fully interchangeable and
suitable for underwater treatment (IPx7 rated).
COMBINATION 850 13 ISSUE 2

The Combination 850 is designed to operate from any 50/60 Hz single phase
supply between 100 and 240 V ac capable of supplying 50 VA. Connection is
via an IEC socket at the rear of the unit.
All information on model, serial number, and month/year of manufacture is
located on the rear panel.
Each Combination 850 Unit is supplied with a detachable mains cable, carrying
handle, spare fuses, a 5 cm2treatment head, 180ml bottle of Therasonic
coupling medium, 4 pole patient lead, 2 pole patient lead, 4 medium (100 x 70
mm) rubber pad electrodes, 4 medium sponge covers, electrode connection
cables, 2 elasticated stretch bandages and this manual.
The Combination 850 has been designed to meet the requirements of IEC
601-1:1988 (BS5724:Part 1:1989) "Medical Electrical Equipment, Part
1:General requirements for Safety", IEC 601-2-5:1984 (BS5724:Part 2.5:1985)
"Medical Electrical Equipment, Section 2.5 Specification for safety of ultrasonic
therapy equipment" and IEC601-2-10:1987 (BS5724:Section 2.10:1988)
"Specification for nerve and muscle stimulators".
Interferential Therapy
Output (Mains operation only) 0 - 100mA peak Constant Current or
0 - 65 V peak Constant Voltage
Carrier Frequency 4 kHz
AMF 0 - 250 Hz
Swing Pattern 1/1. 6/6 and 6/\6
Treatment Timer 0 - 30 minutes
Vector 10 seconds, 20% both channels
Combination Therapy
Ultrasound Output 0 - 1 W/cm2CW
0 - 2 W/cm2in pulsed modes
Interferential Output 0 - 40 mA peak Constant Current
0 - 40V peak Contant Voltage
Both the maximum ultrasound intensity and the maximum interferential current
are limited for battery operation.
COMBINATION 850 14 ISSUE 2

Pulsed Mode Ultrasound Waveform
Envelope of ultrasound wave
Pulse
Width
(2 ms)
Off Time
(See table)
Pulse Off Duty Temporal peak
Mode Frequency Time Cycle to average ratio
1:1 250 Hz 2 ms 50% 2:1
1:2 166 Hz 4 ms 33% 3:1
1:4 100 Hz 8 ms 20% 5:1
1:9 50 Hz 18 ms 10% 10:1
The pulse width is fixed at 2 ms
Output Display
The 850 display shows the temporal-peak spatial-average ultrasound intensity
and optionally the temporal-average power or the temporal-peak power as
selected.
COMBINATION 850 15 ISSUE 2

The maximum output current is 100 mA peak per channel and the maximum
output voltage is 65 V peak.
The maximum load impedance in ohms at any given output current is given by:
Maximum Impedance = 65000/(peak output current in mA)
4 Pole Interferential Waveform
1 cycle
1 cycle
Channel A
Channel B
Carrier
4 kHz
Frequency
4 kHz
Period
250 us
Frequency
3.75-4 kHz
Period
267-250 us
Channel A Channel B
2 pole Interferential Waveform
One cycle of AMF
0 - 250 Hz
One cycle of Carrier
4 kHz
OV reference
COMBINATION 850 16 ISSUE 2

Preset AMFs
Optional Accessories
ML9010S Rigid carrying case
EMS514 Lightweight durable shoulder carrying bag
NC3052A Set of 4 sponge electrode covers (small)
NC3053A Set of 4 sponge electrode covers (medium)
NC3054A Set of 4 sponge electrode covers (large)
NC3052B Set of 4 conductive rubber electrodes 70 x 50 mm (small)
NC3053B Set of 4 conductive rubber electrodes 100 x 70 mm (medium)
NC3054B Set of 4 conductive rubber electrodes 130 x 100 mm (large)
NC3055A 4 pole patient lead
NC3056A 2 pole patient lead
NC3057 Pair of electrode connection cables (Blue)
NC3058 Pair of electrode connection cables (Yellow)
NC3061 Twin four field electrode
Base Peak
100 Hz 100 Hz
0Hz 10Hz
0Hz 25Hz
0 Hz 100 Hz
10 Hz 150 Hz
50 Hz 200 Hz
100 Hz 150 Hz
80 Hz 130 Hz
COMBINATION 850 17 ISSUE 2

Controls and Markings
IEC Symbol 878-01-01
Mains On
IEC Symbol
878-01-02
Mains Off
Mains Indicator Light
Mains Switch
Interferential Output
Control
Interferential
Output Socket
IEC Symbol 348
Attention, Consult
Accompanying Documents
IEC Symbol
878-02-03
Type BF Equipment
IEC Symbol 878-01-37
Output
Figure 1 - Combination850 Front Panel
The Mains Switch is a two-position rocker switch: up for on, down for off.
The Mains Indicator Light is a green LED which is illuminated when the
mains switch is on.
The Interferential Output Socket is for connection of the 2 or 4 way patient
leads. When used with suction electrodes this socket is connected to the input
socket on the suction unit.
The Ultrasound Output Socket is for connection of either a 5 cm2or 0.5 cm2
transducer.
Ultrasound
Output Socket
COMBINATION 850 18 ISSUE 2

Name and Address of Manufacturer
Fuse type and
rating
Mains Fuses
Mains inlet
IEC Symbol 348
Attention, Consult Accompanying
Documents
Model Number
Serial Number and Date of
Manufacture Details of mains supply
Rated interferential
and ultrasound output
frequencies and
intensities
Classification
Figure 2 - Combination850 Rear Panel
CE Mark showing
conformity to
93/42/EEC