Enraf Nonius TensMed 911, User Manual

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7
7 Application of Electrodes
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CAUTION:
•
Connection of accessories other than the ones specified by the manufacturer can adversely
affect the safety of the patient and correct functioning of the equipment, and is therefore not
permitted.
NOTE:
•
The description below applies to electrotherapy applications in general. The electrolytic effects
mentioned do not apply to the Tensmed 911 as this device only generates fully balanced TENS
currents, that do not contain a DC component.
7.1 Before treatment
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Check the patient for contraindications and warnings as described in paragraph 4.1 and 4.2
•
Test the heat sensibility of the treatment area.
•
Rinse the treatment area. Shaving a hairy skin is recommended.
7.2 Self-adhesive electrodes.
Self-adhesive electrodes have higher series impedance than carbon rubber electrodes. This can cause
the stimulator to terminate treatment at higher current amplitudes. When this occurs it is recommended to
continue the treatment with carbon rubber electrodes, combined with properly moistened sponge pads.
Self-adhesive electrodes are not recommended for use with currents that contain a DC component.
7.3 Electrolytic effects
Electrolysis occurs under the electrodes when current types with a DC component are applied. Because
the largest concentration of electrolytic by-products caused by ion migration occur under the electrodes,
we recommend the use of the supplied sponges to keep the effects to a minimum. Make sure that the
sponges are kept well moistened and place the thick side of the sponge between the flexible rubber
electrodes and the patient.
7.4 Current density
According to IEC 60601-2-10 the maximum permissible “current density” is 2 mA RMS. per cm². With the
rubber electrodes this requirement is automatically met, as the output current of the stimulator is limited to
50 mA RMS. With smaller electrodes, such as the 3.2 mm self adhesives, this is not the case. To verify
that the maximum permissible current density of 2 mA RMS. per cm² is not exceeded, divide the RMS
output current in mA by the effective electrode area in cm²: A value of less than 2 should result. For
asymmetrical TENS currents the RMS value of the output current can be calculated as follows:
I
RMS
= I
peak
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( Phase duration [µs] * pulse frequency [Hz] * 10
6
)
For symmetrical TENS currents, the Phase duration should be multiplied by 2. The value of the peak
current I
peak
can be taken from the current display.
This device has Constant Current (CC) output characteristics, that may cause unpleasant connection and
disconnection reactions if the electrodes are not securely placed or lose contact with the skin. Make sure
the output is set to 0 mA when you apply or remove the electrodes.
7.5 Connection and disconnection reactions
This device has Constant Current (CC) output characteristics, that may cause unpleasant connection and
disconnection reactions if the electrodes are not securely placed or lose contact with the skin. Make sure
the output is set to 0 mA when you apply or remove the electrodes.