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To avoid malfunctions of the MultiStim SENSOR, please check all functions before the intervention and
make sure that the accessories are suitable for the application. The accessories used must correspond to
safety class type BF.
To protect the patient from electrophysiological shock by electrostatic discharge (ESD), it is necessary to
wear corresponding clothing and to move about in an appropriately protected environment. An elec-
trostatic discharge (ESD) can cause extremely high current densities to appear at the tip of the cannula,
which can damage the surrounding tissue.
Conformity with the following standards:
EN 60 601-1; 14971:2000; EN 60601-1-1; EN 60601-2-10; EN 60601-1-4;
EN 60601-1-2; 13485:1996; 9001:2000; UL 60601; MPG; Directive 93-42-EWG
2.4 Constant voltage or constant current
According to Ohm's law U5R 3 I, it is possible to use both, the voltage and the current intensity as the
quantity to be measured to determine the intensity (amplitude) of the electrical stimulus. The devices
are respectively referred to as voltage-constant or current-constant.
The electrical resistance (impedance) in the electrical circuit of a stimulation, which represents the
sum of skin-, tissue-, cannula-, electrode cable-resistance etc., will vary within wide ranges. It may vary
between <1 kV and infinite. The factors skin humidity, conductivity of the skin and of the tissue and the
potential resistance of the adhesive electrode can hardly be influenced.
If the voltage (V) is selected as the measure for the intensity of the stimulus impulse, then currents may
appear during an application, which – in accordance with Ohm's law and depending on the resistance
– will differ by a manifold.
It is therefore better to use a nerve stimulator which permits the exact adjustment of the current intensity
(mA) between the two electrodes, the adhesive electrode (anode) and stimulation cannula (cathode).
The stimulator with constant current setting must, however, be provided with a very high output
impedance – ideally infinite – so that the resistances which may perhaps occur in the external electrical
circuit will be negligible, and so that the actually flowing current will be indicated exactly on the display.
Current-constant devices which permit the selection of the current intensity (mA) for the stimulus
impulse have gained acceptance within the last few years.
For the MultiStim SENSOR, the external load resistance can amount to as much as 12 kV. If this load
resistance is exceeded, then the actually flowing patient current (the actual stimulation current) can be
lower than the adjusted nominal stimulation current. In this case, the nominal stimulation current and
the actual stimulation current are indicated separately and visual and acoustic warning indications are
emitted. And the relevant impedance is continuously calculated and indicated on the LCD-display in
addition.
The MultiStim SENSOR is a precision instrument for the localisation of nerve tracts in the human organ-
ism. It was developed to stimulate nerve fibres in the living organism using cannulae for invasive stimu-
lation which normally show a very high contact impedance, to be able to determine the spatial posi-
tion of these nerve fibres in relation to the tip of the electrode. The stimulation cannulae are designed
so that a local anesthetic can be injected in the proximity of the nerve fibre, which will cause a revers-
ible interruption of the conductive system.
2.5 Accessories
The MultiStim SENSOR can be connected with a main patient line for the cannula and PEG-cable:
26
XS190056I.indb 26
Connection for PEG-handle
White connection: Cannula
Clamp for adhesive electrode
Monopolar PEG
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08.12.17 09:33
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