Organon TOF-Watch Owner's Manual

TOF-Watch

®

Organon (Ireland) Ltd., Drynam Road, Swords, Co. Dublin, Ireland Operator manual

TOF-Watch

®

Operating manual page 3

Manuel d'utilisation page 21

Bedienungsanleitung Seite 41

Manual del usuario página 61

® Registered trademark in one or more countries

Scheme of buttons and display symbols
Schéma des touches et symboles d’affichage
Tastaturübersicht und Displaysymbole
Esquema de los pulsadores y símbolos

Operating manual Contents

Scheme of buttons and display symbols 5

1 Introduction 6

1.1 General 6

1.2 Intended use 6

1.3 Actions upon delivery 6

2 Short set-up 6

2.1 Checking patients for muscle relaxation 6

2.2 Checking patients for residual curarization 7

2.3 Nerve location for loco-regional anesthesia 7

3 Pre-Operative set-up 7

3.1 Cable connections (objective monitoring) 7

3.2 Cable connections (subjective monitoring) 8

3.3 Cable connections (loco-regional anesthesia) 8

3.4 Electrodes 8

3.5 Electrode placement 8

3.6 Position of the transducer 9

3.7 Arm position 9

3.8 Connection to stimulator 9

3.9 Skin resistance 9

3.10 Control twitch height 10

3.11 Calibration 10

3.12 Sensitivity 10

3.13 Stimulation units 10

4 Survey of functions 10

4.1 General functions 10

4.1.1 Stop / on-off button (1) 10

4.1.2 Secondary function button (4) 11

4.1.3 Calibration button (22) 11

4.1.4 mA(µC) up (21) and down buttons (23) 11

4.1.5 Timer function 11

4.2 Primary functions 12

4.2.1 Train Of Four stimulation 12

4.2.2 1 Hz stimulation 12

4.2.3 Post Tetanic Count stimulation 13

4.3 Secondary functions 13

4.3.1 Double Burst Stimulation 13

4.3.2 Tetanic stimulation 14

4.3.3 0.1 Hz stimulation button 14

5 Set-up menu 15
6 Survey of display 16
7 Further information 17

7.1 Cleaning 17

7.2 Unusual patterns 17

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8 Error signals 18

9 Accessories 18
10 Technical specifications 19
11 Symbols 19
12 Warnings! 20

4 | TOF-Watch Operator manual 33.500/B

TOF-Watch

®

Scheme of buttons and display symbols

Stop / on-off button.
Post Tetanic Count / Tetanic stimulation button.
Train Of Four / Double Burst Stimulation button.
Secondary function button.
Secondary function symbol.
Calibration symbol.
Device on / stopped symbol.
Battery status symbol.
Internal error symbol.
Stimulation beep symbol.
Acceleration transducer symbol.
Resistance too high symbol.
Needle electrode symbol.
Timer / stimulation symbol.
Stimulation mode indication.
Frequency symbol.
Micro-coulomb symbol.
Milli-ampères symbol.
Value for TOF ratio, Twitch height, PTC or stimulation current.
Percent symbol: used for TOF ratio or Twitch height.
mA(µC) up button.
Calibration button.
mA(µC) down button.
1 Hz / 0.1 Hz stimulation button.

5 | TOF-Watch Operator manual 33.500/B

1 Introduction

1.1 General

Monitoring the effect of neuromuscular blocking agents (NMBAs) can be accomplished in
several ways.
The most frequently used method is clinical evaluation using a peripheral nerve stimulator.
Although the technique is simple, it lacks accuracy because of it’s subjective interpretation of
the responses.
Accurate and objective information on the degree of neuromuscular paralysis can be obtained
by measuring the force of contraction of a certain muscle (mechanomyography).
However, the equipment needed is rather bulky and difficult to use during routine surgery
because of the elaborate set-up procedure and its sensitivity to movement.
A good alternative for force measurement is the measurement of acceleration
(acceleromyography). According to the second law of Newton: Force equals Mass times
Acceleration (F = M x a), the acceleration of a muscle has a linear correlation with the
contraction force of that muscle. It has been shown that there is a good correlation between
the results of acceleromyography and mechanomyography.

1.2 Intended use

The TOF-Watch is an instrument for monitoring the neuromuscular transmission during surgery
or in the intensive care unit by means of acceleromyography. The TOF-Watch can also be used
as a peripheral nerve stimulator. Moreover, it can be used to localize nerves for loco-regional
anesthesia.
Consequently, the TOF-Watch is only to be operated by trained medical personnel.
Before operation, please refer to the Warnings! in chapter 11.

1.3Actions upon delivery

Upon delivery of the TOF-Watch, please check the contents of the package for completeness
and damage during transport.
The TOF-Watch should be stored at room temperature at ambient moisture conditions.

2 Short set-up

2.1 Checking patients for muscle relaxation

In the set-up menu of the TOF-Watch, display of the stimulation strength can be switched from
mA (default setting) to µC, according to local preferences. As a default setting, the stimulation
current is set at 50 mA.

1 Place electrodes in position, attach the acceleration transducer to the thumb with adhesive

tape.
2Turn TOF-Watch on by pressing the button (1) and holding it down for 1 second.
3Administer the induction agent.
4 When the patient is sedated adequately, press (22) for automatic calibration (optional).
5Hold down the button (3) for repetitive TOF stimulation.

The TOF-Watch is now ready for further monitoring the neuromuscular transmission.

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During surgery muscle relaxation can be monitored continuously to assess the need for either
repeated administration of a muscle relaxant or for the use of a reversal agent during recovery.

2.2 Checking patients for residual curarization

The use of automatic set-up of the TOF-Watch on patients already relaxed will result in
incorrect selection of internal gain due to fading. The following procedure should be used:
1 Place electrodes in position, attach the acceleration transducer to the thumb with adhesive

tape.
2Turn TOF-Watch on by pressing the button (1) and holding it down for 1 second.
3 The strength of the stimulation (mA or µC) can be adjusted manually by pressing the

mA(µC) up (21) or down button (23).
4Press (3).

Since no control twitch height has been established, only the TOF ratio yields information
about the recovery of a patient and not a single twitch measurement.

2.3 Nerve location for loco-regional anesthesia

The TOF-Watch can be used for nerve location for loco-regional anesthesia using a special
stimulation cable. This cable contains one lead with a connector fitting to a surface electrode
and one lead with a 2 mm plug to be connected to a needle electrode.
Once this cable is inserted in the TOF-Watch, the instrument automatically reverts to the loco­regional anesthesia mode. Since only a visual assessment of the response is needed, no
responses are shown.

1 Connect special stimulation cable to the TOF-Watch
2 Place the surface electrode in position
3Turn TOF-Watch on by pressing the button (1) and holding it down for 1 second.
4Start the repetitive 1Hz stimulation by pressing the (24) button.
5 The strength of the stimulation (mA or µC, shown on the display) can be adjusted manually

by pressing the mA(µC) up button (21) or down button (23).

The TOF-Watch is now ready for locating the nerve with the needle electrode.

3 Pre-Operative set-up

3.1 Cable connections (objective monitoring)

The TOF-Watch can be used for objective monitoring by using two cables:
A) acceleration transducer cable and B) stimulation cable.
When surface electrodes are used, the instrument automatically uses stimulation pulses of 200
µs at 0 - 60 mA (0 - 12 µC).
The pre-installed default current is set at 50 mA.
Attach the stimulation cable to the surface electrodes placed on the ulnar nerve.
Attach the acceleration transducer with its’ largest flat side to the thumb by means of adhesive
tape. Connect both cables to designated color-coded outlets on the TOF-Watch (reversal of the
cables is not possible because of a mechanical barrier).

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3.2 Cable connections (subjective monitoring)

When the acceleration transducer is not connected to the TOF-Watch, the instrument can be
used as a peripheral nerve stimulator.
When surface electrodes are used, the instrument automatically uses stimulation pulses of 200
µs at 0 - 60 mA (0 - 12 µC).
Instead of the patient response, the TOF-Watch automatically shows only the stimulation
strength in mA (µC) and stimulation mode.
The pre-installed default stimulation strength is set at 50 mA. Attach the stimulation cable to
the surface electrodes placed on the ulnar nerve (see above), and connect to the designated
color-coded outlet on the TOF-Watch (insertion of the cable in the wrong outlet is not possible
because of a mechanical barrier).

3.3 Cable connections (loco-regional anesthesia)

When the special cable for a needle electrode is used, the TOF-Watch can be used for nerve
location in loco-regional anesthesia.
The TOF-Watch will automatically revert to the loco-regional anesthesia mode, enabling
stimulation with a pulse width of 40 µs and a current ranging between 0 and 6.0 mA.
The total charge delivered varies between 0 and 0.24 µC. In the set-up menu, display of the
strength of the stimulation can be switched from µC (pre-installed) to mA.
The pre-installed default setting is 0 µC. No patient responses are shown on the display.
Attach the special cable to a needle electrode and a surface electrode, and connect to the
designated color-coded outlet on the TOF-Watch (insertion of the cable in the wrong outlet is
not possible because of a mechanical barrier).

3.4 Electrodes

When monitoring neuromuscular transmission, the TOF-Watch should always be used with
round surface electrodes with snap connection. Small (pediatric) electrodes are advisable to
obtain a sufficient current density. In order to ensure a steady quality of the test, be sure only
to use CE marked electrodes.

3.5 Electrode placement

Acceleromyography can take place by stimulating the facial nerve and monitoring the response
of the orbicularis oculi muscle or by stimulating the posterior tibial nerve and monitoring the
response of the flexor hallucis brevis muscle. Usually, however, for routine monitoring purposes
stimulation of the ulnar nerve and acceleration measurements at the adductor pollicis is
preferred.
The electrodes are placed over the ulnar nerve on the volar side of the wrist. The distal electrode
is positioned where the proximal bending line crosses the radial side of the flexor carpi ulnaris
muscle. The proximal electrode can be placed either 2-3 cm proximal of the distal electrode or
over the ulnar nerve at the elbow.

■■ Correct positioning of the electrodes is important. Small displacements may result in

considerable changes in stimulation current requirements. Furthermore, the electrodes must
be positioned in such a way to avoid direct stimulation of the muscle.

■■ Place the electrodes on each side of the expected position of the ulnar nerve. In this way,

the effect of any minor misjudgment of the actual nerve position is minimized.

■■ It has been found that slight pressure on the electrodes may improve the stimulation

considerably. Therefore, taping the electrodes to the skin may be advisable.

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Figure 2. Electrode and transducer placement

3.6 Position of the transducer

The transducer should be placed with its largest flat side against the thumb.
The transducer cable must be fixed in such a way that no traction is applied to the transducer
and that movement of the thumb is not obstructed in any way.

■■ Small sideways movements of the thumb may be noticed during stimulation. If this is the

case, reposition the transducer in such a way that the movement is perpendicular.

■■ The more distal the transducer is placed on the thumb, the stronger the acceleration signal.

This effect can be used to adjust the signal strength.

3.7 Arm position

The arm, used for the acceleration measurement, should be kept immobile during the whole
procedure. Movement of the arm to another position may change the twitch height
considerably. Although the twitch height may still differ from the original value, the train-of­four ratio remains correct. At later stages of recovery the patient may perform voluntary
movements of the hand, which in turn may disturb the measurements and recordings.

3.8 Connection to stimulator

Always make sure that the TOF-Watch is switched off or that the display shows the stop symbol

(7) before touching the electrodes.
The proximal electrode is usually connected to the white (Positive) clip on the stimulator cable.
The distal electrode should be connected to the black (Negative) clip.
If both electrodes are near the wrist, the polarity is less critical. The stimulation pulses are
monophasic. Switching the electrode connection (exchanging with ) may sometimes
increase the stimulation considerably.

3.9 Skin resistance

The skin resistance is part of the total resistance in the stimulating circuit, which also includes
electrode resistance. The stimulator in the TOF-Watch is of the constant current type.
This means that the stimulation voltage automatically increases with the resistance.
As long as the voltage remains below the maximum value (= 300 V) the stimulator can deliver
the selected pulse. For a maximal current of 60 mA, the maximal resistance will be 5 kOhm.
If the resistance is above this value, the “skin resistance too high” symbol (12) will be
displayed, and the stimulation stops. If the current is reduced, the corresponding voltage drops
and stimulation can be resumed.

■■ Insufficient cleaning of the skin may be the cause of too high skin resistance.

Note that there is not necessarily any relation between high skin resistance and problems
of reaching supramaximal stimulation.

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3.10 Control twitch height

The patient should be anesthetized before operating the stimulator because nerve stimulation
can be painful for a conscious patient.
Control twitch height is the twitch height when the patient is not relaxed. Control twitch height
is set to 100% at calibration.

3.11 Calibration

The size of the transducer signal varies from patient to patient. In order to establish a control
twitch height value of 100% for the 1Hz or 0.1Hz modes, the transducer gain is set by pressing
the button (22) for more than 1 sec.

■■ If the responses of a non-relaxed patient are too small for an accurate measurement, as

can be seen in children or when using the orbicularis oculi muscle, then a gain calibration
will optimize the sensitivity.

3.12 Sensitivity

It may be noticed that the thumb makes very small movements although no response is shown
on the display. This is not an error: the movement is below the threshold of 3% control twitch
height at which the TOF-Watch starts to display the responses.

3.13 Stimulation units

The TOF-Watch can show the strength of the electrical stimulation in both milli-ampères [mA]
and micro-coulomb [µC]. For routine monitoring the default setting is in mA, for use in loco­regional anesthesia the default setting is in µC. It is possible to change between the two modes
in the Set-up menu - see page 15.

4 Survey of functions

Some of the buttons have a double function: one function when activated alone, and another if
the secondary function button (4) is pressed prior to the function button.

Activation of the secondary function is indicated by the ■ symbol on the display.

Furthermore, the period of time a button is activated determines how the function of the
button is performed. A short activation (< 1 s) elicits a single stimulation, a long activation
(> 1 s) of a function button enables continuous stimulation.
Abbreviations:

Short activation (short): < 1 s
Long activation (long):> 1 s (acknowledged by a short beep)

4.1 General functions

4.1.1 Stop / on-off button (1)

short: Stops stimulation/clears display
long: Turns TOF-Watch on/off

(if activated more than 1 second).

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4.1.2 Secondary function button (4)

short: Activation of secondary function mode.

If this button is pressed prior to a button with a secondary function (description
above the button), the secondary function is carried out instead of the primary

function. This is indicated by the ■ symbol on the display. If no buttons are

activated, a built-in 5 sec. time-out reverts to primary mode.
long: Activation / deactivation of stimulation beep.
By pressing this button for more than 1 sec. the stimulation beep is toggled on and
off and the (10) symbol is showed for 1 sec (see also Set-up menu on page 15).

Note: If the stimulation beep is switched on, a short beep can be heard each time the

TOF-Watch performs a stimulation. When not desired, be sure to switch off the
stimulation beep in cases where beeps from other operating equipment are more
important (e.g. heart monitoring systems).

4.1.3 Calibration button (22)

long: Starts calibration (adjust gain to 100% control twitch

height) or returns to standard gain.

Notes: Calibration is only possible when the symbol is shown in the display.

If flashes after completion of calibration the acceleration transducer signal
is either too low or too unstable.

4.1.4 mA(µC) up (21) and down buttons (23)

short: Stimulation strength is shown in display, or if already

shown stepped up or down.

long: Stimulation strength is continuously stepped up or down.

If both up and down are activated simultaneously, the set-up mode is entered.
See page 15 for more information.

4.1.5 Timer function

The display is used to show various time-related symbols.

Stop watch showing time to next stimulation.

The center dot of the stop watch indicates that the TOF-Watch is currently performing
a stimulation.

The display normally holds a result for about 15 sec. after a stimulation has been performed.

µC

mA

(µ

(

11 | TOF-Watch Operator manual 33.500/B

After this time period, the measurement is considered to be too old for proper clinical evaluation
and the result is cleared.

4.2 Primary functions

In general, when a function is activated which is not allowed, an attention beep will sound.
Moreover, during a time-out period (PTC and TET), this function will also be flashing if the
TOF-Watch is in stop mode .
In case a function is allowed but only after some residual time (13.5 s for TOF, 20 s for DBS),
a count down procedure will be initiated and indicated on the display.

4.2.1 Train Of Four stimulation press (3)

short: Starts one TOF stimulation (on demand).
long: Starts repetitive TOF stimulation.

TOF stimulation occurs in 15 second cycles. The numeric display shows the train­of-four ratio in %, if all 4 responses were detected. When less than four responses
are detected or if the first twitch is less than 20%, only the number of responses is
displayed (without the % symbol). The TOF-Watch automatically excludes the use
of DBS and TOF for 12 sec. after the last TOF.

4.2.2 1 Hz stimulation press (24)

short: Starts one stimulation (on demand).
long: Starts repetitive 1Hz stimulation.

The display shows the twitch height of the last response. However, this is only valid
when the twitch has been calibrated. When not calibrated after switching on, the

▼ is flashing together with the % and an internal reference control twitch value

is used for the calculation.

Hz

%

%

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4.2.3 Post Tetanic Count stimulation (PTC) press (2)

Starts Post Tetanic Count (if allowed).

PTC starts with stimulations at a frequency of 1 Hz for 15 seconds. The display
shows PTC. When no responses are detected (i.e. when the neuromuscular block is
deep), this is followed by a 5 sec. 50Hz stimulation. After a 3 sec. pause,
stimulations are performed at a frequency of 1 Hz for 15 seconds, while the number
of detected responses (Post Tetanic Count, updated after each stimulation) is shown
in the display. A short information beep indicates that the PTC is finished and the
number of detected responses is shown on the display for 12 seconds after which
the TOF-Watch automatically enters the continuous TOF stimulation mode.

■■ Post Tetanic Count can only be used when the responses to 1 Hz, 0.1 Hz or TOF

have disappeared (when the patient is deeply relaxed).

■■ The final Post Tetanic Count remains in the display for 12 sec, after which the

TOF-Watch automatically enters continuous TOF stimulation mode.
If the patient responds (more than five consecutive responses) during the first 15
stimulations, the TOF-Watch automatically switches to TOF-mode after 5 seconds.

■■ The TOF-Watch automatically excludes the use of the PTC button for 2 minutes after

successful operation of PTC or TET. If activated before the time-out period has expired
an information beep will sound, PTC will, if no other test is running, be shown
flashing for 5 seconds, and the TOF-Watch automatically reverts to its original mode.

4.3 Secondary functions

Secondary functions can be activated by pressing the secondary function button (4) prior to a
stimulation button. If no stimulation buttons are activated within 5 seconds after pressing the
secondary function button, the TOF-Watch automatically reverts to primary mode. When the

secondary function button (4) is activated, the ■ symbol will be shown on the display.

4.3.1 Double Burst Stimulation (DBS) first press (4),

then (3)

Starts one Double Burst Stimulation (3.2 or 3.3).

The TOF-Watch also includes Double Burst Stimulation as a secondary function.
The set-up menu can be used to select either DBS3.2 or DBS3.3.
With DBS, only tactile evaluation can be used to evaluate the patients’ relaxation
as no registration is performed. The display shows the stimulation strength in mA
or µC, but no response.
The TOF-Watch automatically excludes the use of DBS and TOF for 20 sec. after
the last DBS.

13 | TOF-Watch Operator manual 33.500/B

4.3.2 Tetanic stimulation first press (4),
then (2)

Starts tetanic stimulation (if allowed).

As another secondary function the TOF-Watch includes 5 sec. of tetanic
stimulation (50 or 100 Hz in display). The TOF-Watch automatically excludes the
use of this button for 2 min. after the last TET or the last PTC. The set-up menu
can be used to select between 50Hz or 100Hz tetanic stimulation.
The display shows the stimulation strength in mA or µC, but no response.

4.3.3 0.1 Hz stimulation button first press (4),
then (24)

Starts repetitive 0.1 Hz stimulation.

The third secondary function is the 0.1 Hz stimulation. The display shows the
twitch height of the last response. However, this is only valid when the TOF-Watch

has been calibrated. If not, the ▼ flashes together with % and an internal

reference control twitch value is used for the calculation.

Hz

%

▼

Hz

mA

mA

14 | TOF-Watch Operator manual 33.500/B

5 Set-up menu

The set-up menu can be activated and manipulated using the buttons described below:

mA(µC) up (21) and down buttons (23)

Press both mA(µC) up (21) and down (23) simultaneously to enter the set-up
menu or to store the setting.

Notes: The set-up mode can only be accessed when the TOF-Watch is stopped i.e. the

symbol is shown in the display.
The setting is permanently stored in the TOF-Watch, even when the battery is
removed.

Press mA(µC) up (21) or down (23) one at a time to modify the setting of the
parameter.

Calibration button (22)

Press the CAL button (22) to go to next parameter to be modified.

The following parameters can be changed in the set-up menu: Default settings are shown bold.

Set-up parameter: Set-up Display

Surface electrode flashing (stimulation units)

mA: Surface electrode stimulation strength in milli-ampères.
µC: Surface electrode stimulation strength in micro-coulomb.

Surface electrode flashing (stimulation size)

50 mA: Default surface electrode stimulation strength can be

adjusted between 0 and 60 mA/12 µC.

Needle electrode flashing (stimulation units)

µC:Needle stimulation strength shown in micro-coulomb.
mA: Needle stimulation strength shown in milli-ampères.

Needle electrode flashing (stimulation size)

0.0 µC: Default needle electrode stimulation strength can be

adjusted between 0.0 and 6.0 mA/0.24 µC.

(µ

(

15 | TOF-Watch Operator manual 33.500/B

Loudspeaker flashing

0:Stimulation beep off.
1: Stimulation beep on.

DBS flashing

3.2:DBS3.2 is used

3.3: DBS3.3 is used

100 Hz (or 50 Hz) flashing

100 Hz:100 Hz tetanic stimulation.

50 Hz: 50 Hz tetanic stimulation.

6 Survey of display

Loudspeaker (10): used to indicate sound set-up.
Flashing “1” or “0” is used to indicate if beep is on or off.

Acceleration transducer (11; flashing). Absence of acceleration transducer or
unsteady/too low signal during calibration.

Bad surface electrode connection (12; flashing).

Surface electrode (12; flashing): Skin resistance too high.
Set-up: Indicates set-up of stimulation strength for surface electrodes.

Needle electrode (13; flashing): Skin resistance too high.
Set-up: Indicates set-up of stimulation strength for needle electrodes.

Stimulation in progress (14).

Time to next stimulation (14).

Hz Frequency of stimulation pattern (16).

µC µC (used when: changing the stimulation strength, DBS, TET, LA and if no

acceleration transducer is detected) (17).

mA mA (used when: changing the stimulation current, DBS, TET, LA and if no

acceleration transducer is detected) (18).

Hz

16 | TOF-Watch Operator manual 33.500/B

% Percent (used for TOF, 1 Hz and 0.1 Hz) (20).

TOF: Ratio between first and fourth response.
1 Hz, 0.1 Hz: Twitch height compared with reference value, flashing

symbol means that the instrument has not been
calibrated after switching on.

■

Second / shift mode (same symbol as on the button) (5).

▼

Device calibrated (same symbol as on the button) (6).
Flashing symbol means that the instrument has not been calibrated after
switching on.

Device on / stopped (same symbol as on the button) (7).

Internal Error (9).

Battery empty (8).

Battery low (8).

7 Further information

7.1 Cleaning

The TOF-Watch case may be cleaned with a damp cloth. Thorough cleaning of the device can
be achieved by using a cloth moistured with either 70% ethanol, methanol, a chlorohexidine
solution or 0.5% hypochlorite. Other chemical cleaners may damage the case finish and are
not recommended. Do not use abrasive cleaners as these will damage the surface.
Do not allow liquid to enter the case.

7.2Unusual patterns

“Persisting responses” - Direct stimulation:
If the thumb is influenced by direct stimulation of the muscles under the stimulation electrodes
this can result in an apparent response which does not disappear.
To eliminate this phenomenon the hand must be fixed in such a way that the muscle
stimulation does not result in a movement of the thumb. Alternatively try changing polarity or
position of the electrodes or try to lower the stimulation current.

Note: The TOF-Watch can show twitches higher than 100%.
Large twitches will be seen especially when no calibration has been performed or for a brief
period of time after administration of a depolarizing relaxant.

17 | TOF-Watch Operator manual 33.500/B

8 Error signals

Whenever the TOF-Watch detects an error the stimulation is suspended and the user is alerted
by two short attention beeps followed by one of the following error symbols (Internal error and
Battery empty one long beep however):

Flashing acceleration transducer symbol (11)

Normal mode: Acceleration transducer has been removed.
Calibration mode: Unstable or too low acceleration transducer signal.

Flashing bad surface electrode connection symbol (12)

All modes: Missing or bad electrode connection.

Flashing surface electrode symbol (12)

All modes: Skin resistance too high.

Flashing bad needle electrode connection symbol (13)

All modes: Missing or bad electrode connection.

Flashing needle electrode symbol (13)

All modes: Skin resistance too high.

Both symbols flashing simultaneously (12) + (13)

All modes: No stimulation cable connected to TOF-Watch

Battery empty symbol (8)

All modes: Battery empty.

Internal error symbol (9)

All modes: Internal error detected.

9 Accessories

Standard (Included in TOF-Watch package)

■■ Acceleration transducer with cable 1.5 m.

■■ Stimulation cable for surface electrodes 1.5 m.

■■ Operating manual.

Optional

■■ Clamp for IV-pole mount.

■■ Stimulation cable for a needle electrode 1.5 m (loco-regional anesthesia).

■■ Surface electrodes.

Spare parts

■■ Acceleration transducer with cable 1.5 m.

■■ Stimulation cable for surface electrodes 1.5 m.

+

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19 | TOF-Watch Operator manual 33.500/B

10 Technical specifications

Microprocessor-controlled.
Custom design LCD with numerical presentation of twitch data.

Automatic calibration: Automatic adjustment for optimal gain and 100%

reference.

Stimulation modes: TOF (Train Of Four)

PTC (Post Tetanic Count)
1 Hz twitch

0.1 Hz twitch
DBS3.3 and 3.2 (Double Burst)
Tetanic stimulation (Burst),
5 sec. - 50 Hz or 100 Hz

Output (accuracy ±5% of full scale value):

Surface electrodes Constant current, 0 - 60 mA (0 - 12 µC) up to 5 kOhm.

Monophasic, 200 µs pulse width.

Needle electrodes Constant current, 0 - 6 mA or (0 - 0.24 µC) up to 5 kOhm.

Monophasic, 40 µs pulse width.
Transducer: Acceleration transducer (accuracy ±5% of full scale value).
Battery: 9V Alkaline or NiCd (6LR61 / 6AM6).
Supply voltage: 9V=, 140 mA max.
Type: BF

Weight: Approximately 250 gram with battery.
Dimensions: 200 x 90 x 50 mm.
Safety: Complies with IEC601-1.
EMC: Complies with EMC directive, 89/336/EEC, § 10 part. 1

when used with standard or optional accessories.

11 Symbols

Attention, consult accompanying documents.

Type BF equipment.

IPXO Degree of protection against ingress of water (non-protected).

Complies with Medical Device Directive, 93/42/EEC (class 2A).

0543

!

12 Warnings!

■■ Caution (US only): Federal law restricts this device to sale by or on the order of a

physician.

■■ Do not apply the TOF-Watch to patients with cardiac pacemakers without

checking that the stimulation does not influence the pacemaker.

■■ Always make sure that no other equipment can touch the stimulation electrodes.

■■ Cover the stimulation electrodes with insulating material so that, e.g., catheters

can never be exposed to stimulation.

■■ Check each time before use that the material insulating the acceleration

transducer and the stimulation cable is intact and does not show signs of wear
and tear.

■■ Never touch the electrodes unless the stimulation has been stopped.

When the display shows the stop symbol (7) there is no stimulation.
If this is not the case, press the button (1).

■■ Do not use the TOF-Watch in the presence of flammable anesthetics.

■■ 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.

■■ Operation in close proximity (e.g. 1 m) to short-wave or micro-wave therapy

equipment may produce instability in the stimulator output.

■■ Do not stack the TOF-Watch directly on top of other electronic equipment.

If stacking is necessary, observe the TOF-Watch to verify normal operation before
applying it to the patient.

■■ Patients with nerve damage, Bell’s palsy, Myasthenia gravis or other

neuromuscular problems may not respond properly to stimulation. Therefore the
TOF-Watch may show unusual patterns when monitoring relaxation in these
patients.

■■ Do not apply electrodes to patients in areas where inflammation or injury is

evident.

■■ The TOF-Watch adds information on the patient’s situation as far as relaxation is

concerned. It does not replace any clinical judgment performed hitherto, or any
test made when no TOF-Watch was available.

■■ Monitoring neuromuscular transmission or neuromuscular block can only be

performed using surface electrodes.

■■ Be sure only to use CE marked electrodes.

■■ Use of accessories, transducers, and cables other than the ones supplied with

TOF-Watch may result in degrade electromagnetic compatibility performance of
the device.

!

20 | TOF-Watch Operator manual 33.500/B

21 | TOF-Watch Operator manual 33.502/B

Manuel d’utilisation Sommaire

Schéma des touches et symboles d’affichage 23

1 Introduction 24

1.1 Généralités 24

1.2 Fonction du système 24

1.3 Vérification à la livraison 24

2 Mode d’emploi résumé 24

2.1 Contrôle de la relaxation musculaire du patient 24

2.2 Contrôle de la curarisation résiduelle du patient 25

2.3 Localisation des nerfs pour anesthésie loco-régionale 25

3 Installation pré-opératoire 25

3.1 Connexions du câble (monitorage objectif) 25

3.2 Connexions du câble (monitorage subjectif) 26

3.3 Connexions du câble (anesthésie loco-régionale) 26

3.4 Électrodes 26

3.5 Positionnement des électrodes 26

3.6 Position du capteur 27

3.7 Position du bras 27

3.8 Connexion au stimulateur 27

3.9 Résistance de la peau 27

3.10 Hauteur du twitch de contrôle 28

3.11 Calibration 28

3.12 Sensibilité 28

3.13 Unités de stimulation 28

4 Description des touches de fonction 28

4.1 Fonctions générales 28

4.1.1 Touche stop / marche-arrêt (1) 28

4.1.2 Touche fonction secondaire (4) 29

4.1.3 Touche calibration (22) 29

4.1.4 Touches mA(µC) haut (21) et bas (23) 29

4.1.5 Fonction horloge 29

4.2 Fonctions principales 30

4.2.1 Stimulation TOF 30

4.2.2 Stimulation 1 Hz 30

4.2.3 Stimulation PTC 31

4.3 Fonctions secondaires 31

4.3.1 Stimulation Double Salve (DBS) 31

4.3.2 Stimulation tétanique 32

4.3.3 Touche stimulation 0.1 Hz 32

5 Menu d’installation 33
6 Description des symboles d’écran 34
7 Informations complémentaires 35

7.1 Nettoyage 35

7.2 Profils inhabituels 35

22 | TOF-Watch Operator manual 33.502/B

8 Messages d’erreur 36

9 Accessoires 37
10 Spécifications techniques 38
11 Symboles 38
12 Mise en garde! 39

23 | TOF-Watch Operator manual 33.502/B

TOF-Watch ®

Schéma des touches et symboles d’affichage

Touche stop / marche-arrêt.
Touche Post Tetanic Count / stimulation tétanique.
Touche Train Of Four (Train de quatre) / Double Burst (stimulation
double salve).
Touche fonction secondaire.
Symbole fonction secondaire.
Symbole calibration.
Symbole système en marche / arrêt.
Symbole état de la pile.
Symbole erreur interne.
Symbole signal sonore de stimulation.
Symbole capteur d’accélération.
Symbole résistance trop forte.
Symbole électrode-aiguille.
Symbole horloge / stimulation.
Mode de stimulation.
Symbole fréquence.
Symbole micro-coulomb.
Symbole milli-ampères.
Valeur du rapport TOF (train de quatre), hauteur du twitch, courant de stimulation ou PTC.
Symbole de pourcentage : utilisé pour le rapport TOF ou la hauteur du twitch.
Touche mA(µC) haut.
Touche calibration.
Touche mA(µC) bas.
Touche stimulation 1 Hz / 0.1 Hz.

24 | TOF-Watch Operator manual 33.502/B

1 Introduction

1.1 Généralités

Le monitorage de l’effet des agents curarisants peut s’effectuer de plusieurs façons.
La manière la plus courante est l’évaluation clinique effectuée à l’aide d’un stimulateur de
nerfs périphériques. Cette méthode, facile certes, manque de précision, l’interprétation des
réponses étant subjective.
Des informations exactes sur le degré de bloc peuvent être obtenues en mesurant la force de
contraction d’un muscle spécifique (mécanomyographie), méthode qui a toutefois
l’inconvénient de faire appel à un matériel relativement volumineux et d’être difficile à utiliser
en raison de la procédure complexe de réglage et de sa sensibilité à tout mouvement.
La mesure de l’accélération (accéléromyographie) constitue une alternative de choix à la
mesure de la force. Selon la deuxième loi de Newton
(La force est égale au produit de la masse par l’accélération, F = M x a), l’accélération d’un
muscle est corrélée de façon linéaire à la force exercée par ce muscle. Il a été démontré qu’il
existe une bonne corrélation entre les résultats de l’accéléromyographie et de la
mécanomyographie.

1.2 Fonction du système

Le TOF-Watch est un nouveau dispositif destiné au monitorage du bloc neuromusculaire en
salle d’opérations ou de réanimation.
Le TOF-Watch, qui repose sur le principe de l’accéléromyographie, peut également être utilisé
comme stimulateur des nerfs périphériques.
Il peut enfin servir à localiser les nerfs pour une anesthésie loco-régionale.
En conséquence, le TOF-Watch ne doit être utilisé que par du personnel médical qualifié.
Consulter le chapitre 11: Mise en garde!, avant toute utilisation !.

1.3 Vérification à la livraison

Lors de la livraison de votre TOF-Watch, veuillez vérifier que le contenu de l’emballage est
complet et qu’il n’a subi aucun dégât pendant le transport. Le TOF-Watch doit être gardé à
température et humidité ambiantes.

2 Mode d’emploi résumé

2.1 Contrôle de la relaxation musculaire du patient

Dans le menu d’installation du TOF-Watch, l’affichage de l’intensité de stimulation peut être
commuté de mA (réglage par défaut) à µC, selon les préférences.
Le courant de stimulation est réglé en usine à 50 mA.

1 Placer les électrodes et fixer le capteur d’accélération sur le pouce du patient avec du ruban

adhésif.
2 Mettre en marche le TOF-Watch en pressant la touche (1) pendant 1 seconde.
3Administrer l’inducteur d’anesthésie.
4 Lorsque la sédation du patient est satisfaisante, presser la touche (22) pour effectuer

une calibration automatique (facultatif).
5 Garder la touche (3) enfoncée pour une stimulation TOF répétitive.

25 | TOF-Watch Operator manual 33.502/B

Le TOF-Watch est maintenant prêt au monitorage du bloc neuromusculaire.

Pendant une intervention chirurgicale, la relaxation musculaire peut être surveillée en continu
pour juger de la nécessité d’une nouvelle administration de myorelaxant ou de l’utilisation d’un
antagoniste lors de la récupération.

2.2 Contrôle de la curarisation résiduelle du patient

L’utilisation du réglage automatique du TOF-Watch sur des patients déjà myorelaxés donnera
une sélection incorrecte du gain interne. La procédure suivante doit être suivie :

1 Placer les électrodes et fixer le capteur d’accélération sur le pouce du patient avec du ruban

adhésif.
2 Mettre en marche le TOF-Watch en pressant la touche (1) pendant 1 seconde.
3L’intensité de la stimulation (mA ou µC) peut être ajustée manuellement en pressant la

touche mA (µC) haut (21) ou bas (23).
4Presser la touche (3).

La hauteur du twitch de contrôle n’ayant pas été établie, seul le ratio TOF - et non une mesure
isolée du twitch - donne des informations sur la récupération d’un patient.

2.3 Localisation des nerfs pour anesthésie loco-régionale

Il est possible d’utiliser le TOF-Watch pour localiser les nerfs pour une anesthésie loco-régionale.
Cette possibilité nécessite l’utilisation d’un câble de stimulation spécial. Ce câble est muni d’un
connecteur-pression à fixer sur une électrode de surface ronde et d’une broche de 2 mm à relier
à une électrode-aiguille. Après avoir inséré ce câble dans le TOF-Watch, l’appareil revient
automatiquement au mode anesthésie loco-régionale. Comme une simple appréciation visuelle
de la réponse suffit, aucune réponse n’est affichée.

1 Connecter le câble de stimulation spécial au TOF-Watch.
2Positionner l’électrode de surface.
3 Mettre en marche le TOF-Watch en pressant la touche (1) pendant 1 seconde.
4 Lancer la stimulation répétitive à 1 Hz en pressant la touche (24).
5L’intensité de la stimulation (mA or µC, affiché sur l’écran) peut être ajustée manuellement

en pressant la touche mA(µC) haut (21) ou bas (23).

Le TOF-Watch est maintenant prêt à localiser les nerfs à l’aide de l’électrode-aiguille.

3 Installation pré-opératoire

3.1 Connexions du câble (monitorage objectif)

Le TOF-Watch peut être utilisé pour un monitorage objectif au moyen de deux câble :
A) un câble de capteur d’accélération et B) un câble de stimulation. Lors de l’utilisation des
électrodes de surface, l’appareil recourt automatiquement à des impulsions de 200 µs à
0 - 60 mA (0 - 12 µC). L’intensité du courant est réglée en usine à 50 mA.
Fixer le câble de stimulation aux électrodes de surface placées sur le trajet du nerf cubital.
A l’aide d’un ruban adhésif, fixer le capteur d’accélération, côté plat contre le pouce.