Mainline Medical TOF-Watch S Operator's Manual

TOF-Watch®S

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

TOF-Watch®S

Operating manual page 3

Manuel d'utilisation page 23

Bedienungsanleitung Seite 43

Manual del usuario página 63

® 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 12

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 TOF

S

Stimulation 13

4.3.2 Double Burst Stimulation (DBS) 14

4.3.3 0.1 Hz stimulation button 14

4.3.4. µs button 14

4.3.5. Sensitivity button 15

5 Set-up menu 15
6 Survey of display 17

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7 Further information 18

7.1 Cleaning 18

7.2 Unusual patterns 18

8 Error signals 19

9 Accessories 19
10 Technical specifications 20
11 Symbols 20
12 Warnings! 21

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TOF-Watch®S

Scheme of buttons and display symbols

Stop / on-off button.
Post Tetanic Count / Double Burst Stimulation button.
Train Of Four / Train Of Four

S

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.
Micro-second (µs) symbol.

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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.
The TOF-Watch should only be operated by trained medical personnel.
Before operation, please refer to the Warnings! in chapter 12.

1.3Actions upon delivery

Upon delivery of the TOF-Watch, please check the contents of the package for completeness
and any possible 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 s.
3Administer the induction agent.
4 When the patient is adequately sedated, press (22) for automatic calibration (optional).
5Hold down the button (3) for repetitive TOF stimulation.

The TOF-Watch is now ready for the further monitoring of 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 the 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 s.
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 as an aid in 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 on the display.

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 s.
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 use in 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 (300 µs) at 0 - 60 mA (0 - 12/18 µC). The pre-defined 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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