Control Twitch Height; Calibration; Sensitivity; Stimulation Units - Organon TOF-Watch SX Manual Del Usuario

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 s.
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 observed 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 loco-
regional anesthesia the default setting is in µC. It is possible to change between the two modes
in the Set-up menu - see page 16.
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
Furthermore, the period of time that a button is activated determines the selection of the
function.
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):
Long activation (long):
4.1

General functions

4.1.1

Stop / on-off button (1)

short:
long:
10 | TOF-Watch SX Operator manual 33.512/A
symbol on the display.
< 1 s
> 1 s (acknowledged by a short beep)
Stops stimulation/clears display
Turns TOF-Watch on/off
(if activated more than 1 s).