Chattanooga
™
Primera Operation Manual
11
RATE
[Hz or pulses per second]
The
RATE
to be selected depends primarily on the electrode placement on the
patient’s body. If one uses contiguous and dermatome (the electrodes alongside
or over the area of pain) electrode placement, a higher rate of 80 Hz - 100 Hz
is desirable. The patient should experience steady continuous stimulation. It
has been found that an optimal setting of 80 or 90 Hz with a pulse width of 200
µ
S
has good effect for most patients and is a good first choice for pain-gating.
Patients using Trigger, motor or acupuncture points tend to respond to low rate
stimulation 2 Hz - 10 Hz and pulse width of 200
µ
S. The desired effect is for
the patient to feel individual pulses.
PULSE WIDTH
[Duration]
The wider pulse widths will deliver stronger stimulation for any given intensity
[mA] setting. By using a combination of intensity and pulse duration, it is felt
that various pulse widths are capable of stimulating different groups of nerve
fibres. The wider pulse duration is needed to recruit motor fibres, where as the
narrow pulse duration is used more on the sensory fibres.
The selection of which pulse duration to use is dependent upon the intended
treatment protocol.
Stimulating the larger nerve fibres is thought to reduce the speed and the
amount at which information is transmitted along the smaller nerve fibres. Also
under certain circumstances the brain is thought to produce its own
analgesic pain-killing substances, known as endorphins or endogenous opiods.
Intensity [mA]
Patients respond differently to the level of intensity, this is due to differences
in individual patient’s skin resistance, enervation and the type and condition of
electrode being used.
A good formula for setting the intensity is to increase the current so that the
patient feels slight muscle contraction, but not strong enough to move a joint,
and then slightly reduce the intensity so that it feels comfortable. When using
low rate TENS settings, individual twitches will occur. The higher rate TENS
settings will increase muscle tension. It is not advised to increase the intensity
to experience strong muscle contraction.
Using the Chattanooga Primera ™ unit
in TENS mode
