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FREQUENTLY ASKED
QUESTIONS
Summary of Categories:
» Polyvinylidene Fluoride Film (PVDF)
» General
» Airflow
» Gemini
» Snore
» Disposables
» Reusables
» Electrodes
» Precision Chin Patch
» Dual Snap Electrodes
» Adapter Cables
Polyvinylidene Fluoride Film (PVDF)
Q. Why are Dymedix
Airflow Sensors better than thermocouples or thermistors?
A. Dymedix patented
pyro/piezoelectric sensors are made of Polyvinylidene Fluoride
(PVDF) film. PVDF film is a flexible, lightweight, tough, specially
treated plastic film that generates a voltage when exposed to
temperature changes (pyroelectricity) during breathing and sound
vibration (piezoelectricity) during snoring. These signals can
occur both separately and simultaneously and have:
·
Linear response to both temperature
and pressure
·
Accurate detection of both oral and
nasal airflow
·
Improved signal-to-noise ratio
·
No thermal lag compared to thermistor
or thermocouple technology.
·
The ability to detect subtle flow
limitations associated with Respiratory Effort Related Arousals
(RERA).
Q. How do Dymedix
Sensors compare to air pressure transducers?
A. Dymedix Sensors
are superior to Air Pressure Transducers in accurately detecting
mouth breathing, even when compared to oral/nasal cannula. Dymedix
sensors have demonstrated, in clinical studies,
better accuracy in scoring apneas and hypopneas. Air Pressure
transducers have demonstrated the following issues:
·
Reductions in nasal air flow due to
mucus or anatomical issues, which may cause false
positives.
·
Increased nasal flow resistance due
to the introduction of the probes into the patient’s
nares.
·
Misalignment of the nasal prongs
during patient movement can cause false
positives.
·
Non-linearity of pressure transducers.
This means that they do not accurately track changes in the amplitude
of the airflow signal and tend to overscore apneas and hypopneas.
·
Cannot be used simultaneously with
end-tidal CO2 or oxygen cannula.
General
Q. My patient has
a moustache and beard. Can I still use a Dymedix airflow or
snore sensor?
A. Dymedix Airflow
Sensors are recommended for patients with mustaches. Position
the sensor on the patient so that the two top extensions are exactly
below the nares of the nose. When removing a disposable sensor
at the conclusion of the study, gently pull the sensor off using
a downward pulling motion. Removal of a disposable sensor is
best done by peeling the sensor off in the direction of the growth
of body hair. The Over-The-Nose (OTN)
Snore sensor is ideal for patients with beards.
Q. Will the
adhesive tape on the back of the disposable Dymedix sensor work
on patients with a mustache or that perspire excessively?
A. Medical tape
may be used over the sensor, but is usually unnecessary even with
those patients with a moustache, that perspire excessively, or have
excessively oily skin. Remove perspiration and oil from the lip
prior to applying the sensor.
Q. How do your
sensors work on the EdenTrace units?
A. Dymedix Sensors
demonstrated superior signals with the EdenTrace II & IIPlus
recorders, and they are less expensive! Dymedix airflow,
Snore and Gemini
sensors are available for EdenTrace.
Airflow
Q. What are the advantages
of disposable sensors?
A. The benefits of
single-use disposable sensors include the reduced biohazard exposure
to both patient and technician in addition to freeing the technician
to spend more time with the patient or to analyze sleep studies
instead of cleaning or repairing sensors.
Q. Will the Airflow
sensors work with a CPAP or BIPAP?
A. Yes!
Q. I put the airflow
sensor on me, to see what the signal looked like. All I see
is 60 hertz artifact, what is wrong?
A. You need to have
yourself grounded by applying an electrode to your body and
plugging it into the ground receptacle in the head box. The
airflow sensor must be plugged into the adapter cable, the adapter
cable then plugs into the flow channel of your headbox. Turn
the 60-hertz filter on. Adjust your filters as you would for
an airflow signal. The Dymedix sensor is very sensitive and
produces a higher amplitude waveform. Therefore, you may need
to reduce the sensitivity or gain setting lower than you usually do
with other sensors.
Q. The airflow
waveform looks different than the waveform I am used to seeing.
Why?
A. The Dymedix
sensors use a different technology than thermocouples or thermistors.
The PVDF film responds more quickly to temperature change, therefore
a more realistic waveform is seen. If you are not interested in
detecting subtle flow limitations associated with RERA, purchase
a Sinusoidal adapter cable. The waveform will then evoke the same
as a thermistor/thermocouple.
Q. The oral airflow
signal I get is really low amplitude, I adjusted the gain, but it
still is too low. Why?
A. Positioning
of the disposble or the reusable sensor is quite important for obtaining
a quality signal. After removing excess oil and perspiration
from the lip, remove the backing from the disposable sensor. With
either style sensor, position the two upward facing extensions directly
below each nare. The indentation between the two extensions
should touch the septum of the nose. The lower tab should
extend slightly below the patients upper lip. The extension
over the lip is to enable detection of oral airflow. The proper
choice of the size of the sensor is important to obtaining a quality
signal, and for patient comfort. Look at the distance between
the septum and the upper lip when choosing the proper size.
Remember the sensor should touch the nasal septum and extend over
the upper lip. Airflow disposable sensors come in five sizes,
pediatric, children's, small, medium and large. RealFlo™ resuable
sensors come in sizes long and short.
Q. Can I cut
the airflow sensor to make it smaller?
A. No. The PVDF film
is positioned within the sensor to obtain the best signal.
Cutting could damage the film and destroy the capability of sensing.
Gemini
Q. How is the Gemini
signal unique compared to the other available sensors?
A. Dymedix has the
only PVDF technology-based disposable combination airflow/snore
sensor available in the market. The large sensor signal output is
reduced to make it compatible with existing polysomnography systems.
The Dymedix sensor will produce a signal approximately 1.6 times
greater than sensors utilizing thermistor technology. The signal-to-noise
ratio is improved as well. Due to the thermal mass of thermistor
and thermocouple sensors, a patient's rapid, shallow breathing may
appear as nearly a flat line on the Polysomnograph and possibly
be interpreted as apnea or a hypopnea. Thermistors and thermocouples
are not capable of detecting subtle flow limitations. The Dymedix
Gemini sensor accurately tracks rapid, shallow breathing, and flow
limitations, thus improving the accuracy of your Polysomnograph
scoring and diagnosis. The sensor detects vibration of the skin
during snoring. These signals are then separated into the two output
channels of the Gemini adapter cable. By detecting snore signals
at the lip, carotid artery artifact, hunting for the "sweet
spot" and excess neck tissue are no longer of concern.
Q. What are the advantages
of disposable sensors?
A. The benefits of
single use disposable sensors include the reduced biohazard exposure
to both patient and technician in addition to freeing the technician
to analyze sleep studies instead of cleaning or repairing sensors.
Q. Will the Gemini
sensor work with a CPAP or BIPAP?
A. Yes!
Q. I put the Gemini
sensor on me, to see what the signal looked like. All I see
is 60 hertz artifact, what is wrong?
A. You need to have
yourself grounded by applying an electrode to your body and plugging
it into the ground receptacle in the head box. The Gemini
sensor must be plugged into the adapter cable, the adapter cable
output for snore and airflow channels are then plugged into the
flow and snore channels of your headbox. Turn the 60-hertz
filter on. Set your filters and sampling rate per the instructions
for use included with your sensors. The Dymedix sensor is
very sensitive and produces a higher amplitude waveform. Therefore,
you may need to reduce the sensitivity or gain setting lower than
you usually do with other sensors.
Q. The airflow
waveform looks different than the waveform I am used to seeing.
Why?
A. The Dymedix
sensors use a different technology than thermocouples or thermistors.
The PVDF film responds more quickly to temperature change, therefore
a more realistic waveform is seen. If you are not interested in
detecting subtle flow limitations associated with RERA, purhcase
a Sinusoidal adapter cable. THe waveform will then evoke the same
as a thermistor/thermocouple.
Q. The airflow and/or
snore signal I get is really low amplitude, I adjusted the gain,
but it still is too low. Why?
A. Positioning
of the sensor is quite important for obtaining a quality signal.
After removing excess perspiration and oil from the lip, remove
the backing from the sensor. Position the sensor with the notch
pointing upwards. The indentation between the two extensions
should touch the septum of the nose. The lower tab should extend
slightly below the patients upper lip. The extension over the
lip is to enable detection of oral airflow. The proper choice
of the size of the sensor is important to obtaining a quality signal,
and for patient comfort. Look at the distance between the septum
and the upper lip when choosing the proper size. Remember the sensor
should touch the nasal septum and extend over the upper lip. Gemini
sensors come in five sizes, pediatric, children's, small, medium
and large.
Q. Can I cut
the Gemini sensor to make it smaller?
A. No.
The PVDF film is positioned within the sensor to obtain the best
signal. Cutting could damage the film and destroy the capability
of sensing.
SNORE
Q.
Where is the throat snore sensor
to be placed?
A. Using 2 fingers, hold them
on the left or right side of the patient's neck. Ask the patient
to make snoring sounds. Wherever the maximum vibration is
felt, place the snore sensor directly over this spot.
Q. Where is the Over-The-Nose
(OTN) Snore sensor to be placed?
The
Over-The-Nose snore sensor picks up vibration on the nose. The sensor
is shaped like a stocking, the "foot" portion should be
on the fleshy portion on the side of the nose (see image below).
Q. What
filter settings do I need?
A. See instructions for use
or product
specifications sales sheet.
Q. Does
the sensor detect the sound of the snore?
A. No,
it is detecting the vibration caused by the snore. This technology
is more accurate because vibration frequencies are lower than acoustic
frequencies and more closely match your PSG filter and sampling
rate capability. Patented noise cancelling circuitry in the adapter
cable reduces the background noise.
Q. What if I
have followed all of the instructions, but still can't get it to
work?
A. Call Tech
Support at 888-212-1100 for immediate help. Tech Support is
available 24/7.
Q. I
am not getting a good signal; in fact, it looks nothing like a snore
signal. What could I be doing wrong?
Set
the sampling rate for the snore channel to the maximum. Save the
montage. Next, check that you have the wires coming from the
adapter cable [megaphone/speaker symbol] plugged into the snore
inputs of the headbox. Finally, make sure the patient is grounded
to the headbox, and if necessary, turn your 60 Hz filter "on".
Q. I seem to be picking
up a lot of electrical interference, what could be wrong?
A.
Having a ground electrode applied to the patient is very important
for cancellation of 60 Hz artifact. In addition, turning on
the 60 Hz filter (notch filter) will help.
Q. My snore signal looks really different.
What is wrong?
A.
Set the filters as you normally would for EMG signals, (High frequency=120
Hz or higher; Low frequency =10 Hz). Set the sampling
rate to 200 samples per second or your highest available setting,
and save your montage. If your PSG does not have these settings,
set to the closest value available.
Q. I put a snore sensor on my patient's neck,
and an airflow sensor under his nose. I
am unable to plug both into my Gemini adapter cable.
A. Only Gemini
sensors are capable of producing both airflow and snore signals. If
you would like to use a snore sensor on the patient's neck, and
a separate airflow sensor on his face, you need two adapter cables. A
yellow snore adapter cable is needed for the snore signal, and will
plug into the snore channel of your head box. A red airflow adapter
cable is needed for the airflow sensor signal.
Q. Is it okay to put tape right over the snore
sensor or the airflow sensor?
A. Yes, taping across the snore sensor will
not inhibit the signal. The airflow sensor should
not have tape over the upper nasal extensions or the portion extending
below the upper lip. Taping across the airflow sensor with
a narrow piece of tape is acceptable, but not usually necessary.
Disposables
Q. What are the advantages
of disposable sensors?
A. The benefits
of single-use disposable sensors include the reduced biohazard exposure
to both patient and technician in addition to freeing the technician
to analyze sleep studies instead of cleaning or repairing sensors.
Dymedix is proud to be
able to bring to the market a technology whose application allows
for better accuracy in diagnosis and a clean sensor for each patient.
Reusables
Q. What is
the suggested way of holding the sensor in position?
A.
The airflow sensor should have tape applied over the wires on each
side of the sensor.
The
snore sensors should have tape applied over the sensor itself, plus
an additional tape on the wire for the OTN sensor.
  
Q. We've
been using your disposable sensors for quite some time now. Do your
reusable sensors get as sensitive a signal?
A.
Yes. All circuitry used will produce the same clean signal as with
our line of disposables.
Q. How
many electrodes are in the electrode kit?
A. 10 - two eye
electrodes [EOG], one ground electrode, three electrodes for chin
EMG, two snap electrodes for EKG, two dual snap electrodes - one
for each leg.
Q. Why
would I want to order these kits?
A. They
are convenient and require no cleaning. They are excellent
for home studies, ICU studies, portable studies within the hospital,
pediatric patients, compromised patients in the lab, patients with
a known transmittable disease.
Q. Why
do they come in a resealable pouch?
A. If you do
not use all of the electrodes in the pouch, you should reseal them
in the pouch to insure the gel does not dry out.
Q. Can
I use the dual electrodes only on legs?
A. They could
be used for intercostal electrodes, scalenes, or arms.
Q. Will the snap
electrodes fit on the snap wires I already have?
A.
Yes. If you don't currently have snap wires, Dymedix also
has dual-snap cables (100" and 120"). A unique feature
of the electrodes and the wires, is that they eliminate two wires
when you use one dual snap electrode per leg. Only one dual
cable needs to be placed down each leg, rather than two wires per
leg. Talk about convenience!
Q.
I often see noisy signals from my electrodes, particularly later
in the night.
A.
Shave, clean and remove perspiration and excess oil from the electrode
site. Add a small drop of gel or water to the pre-gelled electrode.
(This is a good practice for all your pre-gelled electrodes, regardless
of manufacturer).
PRECISION CHIN PATCH
Q. I normally
put just 2 electrodes on for chin EMG, what is the 3rd
electrode for?
A. Many labs
put an extra chin electrode on the patient for backup purposes.
If an electrode stops working, you can just re-reference to the
3rd electrode from the control room without going into
the patient's room.
Q. What should
I do with this extra electrode?
A. Plug it into
any unassigned channel in your head box. You can re-reference
right from your system during the night if you need to. Do
not plug it into a reference, or ground channel.
Q. Can
I put tape over the patch?
A.
Yes, but you will find this will not be necessary if you prep the
skin before applying the Precision Chin Patch.
DUAL SNAP ELECTRODES
Q. Where
would I use these?
A.
They are excellent for leg EMG, arm EMG, intercostal electrodes,
or scalene electrodes.
ADAPTER CABLES
Q. Why is an adapter
cable needed?
A. Since Dymedix sensors
are many times more sensitive than other sensors, we've had to attenuate
the signal with the use of circuitry in the adapter cable.
The adapter cables also include noise-cancellation circuitry to
further improve the quality of your signals.
Q. Can I use another
manufacturer's adapter cable with Dymedix sensors?
A. No, you must use
a Dymedix adapter cable. The signal produced by our sensors requires
the circuitry found only in Dymedix adapter cables.
Q. Are there different
cables for the various polysomnograph devices?
A. Yes, there are separate
cables for the Alice 3, Alice 4, Suzanne, and EdenTrace polysomnographs.
The cable with the 1.5mm safety pin connector works for most other
brands (DIN standard).
Q. Is there
an adapter cable that specifically works for the EdenTrace devices?
A. Yes, adapter
cables for Airflow, Snore and Gemini Sensors are available for the
EdenTrace II and IIPlus recorders.
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