Airflow Pressure Transducer
Why is the BRAEBON Pressure Transducer the best on
the market?
All BRAEBON Pressure Transducers only use laser-trimmed silicone wafer differential pressure transducer technology which is
precisely calibrated with built-in circuit overload protection.
This technology is highly stable and linear for both positive
and negative pressures. Look carefully and you'll find inferior
competitors' devices branded as pressure transducers, but
containing piezo sensors inside. A piezo sensor is light years
behind true differential pressure transducer technology. Additional
reasons why BRAEBON Pressure Transducers are the best: All
BRAEBON Pressure Transducers have On/Off switches; Only BRAEBON
Pressure Transducers are smart enough to automatically turn
off because your sleep-deprived techs will often forget; Quality,
reliability and a one-year hassle-free warranty.
Why use a BRAEBON Pressure Transducer?
To accurately and reliably detect flow limitation and Upper
Airway Resistance Syndrome (UARS). Published research has
concluded that monitoring flow noninvasively with a nasal
cannula can detect flow limitation extending your diagnostic
reach to include UARS. Flow limitation appears as a flattening
or plateau on the inspiratory waveform and is best viewed
with a low frequency filter of 0.01 Hz or less (decay time
constant of 5 seconds or longer). For those of you who remain
interested in using the gold standard of Respiratory Effort
Related Arousals (RERAs), BRAEBON's Dual Pressure Transducer
is rated for use with air-filled esophageal catheters (BRAEBON
only recommends Ackrad Laboratories' catheters). The simplicity
of the BRAEBON Dual Pressure Transducer plus the comfort of
modern air-filled catheters results in simple esophageal monitoring.
Note: If you're not using a BRAEBON Pressure Transducer, make
sure your pressure transducer is both stable and linear with
negative pressures before use. What you may discover may surprise you!
What age groups can I record with a Pressure Transducer?
Any age group can be recorded with a Pressure Transducer.
Ensure that your cannula, catheter, or mask is age appropriate
and recording will be straightforward.
Should I use an AC or DC connection for Polygraph
settings?
If you have a low frequency filter of 0.01 Hz or lower plug
the transducer into your headbox (AC). If you only have a
low frequency filter of 0.1 Hz then use a direct coupled connection
(DC). For DC connections you may require a connection cable
from the patient room to your amplifier. These cables may
be from 6 feet to 100 feet in length, but high quality co-axial
cable must be used. BRAEBON recommends RJ-174U shielded co-axial
cable.
What polygraph settings should I use?
BRAEBON recommends you start by using the following settings,
but what works for you will depend on your patient's breathing
and your amplifier.
How do I connect the Pressure Transducer for CPAP
and Esophageal Recording?
Do I need to calibrate the Pressure Transducer
if I use a nasal cannula?
No, a pressure transducer used with a nasal cannula essentially
functions as an uncalibrated pneumotachograph. As such, calibration
is not needed when using a nasal cannula.
How do I calibrate the Pressure Transducer for Esophageal
Pressure Recording?
Data required for esophageal pressure recording can be obtained
when the system is calibrated with a water manometer. The
0580Pes device is already calibrated when it leaves the factory.
If you wish to perform additional calibration proceed as follows:
Material required: one piece of ¼" diameter (6.25mm) clear
flexible tubing) six feet in length; two 3-way stop-cocks;
two 10cc luer connector syringes; one piece of board for mounting
the tubing; luer connectors as needed.
- Fill the baseline syringe with water (colored water may help in reading values).
- Connect the baseline syringe to the stop-cock on the bottom of the water manometer.
- Turn the stop-cock so that you can adjust the baseline water level.
- Adjust the baseline water level to read 0cm H2O.
- Before connecting the sensor to the water manometer make sure that the sensor?s baseline voltage is set to the proper value. This is usually zero volts DC.
- Connect the sensor to the stopcock with the pressure adjust syringe. Ensure a hydrophobic (safety) filter is properly installed.
- Set the pressure in the system by moving the pressure adjust syringe until the manometer reads the correct pressure. Usually ±10 cm H2O.
- Adjust the sensor's gain until the sensor?s voltage is set to the proper value. Usually ± 0.75 volts DC is set to equal ±10 cm H2O.
- Repeat steps 7-8 for each pressure-voltage setting.
Here's an alternate way of calibrating your esophageal pressure transducer and catheter:
Attach the catheter to the oral input side of the transducer
and inject 1cc of air into the catheter. Attach the output
signal cable from the transducer to your amplifier's DC input.
Lay everything flat on a desktop or table. Perform a DC calibration
on your collection software and "tell" your software that
the low DC value is 0 cm H2O. Now, take a water-filled cylinder
and insert the catheter into the cylinder so that the middle
of the catheter is 10 cm below the surface of the water. Perform
a DC calibration on your collection software and ?tell? your
software that the high DC value is 10 cm H2O. You?re done!
Because all BRAEBON Pressure Transducers use high-end components
the linear calibration you just performed will be stable and
reliable up to +/-350 cm H2O.
What is the Nasal Differential port on the BRAEBON
Dual Pressure Transducer?
The Nasal Differential port is your baseline. When you attach
nothing to it you are using atmospheric pressure as the baseline
for your Nasal Input. If you attach a CPAP circuit to the
Nasal Differential, you are now using CPAP pressure as the
baseline rather than atmospheric pressure.
Do I have to use all the outputs from the BRAEBON Pressure
Transducer?
No. If you do not want to look at snoring with the pressure
transducer it is recommended that you use the Airflow Signal
(Filtered) output only. This will give you a better opportunity
to view the flow limitation because snoring may mask the plateau
on the inspiratory waveform - which is a real important reason
why you're looking at the pressure signal.
How long will the battery last?
This depends on the model of Pressure Transducer you are using.
Alkaline AA batteries in the Dual Transducer will last about
35 8-hour recordings; lithium AA batteries will last longer.
The battery in the Single Input Transducer will last about
30 8-hour recordings for the high gain version, and about
150 8-hour recordings for the low gain version. Actual battery
life may vary.
How do I know if the Pressure Transducer is working
properly?
Turn it on and look for the blinking green status LED. The
proper LED sequence is one green blink followed immediately
by one red blink, two second pause, one green blink, followed
by an extended pause and then one green blink every 10-15
seconds indicating the unit is on and functioning properly.
Why do I see continuous green-red flashing on the
LED?
Change the batteries. If it doesn't go away call customer
service.
Why do I see a spike about every 10 seconds?
Your batteries are dying and need to be changed. The product
was designed to give you visual cues to let you know when
to change the batteries. Because the Pressure Transducer is
in the bedroom you won't be able to see the LED change from
green to red if the battery starts to fade in the middle of
the night. We've provided an intermittent spike on the output
signal which tells you about impending battery life expectancy
from the comfort of your computer monitor.
The signal looks funny and doesn't look like an airflow
thermistor. Why?
The signal from an Airflow Pressure Transducer looks sinusoidal
during normal breathing just like an airflow thermistor, but
appears differently during sleep-disordered breathing. This
is what you want to see if your system is set up properly.
Specifically, the shape (or morphology) of the waveform looks
differently when there is snoring, UARS, apnea, and hypopnea. When the top of the inspiratory waveform looks flat (i.e.,
there's a plateau), this means you are seeing a change from
the normal sinusoidal waveform and are now observing flow
limitation and UARS. Pressure Transducer technology actually
offers you much more diagnostic information than a thermistor
because all temperature sensing devices - disposable or reusable
- have a low frequency filter built into the product. This
means the signal returns to baseline faster and reduces your
chances of seeing the clinically important flow limitation.
On the one hand, the low frequency filter built into the temperature
sensing devices will make your signal look clean and smooth,
but this signal is actually a function of the electronic circuitry
and is not what is really happening during sleep. On the
other hand, BRAEBON Pressure Transducers do not have low frequency
filters to limit your ability and they extend your diagnostic
arm by giving you a much more complete picture of what is
really going on during sleep.
I've connected the Pressure Transducer using AC directly into
the jackbox, but the signal output from the Pressure Transducer
looks funny and has sharp mountain peaks and valley troughs.
Why?
This is simple. Your low frequency filter setting (LFF) is
too high. Set your LFF to 0.01 Hz. If you can't set your LFF
to 0.01 Hz try a DC connection. There are a few polygraph
systems out there that allow you to set your software LFF
off or very low, but always have a hardware LFF around 0.1
Hz. Check with your polygraph manufacturer to make sure your
hardware amplifier doesn't have a built-in LFF.
Do I need a snoring microphone if I use a Pressure
Transducer?
This depends on your preference. Some sleep laboratories use
the snoring signal from the BRAEBON Pressure Transducer while
others continue to use a snoring microphone. We suggest you
judge for yourself and make an informed decision based on
your own observations.
Is a Pressure Transducer better than a disposable
airflow temperature sensor?
Absolutely. Both single-use cannulas and single-use temperature
sensors are to be discarded after patient use, but disposable
cannulas are significantly less expensive, provide more clinical
information, and are backed by peer-reviewed published research.
Despite claims by the manufacturer, NO disposable temperature
device will show clinically significant flow limitation as
well as a BRAEBON Pressure Transducer. Furthermore, the BRAEBON
Dual Pressure Transducer can be used to record gold standard
RERAs with a disposable esophageal catheter. No matter if
you are using cannulas or catheters, the BRAEBON Pressure
Transducer easily outperforms any disposable temperature device
hands down.
How long is the warranty?
All BRAEBON Pressure Transducers are covered by the only one-year
no-hassle replacement warranty.