It is important to return the warranty card supplied with your Doppler as soon as possible.
Your MedaSonics Doppler is protected by a limited warranty. Specific warranty terms
and conditions were included with your Doppler or may be obtained by calling Customer
Service at 1-800-243-2974.
Ultrasonic frequency: 2.25 MHz
Outputs: Two 2.5 mm jacks to drive one or two headsets, one headset and a speaker or a
Controls: Volume control and push-button ON-OFF.
Power Source: One standard 9 volt alkaline battery.
Dimensions: 12.6 cm x 6.4 cm x 2.5 cm (4.95” x 2.5” x 1.0”).
Weight: 133 gm (4.7 oz) with battery.
Construction: Rugged ABS plastic case, integral transducers, solid state circuitry.
Spare Parts List
101-0231-010 Repair Kit (misc. parts to repair 3-4 units)
150-0144-010 Battery Connector
203-0765-020 Battery Cover
101-0008-010 Headset (SH3A)
200-0004-050 Headset Cord
150-0033-010 Headset Jacks
Fetal Ultrasound Stethoscope®
The MedaSonics ULTRASOUND STETHOSCOPE® Doppler Fetal Pulse Detector Model
FP3B has been designed specifically for detection of the fetal heart rate and circulation.
Clinical experience has demonstrated that Doppler ultrasound is a simple, noninvasive aid
in the management of routine as well as problem pregnancies. The Fetal Doppler is
designed to replace the conventional fetoscope in most applications. It has been manufactured to give quality performance in a rugged, truly pocket size package. Optional speakers
provide reassurance to the mother by allowing her to easily hear the fetal heartbeat.
The MedaSonics ULTRASOUND STETHOSCOPE is based on the Doppler shift principle.
At the narrow end of the instrument is the faceplate, covering two piezoelectric crystals.
One crystal is a transmitter of very low power ultrasonic waves at a frequency of approximately 2.25 MHz. As these ultrasonic waves reach moving tissue such as the fetal heart or
blood cells, they are reflected and their pitch is shifted slightly. This change in pitch is the
Doppler shift. These reflected waves as they arrive at the receiving crystal are detected and
greatly amplified. Further processing converts the Doppler-shifted ultrasonic waves into
audible sounds of the fetal pulse.
Other Products Available
Pocket Speaker • Model SA2
Tabletop Speakers • Models SA3, SA6
FetalCalc™ Speaker with heart rate display
Fetal Doppler • First Beat® and FetalPulse Plus™ Doppler Systems
Blood Flow Dopplers • CardioBeat®, Model BF4B, Model BF5A
DoubleBeat™ • Multi-Use Doppler
Versatone® D8 • Multi-Use Doppler System
The most easily heard sound of clinical significance is the fetal pulse produced by the moving heart or by blood flow in the umbilical cord or in a fetal artery. A distinctive placental
sound is also identifiable. Maternal and fetal sounds are readily differentiated on the basis
of the pulse rates.
Instructions for Use
1. Ordinarily the patient will lie on her back, abdomen exposed. The examination can also
be easily performed with the patient on her side (first one and then the other) or even
sitting or standing.
95 Corporate Drive, Trumbull, CT 06611
Phone: (203) 601-5200 Fax (800) 262-0105
Toll Free: (800) 243-2974
Part #35390 Rev 8/02
2. Spread a generous amount of ultrasound coupling agent on the body surface to be
examined. A fluid coupling agent is essential for proper operation. Commercial
preparations provide good coupling, however, a soap solution or even water can be used
Do not use alcohol as a coupling agent. A tube of commercial coupling agent is supplied
with each instrument.
3. Plug headset or speaker into either output jack. Set volume control midway. Place
the faceplate-crystal end of the instrument on the abdomen. Press side-mounted
ON button. Adjust volume control as desired. Unit will remain on as long as button
is depressed and for a few seconds after it is released. The FP3B is designed for
one-handed operation, with the middle finger controlling the ON button and the index
finger controlling the volume.
4. Search for fetal heart signals by slowly moving the instrument across the abdomen.
The sensitivity pattern is like a searchlight, so angle the stethoscope for best signal.
In general, the fetal pulse can be detected as soon as the uterus is palpable above the
If desired, the mother may listen, too, through another headset plugged into the second
output jack, or by means of the Model SA2, SA3, SA6 or the Fetal Calc speaker/heart
rate display. The extra headset and speaker are available as optional equipment. A tape
recorder may also be connected to one of the outputs.
The FP3B ULTRASOUND STETHOSCOPE Doppler fetal pulse detector may be used to:
1. Detect fetal life as early as 9 weeks; reliably after 12 weeks.
2. Make frequent checks of fetal heart rate throughout labor and delivery, particularly
during and immediately following contractions. Hospital personnel can carry the
instrument with them as they would a stethoscope.
3. Confirm the presence of a live fetus throughout pregnancy, even when maternal
obesity or hydramnios prevents hearing the fetal heartbeat with a conventional
4. Ease the fear and concern of the anxious expectant mother. Hearing the fetal heartbeat
may be particularly reassuring early in pregnancy.
5. Aid in localizing the placenta in patients with third trimester bleeding and prior to amniocentesis or intrauterine transfusion. Placental sounds have a “blowing” characteristic,
along with a pulsatile component. Accurate localization of the placenta requires some
practice in search and recognition techniques.
Cautions and Considerations
1. Sensitivity should be verified whenever expected Doppler signals cannot be found.
Instrument sensitivity may easily be verified on the radial artery.
2. Caution: Do not use in the presence of explosive anesthetics.
3. According to the American Institute of Ultrasound in Medicine, no confirmed biological
effects on patients or instrument operators caused by exposure at intensities
typical of present diagnostic ultrasound instruments have ever been reported.
Although the possibility exists that such biological effects may be identified in the
future, current data indicate that the benefits to patients of the prudent use of
diagnostic ultrasound outweigh the risks, if any, that may be present.
Care and Service
1. The transducer crystal area should be wiped clean with a tissue after each use. Do not
clean with alcohol or other organic solvents. Do not autoclave the unit; do not immerse
it in liquid, and avoid dropping it.
2. To replace the 9 volt battery, slide the battery cover in the direction indicated by the
arrow on the cover. Remove the battery from the chamber. Unplug the clip from the old
battery and connect it to a fresh one. Observing proper polarity, carefully put the new
battery into the chamber. Be sure the wire of the battery clip is not in the way of the
cover. Slide the cover back in place. Replace the battery with a fresh one after six months.
3. Is it working? A quick check can be made by listening to one’s own vascular sounds
to verify sensitivity. In the event of any difficulty, make sure the battery is fresh, the
volume control is up, the transducer crystal area is clean, and that enough coupling
agent is being used. If the coiled cord or the headset is damaged, please call
Medasonics to order a replacement.
4. Transducer Inspection: Carefully inspect the piezoelectric transducer crystal for cracks
or chips. If the crystal is cracked, advise personnel to discontinue use of the instrument
because ultrasound coupling agent will enter the front of the unit and internal damage
5. Headset Test: With the volume turned up, test the headset for intermittent connections
by vigorously moving the cord at both ends. Be sure the plug fits snugly and that both
headset jacks are making the connection. To test for lost sound or poor quality of sound,
the headset must be compared with a Model SH3A headset that is known to be working well. Check that the sound pathway in the earpieces is not obstructed. Continued
acoustic problems indicate that the headset transducer assembly should be replaced.
6. Volume Control / On/Off switch Test: While listening to the background noise, vary the
volume from full to OFF and listen for excessive static caused by the potentiometer
wiper. Also, press the ON button several times to the ON/OFF momentary switch for
intermittent operation. When the switch is released, the sound will decay in two or three
Warning: Do not spray clean the volume control as most control cleaners will
harm the plastic case.
7. MedaSonics maintains a service facility which has the capability to promptly repair all
products returned to the factory. Because of special jigs, fixtures, and reference are
required, repairs should not be attempted on the internal tuning adjustments and the
piezoelectric transducer “crystal”. Instruments requiring repair in these areas must be
returned to the factory for service. Prepaid insured shipment for factory service should
be made to:
Customer Service Manager
95 Corporate Drive
Trumbull, CT 06611