Operators Manual
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Corometrics® Fetal Acoustic Stimulator Operator’s Manual Software Version 1 1168AA, Revision B
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GUARANTEE All equipment sold by GE Medical Systems Information Technologies, is fully guaranteed as to materials and workmanship for a period of 1 year. GE Medical Systems Information Technologies reserves the right to perform guarantee service operations in its own factory, at an authorized repair station, or in the customer’s installation. Our obligation under this guarantee is limited to repairing, or, at our option, replacing any defective parts of our equipment, except fuses or batteries, without charge, if such defects occur in normal service. Claims for damage in shipment should be filed promptly with the transportation company. All correspondence covering the instrument should specify the model and serial numbers. GE MEDICAL SYSTEMS Information Technologies A GE Medical Systems Company
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Corometrics Fetal Acoustic Stimulator - 1168AA, Revision B
GE Medical Systems Information Technologies will make available on request such circuit diagrams, component diagrams, component parts lists, descriptions, calibration instructions, or other information which will assist the users or appropriately qualified technical personnel to repair those parts of the equipment which are classified by GE Medical Systems Information Technologies as repairable. Refer to your monitor’s Service Manual for further information.
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CAUTION: In the United States of America, Federal Law restricts this device to sale by or on the order of a physician.
Corometrics and Marquette are registered trademarks of GE Medical Systems Information Technologies. GE is a registered trademark of General Electric Company. All other product and brand names are trademarks or registered trademarks of their respective companies. ©1994-2004 GE Medical Systems Information Technologies. All rights reserved. No part of this manual may be reproduced without the permission of GE Medical Systems Information Technologies.
Corometrics Fetal Acoustic Stimulator - 1168AA, Revision B
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For Your Notes
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Corometrics Fetal Acoustic Stimulator - 1168AA, Revision B
CE Marking Information
CE Marking Information Compliance
0459
The Fetal Acoustic Stimulator bears CE mark CE-0459 indicating its conformity with the provisions of the Council Directive 93/42/EEC concerning medical devices and fulfills the essential requirements of Annex I of this directive. The product is in radio-interference protection class A in accordance with EN 55011. For devices manufactured in the United States or India, the CE mark is applied under the authority of Notified Body GMED (0459).
Fetal Acoustic Stimulator - 1168AA, Revision B
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CE Marking Information
For your notes
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Fetal Acoustic Stimulator - 1168AA, Revision B
Contents CE Marking Information... 1 Compliance... 1
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Introduction... 1-1 Device Description... 1-1 Indications for Use... 1-1 Effectiveness... 1-2 Instructions for Use... 1-2
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Operation... 2-1 General... 2-1 Stimulator-Recorder Connection... 2-2 Battery Replacement... 2-2 Care and Cleaning... 2-3 Precautions... 2-3
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Theory of Operation/Specifications... 3-1 General... 3-1 Theory of Operation... 3-1 Stimulator Specifications... 3-1 Replacement Part... 3-2
Fetal Acoustic Stimulator - 1168AA, Revision B
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Fetal Acoustic Stimulator - 1168AA, Revision B
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Device Description
Introduction
The Corometrics Model 146 Acoustic Stimulator is a unique, hand-held device which generates a low frequency vibro-acoustic stimulus directed towards the fetus to improve the efficiency of the nonstress test (NST). The unit is completely self-contained and battery-operated with the means to directly connect to the Corometrics 145, 150, 151, 155, 116, 118, and 120 Maternal/Fetal Monitors for automatic documentation.
Indications for Use The Corometrics Model 146 Acoustic Stimulator is indicated for use as an adjunct to antepartum nonstress testing between 28-42+ weeks of gestation. The Model 146 directs a low frequency vibro-acoustic stimulus towards the fetus to elicit a fetal heart rate response (acceleration) which is indicative of fetal well-being.
CAUTION–The role of fetal vibro-acoustic stimulation and use of the Corometrics Model 146 Acoustic Stimulator during the intrapartum period have not been clearly determined. Cases have been observed in which the initial acceleratory response and associated fetal movements are followed by a prolonged deceleration. It has been postulated that the deceleration may be a result of umbilical cord compression.* WARNING––The long term effects on the fetus due to vibrations emitted by the Corometrics Model 146 Acoustic Stimulator are not known. WARNING––Rare cases of fetal tachyarrhythmia have been reported following vibroacoustic stimulation. The risk of tachyarrhythmia may be higher in fetuses with pre-existing arrhythmia. *Sherer DM, Menashe M, Sadovsky E. Am J Obstet Gynecol 1988: 159:334-5
Fetal Acoustic Stimulator - 1168AA, Revision B
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Effectiveness
5.
Activate stimulator for approximately 2 seconds.
The effectiveness of the Corometrics Model 146 Acoustic Stimulator, used as adjunct to nonstress testing, is comparable to results obtained from the nonstress test (NST).
6.
Wait for 1 minute.
7.
If necessary, stimulator may be reapplied 2 additional times at least 1 minute apart.
8.
In the absence of reactivity, complete standard NST protocol.
9.
If NST is non-reactive after 40 minute period, proceed with further fetal evaluation. (e.g. Contraction Stress Test (CST), Biophysical Profile).
Instructions for Use Procedure: 1.
Explain device and demonstrate vibro-acoustic stimulus (e.g. against palm of hand) to mother to acquaint her with device and relieve any anxiety regarding its use.
2.
Perform a 5 minute basal observation for spontaneous fetal heart rate (FHR) accelerations and/or spontaneous uterine activity (UA) before applying device.
3.
Locate the fetal vertex.
4.
Apply stimulator to maternal abdomen over fetal head.
10. Clean the device after each use. Refer to Section 2.4 for care and cleaning recommendations.
9 Shortly after administering the vibro-acoustic
stimulus, it is not unusual to observe a prolonged period of fetal heart rate accelerations as well as an altered baseline fetal heart rate and increased “variability”. Practitioners should be aware of these potential changes in fetal state and heart rate characteristics. These changes generally correlate well with fetal well-being.
9 Do not apply any type of coupling gel or cream to the device.
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Operation
Fetal Acoustic Stimulator
General There is one control (push button) and one connector on the Model 146 Fetal Acoustic Stimulator. The function and operation of these two items are discussed in the following sub-sections.
Stimulus The white pushbutton on the stimulator (see above figure) allows the operator to apply power to the vibrating diaphragm of the device. Fetal Acoustic Stimulator - 1168AA, Revision B
Depressing the pushbutton activates the stimulator. It remains activated as long as the button is held down, up to a maximum of 3 seconds. If the pushbutton is depressed longer than 3 seconds, stimulation will stop. Releasing the button and then depressing it again repeats the stimulation.
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Stimulator/Corometrics Monitor Connection Stimulator Battery Compartment
Stimulator-Recorder Connection If the stimulator is plugged into a fetal monitor whose recorder is turned on, depressing the stimulator’s pushbutton causes a mark to be printed on the strip chart. If strip chart annotation of stimulations is desired, the stimulator plug must be inserted in the Remote Mark jack of the fetal monitor. On Corometrics monitors, it should be connected to the Remote Mark jack labeled with a musical note. (See above Figure.) In this way, stimulations will be annotated on the strip chart as musical notes, making them esily distinguishable from other marks. 2-2
Battery Replacement The battery should be replaced if the stimulator’s sound level diminishes or if it fails to operate. The stimulator operates on a 9-volt battery. An alkaline battery is recommended for maximum battery life. Replacement is accomplished in the following manner:
Fetal Acoustic Stimulator - 1168AA, Revision B
Operation: General
1.
Insert coin or other flat edge in slot on battery cover and lift upward as depicted in See “Stimulator Battery Compartment” on page 2-2.
Care and Cleaning Dampen soft cloth or towel in a soapy solution and wring out throughly. Rub soiled area of the stimulator until it is clean; then dry with a soft, dry cloth. Take care to prevent area around vibrating diaphragm from getting excessively wet.
Precautions This equipment is not designed for use in an explosive atmosphere, in the presence of flammable anesthetics, or inside an oxygen tent. Use of the stimulator under these conditions may present an explosion hazard.
9 Do not immerse stimulator or hold under running water.
Stimulator Battery Connection
2.
Lift out battery and remove battery connector as shown in the above figure.
3.
Attach connector to new battery. Place battery inside stimulator and install cover.
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Operation: General
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Fetal Acoustic Stimulator - 1168AA, Revision B
General
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Theory of Operation/Specifications
This section contains the Theory of Operation and Specifications for the Model 146 Fetal Acoustic Stimulator.
Stimulator Specifications
Theory of Operation
The push button (S1) connects battery ground to the circuitry. When S1 is depressed, C1 charges through R2. The rising voltage on pin-2 of U1 causes it to output a positive pulse on pin-3. The duration of this pulse, 3 seconds, is determined by R5 and C3. This positive pulse turns on Q2, which shorts the remote mark input of the fetal monitor to the ground. The pulse also feeds the reset input, pin-4 of U2. For the length of time the pulse is high, U2, configured as an oscillator, outputs a pulse wave on pin-3. The length of time this pulse is high is determined by R6 and C5, while the interval between pulses is determined by R7 and C5. The pulse wave turns on Q3, which drives the audio transducer.
Fetal Acoustic Stimulator - 1168AA, Revision B
Audio frequency: 75 Hz ± 10% with harmonics ranging from 20 to 9000 Hz. Maximum stimulation duration: 3 sec ± 0.5 seconds Sound Intensity: 82 dB maximum at 1 meter in air (74 dB nominal) Length: 6.0 in (15.2 cm) Width: 1.8 in (4.6 cm) Depth: 2.2 in (5.6 cm) Weight: 8 oz (227 g)
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Replacement Part Item 1
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Part # 0146AAY
Description
Qty
Model 146 Fetal Acoustic Stimulator
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Fetal Acoustic Stimulator - 1168AA, Revision B
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