EDAN SONOTRAX Basic User Manual - page 22

SONOTRAX Series Ultrasonic Pocket Doppler User Manual                              Operation 

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NOTE:  

1  The setting under this mode will be saved automatically after mode switches 

or normal power off. 

2  After changing frequency, the records related to the original frequency will be 

cleared automatically. 

3.6 Fetal Heart (FH) Examining 

FH examining with 2.0MHz/3.0MHz obstetrical probe 

1) Confirm the fetus’s position by hand. 

2) Determine the probable probe location for ideal FHR examining. 

3) Take out the probe and switch on the Doppler. 

4) Apply a certain amount of coupling gel to the probe faceplate and place the probe against the 

abdomen at the predetermined location. Move the probe around or tilt it until clear and 

rhythmic heart sound is heard from the headphone or speaker. At the same time, a numeric 

FHR is displayed on the LCD (except SONOTRAX Lite). 

NOTE: 

1  The best quality records will only be obtained if the probe is placed in the optimum 

position. 

2  Positions with strong placental sounds or umbilical blood flow sound should be 

avoided. 

3  If the fetus is in the cephalic position and the mother is supine, the clearest heart 

sound will normally be found on the midline below the umbilicus. During examining, 

the pregnant woman’s prolonged lying in the supine position should be avoided 

owing to the possibility of supine hypotension. Sitting up or lateral positions are 

preferable and may be more comfortable. 

4  It is impossible to examine FHR unless a fetal heart sound is present. The fetal pulse 

can be distinguished from the maternal pulse by feeling the mother’s pulse during 

the examination.