FHR Monitoring

Question 1

What are some external electronic fetal monitoring techniques?

Answer 1

Doppler US transducer and pressure sensitive tocodynanmometer

Question 2

Describe a Doppler US transducer

Answer 2

Placed on maternal abd overlying the fetal heart; records reflected sound waves from the fetal heart back to the transducer

Question 3

Describe a pressure sensitive tocodynanmometer

Answer 3

Detects and records contractions; useful for measuring the frequency of contractions but not the strength

Question 4

What are some internal electronic fetal monitoring techniques?

Answer 4

Fetal scalp electrode and intrauterine pressure catheter

Question 5

Describe a fetal scalp electrode (FSE)

Answer 5

Rate is composed from the R wave peaks of the fetal echocardiogram; maternal and fetal movement will not alter the quality of signal; rare cases of fetal pustules have been reported; avoid in HIV pts

Question 6

Describe IUPC

Answer 6

Soft plastic catheter transcervically; gives precise measurement of the intensity of the uterine contractions in mmHg

Question 7

What provides the most accurate information for fetal monitoring?

Answer 7

Internal electronic fetal monitoring; requires membranes to be ruptured

Question 8

How do uterine contractions affect fetal oxygen levels?

Answer 8

Exchange of respiratory gases is momentarily interrupted during a contraction; a normal fetus can tolerate these changes; when hypoxia is severe it will result in anaerobic metabolism resulting in fetal acidosis

Question 9

How do uterine contractions affect FHR?

Answer 9

Can affect FHR by increasing or decreasing the rate in association with each given contraction

Question 10

What is normal uterine activity?

Answer 10

5 contractions or less in 10 mins, averaged over a 30min window

Question 11

What is tachysystole?

Answer 11

> 5 contractions in 10 minutes, averaged over a 30min window (presence or absence of associated FHR decelerations)

Question 12

What is a normal FHR?

Answer 12

110-160bpm

Question 13

What FHR is considered tachycardic?

Answer 13

> 160bpm

Question 14

What FHR is considered bradycardia?

Answer 14

<110bpm

Question 15

What are some causes of bradycardia?

Answer 15

Fetal hypoxia (late sign of hypoxia), obstetric anesthesia, pitocin, maternal hypotension, prolapsed or prolonged compression of the umbilical cord, heart block

Question 16

What are some causes of tachycardia?

Answer 16

Early sign of fetal hypoxia, excessive oxytocin augmentation, arrhythmia’s, prematurity, maternal fever, fetal infection (chorioamnionitis = MCC of tachycardia)

Question 17

What produces tachycardia in response to hypoxia?

Answer 17

Chemoreceptors

Question 18

What influences the FHR via the vagus N in response to changes in fetal BP?

Answer 18

Baroreceptors

Question 19

Decreased variability is an indicator of what?

Answer 19

Possible fetal stress; is ominous if associated with persistent late decelerations; is associated with hypoxia and acidemia

Question 20

What are causes of decreased baseline variability?

Answer 20

Prematurity, sleep cycle, maternal fever, fetal tachycardia (chorioamnionitis), fetal congenital anomalies (CNS and cardiac), maternal hyperthyroidism, maternal drugs or substances (caffeine, nicotine, cocaine, meth, narcotics)

Question 21

What is a sinusoidal pattern?

Answer 21

Smooth, sine wave-like undulating pattern in FHR baseline with a cycle frequency of 3-5 per min; seen with fetal anemia

Question 22

Does electronic fetal monitoring result in reduction of cerebal palsy?

Answer 22

No