Intrapartum FHR Monitoring Flashcards

1
Q

What is the positive predictive value for fetal well being of a normal NST?

A

> 99%

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2
Q

What is the PPV of an abnormal tracing for hypoxia/acidosis?

A

< 50%

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3
Q

What is the definition of tachysystole?

A

> 5 UCs in 10 minutes

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4
Q

How is a baseline heartrate determined

A

Must be at least 2 minutes of baseline in a 10 minute period

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5
Q

What is the normal FHR baseline?

A

110 - 160

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6
Q

How many beats per minute does the fetal heart rate increase for a maternal temp?

A

Increase in 10 bpm for every 1 degree increase in maternal temp

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7
Q

In what setting is fetal tachycardia a sign of fetal hypoxia?

A

Only if the tachycardia is preceded by fetal deceleration (rebound tachycardia)

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8
Q

What are causes of fetal bradycardia?

A

Complete heart block associated with lupus antibodies, hypothermia, hypoglycemia

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9
Q

What is the definition of variability?

A

Fluctuations in FHR that are irregular in amplitude and frequency over a 10 minute window

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10
Q

What is the definition of moderate variability?

A

Change in amplitude of 6 - 25 bpm

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11
Q

What is the definition of minimal variability

A

Change in amplitude of 1-5 bpm

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12
Q

What is the definition of marked variability?

A

Change in amplitude of > 25 bpm

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13
Q

Does absent or minimal variability on it’s own predict fetal hypoxia or acidemia?

A

No, only in the setting of recurrent deceleration

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14
Q

What does Moderate variability reliably exclude?

A

Fetal metabolic acidemia

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15
Q

What is the definition of an acceleration in a fetus > 32 wga?

A

15 beat increase over baseline lasting 15 seconds but < 2 minutes

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16
Q

What is the definition of an acceleration in a fetus < 32 wga?

A

10 beat increase over baseline lasting 10 seconds but < 2 minutes

17
Q

What is the definition of a prolonged acceleration?

A

> 2 minutes but < 10 minutes

18
Q

FHR accelerations reliably exclude what in the fetus?

A

fetal metabolic acidemia

19
Q

Accelerations guarantee a fetal pH greater than

A

7.2

20
Q

Does absence of fetal accelerations reliably predict fetal acidemia?

A

No

21
Q

What is the definition of recurrent decelerations?

A

Occurs with > 50 of uterine contractions in a 20 minute window

22
Q

Late deceleration always indicate fetal _____ but NOT indicate fetal _____.

A

hypoxia, acidemia

23
Q

What do the shoulders (slight increase in FHR at the beginning and end) of variable deceleration indicate?

A

Venous compression (decreased venous return) increases HR

24
Q

How long does a true sinusoidal pattern last?

A

> 20 munutes?

25
Q

What is a sinusoidal pattern associated with?

A

strongly associated with fetal hypoxia due to anemia

26
Q

What is the definition of pathologic fetal acidemia?

A

pH of < 7.0 and a base deficit > 12 mEq/L

27
Q

What is the percent risk of fetal seizures associated with pathologic fetal acidemia?

A

8%

28
Q

What is the risk of death associated with pathologic fetal acidemia?

A

9%

29
Q

What long term affect is a fetus at risk of with pathologic fetal acidemia?

A

increased risk for long term neurological complications

30
Q

What percentage of fetuses will have no complications in the setting of pathologic fetal acidemia?

A

50%

31
Q

What technique during labor can help determine if acidemia is present?

A

Scalp stimulation

32
Q

What is the definition of a category 1 tracing?

A

normal baseline (110-160), moderate variability, No decelerations, +/- accelerations

33
Q

What is the definition of a category 3 tracing?

A

Absent variability AND any of the following: recurrent late deceleration, recurrent variable decelerations, bradycardia, sinusoidal pattern

34
Q

What is the definition of category 2 tracing?

A

ANYTHING ELSE: bradycardia but with variability, fetal tachycardia, absent/minimal variability BUT no decels, absent fetal accelerations, Decelerations but moderate variability,

35
Q

External feta monitoring has ____ cesarean delivery rates and has ____ rates of CP

A

increased, had no affect on

36
Q

FHR monitoring has a a ____ false negative rate but a ____ false positive rate

A

very low, very high

37
Q

Both _____ and ____ reliably exclude metabolic acidemia

A

Moderate variability, fetal accelerations