Intrapartum FHR Monitoring

Question 1

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

Answer 1

> 99%

Question 2

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

Answer 2

< 50%

Question 3

What is the definition of tachysystole?

Answer 3

> 5 UCs in 10 minutes

Question 4

How is a baseline heartrate determined

Answer 4

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

Question 5

What is the normal FHR baseline?

Answer 5

110 - 160

Question 6

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

Answer 6

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

Question 7

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

Answer 7

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

Question 8

What are causes of fetal bradycardia?

Answer 8

Complete heart block associated with lupus antibodies, hypothermia, hypoglycemia

Question 9

What is the definition of variability?

Answer 9

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

Question 10

What is the definition of moderate variability?

Answer 10

Change in amplitude of 6 - 25 bpm

Question 11

What is the definition of minimal variability

Answer 11

Change in amplitude of 1-5 bpm

Question 12

What is the definition of marked variability?

Answer 12

Change in amplitude of > 25 bpm

Question 13

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

Answer 13

No, only in the setting of recurrent deceleration

Question 14

What does Moderate variability reliably exclude?

Answer 14

Fetal metabolic acidemia

Question 15

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

Answer 15

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

Question 16

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

Answer 16

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

Question 17

What is the definition of a prolonged acceleration?

Answer 17

> 2 minutes but < 10 minutes

Question 18

FHR accelerations reliably exclude what in the fetus?

Answer 18

fetal metabolic acidemia

Question 19

Accelerations guarantee a fetal pH greater than

Answer 19

7.2

Question 20

Does absence of fetal accelerations reliably predict fetal acidemia?

Answer 20

No

Question 21

What is the definition of recurrent decelerations?

Answer 21

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

Question 22

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

Answer 22

hypoxia, acidemia

Question 23

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

Answer 23

Venous compression (decreased venous return) increases HR

Question 24

How long does a true sinusoidal pattern last?

Answer 24

> 20 munutes?

Question 25

What is a sinusoidal pattern associated with?

Answer 25

strongly associated with fetal hypoxia due to anemia

Question 26

What is the definition of pathologic fetal acidemia?

Answer 26

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

Question 27

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

Answer 27

8%

Question 28

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

Answer 28

9%

Question 29

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

Answer 29

increased risk for long term neurological complications

Question 30

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

Answer 30

50%

Question 31

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

Answer 31

Scalp stimulation

Question 32

What is the definition of a category 1 tracing?

Answer 32

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

Question 33

What is the definition of a category 3 tracing?

Answer 33

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

Question 34

What is the definition of category 2 tracing?

Answer 34

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

Question 35

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

Answer 35

increased, had no affect on

Question 36

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

Answer 36

very low, very high

Question 37

Both _____ and ____ reliably exclude metabolic acidemia

Answer 37

Moderate variability, fetal accelerations