Fetal HR Monitoring and Antenatal Surveillance Flashcards Preview

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Flashcards in Fetal HR Monitoring and Antenatal Surveillance Deck (125):
1

HISTORICAL FACTS MY FRIENDS

1. Fetal heart first heard in 17th century by a physician in France named Marsac.
2. Evory Kennedy published a book in 1833 in Dublin “Observations on Obstetric Auscultation.”
3. The head stethoscope (fetoscope) was first reported in 1917 by David Hillis an Obstetrician in Chicago.
4. The first commercially available monitor was produced by Hewlett-Packard in 1968.

2

What are the 2 external monitoring instruments?

1. Tocodynamometer
2. Doppler

3

What are the 2 internal monitoring instruments?

1. Intrauterine pressure catheter
2. Fetal scalp electrode

4

What does a tocodynamometer measure?

External contraction monitor...so it measures frequency and duration (NOT STRENGTH)

-This is the belt thing with the button on it

5

What does an intrauterine pressure catheter measure?

Strength, frequency, and duration
-This is inside the uterus

6

What does a doppler do?

US through abdomen that measures HR

7

What does a fetal scalp electrode measure?

It monitors the R-R of QRS complex and extrapolates HR...This is very accurate

8

What develops first, S or PS nervous system?

Sympatetic

9

What does the sympathetic nervous system give a base HR of?

150-160 bpm

-Remember, normal is 110-160 bpm

10

What does the development of the PS nervous system do?

Lowers the rate and gives variability...
Flat rates aren't good... variability shows that the baby is neurologically intact

11

What is the PS nervous system mediated through?

The Vagus nerve

12

A normal FHR pattern indicates what?

Greater than 95% probability of well-being

13

True or False: FHR has a high false positive rate

TRUE- Good Apgar scores and normal pH in the presence of abnormal FHR patterns is 80%

14

So what kind of tool is FHR monitoring?

Screening (not diagnostic)

15

What is a normal fetal heart rate?

110-160 bpm

16

What constitutes tachycardia in a fetus?

Over 160 bpm

17

What constitutes bradycardia in a fetus?

Under 110 bpm

18

What are baseline characteristics with FHR monitoring?

FHR and variability

19

What are periodic and episodic changes seen with FHR monitoring?

Accelerations and decelerations

20

What are causes of tachycardia?

1. MATERNAL FEVER
2. INFECTION- maternal or fetal
3. Hypoxemia
4. Prematurity
5. Dehydration
6. Thyrotoxicosis
7. Pharmacological Agents

21

What are causes of bradycardia?

1. HYPOXEMIA
2. Pharmacological Agents
3. Fetal Arrhythmia's (heart block)
4.Maternal Hypotension.

22

What changes over time of the fetal heart rate?

Variability

23

True or False: The more variability the better

TRUE.. More variability, baby is well

24

What are 2 types of variability?

Short term and long term

25

What is short term variability?

Beat to beat changes in FHR

26

What is normal short term variability?

Between 5-25 bpm

27

What is long term variability?

Undulations of fetal HR around baseline

28

How many undulations per minute is normal?

3-5

29

True or Fase: A good baby will have an increase over baseline of 15bpm lasting at least 15 seconds

TRUE- This ensures the absence of fetal acidosis

30

Changes in baseline FHR can be related to what?

Uterine contractions

31

What are 2 types of changes in baseline FHR related to uterine contractions?

1. Accelerations
2. Decelerations

32

What are accelerations?

FHR increase in response to uterine contractions

33

What are decelerations?

FHR decreases in response to uterine contractions

-Decelerations can be early, late, variable, or mixed

34

Describe early decelerations

Has an onset, maximum fall and recovery that coincides with the onset, peak and end of the uterine contraction

35

What do early decelerations result from?

Fetal head compression (Vagal response)

36

Are early decelerations gradual?

Yes... onset to nadir >/= 30 seconds decrease in with return to baseline

-This coincides with the peak of contraction like a mirror image

37

Are early decelerations associated with fetal distress?

No

38

Describe late decelerations

Onset, e maximal decrease and recovery that is shifted to the right in relation to the contraction

39

What are late decelerations associated with?

Uteroplacental insufficiency

40

WHat is more pronounced with severe decelerations?

Fetal hypoxia and acidosis

41

What are late decelerations associated with?

Low scalp pH values and high base deficits (indicating metabolic acidosis)

42

What is the severity of a late deceleration graded by?

The magnitude of the decrease in FHR at the nadir

43

What is most frequently encountered abnormal FHR pattern?

Variable decelerations

44

What causes variable decelerations?

Umbilical cord compression

45

Describe variable decelerations

Variable time of onset, variable form and may be nonrepetitive

46

If cord compression is prolonged, what can happen?

Hypoxia can be present and show a combined respiratory and metabolic acidosis

47

Hos is severity of a variable deceleration graded?

By their duration

48

More detailed description of variable deceleration?

-Visually Apparent, abrupt (onset to nadir or = to 5bpm below the baseline and lasts > or = 15 sec but < 2 minutes.

49

What is a prolonged variable deceleration?

> or = to 15bpm below baseline lasting > or = to 2min but < 10 min

50

What are 5 strategies for intervention in variable decelerations?

1. STOP PITOCIN !!!!!!
2. Change in maternal position left to right.
3. 100% O2.
4. Amnioinfusion
5. Delivery

51

What are 6 strategies for intervention in late decelerations?

1. STOP PITOCIN !!!!!!
2. Change in maternal position left to right. Supine Hypotension (Poseiro Effect)
3. 100% O2.
4. Scalp Stimulation: Rub head with finger
5. Tocolytics
6. Delivery- if fetus is in distress and vaginal delivery is remote, Cesarean Section is indicated.

52

What is the passage of fecal stool into the amniotic fluid?

Meconium

53

When does early passage of fetal stool into the amniotic fluid occur?

Prior to rupture

54

When does late passage of fetal stool into the amniotic fluid occur?

After rupture, is usually heavy and caused by cord compression, stress, ect.

55

What is associated with poorer outcome related to meconium?

Heavy meconium...? huh

56

What is the treatment for passage of fetal stool into the amniotic fluid?

Amnioinfusion

57

What is indicated when fetal distress is suggested?

Fetal Scalp pH

58

Fetal blood pH correctly predicts neonatal outcome what % of the time?

82%

59

What is the false positive and false negative rate with fetal scalp pH?

-False +: 8%
-Flase -: 10%

60

A pH less than what indicates what the fetus is distressed?

7.25

61

Cerebral dysfunction doesn't seem to occur unless what 3 things happen?

1. 5 minute apgar score is less than 3
2. Umbilical artery blood pH is less than 7
3. Resuscitation is necessary at birth

62

What has happened to the frequency of cerebral palsy?

The frequency of it is unchanged (2/1000)

63

What are 2 reasons to use antenatal surveillance?

1. To indentify patients at risk of fetal mortality or morbidity
2. To decrease the mortality and morbidity rate

64

What are some patients at risk that should have antenatal surveillance?

1. Post date pregnancy
2. HTN
3. Diabetes
4. Previous stillborn
5. IUGR
6. Renal Disease
7. Multiple Gestation
8. Other: Hyperthyroidism, anemia, ect.

65

What counts as post-date pregnancy?

After 42 weeks

-Really, death goes up after 41.5, but anything after 41 is higher risk

66

What does a non stress test measure?

Baseline FHR, accelerations, and variability

67

What is a reactive non stress test?

2 accelerations of 15bpm above baseline lasting 15 seconds each in a 20 minute period

68

What is a non-reactive non stress test?

One of the things in a reactive stress test is lacking
-Like 1 acceleration, it doesn't go 15bpm above baseline, or there are no accelerations

69

When is a non stress test usually done?

After 32 weeks gestation

70

What is a good outcome for a non stress test?

REACTIVE

71

What are 2 other names for a contraction stress test?

Oxytocin stress test or nipple stim test

72

What is required for a contraction stress test?

Must have 3 contractions lasting 40-60 seconds in a 10 minute period

73

What does the contraction stress test approximate?

The stress a fetus might have in the 1st stage of labor

74

When is a contraction stress test usually done?

When there is no danger of preterm labor, uterine rupture, ect.

75

Would you do a contraction stress test preterm?

NOOOOOOO... what if you can't stop the labor... baby needs to be at least 37 weeks

76

So what is the general idea with a contraction stress test?

To cause contractions to see how the baby would respond

77

What is a negative CST test?

No late decelerations with adequate contraction

78

What is a positive CST test?

Late decelerations with >50% of the contractions

-So basically late decelrations after 2 contractions

79

What is a suspicious CST test?

Inconsistent late decelerations under 50%

-So maybe a late deceleration after 1 contraction

80

What is an unsatisfactory CST test?

Inadequate uterine activity- No contractions induced

81

What does a biophysical profile use?

Real time US and an NST

82

What are 5 components measured by a BPP?

NST, fetal breathing movement, fetal tone, fetal movement, and amniotic fluid volume

83

What is the max score on a BPP?

10... get a score of 2 or 0 for each category

-AKA you can't get an odd number for a score with this test

84

How is fetal breathing assessed?

Movement of the diaphragm

85

What 3 tests can be done to determine fetal well being?

NST, CST, BPP

86

What gets 2 points for fetal breathing movement?

At least one episode of >30 seconds in a 30 minute period

-Diaphragm moving
-This takes time so a tech has to do it

87

What gets 2 points for gross body movement?

3 discreet body, limb movements in a 30 minute period

88

What gets 2 points for fetal tone?

One episode of active expansion with return to flexion of fetal limbs, hands, or trunk

-Basically just stretching or even moving limbs

89

What gets 2 points for NST?

Reactive test

90

What gets 2 points for amniotic fluid volume?

At least 1 pocket of amniotic fluid volume measuring 2cm in 2 perpendicular planes

-If there is low fluid... probably intervene
-Assess the 4 quadrants of the uterus

91

What is done with a BPP score of 10?

Normal... repeat weekly

92

What is done with a BPP score of 8?

Normal...repeat weekly or twice weekly in diabetics or post-dates

-If there is oligohydraminos, DELIVER

93

What is done with a BPP score of 6?

Suspect chronic asphyxia
-Greater than 36 weeks, DELIVER

94

What is done with a BPP score of 4?

Suspect chronic asphyxia
-If greater or equal to 32 weeks, DELIVER

95

What is done with a BPP score of 0-2?

Strongly suspect asphyxia
-DELIVER REGARDLESS OF AGE

96

What is the most and least important past of a BPP?

-Most important is fluid
-Least important is breathing ("last to go, first to show")

97

When would you test a pregnant lady with diabetes?

28-40 weeks (depends on type)

98

When would you test a pregnant lady with preeclampsia?

At diagnosis >26 weeks

99

When would you test a post-date pregnant lady?

41-42 weeks

100

When would you test a IUGR lady?

At diagnosis

101

When would you test a lady with a previous stillbirth?

32 weeks

102

When you are using an intrauterine monitor for HR, where should it be?

On the hard part of the scalp... no the fontanelle
-This will measure HR and contraction

103

In monitoring a baseline rate, the mean FHR is rounded to increments of 5BPM during a 10 minute segment excluding?

1. Period or episodic changes
2. Periods of marked FHR variability
3. Segment of the baseline that differ by more than 25bpm

104

True or False: In any 10 minute window, the minimum baseline duration must be at least 2 minutes or the baseline is considered indeterminate

TRUE

105

What is the definition of variability?

Fluctuations in baseline FHR of 2 cycles per minute or greater, irregular in amplitude, and frequency, and visually quantitated as the amplitude of peak to trough

106

What is absent baseline variability?

Amplitude range is undetectable

107

What is minimal baseline variability?

Amplitude range 2-5 bpm

108

What is moderate baseline variability?

Amplitude range 6-25 bpm

109

What is marked-amplitude variability?

Over 25 bpm

110

What kind of monitors do most patients get?

External
-Really only internal if patient is already in labor and you need to keep an eye on the baby

111

What acceleration indicates fetal well being (not hypoxic)?

15 seconds, 15 beats above the baseline
-2 of these in a 20 minute period
-This is the reactive NST

112

What do decelerations indicate?

Change in fetal oxygenation for different reasons

113

Is minimal variability good?

NO

114

What is an early deceleration due to?

Transient vagal response... head is compressed into pelvis... this isn't a bad thing... seen in full-blown labor

115

Where do early decelerations happen?

Right over the contraction

116

What do variable decelerations look like?

A V... they are variable when they occur and are the most common and most frequent decelerations

117

What causes variable decelerations?

Cord compression

118

When do late decelerations happen?

They lag behind the contraction...this is bad

119

What are late decelerations due to?

Uteral-planceta deficiency... the baby isn't recovering from the contractions and this is BAD

120

If there are repetitive late decelerations...50% or more what can you do?

SOMETHING
-O2, shift position (Left-lateral recumbent), prep C-section, internal monitors

121

What is an acceleration?

Visually apparent abrupt increase in FHR above the baseline with onset to peak in under 30 seconds

-Duration is quantitated from beginning to end of acceleration

122

Accelerations beyond 32 weeks?

15 bpm above baseline... duration is 15 seconds to 2 minutes

123

Accelerations prior to 32 weeks?

10b bpm above baseline... duration is 10 seconds to 2 minutes

124

What is the duration of a prolonged acceleration?

2- 10 minutes

125

What is considered a bseline change?

Acceleration of more than 10 minutes