Lecture 03 Fetal Assessment Flashcards Preview

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Flashcards in Lecture 03 Fetal Assessment Deck (76):
1

Leopold Maneuvers: What does the 1st maneuver assess for?

1. Used to feel the fundus and identify how the fetal lie and presenting part. 2. Feel for shape, consistency, and mobility. The fetal head will be firm and round. The breech (buttocks and legs) will feel softer and less defined.

2

Leopold Maneuvers: What does the 2nd maneuver assess for?

1. Used to palpate the back and identify fetal presentation. 2. Fetal back will feel smooth and hard. The hands, feet, elbows will feel like irregular nodules.

3

Leopold Maneuvers: What does the 3rd maneuver assess for?

1. Determining which fetal part lies over the pelvic inlet to identify fetal attitude 2. Can you get fingers between pubic bone and baby? If can, then baby is in the pelvis.

4

Leopold Maneuvers: What does the 4th maneuver assess for?

1. Used to feel cephalic brow 2. Determination of the direction and degree of flexion of the head. *Flexion is the degree that the baby's head is tucked into it's chest. Complete flexion is optimal (cervix doesn't have to be as dilated compared to other degrees of flexion). Why is flexion important? The amount of flexion going on will alter the diameter of the baby’s head as it moves through the pelvis, the cervix, and through the vagina.

5

What is a Leopold's Assessment able to tell us? (8)

1. Assess fetal movement 2. Assess maternal abdominal tenderness, temp and color 3. If fundal height is appropriate for gestational age 4. Determine uterine activity 5. Assess maternal vital signs and risk factors 6. Determine presence of labor and status of membrane 7. Evaluate fetal heart tones to make sure it's a baby 8. Assess cervix if there's no contraindications.

6

What are 2 external types of fetal heart rate monitoring?

1. Doppler Ultrasound 2. Tocodynamometer

7

How does the doppler ultrasound work?

Indirectly records FHR. Uses reflected sound waves to evaluate blood as it flows through a blood vessel.

8

How does the Tocodynamometer work?

1. Used to measure uterine contractions. 2. Pressure sensitive button located on transducer creates a waveform on the uterine activity channel

9

What are 2 types of internal fetal monitoring?

1. Fetal scalp electrode (FSE)/ISE Internal Spiral electrode: an internal fetal heart monitor 2. Intraueterine pressure catheter (IUPC): internal contraction monitor

10

What are special considerations for internal fetal monitoring?

1. It induces the baby once it's done 2. It can't be done if the placenta is in the way and may get punctured

11

How does ISE (internal spiral electrode)/FSE work?

It monitors the input from both electrodes and calculates a rate by measuring the interval between “R” waves. The fetus has higher “R” waves than mom, so monitor calculates through the fetus to the spiral electrode

12

What are some benefits of ISE/FSE?

continuous detection of FHR, detection of dysrhythmia, maternal position does not effect.

13

What are some limitations of ISE/FSE?

membrane rupture necessary, electronic interference may occur, small risk of fetal hemorrhage or infection, and may be contraindicated: placenta previa, undiagnosed vaginal bleeding, HIV, active herpes, GBS, and coagulation defects

14

What are benefits with IUPC?

Benefits: Accurate assessment of contraction frequency, duration, intensity and resting tone; withdrawal of amniotic fluid for testing, amnioinfusion port, may recalibrated or flushed to validate accuracy

15

What are limitations of IUPC?

Limitations: invasive procedure, need ruptured membranes, increased risk of infection and perforation, placement of IUPC and maternal position may effect baseline and contraction pressures, catheter may become obstructed, and contraindicated in some presentations, stations, significant bleeding, or infection

16

What is considered uterine activity?

A contraction that occurs when the uterine muscle shortens.

17

Def of UA frequency?

expressed in minutes from the onset of one contraction to the onset of the next

18

Def of UA (Uterine Activity) duration?

expressed in seconds from the onset to the end of a contraction

19

Def of Tachysystole? Where may it be seen

- >5 contractions in a 10 minute window, lasting 45 – 90 seconds, averaged over 30 minutes. Applies to induced as well as spontaneous contractions. May be seen with “cocaine abuse”, oxytocin, prostaglandins. It’s more likely we’re stressing out our baby

20

Def of Hypertonus?

resting tone >25 mmHg. Baby isn’t going back to normal baseline

21

Physiologic Factors That Regulate the Fetal Heart Rate: What are some hematologic adaptations?

Since the fetal blood levels of oxygen is much lower than maternal levels, the fetus compensates by having a higher fetal cardiac output

22

Physiologic Factors That Regulate the Fetal Heart Rate: How does the parasympathetic nervous system affect FHR?

1. PNS is controlled by vagus nerve and stimulation results in decreased firing or SA node 2. Influences the presence of variability in the FHR 3. Influences increases with gestational age

23

Physiologic Factors That Regulate the Fetal Heart Rate: How does the Sympathetic Nervous System affect FHR?

1. Innervates via nerve fibers throughout myocardium 2. Stimulation causes increase in myocardial contraction strength, FHR, and cardiac output.

24

Central Nervous System: Physiologic Factors That Regulate the Fetal Heart Rate: What does the medulla oblongata do?

1. It controls the Autonomic Nervous system, which consists of PNS and SNS. 2. When fetal HR is normal (Normal baseline, moderate variability, accelerations, no recurrent deceleration), an indication that the fetus has an intact and well oxygenated brain stem, ANS and fetal heart.

25

Central Nervous System: Physiologic Factors That Regulate the Fetal Heart Rate: What does the cerebral cortex do?

1. Exerts control over fetal HR with increased fetal activity and sleep

26

Central Nervous System: Physiologic Factors That Regulate the Fetal Heart Rate: What does baroreceptors do?

1. Stretch receptors located i the vessel walls of aortic arch and carotid sinus senses blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained.

27

Central Nervous System: Physiologic Factors That Regulate the Fetal Heart Rate: What does chemoreceptors do?

1. Senses biochemical changes (O2 tension, CO2 tension and acid base balance) - located in aortic bodies and carotid bodies as well as medulla oblongata.

28

Fetal HR Assessment: How do you determine FHR Baseline?

1. Approximate the mean FHR rounded to increments of 5 bpm during a 10 minute window, excluding accelerations, decelerations and periods of marked FHR variability (>25bpm) 2. There has to be at least 2 min of identifiable baseline segments in any 10 min window or baseline is indeterminate.

29

What is the FHR baseline controlled by?

1. By vagus nerve and becomes more dominant with maturity, dropping the baseline.

30

What's the range of normal FHR?

110-160 bpm

31

What is considered a Tachycardia HR? Maternal causes? Fetal Causes?

Tachycardia: baseline FHR >160 bpm Maternal causes: fever/infection, dehyrdation, drugs, anemia, anxiety Fetal causes: infection, activity, compensatory response following an acute event, chronic hypoxia, anemia, and SVT ( supraventricular tachycardia)

32

What mechanism causes FHR variability?

The interaction between sympathetic and parasympathetic systems.

33

What is FHR variability? How is it determined?

1. Baseline FHR variability: fluctuations in baseline FHR that are irregular in amplitude and frequency. 2. Is determined in a 10 min window, excluding accerlerations and decerlerations.

34

What's the amplitude range of Absent FHR variability?

Undetectable

35

What's the amplitude range of Minimal FHR variability?

Amplitude range: undetectable to 5

36

What's the amplitude range of Moderate FHR variability?

Amplitude: 6~25 bpm

37

What's the amplitude range of Marked FHR variability?

Amplitude > 25 bpm

38

What can absent/minimal variability be related to? (9)

1. Fetal sleep (average nap is 20 min, rarely more than 40 min)

2. Drugs (Narcotics, nubain, nicotine, cocaine)

3. Hypoxia, metabolic acidosis

4. Severe fetal anemia

5. SVT/Heart Block

6. Chromosomal abnormalities

7. Fetal brain death, anencephaly (without the brain)

8. Deteriorating IUGR (Intrauterine growth restriction)

9. Elevated temperature/infection

39

What can marked variability be related to? (4)

1. Usually compensatory response to hypoxemic event, i.e cord compression or uterine tachysystole

2. May follow administration of ephedrine for maternal hypotension

3. Often seen with application of forceps of vacuum extractor

4. Usually seen in short bursts ~1 min

40

Know this: What is the single most important characteristic of FHR?

Variability is the most important characteristic of FHR. Moderate fetal heart rate variability predicts the absence of fetal metabolic acidemia at the time it is observed.

41

What does an acceleration look like on a graph?

Visually apparent as an abrupt increase in FHR. Abrupt increase is defined as increase from onset of acceleration to the peak in

42

What does acceleration indicate?

Well oxygenated fetus

43

For a fetus >32 weeks, how can you tell if a peak is an acceleration?

Acceleration peaks in 15 bpm. It must at least 15 seconds from the onset and return to the baseline

44

For the fetus <32 weeks, accelerations are defined as having a peak of?

The peak is >10 bpm and >10 seconds of duration from the onset to the return of the baseline.

45

What is considered a prolonged acceleration?

is >2 minutes but <10 minutes in duration.  Greater than 10 minutes is considered a baseline change.

46

How does FHR deceleration look on a graph?

It's visually apparent, symmetrical, gradual decrease and return of FHR is associated with uterine contraction.

47

What is considered a gradual FHR deceleration?

If the time between the onset to the nadir of deceleration is > 30 seconds.

48

Head compression causes FHR deceleration, what are the physiologic steps behind it? (4)

Pressure on fetal head -> increase intracranial pressure -> alteration in cerebral blood flow -> central vagal stimulation -> FHR deceleration

49

What are early deceleration associated with? (2) When is it typically seen in normal labor?

1. CPD, (cephalopelvic disproportion)

2. Unengaged presenting part, presistent OP

In normal labor, it's typically seen between 4 and 7 cm dilation

50

What are 2 interventions for early deceleration

1. Monitor for deterioration of pattern/loss of variability 2. Monitor descent of head, position, and cervial status Usually a benign pattern and not a hypoxic pattern

51

What's the difference between Early and Late Deceleration?

In early deceleration, the nadir occurs with the peak of a contraction. In late deceleration, the nadir is delayed in timing and occurs after the peak of contraction.

52

What is the physiology behind Utero-placental compromise that causes deceleration? (6)

decreased utero-placental oxygen transfer to fetus -> chemoreceptors stimulus -> Alpha Adrenergic Response -> Fetal HTN -> Baroreceptor stimulus -> Parasympathetic response

53

Why is it important to understand the pathophysiology behind decelerations?

Knowing the patho gives you the ability to rationalize what intervention to take.

54

Late decleration are caused by uteroplacental insufficiency. What does this insufficiency do?

alters maternal fetal gas exchange.

55

Late decleration are caused by uteroplacental insufficiency. What may it be caused by? (5)

1. Gestational or chronic hypertension, hypertension due to drug use (cocaine, heroin, amphetamines)

2. Placental changes due to postmaturity, calcification, old or new abruption sites, placental malformation

3. Uterine tachysystole or hypertonus

4. Chronic maternal diseases

5. Cardiopulmonary disease: has 5 min to give birth to baby before it dies. All blood gets shunts to central body of mom and baby dies.

56

What is uteroplacental insufficiency associated with?

Decreased variability, fetal myocardial depression and fetal acidosis.

57

What can maternal hypotension result from?

1. Supine position 2. Trauma or blood loss 3. Regional anesthesia 4. Drug use

58

Supine hypotension can cause late deceleration by..

impeding blood flow to the placenta or diminish maternal oxygen saturation.

59

What are interventions for late deceleration? (7)

1. Change position-preferably to left lateral recumbent

2. Discontinue oxytocin/prostaglandins

3. Check BP

4. Give IV fluid bolus

5. Administer oxygen: non rebreather mask 8~10 litres. Tell mother that this is for the baby, not necessary for her

6. Give terbutaline: Decrease contraction frequency that may be altered O2 perfusion 7. Notify anesthesia if associated with epidural response

60

What do variable decelerations look like?

1. Apparent abrupt decrease in FHR

61

How is variable deceleration defined?

Abrupt FHR decrease is defined from the onset of decleration to the beggining of the FHR nadir

62

What are the parameters of variable deceleration decrease in FHR?

•The decrease in FHR is >15 bpm, lasting >15 seconds, and <2 minutes in duration.

63

Physiology of Variable Deceleration: What occurs behind CORD compression? (long)

1. Anterior acceleration Umbilical vein compressed Slows flow of oxygenated blood to fetus decreased fetal blood pressure Decreases in BP and oxygenation compensated for by stimulation of the chemoreceptors and baroreceptors via the sympathetic nervous system. 2. Deceleration of fetal heart rate Compression of the umbilical cord continues compressing and occluding the umbilical arteries Stops blood flow from the fetus to the placenta Fetal blood pressure rises and triggers the baroreceptors. Vagus nerve stimulated, causing a drop in the fetal heart rate via the parasympathetic nervous system. 3. Posterior Acceleration As the occlusion subsides, the arteries open and fetal blood pressure begins to fall. Fetal heart rate increased to compensate for drop in blood pressure and decreased pO2. Stimulation occurs through the baroreceptors, chemoreceptors and the sympathetic nervous system.

64

What are concerning elements of variable decelerations? (4)

1. Prolonged Recovery 2. Prolonged duration 3. Loss of variability 4. Prolonged smooth overshoots

65

What are reassuring elements of variable decelerations?

1. Rapid return to baseline

2. Variability

3. Accelerations before and after

4. When moderate variability is associated with variable decels, it is strongly predictive of non acidemic, vigorous infant at birth.

66

What are interventions for cord compression in a compromised fetus? (8)

1. Check for cord prolapse

2. Change position

3. Discontinue oxytocin, prostaglandins

4. Check BP

5. Give IV fluid bolus 6. Administer oxygen

7. Give terbutaline

8. Consider amnioinfusion

67

What are interventions for cord compression in a well oxygenated fetus?

Change maternal position to alleviate cord compression.

68

What are the parameters of prolonged deceleration?

>15 bpm, lasts >2 min, but 10 min is a baseline change

69

When is prolonged deceleration commonly seen?

Following epidural anesthesia associated with drop in maternal BP

70

What are some nursing interventions for prolonged deceleration? (6)

1. Vaginal exam to assess for cord prolapse 2. Change position 3. Discontinue oxytocin or prostaglandins 4. Check BP 5. Give IV fluid bolus 6, Administer oxygen *Notice every deceleration intervention is pretty much the same

71

What does a Sinusoidal FHR look like?

It has visually apparent, smooth sine wave-like undulating patter in the FHR baseline with cycle freq of 3~5 /min that persists for >20 min

72

What are some characteristics of sinusoidal patter? (4) What is it correlated with?

1. Minimal to absent variability. 2. No accelerations. 3. Strongly associated with fetal hypoxia 4. Seen with severe fetal anemia : can be a terminal pattern This is strongly correlated high fetal mortality and morbidity.

73

What are the differences between Sinusoidal and Pseudosinusoidal? (5)

In Pseudosinusoidal: 1. Waves are not uniform. 2. Variability is usually present. 3. Usually seen with admin of narcotics/nubain/stadol. 4. Has been correlated with fetal thumb sucking as evidenced on ultrasound 5. FHR tracing as accels or decels or returns to normal

74

VEAL/CHOP is a mnemonic to remember dif types of decelerations/acceleration you see and what it's caused by. Describe the mnemonic.

Variable -> caused by Cord compression Early -> caused by Head compression Acceleration -> it's OKay Late -> Placenta insufficiency

75

What's the difference between Variability and Variable?

Variability: Beat to beat variable in FHR. Jagged line in fetal baseline, and is determined in 10 min period. Variable: decrease, deceleration in FHR Variable deceleration has a bigger dip in HR

76

What is considered a bradycardia HR? Maternal causes? Fetal Causes?

:  baseline rate is <110 bpm

•Maternal causes:  supine position, hypotension, cardiopulmonary compromise, uterine rupture

•Fetal causes:  hypoxia or acute hypoxemia, umbilical cord occlusion, complete heart block, chronic head compression.

•REMEMBER:  the lower the rate -  the less the fetal cardiac output.