Hehi Test #3 - Fetal Heart Rate Monitoring

Front 1

Factors that could have adverse effect on FHR

Back 1

1. Intrinsic fetal disease
2. Placenta disease
3. Cord compression - intermittent during labor after ROM
4. Maternal disease
5. Drugs administered for analgesia/ anesthesia
6. Maternal hypotension from supine position

Front 2

Auscultation

Back 2

1. Doppler - hand held; used in clinics- for low risk patients only
2. Ultrasound transducer
3. Fetoscope

- auscultate full 60 seconds, counted in beats per minute
- Before, during, and after uterine contraction

*In low risk patients, done q30min. (1st stage of labor), q15min. (2nd stage of labor)

Front 3

Electronic Fetal Monitor - external

Back 3

External
- Ultrasound - fetal HR
- baseline rate, cariability, periodic patterns
- Tocodynamometer - measures uterine contractions; frequency duration - can NOT measure intensity

Front 4

Electronic Fetal Monitor - internal

Back 4

1. Fetal Scalp electrode (used in obese moms) - fetal HR
2. Intrauterine pressure catheter (IUPC) - measures frequency, duration, intensity (MVUs - montevideo Units), and resting tone

Front 5

Baseline

Back 5

The approximate mean FHR rounded to increments of 5 beats/min. during a 10 min. segment, excluding:
1. periodic or episodic changes (accelerations, decelerations)
2. Periods of marked FHR variability - 25 bpm or more
3. Segments of baseline that differ by >25 beats/min.

Normal = 110-160 bpm
Bradycardia = <110bpm (SOS)
Tachycardia = > 160 bpm

Front 6

Maternal Causes of bradycardia

Back 6

1. Maternal position - supine or mom lying on cord
2. Maternal hypotension - positioning or epidural
3. Drug response - sedatives
4. Connective tissue disease (SLE) - lupus
5. Prolonged maternal hypoglycemia

Front 7

Fetal Causes of bradycardia

Back 7

1. Mature parasympathetic nervous system
* 2. Intermittent umbilical cord occlusion or prolapsed cord
* 3. Decompensated fetus - no O2 reserves
4. Hypothermia - usually not measured
5. Cardiac conduction defect
* 6. Vagal stimulation - rapid descent - ready to deliver

Front 8

Maternal causes for tachycardia

Back 8

1. Fever - antibiotics started to prevent transmission to fetus
2. Infection
3. Dehydration
4. Hyperthyroidism - rare
5. Endogenous adrenaline/ anxiety
6. Medications/ drugs
7. Anemia

Front 9

Fetal causes for tachycardia

Back 9

1. Infection - mom gets antibiotics; ARF sepsis
2. Prolonged fetal activity or stimulation
3. Compensatory effect following hypoxia
4. chronic hypoxia
5. Cardiac abnormalities, heart failure - preemies = immature PNS
6. Fetal dysrrhythmias
7. Prematurity
8. Congenital anomalies

Front 10

Baseline Variability

Back 10

single most important characteristic of FHR - ensures acid/base balance; specifically ensures lack of metabolic acidosis

- Fluctuation in the baseline FHR of two cycles/ min. or greater
- Represents the interplay and balance between the sympathetic and parasympathetic divisions of the autonomic nervous system

Front 11

Classifications of variability

Back 11

Absent - undetectable (nonreassuring)
Minimal - undetectable/ < 5 bpm
Moderate - 6-25 bpm
Marked - >25 bpm

Front 12

Decreased variability

Back 12

Causes include but are not limited to:
1. HYPOXEMIA/ ACIDOSIS (ABSENT ONLY)
2. Drugs - sedatives
3. Fetal sleep cycles - < 20 min. duration
4. Congenital anomalies

Front 13

Absent Variability

Back 13

emergency - notify midwife + physician
- Abnormal - unable to rule out fetal acidosis

*Metabolic acidosis is the only link to neurologic injury in baby

Front 14

Sinusoidal Baseline

Back 14

Characterized by smooth, sine wive-like pattern or regular frequency and amplitude

Still considered absent variability because it is too regular - nonreassuring

Front 15

Evens associated with sinusoidal

Back 15

1. Severe fetal anemia
2. Rh isoimmunization
3. Abruption - fetal/ maternal hemorrhage
4. Sever fetal acidosis

Front 16

Accelerations

Back 16

Reassuring - sign of fetal well-being
>32 weeks

Abrupt increase (defined as onset of acceleration to peak in <30 seconds) in FHR above the baseline

- Acme is > 15 bpm above the baseline and last > 15 seconds and < 2 min. from onset to return to baseline

If < 32 weeks, acme > 10 bpm above baseline with duration of > 10 seconds

Front 17

Prolonged acceleration

Back 17

> 2 min. < 10 min.

Front 18

Early decelerations

Back 18

- Gradual decrease (onset of develeration to nadir > 30 seconds) and to return to baseline FHR associated with uterine contration

- Nadir of deceleration occurs as the same time as the contration

Mirrors contraction

Front 19

Physiology of early deceleration

Back 19

Reflex vagal response to head compression

Not associated with oxygenation

Seen most in 1st part of active phase of labor

Front 20

Late decelerations

Back 20

- Gradual decrease (onset of deceleration to nadir > 30 seconds) and return to baseline associated with uterine contraction

- Nadir of deceration occurs after the peak of the contraction

Front 21

Physiology of late deceleration

Back 21

1. Dimished uterine blood flow with uterine contraction
2. Critical reduction of pO2 following peak of UC
3. Hypoxic slowing of heart rate
4. Uteroplaecental insufficiency (UPI)

Front 22

Causes of Uteroplacental insufficiency

Back 22

1. Maternal disease
2. Preeclampsia
3. Diabetes Mellitus
4. Too many uterine contractions
5. Fetal anemia
6. Infection

Front 23

Variable decelerations

Back 23

Abrupt decrease (onset of deceleration to beginning of nadir < 30 sec.) in FHR of > 15 bpm and lasting >15 sec. and < 2 min. from onset to return to baseline

Front 24

Physiology of variable deceleration

Back 24

1. Umbilical cord compression
2. Stimulation of baroreceptors - response originates in carotid bodies and aortic arch; transmitted to the midbrain and then to PNS; decrease in FHR

Front 25

Etiology of variable decelerations

Back 25

1. Short umbilical cord
2. Nuchal cord
3. Body entaglement
4. Prolapse cord
5. Second stage of labor
6. Decreased amniotic fluid
7. knot in cord

Front 26

Prolonged Decelerations

Back 26

Decrease in FHR from baseline for > 15 bpm, lasting > 2 min., but < 10 min. from onset to return to baseline

Front 27

Etiology of prolonged decerations

Back 27

1. Maternal hypotension
2. Cord prolapse
3. Rapid cervical change
4. Sudden fetal descent
5. Uterine hypertonus - too frequent contractions and resting tone is high

Front 28

Interpretation of Fetal Heart Rate Patterns - category I (Normal)

Back 28

Include all of the followin:
1. baseline rate 110-160 bpm
2. Baseline cariability - moderate
3. Late or variable decelerations absent
4. Early decelerations present or absent
5. Accelerations persent or absent

- Strongly predictive of normal fetal acid/ base status at the time of observation
- Followed routinely - no action required

Front 29

Interpretation of Fetal Heart Rate Patterns - Category II (Indeterminate)

Back 29

May include any of the following:
1. Baseline rate - bradycardia not accompanied by absent baseline variability
2. Tachycardia
3. Baseline variability = minimal, absent w/o recurrent decelerations, or marked
4. Accelerations - absent after fetal acoustic stimulation
5. Periodic or episodic decelerations - recurrent variable decelerations w/ minimal or moderate baseline variability; prolonged deceleration; recurrent late decelerations with moderate variability

- Not predictive of abnormal acid-base status
- Do not have adequate evidence at present to classify into I or III
- Continue surveillance and reevaluate

Front 30

Interpretation of Fetal Heart Rate Patterns - Categoy III (Abnormal)

Back 30

1. Absent baseline variability and any of the following:
- recurrent late or variable decelerations; bradycardia
2. Sinusoidal pattern - CANNOT RULE OUT METABOLIC ACIDOSIS

- Are predictive of abnormal fetal acid/base status at time of observation
- Requires prompt evaluation:
- Maternal oxygen, position change, D/C labor stimulation, treat hypotension

It is not adequate to only get the midwife in, must also get the M.D. who covers the midwife

Front 31

Nursing Interventions - late decelerations

Back 31

1. Lateral position
2. Oxygen 10 L face mask
3. 500 ml IVF bolus - increase maternal cardiac output
4. Evaluate oxytocin and uterine contraction pattern
5. Evaluate variability
6. Notify M.D. and midwife

Front 32

Nursing Interventions - variable decelerations

Back 32

1. Reposition (right, left, knee chest)
2. Cervical exam - check for cord prolapse, labor progress
3. Evaluate variability
4. Notify M.D./ CNM for repetitive

Front 33

Nursing Interventions - prolonged decelerations

Back 33

1. ID cause
2. Notify M.D./ CNM and anesthesia

Front 34

Nursing Interventions - prolonged decelerations s/t maternal hypotension

Back 34

1. Assess BP q2-3min.
2. IVF bolus
3. Lateral, recumbent position
4. Oxygen 10 L face mask
5. Notify anesthesia
6. Notify M.D./ C.N.M.
7. Prep for delivery (d/c Foley, shave, prep)

Front 35

Nursing Interventions - prolonged decelerations s/t cord prolapse, sudden fetal descent, or rapid cervical change

Back 35

1. Cervical exam
2. Notify anesthesia
3. Notify M.D./ C.N.M. - delivery
4. Prep for delivery
5. Oxygen 10 L face mask

Front 36

Nursing Interventions - prolonged decelerations s/t uterine hypertonus

Back 36

1. Assess uterine tone
2. Decrease and/ or d/c pitocin
3. Terbutaline 0.25 mg IV to bedside
4. Prepare for delivery
5. Oxygen 10 L face mask

Front 37

Take Home Message r/t FHR monitoring

Back 37

1. When in doubt notify MD
2. Make diagnosis
3. Know your terminology
4. Evaluate uterine activity - do you need to D/C pitocin?
5. Reposition
6. Will oxygen help?