Transcript Fetal Heart Rate Monitoring

Fetal Heart Rate
Monitoring
D. Moore, MSN
Why Monitor?
 Allows for life saving interventions
 Gives mother some peace of mind
 The main reason we monitor: to prevent fetal
hypoxemia and hypoxia
 AWHONN and ACOG
What has to be monitored?
 Fetal heart rate baseline
 Baseline fetal heart variability
 Periodic or episodic decelerations
 Changes or trends in FHR patterns over time
 Frequency and intensity of uterine contractions
The Strip
Monitoring Equipment
 External Monitoring
 U/S picks up fetal heart rate
 Tocodynameter picks up uterine pressure changes (CTX)
 Can only measure uterine frequency and duration not
strength
Internal Monitoring
 Used when precise measurements are necessary
 Also used when amnio-infusion is necessary
 Can measure frequency, duration, and strength directly
from monitor without palpation
 Client must have ruptured membranes prior to use
 NEVER to be used with HIV mom
Monitoring Equipment
Fetal Circulatory Patterns
 Early in pregnancy heart rate is controlled by the
sympathetic nervous system
 Rate decreases after parasympathetic
nervous system begins function
(vagal stimulation)
Baseline Fetal Heart Rate
 Observe during periods of rest
 110 – 160bpm is normal
 Measure over a 15 minute period
 Baseline changes – any change that last longer than 10
minutes
Baseline Fetal Heart Rate
 Tachycardia <160bpm – in the presence of good
variability not a sign of distress:
A. maternal fever
B. chorioamnionitis
C. fetal hypoxia
D. tachyarrhythmia's – rate >200; SVT – rate 200 – 240
 Bradycardia <110bpm – in The absence of other nonreassuring patterns is benign
A. Heart block (little or no variability)
B. Occiput posterior or transverse position
C. sign of severe fetal compromise
Baseline Variability
 Beat to beat movement of the fetal heart rate off of the
baseline (undulating pattern, it is the R-R interval
differences in the EKG)
 Amplitude change is measured:
1. Absent – flat line 0 movement
2. Minimal – 1 – 5 beat fluctuation
3. Moderate – 6 – 25 beat fluctuation
4. Marked/Increased -- >26 beat fluctuation
 Minimal variability seems to be the greatest intrapartum
sign of fetal compromise
Baseline Variability
 Causes of minimal variability:
1. fetal sleep cycles – 20- 30 minutes per hour
2. congenital anomalies
3. prematurity
4. pain medications
5. magnesium sulfate infusion
6. fetal metabolic acidosis
7. fetal tachycardia
Variability
Changes in Fetal Heart Rate
 Accelerations: sign of fetal well being
 Must have increase of 15 beats over baseline for 15
seconds
 Must have 2 in 20 minutes for a reactive strip
 Reactivity – denotes fetal well being and may not be
seen in fetus’s younger than 34 weeks
Acceleration
Periodic/Episodic Decelerations
 Periodic decelerations – occur with uterine contraction
 Episodic – occur without uterine contraction
 Decelerations:
1. early and late are periodic
2. variable can be periodic or episodic
 Quantified by the depth (bpm) drop from baseline
Early Decelerations
 Subtle decline of fetal heart rate with the contraction
 Mirrors the contraction
 Caused from head compression
 No intervention necessary
Early Decelertion
Late Deceleration
 Subtle decline of fetal heart rate with the acme of the
contraction without return to baseline until contraction is
complete
 Caused from utero-placental insufficiency
 Intervention:
1. Turn mother to left side
2. O2 per FM
3. Turn off Pitocin
4. Increase IVF for bolus
Late Deceleration
Variable Decelerations
 An abrupt drop of fetal heart rate from baseline with an
abrupt return
 Caused by cord compression
 Intervention
1. Turn mother to left side – usually enough to correct
problem if not continue to:
2. Place O2
3. consider amnioinfusion
Variable Deceleration
Prolonged Deceleration
 Subtle or abrupt decrease in FHR below the baseline that last longer
than 2 minutes but less than 10 minutes
 Causes:
1. prolapsed cord
2. maternal hypotension
3. cord compression
4. abruption
5. artifact (usually maternal heart rate)
6. uterine hyperactivity
 Intervention:
1. check cervix – looking for cord prolapse, rapid fetal descent, cord
compression
2. following interventions will be based on findings of vaginal exam
Prolonged Deceleration
Uterine Activity
 Why monitor?
 How to monitor
 What to monitor for:
1. Frequency
2. Duration
3. Intensity
4. Resting tone
Contraction Frequency
 Measured from the start of one contraction to the start
of the next
Contraction Duration
 Measured from beginning of the contraction to the end
of the contraction
Contraction Intensity
 Dependent upon type of monitoring
 If external monitoring must palpate the fundus for
intensity:
1. mild - feels like the tip of your nose
2. moderate – feels like your chin
3. strong – feels like your forehead
 If internal monitoring can use numbers on strip;
measurement in mmHg
Resting Tone
 Must be measured between contractions
 Should always be zeroed at 20mmHg
 Hypertonicity is any pressure above 30mmHg