Transcript Slide 1

Basic Fetal Monitoring
Review
Ana H. Corona, FNP-C
Nursing Instructor
February 2009
Electronic Fetal Monitoring
• Definition of fetal monitoring
– Method of assessing fetal status before
and during labor
• Why is fetal monitoring important
– To provide insight that may affect fetal
outcomes
• Information is recorded on graph paper
• Information is permanent part of the
maternal medical record
• Information is retrievable for litigation
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Normal Assessment Findings
• FHR between 110-160 in gestations 3240+ weeks
– Rates slightly above 160 are normal in
gestations less than 32 weeks.
• Regular rhythm
• Increases in the FHR associated with fetal
movement that return to original rate range
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Electronic Fetal Monitoring
Clarification
• Information for students is for educational
purposes only
• Students should not assume any
responsibility for interpretation of fetal
monitor tracings
• It takes months to years of experience to
be prepared to interpret fetal monitor
tracings
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Methods of Electronic Fetal Monitoring
• External
– Noninvasive method
– Utilizes an
ultrasonic
transducer to
monitor the fetal
heart
– Utilizes the
tocodynamometer
(toco) to monitor
uterine contraction
pattern
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Methods of Electronic Fetal Monitoring
• Internal Fetal
Monitoring
– Invasive
– FHR is monitored via a
fetal scalp electrode
– Uterine activity is
monitored by an
intrauterine pressure
catheter (IUPC)
• A combination of
external and internal
fetal monitoring is
common
practice
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Advantages and Disadvantages
of Internal Fetal Monitoring
• Advantages
– Patient can move without much interference in data
transmission
– More accurate measurement of data
– Data less likely to be affected by artifact
• Disadvantages
–
–
–
–
–
Invasive
Membranes have to be ruptured and cervix dilated
Application requires more skill
Procedure is uncomfortable for the mother
Risk of trauma and infection for mother and fetus
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Components of the Fetal Monitor Paper Tracing
• Strip has two components
• Upper graph - records FHR data
• Small squares represent 10 bpm
increases as well as 10 seconds duration
• Lower graph records contraction data
• Small squares represent 10 second
duration or 10 mmHg intensity
– Dark line to dark line represents one
minute of time
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Baseline FHR
• Normal baseline FHR in a term fetus 37
completed weeks or more is 110-160 bpm.
– Determination of the baseline FHR is
done between contractions
– Baseline is rounded in increments of 5
bpm example; if the FHR is running 125135 then the baseline FHR should be
documented as 130
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FHR Variability
• Normal changes and fluctuations in
the FHR over time.
• Best assessed between contractions
• Considered to be the best indicator of
fetal well-being
• Variability can be influenced by
hypoxic events, maternal
hemodynamic issues, drugs, etc.
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Examples of Variability
• Absent: Not detectable from baseline
• Minimal: Less than 5 bpm from baseline
– May occur with:
– normal fetal sleep patterns
– mother has received analgesia for pain
• Moderate : 6-25 bpm from baseline (optimal
pattern)
• Marked: More than 25 bpm from baseline
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How Do Uterine Contractions Affect Fetal Heart Rate?
•
Can affect FHR by increasing or decreasing the rate in
association with any given contraction.
• 3 primary mechanisms by which UCs can cause a
decrease in FHR
1.
Fetal head
2.
Umbilical cord
3.
Uterine myometrial vessels
Periodic and Episodic
FHR Characteristics
• Periodic: Refers to changes in the
FHR that occur with or in relationship
to contractions
• Episodic: Refers to changes in the
FHR that occur independent of
contractions
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Examples of Periodic Changes
• Variable decelerations: Result from some type of
cord compression.
– Nuchal cord, True knot
– Decreased amniotic fluid
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Severe Variable Decelerations
Note the depth from the baseline
Baseline
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Early Deceleration
• Occur as a result of vagal stimulation to the fetal
head during contractions which push the fetal
head toward the pelvis.
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Late Decelerations
• Occur in response to utero-placental insufficiency.
Blood flow to the fetus is compromised and there
is less oxygen available to the fetus)
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Late Decelerations with Absent Variability
• Note the smoothness
of the FHR pattern
• Decreased FHR
caused by uteroplacental insufficiency
• Compromised blood
flow to fetus
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Prolonged Deceleration
• Deceleration of the FHR from the baseline
lasting more than 2 minutes but less than
10 minutes.
• No explanation for why these occur
• Commonly associated with uterine
hyperstimulation.
• Can also occur without any uterine activity
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Example Prolonged Deceleration
• Note the duration of the deceleration lasts more
than 2 minutes.
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FHR Accelerations
• Are the most common type of FHR
changes
• Are abrupt changes and will increase from
the baseline 15 bpm lasting 15 seconds
before return to the baseline in a healthy
gestation more than 32 weeks.
• Less than 32 weeks increases of 10 bpm
lasting 10 seconds are indication of a well
oxygenated fetus.
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Example Accelerations
• Note the increase from the fetal heart baseline
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Sinusoidal Pattern
• Persistent wave variation of the baseline only seen
in about 2% of patients.
• Related to severe fetal anemia, hypoxia, or
acidosis.
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Uterine Activity Assessment
• Periodic tightening and relaxing of the
uterine muscle.
• Pituitary gland is triggered to release a
hormone called oxytocin that stimulates
the uterine tightening.
• Difference in Braxton Hicks contractions
and true labor is the strength of the
contractions and the changes in the cervix.
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Characteristics of Contractions
• Frequency: How often they occur? They are
timed from the beginning of a contraction to
the beginning of the next contraction.
• Regularity: Is the pattern rhythmic?
• Duration: From beginning to end - How long
does each contraction last?
• Intensity: By palpation mild, moderate, or
strong.
– By IUPC intensity in mmHg
– Subjectively: Patient description
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Uterine Contraction
Segments of Contractions
•
•
•
•
Increment: Beginning, building of pressure
Acme: Most intense part of the contraction
Decrement: Diminishing of the contraction
Rest: Period of time between contractions
Assessment of Contractions
• Palpation: Use the fingertips to palpate the
fundus of the uterus
– Mild: Uterus can be indented with gentle
pressure at peak of contraction
– Moderate: Uterus can be indented with firm
pressure at peak of contraction
– Strong: Uterus feels firm and cannot be
indented during peak of contraction
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Variable decelerations in FHR during labor
are severe dips occurring at the peak of
contraction. This FHR problem is associated
with which one of the following conditions?
1.
2.
3.
4.
Utero-placental insufficiency
Fetal head compression
Uterine insufficiency
Pressure on the umbilical cord
Answer is D
• These decelerations are common during
labor.
• The FHR drops during the contraction
resulting from stimulation from
chemoreceptors and baroreceptors as the
cord is compressed.
• The nurse should recognize these
readings on the fetal monitor as normal.
A nurse is caring for a client in labor and is
monitoring the FHR patterns. The nurse notes
the presence of episodic accelerations on the
electronic fetal monitor tracing. Which of the
following actions is most appropriate?
1. Document the findings and tell the mother
that the monitor indicates fetal well-being
2. Take the mothers vital signs and tell the
mother that bed rest is required to
conserve oxygen.
3. Notify the physician of the findings.
4. Reposition the mother and check the
monitor for changes in the fetal tracing
Answer is 1
• Accelerations are transient increases in
the fetal heart rate that often accompany
contractions or are caused by fetal
movement.
• Episodic accelerations are thought to be a
sign of fetal-well being and adequate
oxygen reserve.
A nurse is admitting a pregnant client to the
labor room and attaches an external
electronic fetal monitor to the client’s
abdomen. After attachment of the monitor, the
initial nursing assessment is which of the
following?
1. Identifying the types of accelerations
2. Assessing the baseline fetal heart rate
3. Determining the frequency of the
contractions
4. Determining the intensity of the
contractions
Answer is 2
• Assessing the baseline fetal heart rate is
important so that abnormal variations of
the baseline rate will be identified if they
occur.
• Options 1 and 3 are important to assess,
but not as the first priority.
A nurse is monitoring a client in labor. The
nurse suspects umbilical cord compression if
which of the following is noted on the external
monitor tracing during a contraction?
1.
2.
3.
4.
Early decelerations
Variable decelerations
Late decelerations
Short-term variability
Answer is 2
• Variable decelerations occur if the umbilical
cord becomes compressed, thus reducing
blood flow between the placenta and the
fetus.
• Early decelerations result from pressure on
the fetal head during a contraction.
• Late decelerations are an suggests uteroplacental insufficiency during a contraction.
• Short-term variability refers to the beat-tobeat range in the fetal heart rate.
The physician asks the nurse the frequency of
a laboring client’s contractions. The nurse
assesses the client’s contractions by timing
from the beginning of one contraction:
1.
2.
3.
4.
Until the time it is completely over
To the end of a second contraction
To the beginning of the next contraction
Until the time that the uterus becomes
very firm
Answer is 3
• This is the way to determine the frequency
of the contractions
When monitoring the FHR of a client in labor,
the nurse identifies an elevation of 15 beats
above the baseline rate of 135 beats per
minute lasting for 15 seconds. This should be
documented as:
1.
2.
3.
4.
An acceleration
An early elevation
A sonographic motion
A tachycardic heart rate
Answer is 1
• An acceleration is an abrupt elevation
above the baseline of 15 beats per minute
for 15 seconds; if the acceleration persists
for more than 10 minutes it is considered a
change in baseline rate.
• A tachycardic FHR is above 160 beats per
minute.
Which of the following findings meets
the criteria of a reassuring FHR
pattern?
1. FHR does not change as a result of fetal
activity
2. Average baseline rate ranges between
100 - 140 BPM
3. Mild late deceleration patterns occur with
some contractions
4. Variability averages between 6 - 10 BPM
Answer is 4
• Variability indicates a well oxygenated fetus
with a functioning autonomic nervous
system.
• FHR should accelerate with fetal movement.
• Baseline range for the FHR is 120 to 160
beats per minute.
• Late deceleration patterns are never
reassuring, though early and mild variable
decelerations are expected, reassuring
findings.
References
•
•
•
•
AWHONN Clinical Position
Statement
P. Burroughs, MSN, RN
Martin, E.J., (2002) Intrapartum
Management Modules: A Perinatal
Education Program. (pp 119-123).
Lippincott Williams & Wilkins 3rd
Edition.
Simpson, I., & Creehan, P. (2001)
Perinatal Nursing 2nd Edition, (pp
379-383). Philadelphia, New York,
Baltimore, Lippincott.
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