CTG Traces

Report
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Calibration of the CTG
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Calibration of the CTG
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Calibration of the CTG
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Calibration of the CTG
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Features and Terminology of CTG
• The four main features of CTG are:
▫
▫
▫
▫
Baseline rate.
Baseline variability.
Accelerations.
Decelerations.
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Baseline Fetal Heart Rate
• Baseline rate is defined as the level of the fetal heart
rate when it is stable, excluding accelerations and
decelerations.
• It is determined over a time of 5-10 minutes, and
expressed in beats per minute.
Reassuring:
Normal baseline
110 – 160
Non-Reassuring:
Moderate bradycardia
Moderate tachycardia
100 – 109
161 – 180
Abnormal:
Abnormal bradycardia
Abnormal tachycardia
< 100
> 180
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Normal Baseline FHR
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Baseline Bradycardia
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Baseline Tachycardia
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Baseline Variability
• Baseline variability is the minor fluctuations in
baseline fetal heart rate occurring over 3-5
cycles/minute.
Reassuring:
Normal baseline
5 bpm between contractions for
up to 40 minutes
Non-Reassuring:
Non-reassuring baseline
variability
< 5 bpm for 40 minutes or more,
but less than 90 minutes
Abnormal:
Abnormal baseline variability
< 5 bpm for 90 minutes or more
Note: if repeated accelerations are present with reduced variability,
the CTG should be regarded as reassuring.
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Normal Variability
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Reduced Variability
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Reduced Variability
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Accelerations
• Accelerations are abrupt, transient increase in
fetal heart rate of 15 bpm, lasting for 15 seconds.
• The absence of accelerations
otherwise normal CTG is of
significance.
with an
uncertain
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Acceleration
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Decelerations
• Decelerations are a transient slowing of the fetal
heart rate below the baseline of
15 bpm for
15
seconds.
• There are 5 types of decelerations:
▫
▫
▫
▫
▫
Early deceleration
Late deceleration
Variable deceleration
Atypical variable deceleration
Prolonged deceleration
• In addition, there are one specific pattern:
▫ Sinusoidal pattern
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Early Decelerations
• Uniform, repetitive, periodic slowing of the FHR
with onset early in the contraction and return to
baseline at the end of contraction.
• The lowest point of the deceleration coincides with the
highest point of the contraction wave.
• Usually associated with head compression.
• Tend to occur late in the first stage or during the
second stage of labor.
• Benign, not significant, not associated with fetal
hypoxia.
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Early Decelerations
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Early Decelerations
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Early Decelerations
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Late Decelerations
• Uniform, repetitive, periodic slowing of the FHR with
onset mid- to the end of the contraction.
• The lowest point of the deceleration more than 20 seconds
after the peak of the contraction wave, always ending after
the contraction.
• In non-accelerative trace, with baseline variability < 5
bpm, the definition would include decelerations < 15 bpm.
• Late decelerations, if present for > 30 minutes, are always
indicative of fetal hypoxia, and further action is indicated.
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Late Decelerations
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Late Decelerations
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Late Decelerations
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Variable Decelerations
• The MOST COMMON form of decelerations occurring
during labor.
• Variable, intermittent, periodic slowing of the
FHR, with rapid onset and recovery.
• Time relationships with contraction waves are
variable. Sometimes, they may resemble other types of
decelerations in timing and shape.
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Variable Decelerations – cont’d
• Variable decelerations are often caused by umbilical
cord compression.
• Variable decelerations are either typical or atypical.
• Typical variable decelerations are an autonomic
nervous system response to cord compression and are
indicative of the fetus coping well.
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Variable Decelerations – cont’d
• However, the fetus may become tired over time and, if
typical variable decelerations occur with over
50% of contractions for more than 90
minutes, this should be regarded as nonreassuring, particularly if there is any degree
of fetal compromise such as fetal growth
restriction.
• Atypical variable decelerations may subsequently
develop indicating that the fetus is now less able to
cope with cord compression.
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Pure (Typical) Variable Decelerations
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Prolonged Decelerations
• An abrupt decrease in FHR to levels below the
baseline that lasts at least 60-90 seconds.
• If fetal bradycardia occurs for more than 3
minutes, plan should be made to urgently
expedite delivery. A “category 1” birth should be
declared and the woman should be immediately
transferred to the theatre. If the fetal heart rate
recovers within 9 minutes, the decision for
immediate delivery should be reconsidered, if
reasonable, and in consultation with the
woman.
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Prolonged Decelerations
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Sinusoidal Pattern
• A regular oscillation of the baseline long-term
variability (resembling a sine wave).
• Smooth, undulating pattern, lasting at least 10
minutes, has a relatively fixed period of 3-5
cycles per minute at an amplitude of 5-15 beats
per minute above and below the baseline.
• Baseline variability is absent.
• A true sinusoidal pattern is an abnormal feature and is
associated with high rates of fetal morbidity and
mortality.
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Sinusoidal Pattern
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Intrapartum
CTG
Baseline rate
Reassuring
110 – 160 bpm
Non-Reassuring
•100 – 109 bpm
•161 – 180 bpm
< 5 bpm for 40-90 min
(in absence of accelerations)
Abnormal
•< 100 bpm
•> 180 bpm
•Sinusoidal pattern for
min
Comments:
10
Variability
5 bpm or more
< 5 bpm for 90 minutes (in
absence of accelerations)
Accelerations
present
Decelerations
None
•Typical variable decelerations
with > 50% of contractions for
over 90 minutes
•Single prolonged decelerations up
to 3 minutes
•Atypical variable
decelerations > 50% of
contractions for over 30
minutes
•Single prolonged
deceleration > 3 minutes
Opinion
Normal CTG
(all 4 features
reassuring)
Suspicious CTG
(one non-reassuring feature)
Pathological CTG
(two or more non-reassuring, or
one or more abnormal features)
Cervical
Dilatation
Cont’s
Comments:
: 10
min
Liquor Color
Gestational
Age
Comments:
Maternal
Pulse
Action
Date:
Time:
Comments:
Signature:
Status:

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