CTG: patterns
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Transcript of CTG: patterns
CTG: patterns
Aboubakr Elnashar
Benha University Hospital, EgyptAboubakr Elnashar
I. Basal Heart Rate Activity
1. Rate: Normal:110-160 increment 5 bpm (10 m segment)
Bradycardia: < 110 bpm
Tachycardia: > 160bpm
2. Variability Short term= instantaneous (beat to beat v.)
Long term= oscillatory changes in 1 m
3. Sinusoidal: Mild is due to sedation
Marked is due to fetal anemia
4. Arrhythmia: Abrupt spiking, bradycardia or tachy
II. Periodic heart rate Activity
1. Acceleration
2. Deceleration Early
Late
variable
prolongedAboubakr Elnashar
I. Baseline
Tachycardia
Baseline FHR > 160 bpm
Bradycardia
Baseline FHR < 110 bpm
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1. NormalFHR in ten beat
intervals ranging
from 30 bpm to
240 bpm.
Normal FHR is 110
to 160 bpm
1. RATE
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The mean FHR
rounded to increments of 5 bpm during a 10-min
segment, excluding:
— Periodic or episodic changes
— Periods of marked FHR variability
— Segments of baseline that differ > 25 bpm
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Determining the Baseline
Each red line indicates a 2 minute
In any 10 minute segment, the minimum baseline
duration is 2 minutes within the 10 minute segment.
Baseline Rate: 130/mAboubakr Elnashar
2. Tachycardia:FHR ≥160bpm
Fetal tachycardia with fetal
arrhythmia
Severe
tachyAboubakr Elnashar
Uncomplicated baseline tachycardia:161-180 bpm:
Not associated with poor NN outcome.
Mild
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Common Causes of Fetal Tachycardia
Maternal
1. Fever/infection (Amnionitis)
2. Anxiety
3. Drugs:
Anticholinergic: Atropine
Beta sympathomimetic:
Terbutaline
Illicit: Cocaine,Methylamphetamines
Fetal
1. Hypoxia
2. Anemia
3. Cardiac arrhythmias
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3. Bradycardia: baseline FHR ≤110 bpm
• Mild: 100 –110 bpm
• Moderate: 80-100 bpm
• Severe: < 80 bpm
Mild: not associated with poor neonatal outcome.
Prolonged: FHR < 100/ min for 3 min or
< 80 for 2 min
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Causes of bradycardia
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2. VARIABILITY
Changes in the FHR
{interaction of the sympathetic and parasympathetic
systems of the fetus}.
Define:
Fluctuations in the FHR of more than 2 cycles
pm or greater
Amplitude=distance between the highest point
and the lowest point of each of the fluctuation
These fluctuations are irregular in amplitude and
frequency.
The baseline must be for a minimum of 2 min in any 10-min segment
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Types
1. Short term:
Change of FHR from one beat to the next
[Time between cardiac systoles]
in internal fetal scalp electrode
2. Long term:
Oscillation of FHR around baseline /min
[2-6 cycles or waves/min]
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long-term beat-to-beat variability
ranging between 125 and 135 bpm.
Defined as 3-5 cycle/min
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Quantification=degrees
1. Absent:
amplitude range undetectable
2. Minimal:
amplitude range detectable but 5 bpm
3. Moderate (normal):
amplitude range 6–25 bpm
4. Marked:
amplitude range > 25 bpm
What is FHR baseline?
Whether variability exists?
What is Degree?
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To calculate variability you look at how much the peaks &
troughs of the HR deviate from the baseline rate (in bpm)
≥ 25 bpm amplitude range
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(1) Undetectable or absent
(2) Minimal variability:0 -5 bpmAboubakr Elnashar
4) Marked variability: >25 bpm
(3)Moderate variability: >5-<25 bpm
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A. lack of long-term variability
at 31 w during maternal
diabetic ketoacidosis (pH
6.09).
B. Recovery of fetal long- term
variability after correction of
maternal acidemia.
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Abnormal base line variability
Absent: Amplitude range is undetectable
Minimal:
Amplitude range ≤5bpm
Moderate: Amplitude range is 6-25bpm
Marked:
Amplitude range is >25 bpm
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Causes of Reduced variability
single most reliable sign of fetal compromise
• Foetus sleeping: should last no longer than 40 min
most common cause
• Foetal acidosis {hypoxia}
more likely if late decelerations also present
• Foetal tachycardia
• Drugs:Opiates
Benzodiazipine’s
Methyldopa
Mg sulphate
• Prematurity:
variability is reduced <28 w
• Congenital heart abnormalitiesAboubakr Elnashar
3. SINUSOIDAL HEART RATE
Define:
– Regular Oscillation of the Baseline long-term
Variability
– Resembling a Sine wave, with no BTBV.
– Amplitude: 5-15bpm
– 2- 5 cycle/m
– Absence of accelerations
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•Sinusoidal pattern associated with maternal IV meperidine
administration.
•Sine waves are occurring at a rate of 6 cycles/min.Aboubakr Elnashar
Causes
• Mild:
due to sedation
• Marked:
due to fetal anemia associated with:
• Rh isoimmunization
• Fetal hypoxia
• Chronic fetal bleeds
• Fetal-maternal hge
• Severe acidosisPSEUDOSINUSOIDAL
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II. Periodic heart rate Activity
Periodic changes:
accelerations or decelerations in FHR that occur in
direct association with uterine contractions.
Episodic (sporadic) changes:
accelerations or decelerations FHR that occur
independent of uterine contractions, in response to
vaginal exam
maternal vomiting
fetal movementAboubakr Elnashar
AccelerationPeriodic acc Sporadic acc
15bpm 15 sec
<32wks= 10 -10
Acceleration
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1. ACCELERATION
Define:
An increase in the FHR from the most recently
calculated baseline
Onset to peak:
less than 30 sec
The duration
Time from the initial change in FHR from the
baseline to the return of the FHR to the baseline
less than 2 minutes
Prolonged acceleration
lasts 2 min, but < 10 min
Baseline change
If an acceleration lasts 10 minAboubakr Elnashar
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Adequate accelerations:
>32 w
An acme: 15 bpm above baseline
Duration: 15 sec but < 2 min
< 32 w
An acme: 10 bpm above baseline
Duration: 10 sec but < 2 min
< 28 w
Amplitude of accelerations: lower than a
fetus ≥ 32w.
FHR baseline: higher
Variability: less
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Significance
Presence:
at least 2 accelerations/15 m
Reassuring
Sign of a healthy foetus
Absence with an otherwise normal CTG:
uncertain significance
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2. DECELERATION
1. Early deceleration
Define:
In association with a uterine
contraction
Start when uterine contraction
begins
Recover when uterine
contraction stops
Symmetrical=Nadir occurs at the
same time as the peak of the
contraction
Gradual=Onset to nadir:
30 sec or moreAboubakr Elnashar
Gradual decrease
in HR
Both onset and
recovery coincident
with the onset and
recovery of the
contraction.
Onset to Nadir:
30 seconds or more.
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Significance Physiological & not pathological
{increased foetal intracranial pressure causing increased
vagal tone}
Quickly resolves once the uterine contraction ends &
intracranial pressure reduces
May be prevented by avoiding early ROM
Mirror Image
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2. Late deceleration
Define:
In association with a uterine contraction
Gradual=onset to nadir 30 sec or more
decrease in FHR with return to baseline
Onset, nadir, and recovery of the deceleration
occur after the beginning, peak, and end of the
contraction, respectively
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Late deceleration.
Gradual decrease in the HR
Nadir and recovery occurring after the end of the contraction.
Nadir of deceleration occurs 30 seconds or more after the
onset of the deceleration. Aboubakr Elnashar
•Late
decelerations
{uteroplacental
insufficiency
resulting from
placental
abruption}.
Immediate CS
•Umbilical artery
pH: 7.05
• Po2: 11 mm Hg.
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Significance:
uteroplacental insufficiency:
hypoxia and metabolic abnormalities.
one of the most ominous FHR patterns
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Repetitive late deceleration:
increases risk of
Umbilical artery acidosis
Apgar score < 7 at 5 m
Cerebral palsy
If associated with decrease or
loss of BBV
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3. Variable deceleration
Define:Decrease in FHR of > 15 bpm measured from the most
recently determined baseline rate.
Abrupt=Onset to nadir: less than 30 seconds.
lasts > 15 sec and less than 2 min
onset commonly varying with successive contractions
may be v-shaped, u-shaped or w-shaped.
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W-shaped
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•Variable
decelerations
B ―shoulders‖ of
acceleration
compared with
deceleration A.
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FHR effects of partial
occlusion and
complete occlusion of
the umbilical cord
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• Pressure on the cord initially occludes the umbilical vein
acceleration (the shoulder of the deceleration): healthy
response.
• This is followed by occlusion of the umbilical artery sharp
down slope of FHR.
• Finally, the recovery phas {relief of the compression}
sharp return to the baseline another healthy brief
acceleration or shoulder
Variable deceleration with pre- and post-accelerations
(―shoulders‖). Aboubakr Elnashar
Significance
depends upon
how often they occur
how deep they go
how long they last.
how the fetus responds in their presence.
um cord compression
(Common: 50-80% 2nd stage)
Reassuring variable deceleration:Abrupt (sharp) onsetAbrupt return to baselinePreceded & followed by shoulders
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Complicated variable decelerations:
Deceleration
Role of 60
depth >60 bpm
for >60 seconds
rate of 60 bpm
Changes in shape: over-shoot
Slow recovery
Baseline FHR:
Decreased or increased following the
decelerations
BBV:
Absent in or between decelerations
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Re-assuring
a) Abrupt return to base
line
b) BBV: Normal
c) Initial acceleration
d) Secondary
acceleration
Non-reassuring(atypical)
a) Slow return to baseline
b) BBV: Loss during
deceleration
c) Loss of initial
acceleration
d) Persistent acceleration
after recovery
e) Continuation of base
line at low level
f) Biphasic deceleration
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Atypical variable deceleration
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4. Prolonged deceleration
Define:
Decrease in the FHR below the baseline
Deceleration is 15 bpm
lasting 2 min but < 10 min from onset to return
to baseline
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Prolonged deceleration
following uterine rupture
Prolonged deceleration
following vaginal exam
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Significance:
• Non-Reasurring: lasts between 2-3 min
• Abnormal: lasts longer than 3 min it is
immediately classed as Action must be taken
quickly
e.g. FB sampling/emergency CS
Maternal
1. Hypotension
2. Hypoxia
3. Uterine
hyperactivity
4. Abruption
5. Uterine rupture
Fetal
1. Hypoxia
2. Fetal hemorrhage
3. Cord prolapse
4. Cord compression
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Prolonged Decelerationeither Late or Variable
>90 sec & < 10 min,
Drop in FHR of 30 bpm or More
lasting for at least 2 m
Depth& duration
Correlate e Insult
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Abrupt decrease
>15 bpm
Often drops<100
>2 m & < 10 m
Variable pattern
{uterine hyperactivity}
Approximately 3 min
are shown but FHR
returned to normal
after uterine
hypertonus resolved.
Vaginal delivery later
ensued.
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Manual Compression of
a prolapsed umbilical cord
in a 25-w footling breech.
A. 25- sec compression
B. 40 sec compression
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Early DecelerationLate Deceleration
Variable Deceleration
Abrupt decrease
>15 bpm
Often drops<100
>15 S& < 2 m
Variable pattern
Abrupt decrease
>15 bpm
Often drops<100
>2 m & < 10 m
Variable pattern
Prolonged Deceleration
may drops<100Usually did not drops<100
Decelerations
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Thanks
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