Transcript Slide 1

CTG – INTERPRET
WITH CARE
Dr Mona Shroff
www.obgyntoday.info
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Fetal Monitoring in Labor:
Two Acceptable Methods
• Electronic
– In “active” labor –
by convention needs
to be continuous
– High false positives
(K. Nelson 1996)
– Variable
interpretations
• Auscultated
– Prescribed
intervals
– Various devices but
one recorded
number
– Easy to interpret
– Intermittent
– Acceptable for
“high” risk patients
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Why Auscultation?
• Fewer C/S’s
• Simple
• Legally less
• Well liked by
damningpatients
interpretation
• Clear cut action/
clear
response
• Allows changing
• Improves ability to
entire environment
ambulate
in L&D
• Easier
• Decreases patient,
family, nurse and
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physician anxiety
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Electronic Monitoring:
Later Outcome Nigel Paneth 1993 Clin.
Invest Med. Michigan St. Univ
• “Central hypotheses of EFM has
never been tested”
– That is, “that its use (EFM) can
effectively prevent the... brain
damaging birth asphyxia by timely
intervention in labor.”
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For hypothesis to be
true: Paneth (1993)
• EFM must be reliable (inter-observer
agreement on identity and meaning)
• EFM must be valid (patterns
statistically linked with adverse
neurological events)
• EFM and adverse outcome are
related, specifically association is
•
causal
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CRITICISMS TOWARDS CARDIOTOCOGRAPHY
• Insufficient understanding of the (patho-)physiologic
background
• A number of technical pitfalls
• Differences in recording techniques
• Primarily qualitative information (pattern recognition)
• Lack of uniform classification systems
• Confusion due to the many influences on the fetal heart
rhythm
• Substantial intra- and inter-observer variation regarding
the interpretation
• Low validity, high incidence of false-positive findings
• Primarily screening method, too often applied as a
diagnostic
• Leads to an increase in artificial deliveries
•
Lack of agreement on how, when, and whom to monitor
•
Contributes to medico-legal vulnerability
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ARGUMENTS AGAINST
AUSCULTATION
• Hard to do!
– No, not really!
• Requires more staff
– Shouldn’t have to
• Does not meet
standard of care
– Untrue!
• Will cause fetal
harm, or CP?
– No more so than
continuous EFM
May miss something?
-Such as??
• Not legally defensible
– Hardly
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THEN WHY DISCUSS
CTG???
• USEFUL IN HIGH RISK CASES.
• STANDARDISED EVIDENCE
BASED GUIDELINES ARE
BEING LAID FOR CORRECT
USE,INTERPRETATION ,
FURTHER DECISION MAKING
& RECORD KEEPING.
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Appropriate monitoring in an
uncomplicated
pregnancy
For a woman who is healthy and has had an
otherwise uncomplicated pregnancy,
intermittent auscultation should be
offered and recommended in labour to monitor
fetal wellbeing.
In the active stages of labour, intermittent
auscultation should occur
after a contraction, for a minimum of 60
seconds, and at least:
• every 15 minutes in the first stage
• every 5 minutes in the second stage.
.
Grade A Recommendation
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Indications
for the
use of
continuous
EFM
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GRADE B RECOMMENDATION
Continuous EFM should be offered and
recommended for high-risk
pregnancies where there is an increased risk of
perinatal death,
cerebral palsy or neonatal encephalopathy.
Continuous EFM should be used where oxytocin is
being used for
induction or augmentation of labour.
REF:RCOG GUIDELINES
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ADMISSION CTG
Current evidence does not
support the use of the
admission CTG in
low-risk pregnancy and it is
therefore not recommended
Grade B Recommendation
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Selected High-Risk Indications for
Continuous Monitoring of Fetal
Heart Rate
Maternal medical illness
Gestational diabetes
Hypertension
Asthma
Obstetric complications
Multiple gestation
Post-date gestation
Previous cesarean section
Intrauterine growth restriction
Oligohydramnios
Premature rupture of the membranes
Congenital malformations
Third-trimester bleeding
Oxytocin induction/augmentation of labor
Preeclampsia
Meconium stained liquor
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A Continuous EFM should be offered and
recommended in pregnancies previously
monitored with intermittent auscultation:
• if there is evidence on auscultation of a
baseline less than 110 bpm or greater 160
bpm
• if there is evidence on auscultation of any
decelerations
• if any intrapartum risk factors develop.
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Definitions and descriptions of
individual features of fetal heartrate (FHR) traces
Baseline fetal heart rate :The mean
level of the FHR when this is stable,
excluding accelerations and
decelerations. It is determined over
a time period of 5 or 10 minutes
and expressed in bpm.
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– Normal Baseline FHR 110–160 bpm
– Moderate bradycardia 100–109 bpm
– Moderate tachycardia 161–180 bpm
– Abnormal bradycardia < 100 bpm
– Abnormal tachycardia > 180 bpm
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Baseline variability
The minor fluctuations in baseline
FHR occuring at three to five
cycles per minute. It is measured
by estimating the difference in
beats per minute between the
highest peak and lowest trough of
fluctuation in a one-minute
segment of the trace
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ACCELERATIONS
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DECCELERATIONS
• EARLY
:
Head compression
• LATE
:
U-P Insufficiency
• VARIABLE
:
Cord compression
Primary CNS dysfn
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EARLY
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LATE
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VARIABLE
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Atypical Variable
decelerations
With any of the following additional
decelerations components:
– loss
of primary or secondary rise in baseline rate
– slow return to baseline FHR after the end of the
contraction
– prolonged secondary rise in baseline rate
– biphasic deceleration
– loss of variability during deceleration
– continuation of baseline rate at lower level
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Categorisation of fetal heart rate traces
Category
Definition
Normal
All four reassuring
Suspicious
1 non-reassuring
Rest reassuring
Pathological
2 or more nonreassuring
1 or more abnormal
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REDUCED
Hypoxia
Sleep
VARIABILITY
Drugs
Extreme prematurity
CNS abno.
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TACHYCARDIA
Hypoxia
Chorioamnionitis
Maternal fever
B-Mimetic drugs
Fetal anaemia,sepsis,ht failure,arrhythmias
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SPECIAL
PATTERNS
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Sinusoidal pattern
A regular oscillation of the baseline long-term
variability resembling a sine wave. This smooth,
undulating pattern, lasting at least 10 minutes, has a
relatively fixed period of 3–5 cycles per minute and an
amplitude of 5–15 bpm above and below the baseline.
Baseline variability is absent
Associated with Severe chronic fetal anaemia
Severe hypoxia & acidosis
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SINUSOIDAL
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PSEUDOSINUSOIDAL
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CHECKMARK PATTERN
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SALTATORY PATTERN
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LAMBDA PATTERN
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SUSPICIOUS CTG
CTG
PATTERN
CAUSE
CLINICAL
MANAGEMENT
EARLY
2nd Stage
NONE
LATE
Uterine
hypercontractily
VARIABLE
Cord compression
Stop oxytocin
Consider terbutaline sc
Oxygen @ 8-10 l/min
Left lateral decubitus
Consider amnioinfusion
(mild/mod v.d.)
TACHYCAR
DIA
Maternal
Infection screen
fever,tachycardia, Hydrate - crystalloids
dehydration
Stop tocolysis if
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pulse>120
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PATHOLOGICAL
FETAL SCALP
BLOOD Ph
(If facilities available)
FETAL SCALP
STIMULATION TEST
FETAL VIBROACAUSTIC
STIMULATION TEST
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A Systematic Approach to Reading Fetal Heart
Rate Recordings
•
•
•
•
•
•
•
•
•
•
Evaluate recording--is it continuous and adequate for interpretation?
Identify type of monitor used--external versus internal, first-generation
versus second-generation.
Identify baseline fetal heart rate and presence of variability, both longterm and beat-to-beat (short-term).
Determine whether accelerations or decelerations from the baseline
occur.
Identify pattern of uterine contractions, including regularity, rate,
intensity, duration and baseline tone between contractions.
Correlate accelerations and decelerations with uterine contractions and
identify the pattern.
Identify changes in the FHR recording over time, if possible.
Conclude whether the FHR recording is reassuring, nonreassuring or
ominous.
Develop a plan, in the context of the clinical scenario, according to
interpretation of the FHR.
Document in detail interpretation of FHR, clinical
conclusion and plan of management.
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• Prior to any form of fetal monitoring, the
maternal pulse should be
palpated simultaneously with FHR auscultation
in order to
differentiate between maternal and fetal
heart rates.
• If fetal death is suspected despite the
presence of an apparently
recordable FHR, then fetal viability should be
confirmed with realtime
ultrasound assessment.
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RECORD KEEPING IN
CTG
• The date and time clocks on the EFM machine
should be correctly set
• Traces should be labelled with the mother’s
name, date and hospital number
• Any intrapartum events that may affect the
FHR should be noted contemporaneously on the
EFM trace, signed and the date and time noted
(e.g. vaginal examination, fetal blood sample,
siting of an epidural)
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•Any member of staff who is asked to
provide an opinion on a trace should note
their findings on both the trace and
maternal case notes, together with time
and signature
• Following the birth, the care-giver
should sign and note the date,time and
mode of birth on the EFM trace
• The EFM trace should be stored
securely with the maternal notes at the
end of the monitoring process.
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SOME
INTERESTING
CASES
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ACCELERATION OR DECCELERATION ???
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BASELINE BRADYCARDIA WITH
ACCELERATIONS
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HALVING PHENOMENON
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EXCESSIVE VARIABILITY???
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GESTATIONAL DM ; NST ; 8:30am
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GDM ; CST ; 12 noon
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BLUNTED PATTERN WITH VARIABLE
DECCELERATIONS – CNS DYSFUNCTION
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Thank you
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