Fetal Monitoring - Palmetto Health
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Transcript Fetal Monitoring - Palmetto Health
Scott A Sullivan MD MSCR
Maternal-Fetal Medicine
MUSC
October 12, 2010
Disclosures
I have no disclosures or conflicts to report
Disclosures – I am from MUSC!
Learning Objectives
Discuss NICHD Consensus Recommendations
Review fetal physiology and EFM patterns
Alternate technology – what works, what doesn’t and
what is coming
A bit of history…
Marzac – 1620 First description of fetal heart tones
Killian – 1640 Theory that heart tones = fetal health
Kergaradec – 1818 Technique, viability
Kennedy – 1833 Intra-partum monitoring
Von Winkel – 1893 “Fetal Distress” definitions
DeLee / Hillis – 1922 Fetoscope
Matthews – 1940 Amplified fetoscope
Edward H Hon, MD
1915 – 2009
Father of modern EFM
1958
First Viable EFM
1968 – Commercially
available
1972 – First scalp
electrode
1970’s – Coins
deceleration terms
1975 – 20 % of labors
used EFM
EFM – Antepartum Testing
Reactivity translates to a fetal death rate of < 5 /1000
Non-reactivity = fetal mortality rate of 40/1000
False positive rate 50-97(!) %
Unless ominous, requires a confirmatory test
Perinatal Death Rate
PMR / 1000 live births
50
45
40
35
30
25
20
15
10
5
0
PMR
1940
1960
1980
2000
Use of Intra-partum EFM in the US
90
80
70
60
50
% Use
40
30
20
10
0
1975
1985
1995
2004
So How Have We Done?
1975 – 2010
Decreased fetal death incidence
Cesarean section rate increased 110 %
Cerebral palsy incidence unchanged
Lawsuit rate / live-birth rate increased 340 %
EFM vs. IA
Cochrane Review – 2001
9 RCTs
18,561 patients
No difference in Apgars, NICU, fetal death and
cerebral palsy
Reduction in seizures (RR 0.51 0.32-0.82)
Increases in C/S and OVD
Vintzileos – EFM vs IA
1995
Decrease in perinatal mortality (1/1000)
1996
Sensitivity – 97 % vs. 34 %
Specificity – 84 % vs. 91 %
PPV – 34 % vs. 22%
NPV – 99.5 % vs. 95 %
What’s the Problem?
Subjective interpretation
Technological limitations
Lack of interventional guidelines
Confusing terminology
Terminology
Gabbe vs. Williams
“Short-Term”, “Beat to
Beat”
Lack of inter-rater
reliability
1997 Consensus
Inter-rater reliability
4 OBs – 22 % agreement (Nielson)
2 months later, re-reviewed
25 % changed their own interpretation
5 Obs – 29 % agreement (Beaulieu)
NICHD Conference
2008
Series of meetings
Jointly published in
OBG, Pediatrics,
Neonatology
OBG 112(3);Sept 2008 661-666
Category I
Must include ALL :
Baseline 110-160
Moderate variability
No late decelerations
Early decelerations +/Accelerations +/-
Category I
Category I
“Normal”
“Highly Predictive of a normal fetal pH”
No Action Required
Physiology – Cat. I
Physiology – Cat I
Category III
Absent variability, plus either
Recurrent late decelerations
Recurrent variable decelerations
Bradycardia
Sinusoidal pattern
Category III
Category III
“Abnormal”
“Predictive of abnormal acid-base status”
Requires prompt intervention or delivery
MANAGEMENT OF Cat III
Discontinued oxytocin
Begin oxygen 5-6 L/min
Correct maternal hypotension
Trendelenberg position
Increase IV fluids
Vasopressor (ephedrine 15 mg IV)
Assess maternal oxygenation and acid/base status
Terbutaline 0.25 mg SQ for in-utero resuscitation
Environment
Oxygen transfer can be disrupted at any of
these points and can manifest as FHR
deceleration (variable, late, prolonged)
Lungs
Heart
Vasculature
Uterus
Placenta
The degree of oxygen disruption is the
important factor, not the point in the
pathway at which oxygen transfer is
disrupted
Cord
Oxygen transfer
Fetus
Hypoxemia
Hypoxia
Metabolic acidosis
acidemia
Fetal response
Hypotension
Potential
Injury
DECREASED UTEROPLACENTAL
OXYGEN TRANSFER TO THE
FETUS
Chemoreceptor Stimulus
Alpha Adrenergic Response
With
Acidemia
Fetal Hypertension
Baroreceptor Stimulus
Myocardial
Depression
Parasympathetic Response
Deceleration
Without
Acidemia
Category II
“Everything that not categorized as either Category I
or III”
Examples : Tachycardia, bradycardia with normal
variability
Absent variability, marked variability
Lates + variability, unusual variables
Category II
Category II
Category II FHR tracings are considered
“indeterminate”
Not predictive of abnormal fetal acid-base status but
inadequate evidence to classify as Category I or III
Requires evaluation and in-utero treatment if
appropriate
Requires continued surveillance and re-evaluation in
context of clinical circumstances
Variability
Moderate FHR variability is HIGHLY predictive of the
absence of metabolic acidemia at the time it is
observed
Parer JT J Maternal Fetal Neonatal
Med 2006; 19:289-94
Low JA Obstet Gynecol 1999;
93:285-91
Williams KP Am J Obstet Gynecol
2003; 188:820-3
Elimian A Obstet Gynecol 1997;
89:373-6
MINIMAL OR ABSENT FHR
VARIABILITY
CNS depressants: Narcotics, Barbiturates, Benzodiazapines, Sedatives,
Alcohol
Parasympatholytics: Phenothiazines, Atropine
General anesthetics
Magnesium sulfate
Fetal tachycardia due to maternal fever or fetal infection
Preexisting neurological injury
Fetal acidosis/acidemia
NICHD 2008 - Pros
Simple
Better than 1998
More widely adopted
ACOG buy-in
NICHD 2008 - Cons
No evidence the system is actually better
Lack of actionable recommendations
Category II ??
Does not fix problems of EFM
A word about contractions
Normal
≤ 5 contractions / 10 m
Tachysystole
≥ 5 contractions / 10 m
No hyperstimulation!
How About < 32 weeks?
No clear recommendations
< 28 weeks, 50 % will be non-reactive
28-34 weeks, 15 %
“10 x 10”?
VAS?
Artificial larynx used to
stimulate the fetus
Shortens time to reactivity
9.9 minutes
88 dB in the uterus
Appears to be safe
Reactive NST is just as
reliable ?
What’s New?
It’s clear we need something
better
Fetal Pulse-Oximetry
STAN
Fetal Pulse Oximetry
Same technology
Oxygen saturation
Mechanical problems
FPO – Cochrane Review
2007
5 trials
7424 subjects
Overall no decrease in cesarean rate, seizures
Fetal scalp sampling?
East CE, Cochrane Database 2007
STAN
ST Waveform Analysis
Automated analysis of
ST segments
Uses EFM + ST
FDA approved - 2005
2001 Lancet - STAN
Sweden RCT
4966 subjects
STAN vs EFM alone
Decrease in acidosis [RR 0.47 0.25-0.81]
Decrease in OVD [RR 0.83 0.69-0.99]
Amer-Wehlin, Lancet 2001
2006 BJOG - STAN
RCT
1493 subjects
Similar design
No difference in acidosis
No difference in cesarean section or OVD
Ojala K, BJOG 2006
STAN – Cochrane Review
2006
4 trials, 9829 subjects
No difference in C/S, OVD
Decreased acidosis [RR 0.64 0.41 – 0.99]
Decreased HIE [RR 0.33 0.11-0.91]
Insufficient evidence to recommend
Neilson, JP Cochrane Database
2006
Newer things….
Doppler?
WAS – 2009
ANBLIR – 2010 (fuzzy logic, ANN)
NIR photopleythysmography
What does ACOG Say?
Practice Bulletin 106
Endorses terminology
High risk women need
continuous EFM, for
others it is optional
No to FPO
Thank You