Upload
madison-mitchell
View
214
Download
0
Tags:
Embed Size (px)
Citation preview
ELECTRONIC FETAL HEART RATE MONITORING: Where are we and where are we going?
Gary D. V. Hankins, M.D.The University of Texas Medical Branch
Special thanks –Dr. George Macones and Dr. Cathy Spong
ELECTRONIC FETAL HEART RATE MONITORING:A Reevaluation Workshop
April 28-29-2008
Co-sponsored by the Pregnancy and Perinatology Branch (PPB) at the National Institute of Child
Health and Human Development,The American College of Obstetricians and
Gynecologists (ACOG)And
The Society for Maternal Fetal Medicine (SMFM)
Represented
• NICHD – PPB• SMFM• ACOG• ACNM• AWHONN• AAP• RCOG• CCOG• National Cardiovascular Center - Japan
• Group 1: Systems (two vs three vs five tiers)Rationale implications
• Group 2: Definitions of FHR patternsBaseline FHRBaseline FHR variabilityAcceleration
• Group 3: Definitions of FHR patternsLate decelerationEarly decelerationVariable decelerationProlonged deceleration
Breakout Groups
Group 1Leader Gary Hankins
Rapporteur Catherine Spong
Sean Blackwell
Peter Cherouny
Jeff Ecker
Eric Eichenwald
Bill Grobman
David James
Tekoa King
Victoria Lanni Korker
Harold Pollard
Michael Swan
Group 2Leader Tom Moore
Rapporteur Uma Reddy
Vince Berghella
Laura Dean
Sean Esplin
Cynthia Gyamfi
Valerie King
Robert Liston
Donald Mcintire
David Miller
Kathleen Rice Simpson
Caroline Signore
Group 3Leader John Hauth
Rapporteur Rosemary Higgins
Alison Cahill
Eric Carlson
Mary D’Alton
Roger Freeman
Tomoaki Ikeda
Elizabeth Lapeyer
Ken Leveno
Julian Parer
Anne Santa-Donato
Richard Depp
‘The RCOG System – 2001’
• ‘The use and interpretation of cardiotocography in intrapartum fetal surveillance’
• RCOG Evidence-based Clinical Guideline No 8
• Adopted by National Institute of Clinical Excellence (NICE)
• Published for May 2001• For this Workshop focus on
terminology used in EFMCourtesy of Dr. David James
Four arguments for development ofEFM Guideline
1. Intrapartum hypoxia– 1% of all labors– 10% perinatal deaths - CESDI
(Confidential Enquiry into Stillbirths and Deaths in Infancy)
– IP hypoxic death rate = 0.8:1000 births– 10% CP cases
– IP hypoxic CP rate = 0.1:1000 birthsCourtesy of Dr. David James
2. EFM use– 239/248 (96.4%) maternity units in UK use
EFM– 26% did not have an EFM Guideline (30% in
units > 3000 dels)– Fetal blood sampling used in 88%
Four arguments for development ofEFM Guideline
Courtesy of Dr. David James
3. Suboptimal EFM use– CESDI (Confidential Enquiry into Stillbirths
and Deaths in Infancy) 70% of IP deaths have Grade II/III suboptimal care
– Majority of examples relate to EFM• Failure to recognize• Failure to act• Communicate failure
Four arguments for development ofEFM Guideline
Courtesy of Dr. David James
4. Medicolegal issues– > $800 million estimate of NHS
medicolegal costs currently– > 60% are obstetric cases– Majority of obstetric cases relate to fetal
monitoring in labor
Four arguments for development ofEFM Guideline
Courtesy of Dr. David James
Courtesy of Dr. David James
Courtesy of Dr. David James
SOGC.org
Classification of intrapartum EFM tracings
Normal tracingPreviously “Reassuring”
Atypical TracingPreviously “Non-reassuring”
Abnormal TracingPreviously “Non-reassuring”
Baseline 110-160 bpm Bradycardia 100-110 bpm
Tachycardia > 160 for > 30 min to < 80 min.
Rising baseline
Bradycardia < 100 bpm
Tachycardia > 160 for < 80 min.
Erratic baseline
Variability 6-25 bpm
≤ 5 bpm for < 40 min.
≤ 5 bpm for 40-80 min. ≤ 5 bpm for > 80 min.
≥ 25 bpm for > 10 min.
Sinusoidal
Decelerations None or occasional uncomplicated variables or early decelerations
Repetitive (≥ 3) uncomplicated variable decelerations
Occasional late decelerations
Single prolonged deceleration> 2 min. but < 3 min.
Repetitive (≥ 3)complicated variables:
deceleration to < 70 bpm for > 60 secs.
loss of variability in trough or in baseline
biphasic decelerations
overshoots
slow return to baseline
baseline lower after deceleration
baseline tachycardia or bradycardia
Late decelerations > 50% of contractions
Single prolonged deceleration > 3 min. but < 10 min.
Accelerations Spontaneous accelerations present
(FHR increases > 15 bpm lasting > 15 seconds (< 32 weeks’ gestation increase in the FHR > 10 bpm lasting > 10 seconds)
Accelerations present with fetal scalp stimulation
Absence of acceleration with fetal scalp stimulation
Usually absent*
ACTION EFM may be interrupted for periods up to 30 min. if maternal-fetal condition stable and/or oxytocin infusion rate stable
Further vigilant assessment required, especially when combined features present.
ACTION REQUIRED
Review overall clinical situation, obtain scalp pH if appropriate/prepare for delivery
*Usually absent, but if accelerations are present, this does not change the classification of tracing.
Risk of acidemia, evolution of FHR patterns to more serious risk,and recommended action
Variable Risk of acidemia Risk of evolution Action
Green 0 Very low None
Blue 0 Low Conservative techniques & begin preparation
Yellow 0 Moderate Conservative techniques & increased surveillance
Orange Borderline/acceptably low
High Conservative techniques & prepare for urgent delivery
Red Unacceptably high Not a consideration Deliver
Am J Obstet Gynecol 2007; 26.e3
Conservative ameliorating techniques for the modification of variant FHR Patterns
• Position Change
• Hyperoxia
• Correct hypotension
• Adequate intravascular volume
• Correct excessive contractions (eg, decrease oxytocin)
• Avoid constant pushing
• Tocolysis
• Amnioinfusion to correct amniotic fluid deficit
Am J Obstet Gynecol 2007; 26.e3
Risk categories for fetal acidemia related to FHR variability, baseline rate and presence of recurrent decelerations.
MODERATE (NORMAL) VARIABILITY
No Early Mild VD Mod VD Sev VD Mild LD Mod LD Sev LD Mild PD Mod PD Sev PD
Tachy B B B Y O Y Y O Y Y O
Normal G G G B Y B Y Y Y Y O
Mild Brd Y Y Y Y O Y Y O Y Y O
Mod Brd Y Y O O O O
Sev Brd O O O O O
MINIMAL VARIABILITY
No Early Mild VD Mod VD Sev VD Mild LD Mod LD Sev LD Mild PD Mod PD Sev PD
Tachy B Y Y O O O O R O O O
Normal B B Y O O O O R O O R
Mild Brd O O R R R R R R R R R
Mod Brd O O R R R R
Sev Brd R R R R R
ABSENT VARIABILITY
No Early Mild VD Mod VD Sev VD Mild LD Mod LD Sev LD Mild PD Mod PD Sev PD
Tachy R R R R R R R R R R R
Normal O R R R R R R R R R R
Mild Brd R R R R R R R R R R R
Mod Brd R R R R R R
Sev Brd R R R R R
Sinusoidal R
Marked Variability Y
VD, Variable decelerations; LD, Late decelerations; PD, Prolonged decelerations; Brd, Bradycardia; Tachy, Tachycardia
G, Green; B, Blue; Y, Yellow; O, Orange
EFM Interpretation Systems
• 1997 NICHD: 2 tier• RCOG: 3 tier
– Extensive vetting and peer review– National implementation, 50% drop in intrapartum death
rate
• SOGC: 3 tier– Extensive vetting and peer review
• Miller: 3 tier– Least stringent– Common sense approach– Definition, interpretation, management
• Parer: 5 tier– Applied knowledge, interdisciplinary– Variability driven
Outline of Workshop Findings
• Assumptions• Describing FHR tracing components• Categories of the new 3 tier system• Meaning and actions required for each
tier
Assumptions (1)
• The definitions were developed for visual interpretation of FHR patterns. Computerized interpretation is not yet mainstream.
• Both FHR and uterine activity should be of adequate quality for visual interpretation.
Assumptions (2)
• Episodic patterns are those not associated with uterine contractions.
• Periodic patterns are those associated with uterine contractions– Characterized as either “abrupt” or
“gradual” onset
• No distinction is made between short term and long term variability
Assumptions (3)
• FHR tracings should be evaluated in context of clinical conditions including: – gestational age, – medications, – maternal medical conditions, and – fetal conditions (eg, growth restriction, known
congenital anomalies, fetal anemia, arrhythmia etc).
Assumptions (4): An EFM tracing requires qualitative and
quantitative description of:
• Uterine contractions• Baseline FH rate• Baseline FHR variability• Presence of accelerations• Periodic or episodic decelerations• Changes or trends of FHR patterns over
time
Describing Contractions
• Number of UCs per 10 minute window• Averaged over 30’• Normal: ≤ 5 contractions in 10’• Tachysystole: > 5 contractions in 10’
– Presence or absence of decelerations– Spontaneous and stimulated labor– Hyperstimulation and hypercontractility are
to be abandoned.
Describing FHR Baseline
• Rounded to 5 bpm • Assembled from segments of baseline
totaling at least 2’ in the 10’ window• Excludes periods of accelerations,
decelerations and hypervariability• Bradycardia is < 110 bpm• Tachycardia is > 160 bpm
Describing FHR Variability
• Excludes accelerations, decelerations• Quantitated as peak-to-trough• Absent variability: amplitude undetectable• Minimal variability: amplitude detectable
but ≤ 5 bpm• Moderate variability: amplitude 6-25 bpm• Marked variability: amplitude > 25 bpm
Describing Accelerations
• Abrupt increase in FHR– Onset to peak < 30”
• Peak: ≥ 15 bpm lasting 15” from onset to return to baseline
• Prolonged acceleration: ≥ 2’ but < 10’• Acceleration > 10’ = baseline change
Describing Decelerations
• Decrease in FHR associated with uterine contraction– Gradual decrease: onset to nadir ≥ 30”– Abrupt decrease: onset to nadir < 30”
• Recurrent decelerations:– Occurs with ≥ 50% of UCs
• Intermittent decelerations:– Occurs with < 50% of UCs
Classifying Decelerations
Onset Shape Nadir
Early Gradual Symmetrical Matches UC peak
Variable Abrupt Asymmetrical ≥ 15 BPM LASTING ≥ 15” but < 2’
Late Gradual Symmetrical After UC peak
Deceleration Features NOT Defined
• Slow return to baseline • Biphasic decelerations• ‘Reflex’ tachycardia following variable
decelerations• Shoulders or overshoots• FHR fluctuations in the trough of the
deceleration• Mild, moderate and severe
What to Call the Categories?
• Problems– Limited evidence base– Litigation issues
• Possible titles: – Normal, reassuring, non-pathological – Abnormal, pathological– Intermediate, suspicious, non-reassuring, atypical
• Conference Decision: – Reassuring – Equivocal – requires ongoing
assessment/evaluation; – Abnormal – requires urgent action
After Extensive Discussion:
• Concerns about terms: normal, abnormal, equivocal
• Concerns about implied action necessary (e.g., equivocal requires intervention).
• Final Framework:– Category I– Category II– Category III
3 Tier FHR Interpretation System:Category I
• Category I FHR tracings include all of the following:
• Baseline rate:110-160 bpm• Baseline FHR variability: moderate • Late or variable decelerations: absent.• Early decelerations: present or absent.• Accelerations: present or absent.
3 Tier FHR Interpretation System:Category III
• Category III FHR tracings include either:• Absent FHR variability and any of the
following:– Recurrent late decelerations– Recurrent variable decelerations– Bradycardia
• Sinusoidal Pattern for ≥ 20’
3 Tier FHR Interpretation System:Category II
• Category II FHR tracings includes all FHR tracings not categorized as Category I or Category III.
• Represent an appreciable fraction of those encountered in clinical care.
3 Tier FHR Interpretation System:Category II Examples
• Moderate variability with bradycardia • Minimal FHR variability• Absent variability with no recurrent decels• Recurrent variable decels with moderate
variability• Recurrent late decels with moderate
variability
FHR Management Principles
• Correlate with fetal acid-base status• Do NOT predict cerebral palsy• Are only relevant for the point in time
referenced
FHR Categories: Meaning and Action
• Category I– Normal– Strongly predictive of normal acid base status– Follow ‘in a routine manner’
• Category III– Abnormal– Predictive of abnormal acid base– Prompt evaluation required– Resolve the pattern (support measures, delivery)
FHR Categories: Meaning and Action
• Category II– Indeterminate– Not predictive of abnormal acid base status– Inadequate evidence to classify as Category I
or III– Requires evaluation, continued surveillance
and reevaluation