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