Misadventures In FHR Monitoring

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Misadventures InFHR Monitoring

• Brian Crownover, M.D., FAAFP
• Lt Col, USAF, MC
• Family Medicine Residency
• Nellis AFB, NV

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What happened in 1968?
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1968

• Tet Offensive

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1968

• Apollo 8 Orbited Moon

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1968

• Planet of the Apes

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1968
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1968

• Dr. K. Hammacher, Dusseldorf Univ and
  Hewlett-Packard market commercial FHR monitor -
  HP-8020-A to US hospitals
• Marketed as the Baby-sitter (allow fewer
  nurses if auscultation not required)
• Take the guesswork out of that critical phase of
  life
• Credited with saving many tiny lives already in
  Europe

http//www.hparchive.com/measure_magazine/HP-Measu
re-1968-10.pdf
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Overview

• Pearls
• Why care about FHR monitoring
• NICHD terminology (National Institute of Child
  Health and Human Development)
• Sample malpractice settlement cases involving AF
  providers and FHR monitoring
• Pearls

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Take Home Pearls

• CEFM use persists despite evidence of harm
• NICHD terminology is preferred community standard
  and endorsed by major stakeholders
• Absent variability is most worrisome CEFM finding

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Why care about electronic FHR monitoring?

• Liability
• gt50 of hospitals risk management budget spent
  on LD
• 1 allegation in OB med-malpractice cases
• Delayed diagnosis of fetal distress
• gt75 of birth related lawsuits award gt1M

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Why care about electronic FHR monitoring?

• Incorporated into clinical practice without
  confirmatory research evidence
• Continued use in clinical practice despite lack
  of benefit proven in later research

http//www.nice.org.uk/nicemedia/pdf/efmguidelinen
ice.pdf
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Why care about electronic FHR monitoring?

• Continuous electronic fetal monitoring (CEFM)
  was introduced with an aim of reducing perinatal
  mortality and cerebral palsy. This reduction has
  NOT been demonstrated in the systematic reviews
  of RCTs however an increase in maternal
  intervention rates (cesarean and operative
  vaginal deliveries) has been shown. Royal
  College of OB GYN

http//www.nice.org.uk/nicemedia/pdf/efmguidelinen
ice.pdf
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Why care about electronic FHR monitoring?

• Use of EFM increased overall cesarean rate (OR-
  1.53, CI 1.17-2.01) compared to intermittent
  auscultation
• Use of EFM increased vacuum (OR 1.23, CI
  1.02-1.49) and forceps deliveries (OR 2.4, CI
  1.97-3.18)
• Use of EFM did NOT reduce overall perinatal
  mortality (OR 0.87, CI 0.57-1.33)

ACOG Practice Bulletin 70 2005
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Why care about electronic FHR monitoring?

• Bottom line We care because the community
  standard and malpractice lawyers insist we care
• If applying for FDA approval in todays
  environment, CEFM lacks sufficient evidence to
  justify its use
• Premature adoption of technological solutions may
  not bring the desired results, and in fact may
  cause harm

ACOG Practice Bulletin 70 2005
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Additional Training

• Still have doubts?
• NICHD training REQUIRED NLT 20 Jul 08
• ALL DoD providers and nurses who will work with
  fetal HR monitors must complete AWHONN on-line
  training (SG Perinatal Consultant)
• http//www.healthstream.com/HLC/fhmdod
• http//www.awhonn.org/awhonn/

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Now what?

• So if the 800 lb gorilla (CEFM ) is here to stay
• We need to understand its use, current
  terminology, and place in labor management

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NICHD Terminology

• 1995 18 member NICHD consensus panel meets to
  develop standardized CEFM terminology
• 1997 expert opinion based conclusions published
  in the Gray Journal not widely adopted

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NICHD Terminology

• American Journal of Obstetrics and Gynecology
• Volume 177(6) December 1997 pp 1385-1390
• Electronic fetal heart rate monitoring Research
  guidelines for interpretation Clinical Opinion
  National Institute of Child Health and Human
  Development Research Planning Workshop.
• The purpose of the National Institutes of Health
  research planning workshops is to assess the
  research status of clinically important areas.
  This article reports on a workshop whose meetings
  were held between May 1995 and November 1996 in
  Bethesda, Maryland, and Chicago, Illinois. Its
  specific purpose was to develop standardized and
  unambiguous definitions for fetal heart rate
  tracings.

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NICHD Terminology

• 2004 JCAHO published Sentinel Alert 30
• Root cause analysis of 47 fetal deaths
• 72 due to poor team communication (1 cause)
• 34 inadequate fetal monitoring
• Top recommendation Conduct team training to
  teach staff to work together and communicate more
  effectively

http//www.jointcommission.org/SentinelEvents/Sent
inelEventAlert/sea_30.htm
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NICHD Terminology

• Soon thereafter..

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AWHONN

• AWHONN
• Association of Womens Health, Obstetric and
  Neonatal Nurses
• Premier association for LD nurses
• Several high quality CME offerings and
  certifications

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NICHD Terminology

• Soon thereafter..

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NICHD Terminology

• NICHD rapidly endorsed by multiple organizations
• ACOG and AWHONN
• Society for Maternal Fetal Medicine
• US Dept Health Human Services
• Society of OB GYN of Canada
• Royal Australian and NZ College of OB GYN

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NICHD Terminology

• What terminology was dropped?
• No subtypes of variable decel mild moderate or
  severe classification is gone modifiers like
  slow return to baseline dropped
• yet still relevant to consider
• Persistent decels term replaced by recurrent
  (decels occuring 50 Ucx in 20 min window)

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NICHD Terminology

• What other terminology was dropped?
• Baseline variability determined visually as a
  unit no distinction between short and long term
  variability Beat to Beat variability term
  eliminated
• Terms reassuring and non-reassuring not
  formally included

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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• DR define risk low vs. high clinical
  decision
• C contractions r/o hyperstim and time decels
• Frequency
• Duration
• Intensity
• Resting tone

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What is the Baseline Rate?

• 130-140? 135-140? 135? 138? Indeterminate?

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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• B Ra Baseline Rate
• Appx mean FHR rounded to increments of 5 bpm
  during a 10 min segment
• Min baseline duration must be 2 mins per 10 min
  window
• Normal rate is 110-160 bpm
• Excludes periodic changes (occuring with Ucx) or
  episodic changes (not occuring during Ucx)

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Fetal Tachycardia
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Fetal Tachycardia - etiologies

• Hypoxemia rising baseline worrisome
• Infection maternal fever
• Hyperthermia
• Hyperthyroidism
• Anxiety
• Dehydration
• Medications
• Fetal Cardiac Conduction defect

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Fetal Bradycardia
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Fetal Bradycardia - etiologies

• Cord prolapse - immediate eval PE
• Maternal hypotension
• Regional anesthesia
• reason for pre-epidural fluid bolus
• Hypoxemia
• Head compression 2nd stage
• Fetal heart block
• Uterine rupture esp hx uterine surgery
• Placental abruption
• Fetal CNS injury or defect

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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• V Variability
• Appx mean FHR rounded to increments of 5 bpm
  during a 10 min segment
• Min baseline duration must be 2 mins per 10 min
  window
• Normal rate is 110-160 bpm

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Measuring Variability

• Total amplitude height from peak FHR to trough
  FHR over a 1 min window
• Each horiz. small box 10 sec
• Each horiz. big bold box 1 min

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Measuring Variability

• Absent variability no detectable fluctuation in
  the baseline.
• Minimal variability visually detectable
  amplitude range 5 bpm.
• Moderate variability amplitude range 6 and 25
  bpm.
• Marked variability amplitude range gt25 bpm.

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Measuring Variability
Undetectable amplitude range
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Measuring Variability
lt 5 bpm amplitude range
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Measuring Variability
6-25 bpm amplitude range
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Measuring Variability
25 bpm amplitude range
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Variability

• What does moderate variability suggest the
  absence of?
• Fetal respiratory acidosis
• Fetal metabolic acidemia
• Fetal hypoxemia
• Fetal hypercarbia
• Fetal asphyxia

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Variability

• What does moderate variability suggest the
  absence of?
• Fetal respiratory acidosis
• Fetal metabolic acidemia
• Fetal hypoxemia
• Fetal hypercarbia
• Fetal asphyxia

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Variability

• Variability implies absence of
• Fetal metabolic acidemia
• Fetal sleep cycle
• Medication effects
• Variability governed by fetal nervous system,
  mostly parasympathetic system/vagal nerve
• Fluctuates due to changes in pO2 or BP detected
  by chemo and baroreceptors

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Diagram PNS chemoreceptor response
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Diagram chemoreceptor response
Sympathetic outflow 1. peripheral
vasoconstriction 2. central vasodilation 3.
increased fetal HR
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Baroreceptors Aortic Arch
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Diagram baroreceptor response
Baroreceptors detect increased BP Signal
medullary vasomotor center
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Diagram baroreceptor response
Medullary vasomotor center stimulates vagal
nerve/PNS Fetal HR slows to help normalize BP
to usual range
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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• A Accelerations
• abrupt INCREASE in HR 15 bpm onset to nadir lt
  30 secs lasts 15 secs but lt 2 mins
• For preterm patients lt 32 weeks, 15 drops to
  10, ie. Increase 10 bpm and 10 secs

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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• A Accelerations (fetal mvt or sympath n. stim)
• Desirable and reassuring finding

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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• D Decelerations
• Variable abrupt decrease in HR 15 bpm onset
  to nadir lt 30 secs lasts 15 secs but lt 2 mins
• Early gradual decrease in HR onset to nadir
  30 secs nadir occurs WITH peak of Ucx
• Late gradual decrease in HR onset to nadir 30
  secs nadir occurs AFTER peak of Ucx

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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• D Decelerations
• Recurrent decelerations that occur with gt50 of
  contractions in any 20-min period
• Prolonged decelerations gt 2mins but lt 10 mins
  duration

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What kind of Deceleration?
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Early Deceleration

• Considered benign
• Caused by head compression
• May indicate head descent and entry of 2nd stage
  labor

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What kind of deceleration?
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Prolonged Deceleration

• Typically d/t sudden significant change in
  uterine environment
• Requires immediate assessment and Tx
• 15 bpm, lasting 2 minutes
• Often abrupt onset

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What kind of deceleration?
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Vs. this kind of deceleration?
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Both are Late Decelerations, but
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Late Deceleration

• Late decels much more worrisome if accompanied by
  absent baseline variability
• Indicates uteroplacental insufficiency
• Protective compensatory response
• Caused by chemoreceptors triggering vagal PNS
  response during episodes of transient hypoxemia
  during Ucx

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Uteroplacental insufficiency
Intervillous Space Location of oxygen diffusion
from mother to fetus
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Late Deceleration

• Depth of deceleration does NOT correlate with
  degree of hypoxemia
• May be shallow or subtle
• Periph vasoconstriction compensatory response
  fatigues eventually central perfusion declines
  causing hypoxic-ischemic injury -brain/heart

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What kind of deceleration?
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Variable Decelerations

• Usually due to cord compression
• Common 50-80 2nd stage laboring pts
• Definition
• Abrupt decrease FHR (onset to nadir lt 30 sec)
  below baseline
• Decrease 15 bpm
• Duration 15 sec but lt 2 mins

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Variable Decelerations

• What is the physiology?

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Umbilical cord cross section
Single thin walled vein -oxygenated blood from
mother
Two thick walled arteries -deoxygenated blood
back to mother
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Variable Deceleration

• Thin walled Umb vein compressed causing less
  blood flow return to heart and reflex fetal tachy
  (sim to pooling in legs when adults stand up)
• Baroreceptors (aortic arch/carotid body) transmit
  to midbrain and then to sympathetic nervous
  system
• Further cord compression affects Umb artery
  causing increased SVR/BP
• baroreceptors cause compensatory vagal stim and
  lower fetal HR

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Variable Deceleration
Shoulder Umbilical Vein compression relative
hypovolemia ?reflex tachycardia benign
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Nonreassuring Variable Decel characteristics

• Prolonged return to baseline
• gt 60 sec
• Rising baseline rate to tachycardia range
• gt160 bpm
• compensatory sympathetic nervous system response
  to ongoing hypoxemia
• Detected by chemoreceptors

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Nonreassuring Variable Decel characteristics

• Absent baseline variability
• Overshoot
• Gradual smooth accel following the decel
• gt 60 sec with increased rate 10-20 bpm
• Gradual return to original baseline HR

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Variable Decel with Overshoot
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Nonreassuring Variable Decel Mgt

• Consider amnioinfusion to limit cord compression
  if recurrent decels with nonreassuring
  characteristics

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ALSO NICHD Terminology

• DR C. BRAVADO mnemonic
• O Overall assessment
• If nonreassuring, consider intrauterine
  resuscitation
• Shift maternal position incr uterine blood flow
  30 if not supine
• Maternal oxygen facemask
• IV fluid bolus/hydration /- ephedrine
• Reduce pain and anxiety
• Hold/reduce pitocin augmentation terbutaline if
  hyperstim

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Ominous Worrisome Reassuring
Color?
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Green Light

• Characteristics
• Stable baseline in normal range
• Moderate variability
• Accelerations
• No decelerations
• Metabolic acidois unlikely
• Interventions not necessary

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Yellow Light

• Characteristics
• Rising FHR baseline
• Normal range
• Minimal variability
• Accelerations
• Decreasing in frequency
• Decelerations - intermittment
• Metabolic acidosis may develop without corrective
  interventions

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Red Light

• Characteristics
• Prolonged decelerations
• Persistent tachycardia with absent variability
• Recurrent variable decels with absent variability
• Recurrent late decels with absent variability
• Metabolic adicosis cannot be excluded
• STOP!
• Assess maternal-fetal oxygenation
• Proceed with immediate delivery if indicated

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ALSO NICHD Terminology

• Pathophysiology Summary points
• Accels and moderate variability predict absence
  of metabolic acidemia
• Variable decels caused by baroreceptor mediated
  response to elevated SVR caused by umbilical
  artery compression
• Late decels reflect protective serial chemo- then
  baroreceptor response to transient hypoxemia
  during contraction

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Misc - Auscultation

• Equivalent outcomes to CEFM for low risk pts
• Performed with doppler x 60 secs after Ucx
• Frequency (opinion-based recommendations)
• q15-30 mins in active labor
• q 5 mins in 2nd stage while pushing
• Requires 11 nurse-fetus staffing
• Rarely used in US given malpractice environment

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Misc - Montevideo Units
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Sample Malpractice Cases

• From Actual settlements
• See handouts

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Take Home Pearls

• CEFM shown to increase operative deliveries
  without reducing perinatal death or cerebral
  palsy
• NICHD terminology is recommended to help
  standardize communication DoDs new norm
• Absent variability is most specific finding for
  fetal hypoxemia

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Acknowledgements

• Maj Becky Cypher, USAF, NC, Co-author AWHONN FHR
  guidelines
• Dr David Miller, MFM, USC School of Medicine

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