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Misadventures In FHR Monitoring

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Presentation on theme: "Misadventures In FHR Monitoring"— Presentation transcript:

1 Misadventures In FHR Monitoring
Brian Crownover, M.D., FAAFP Lt Col, USAF, MC Family Medicine Residency Nellis AFB, NV

2 What happened in 1968?

3 1968 Tet Offensive

4 1968 Apollo 8 Orbited Moon

5 1968 Planet of the Apes

6 1968

7 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”

8 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

9 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

10 Why care about electronic FHR monitoring?
Liability >50% of hospital’s risk management budget spent on L&D #1 allegation in OB med-malpractice cases Delayed diagnosis of “fetal distress” >75% of birth related lawsuits award >$1M

11 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

12 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

13 Why care about electronic FHR monitoring?
Use of EFM increased overall cesarean rate (OR- 1.53, CI ) compared to intermittent auscultation Use of EFM increased vacuum (OR – 1.23, CI ) and forceps deliveries (OR – 2.4, CI ) Use of EFM did NOT reduce overall perinatal mortality (OR – 0.87, CI ) ACOG Practice Bulletin #70; 2005

14 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 today’s 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

15 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)

16 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

17 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

18 American Journal of Obstetrics and Gynecology
NICHD Terminology American Journal of Obstetrics and Gynecology Volume 177(6) December 1997 pp 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.”

19 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

20 NICHD Terminology Soon thereafter…..

21 AWHONN AWHONN Association of Women’s Health, Obstetric and Neonatal Nurses Premier association for L&D nurses Several high quality CME offerings and certifications

22 NICHD Terminology Soon thereafter…..

23 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

24 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)

25 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

26 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

27 What is the Baseline Rate?
? ? 135? 138? Indeterminate?

28 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 bpm Excludes periodic changes (occuring with Ucx) or episodic changes (not occuring during Ucx)

29 Fetal Tachycardia

30 Fetal Tachycardia - etiologies
Hypoxemia – rising baseline worrisome Infection – maternal fever Hyperthermia Hyperthyroidism Anxiety Dehydration Medications Fetal Cardiac Conduction defect

31 Fetal Bradycardia

32 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

33 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 bpm

34 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

35 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 >25 bpm. 35

36 Measuring Variability
Undetectable amplitude range

37 Measuring Variability
< 5 bpm amplitude range

38 Measuring Variability
6-25 bpm amplitude range

39 Measuring Variability
≥ 25 bpm amplitude range

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

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

42 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

43 Diagram PNS chemoreceptor response

44 Diagram chemoreceptor response
Sympathetic outflow 1. peripheral vasoconstriction 2. central vasodilation 3. increased fetal HR

45 Baroreceptors – Aortic Arch

46 Diagram baroreceptor response
Baroreceptors detect increased BP Signal medullary vasomotor center

47 Diagram baroreceptor response
Medullary vasomotor center stimulates vagal nerve/PNS Fetal HR slows to help “normalize” BP to usual range

48 ALSO & NICHD Terminology
DR C. BRAVADO mnemonic A – Accelerations abrupt INCREASE in HR ≥ 15 bpm: onset to nadir < 30 secs; lasts ≥ 15 secs but < 2 mins ** For preterm patients < 32 weeks, 15 drops to 10, ie. Increase ≥ 10 bpm and ≥ 10 secs

49 ALSO & NICHD Terminology
DR C. BRAVADO mnemonic A – Accelerations (fetal mvt or sympath n. stim) Desirable and reassuring finding

50 ALSO & NICHD Terminology
DR C. BRAVADO mnemonic D – Decelerations Variable: abrupt decrease in HR ≥ 15 bpm: onset to nadir < 30 secs; lasts ≥ 15 secs but < 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

51 ALSO & NICHD Terminology
DR C. BRAVADO mnemonic D – Decelerations Recurrent: decelerations that occur with >50% of contractions in any 20-min period Prolonged: decelerations > 2mins but < 10 mins duration

52 What kind of Deceleration?

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

54 What kind of deceleration?

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

56 What kind of deceleration?

57 Vs. this kind of deceleration?

58 Both are Late Decelerations, but…

59 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

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

61 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

62 What kind of deceleration?

63 Variable Decelerations
Usually due to cord compression Common: 50-80% 2nd stage laboring pts Definition: Abrupt decrease FHR (onset to nadir < 30 sec) below baseline Decrease ≥ 15 bpm Duration ≥ 15 sec but < 2 mins

64 Variable Decelerations
What is the physiology?

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

66 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

67 Variable Deceleration
Shoulder: Umbilical Vein compression = relative hypovolemia →reflex tachycardia; benign

68 Nonreassuring Variable Decel characteristics
Prolonged return to baseline > 60 sec Rising baseline rate to tachycardia range >160 bpm compensatory sympathetic nervous system response to ongoing hypoxemia Detected by chemoreceptors

69 Nonreassuring Variable Decel characteristics
Absent baseline variability Overshoot Gradual smooth accel following the decel > 60 sec with increased rate bpm Gradual return to original baseline HR

70 Variable Decel with Overshoot

71 Nonreassuring Variable Decel Mgt
Consider amnioinfusion to limit cord compression if recurrent decels with nonreassuring characteristics

72 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

73 Ominous Worrisome Reassuring Color?

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

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

76 Red Light Characteristics Metabolic adicosis cannot be excluded STOP!
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

77 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

78 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 1:1 nurse-fetus staffing Rarely used in US given malpractice environment

79 Misc - Montevideo Units

80 Sample Malpractice Cases
From Actual settlements See handouts

81 Take Home Pearls CEFM shown to increase operative deliveries without reducing perinatal death or cerebral palsy NICHD terminology is recommended to help standardize communication; DoD’s new norm Absent variability is most specific finding for fetal hypoxemia

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


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