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Fetal Monitoring

Fetal Monitoring. 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

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Fetal Monitoring

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  1. Fetal Monitoring Scott A Sullivan MD MSCR Maternal-Fetal Medicine MUSC October 12, 2010

  2. Disclosures • I have no disclosures or conflicts to report

  3. Disclosures – I am from MUSC!

  4. Learning Objectives • Discuss NICHD Consensus Recommendations • Review fetal physiology and EFM patterns • Alternate technology – what works, what doesn’t and what is coming

  5. 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

  6. Edward H Hon, MD 1915 – 2009 Father of modern EFM 1958

  7. First Viable EFM

  8. 1968 – Commercially available 1972 – First scalp electrode 1970’s – Coins deceleration terms 1975 – 20 % of labors used EFM

  9. 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

  10. Perinatal Death Rate

  11. Use of Intra-partum EFM in the US

  12. 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 %

  13. 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

  14. 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 %

  15. What’s the Problem? • Subjective interpretation • Technological limitations • Lack of interventional guidelines • Confusing terminology

  16. Terminology • Gabbe vs. Williams • “Short-Term”, “Beat to Beat” • Lack of inter-rater reliability • 1997 Consensus

  17. Inter-rater reliability • 4 OBs – 22 % agreement (Nielson) • 2 months later, re-reviewed • 25 % changed their own interpretation • 5 Obs – 29 % agreement (Beaulieu)

  18. NICHD Conference • 2008 • Series of meetings • Jointly published in OBG, Pediatrics, Neonatology OBG 112(3);Sept 2008 661-666

  19. Category I • Must include ALL : Baseline 110-160 Moderate variability No late decelerations Early decelerations +/- Accelerations +/-

  20. Category I

  21. Category I • “Normal” • “Highly Predictive of a normal fetal pH” • No Action Required

  22. Physiology – Cat. I

  23. Physiology – Cat I

  24. Category III • Absent variability, plus either Recurrent late decelerations Recurrent variable decelerations Bradycardia • Sinusoidal pattern

  25. Category III

  26. Category III • “Abnormal” • “Predictive of abnormal acid-base status” • Requires prompt intervention or delivery

  27. 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

  28. Environment Oxygen transfer can be disrupted at any ofthese points and can manifest as FHRdeceleration (variable, late, prolonged) The degree of oxygen disruption is theimportant factor, not the point in thepathway at which oxygen transfer isdisrupted Lungs Heart Vasculature Uterus Placenta Cord Fetus Hypoxemia Hypoxia Metabolic acidosis acidemia Hypotension Oxygen transfer Fetal response Potential Injury

  29. DECREASED UTEROPLACENTAL OXYGEN TRANSFER TO THE FETUS Chemoreceptor Stimulus Alpha Adrenergic Response WithoutAcidemia WithAcidemia Fetal Hypertension Baroreceptor Stimulus Parasympathetic Response MyocardialDepression Deceleration

  30. 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

  31. Category II

  32. 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

  33. 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; 93:285-91Williams KP Am J Obstet Gynecol 2003; 188:820-3Elimian A Obstet Gynecol 1997; 89:373-6

  34. 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

  35. NICHD 2008 - Pros • Simple • Better than 1998 • More widely adopted • ACOG buy-in

  36. NICHD 2008 - Cons • No evidence the system is actually better • Lack of actionable recommendations • Category II ?? • Does not fix problems of EFM

  37. A word about contractions • Normal ≤ 5 contractions / 10 m • Tachysystole ≥ 5 contractions / 10 m • No hyperstimulation!

  38. How About < 32 weeks? • No clear recommendations • < 28 weeks, 50 % will be non-reactive • 28-34 weeks, 15 % • “10 x 10”?

  39. 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 ?

  40. What’s New? It’s clear we need something better Fetal Pulse-Oximetry STAN

  41. Fetal Pulse Oximetry • Same technology • Oxygen saturation • Mechanical problems

  42. FPO – Cochrane Review • 2007 • 5 trials • 7424 subjects • Overall no decrease in cesarean rate, seizures • Fetal scalp sampling? East CE, Cochrane Database 2007

  43. STAN • ST Waveform Analysis • Automated analysis of ST segments • Uses EFM + ST • FDA approved - 2005

  44. 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

  45. 2006 BJOG - STAN • RCT • 1493 subjects • Similar design • No difference in acidosis • No difference in cesarean section or OVD Ojala K, BJOG 2006

  46. 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

  47. Newer things…. • Doppler? • WAS – 2009 • ANBLIR – 2010 (fuzzy logic, ANN) • NIR photopleythysmography

  48. What does ACOG Say? • Practice Bulletin 106 • Endorses terminology • High risk women need continuous EFM, for others it is optional • No to FPO

  49. Thank You

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