Electronic Fetal Monitoring: An Update

1. Electronic Fetal Monitoring: An Update James Paul Ching Maganito, DO, MPH, MHA, CHES Obstetrics and Gynecology Yakima Valley Farm Workers Clinic Yakima Valley Memorial Hospital

2. Objective • Refamiliarize ourselves with the recent ACOG practice bulletin guidelines, July 2009 • Reemphasize definition to apply to clinical practice and documentation

3. Background • FHR monitoring • Original rationale – screening test for asphyxia to prevent neurologic damage / fetal death • Original research started in the 1960’s • Study done on term pregnancy noted fetal asphyxia of unknown origin in 63% of the research sample (1) (1) Low JA, et al. The prediction and preention of intrapartum fetal asphyxia in term pregnancies. Am J Obstet Gynecol 2001; 184: 724-30

4. Guidelines for Nomenclature and Interpretation of Electronic Fetal Heart Rate Monitoring • 2008 • Eunice Kennedy Shriver National Institute of Child Health and Human Development • American College of Obstetricians and Gynecologist • Workshop focused on FHR monitoring • Three goals • To review and update the definitions for FHR pattern categorization from the prior workshop • To assess existing classification systems for interpreting specific FHR patterns and make recommendations about a system for use in the United States • To make recommendations for research priorities for EFM

5. True or False • With regards to uterine contraction, the term hyperstimulation and hypercontractility is still used today and should be adopted and documented?

6. Uterine Contractions • Definition • Uterine contractions are quantified as the number of contractions present in a 10 minute window, average over a 30 minute period • Documentation should include: frequency, duration, intensity, relaxation time • Terminologies • Normal: < 5 Ctx in 10min avg over 30min window • Tachysystole: > 5 Ctx in 10min avg over 30min window • Always qualified as to the presence or absence of associated FHR decelerations • Applies to both spontaneous and stimulated labor

7. True or False? • FHR baseline should be document as a range in order to avoid any confusion and give the team a better idea of the characteristic of the baseline?

8. Baseline • FHR rounded to increments of 5bpm during a 10min segment, for at least 2mins, excluding • Periodic or episodic changes • Periods of marked FHR variability • Segments of baseline that differ by more than 25bpm • Normal: 110-160bpm • Tachycardia: > 160 bpm • Bradycardia: < 110bpm

9. True or False • Variability should be described and documented as “no,” “good,” or “severe” as well as in terms of short-term versus long-term variability?

10. Baseline Variability • Absent: undetectable • Minimal: < 5bpm • Moderate: 6-25bpm • Marked: > 25 bpm

11. Accelerations • Abrupt increase (onset to peak is < 30secs) • > 32 wk GA, > 15bpm above BL > 15secs but less than 2 mins from onset to return • < 32 wks, > 10bpm above BL > 10secs but less than 2mins from onset to return • Prolonged accelerations last 2mins or more but less than 10mins • > 10 mins is a baseline change

12. True or False • Decelerations are described and documented as persistent, repetitive, or rare? • Decelerations should be described as: • Periodic: associated w/ uterine contractions • Episodic: no association w/ uterine contractions • Recurrent: repetitive

13. Decelerations • Early • Gradual decrease, nadir = peak of ctx • Variable • Abrupt decrease, > 15 bpm lasting 15 secs but less than 2 mins • Late • Gradual decrease, nadir = after peak of ctx • Prolonged • > 15bpm, lasting > 2 mins but less than 10 mins • Sinusoidal • Smooth, sine wave, cycle frequency of 3-5 per min persisting 20mins or more

14. Classification of FHR Tracing • Category I • Category II • Catergory III

15. Classification of FHR Tracings • Category I • BL: 110-160bpm • BL FHR variability: moderate • Accelerations: present • Early Decels: present or absent • Late or variable decels: absent • Monitor Routinely • No Specific Actions required

16. Classsification of FHR Tracing • Category II • BL: • Bradycardia not accompanied by absent variability • Tachycardia • BL Variability • Minimal or marked variability • Absent with no recurrent decels • Accelerations • Absence of induced acceleration after fetal stimulation • Periodic / Episodic decels • Recurrent variable decels • Prolonged decels • Recurrent later decels • Perform Ancillary Test to ensure fetal well being or intrauterine resuscitative measures may be used

17. Classification of FHR Tracing • Category III • BL: Absent with recurrent late/variable decels or bradycardia • Sinusoidal pattern • Prompt evaluation • Depending on clinical scenario, expeditiously resolve abnormal FHR pattern by intrauterine resuscitative efforts • IF NOT resolved – delivery should be undertaken

18. Guidelines for Review of Electronic FHR Monitoring • Pt w/o complications • First stage: q 30mins • Second stage: q 15mins • Pt w/ complications • First stage: q 15mins • Second stage: q 5mins

19. Efficacy of FHR monitoring • INCREASED overall cesarean section delivery rate • INCREASED operative vaginal delivery – vacuum and forcep • Did NOT reduce cerebral palsy risk • False positive rate is > 99% in predicting cerebral palsy • Rationale: 70% of CP occurs before onset of labor & only 4% can be attributed to intrapartum events • Reduced risk of neonatal seizures

20. Poor interobserver and intraobserver variability • The ACOG guidelines highlight a case in which four obstetricians examined 50 FHR tracings; they agreed in only 22% of the cases. Two months later, these four physicians reevaluated the same 50 FHR tracings, and they changed their interpretations on nearly one out of every five tracings. • Foreknowledge of neonatal outcome – alters the reviewer’s impressions of FHR tracings – thus not reliable.

21. Medication Effects on FHR • Narcotics • 75mg meperidine (Demerol) = 10mg morphine = 0.1 fentanyl = 10mg nalbuphine (nubain) • Decrease variability, decrease frequency of accels • Butorphanol (Stadol) • Transient sinusoidal pattern • Corticosteroid • Betamethasone: decrease variability – returns to normal by fourth to 7th day post treatment • Dexamethasone: no change • MgSO4 • Decreased variability with early gestational age • Mg level did not affect variability • Terbutaline • Increase baseline FHR and incidence of fetal tachycardia

22. Ancillary Test to Aid Management of Category II and III • Fetal Scalp Sampling • Consider with Category III – difficult b/c of decrease in physician experience, difficulty, processing sample • Allis Clamp Scalp Stimulation • Vibroacoustic Stimulation • Digital Scalp Stimulation

23. Intrauterine Resuscitation • Discontinuation of labor stimulating agent • Cervical exam • Determine umbilical cord prolapse • Rapid cervical dilation • Descent of the fetal head • Change maternal position • Monitoring maternal blood pressure level (Hypotension) • If secondary to regional anesthetic, volume expansion or IV ephedrine or both • Assessment of pt for uterine tachysystole • Supplemental oxygen for indeterminate or abnormal patterns • There is no data on the efficacy or safety of this therapy • Tocolytic agent • If position and oxygenation does not change FHR pattern • Although tocolytic therapy appears to reduce the number of FHR abnormalities, there is insufficient evidence to recommend it. • Amnioinfusion • Recurrent variable decels • Decrease rate of decel, decrease hospitalization time of pt and newborn

24. Conclusion • Baseline – multiple of 5 • Variability – Absent, Minimal, Moderate, Marked • Accels – no asphyxia • Decels: Early, Variable, Late – Periodic, Episodic, Recurrent (Recurrent periodic/episodic) • If in category II and III – physician should be present to evaluate the pt and fetus

25. Lastly… • Computer vs “expert” human visualization, evaluation, and interpretation of electronic fetal heart tracing has been shown to have no statistical difference.

27. Reference • GE: Electronic Fetal Heart Monitoring: Research Guidelines for Interpretation • ACOG Practice Bulletin. Intrapartum Fetal Heart Rate Monitoring: Nomenclature, Interpretation, and General Management Principles. Number 106, July 2009 • National Institute of Child Health and Human Development workshop report on electronic fetal monitoring: update on definitions, interpretation, and research guidelines. Obstet Gynecol 2008; 112:661-6