Fetal Heart Rate Monitoring: Terminology Update

1. Fetal Heart Rate Monitoring: Terminology Update Sharon Fickley, BSN, RNC-OB Laura Hall, ADN, RNC-OB January 24th, 2011

2. Objectives • Provide brief review of National Institute of Child Health and Human Development (NICHD) 2008 Electronic Fetal Monitoring (EFM) Terminology Update • Discuss physiologic basis for interpreting Fetal Heart Rate (FHR) tracings • Introduce definitions of NICHD Categories for interpreting and discussing FHR tracings

3. Background • 2008 Workshop • Key Players: • National Institute of Child Health and Human Development • American College of Obstetricians and Gynecologists (ACOG) • Society for Maternal-Fetal Medicine

4. Background (con’t) • Purposes: • Review & Update FHR pattern definitions • Assess existing classification systems for interpreting FHR patterns • Make recommendations about system for use in U.S. • Make recommendations for research priorities regarding EFM (ACOG, 2009)

5. Purpose “Using a common language for discussion of fetal status is a key principle of effective clinical communication and has the potential to decrease communication errors” (AWHONN, 2009, p. 72)

6. Methods • Systematic Assessment is Key • Systematic Assessment of FHR tracing includes: • Baseline Rate • Variability • Periodic or Episodic Changes • Uterine Activity • Pattern of or changes in FHR over time • Evaluation of findings within total clinical picture (AWHONN, 2009)

7. Baseline Rate • Approximate mean FHR rounded to increments of 5 bpm during a 10 minute window, excluding accelerations and decelerations and periods of marked variability • Must have at least 2 minutes identifiable, but not necessarily contiguous, baseline segments • If don’t have at least 2 minutes of baseline in 10 minute period, baseline is indeterminate • May need to refer to previous 10 minute window to determine baseline (Macones et al, 2008)

8. Baseline Bradycardia: < 110 bpm Tachycardia: >160 bpm (Macones, et al, 2008)

9. Baseline Variability • Determined in 10 minute window • Excluding accelerations or decelerations • Defined as fluctuations in baseline FHR that are irregular in amplitude {height} and frequency {width} and are visually quantified as the amplitude of the peak-to-trough in beats per minute (bpm) • Absent:amplitude range undetectable • Minimal:amplitude range visually detectable but </= 5 bpm (greater than undetectable but </= 5 bpm) • Moderate:amplitude range 6-25 bpm • Marked:amplitude range > 25 bpm (Macones, et al, 2008)

10. Periodic/Episodic Changes - Accelerations Acceleration: Visually apparent abrupt increase in FHR • Onset to peak <30 seconds • >/= 32 weeks: Peak >/= 15 bpm, lasting >/= 15 seconds from beginning to return to baseline • <32 weeks:Peak >/= 10 bpm, lasting >/= 10 seconds – • >/= 10 minute acceleration = baseline change (Macones, et al, 2008)

11. Periodic/Episodic Changes - Decelerations Early Deceleration: • usually symmetrical • gradual decrease and return of FHR • associated with contraction • onset to nadir >/= 30 seconds • nadir coincides with peak of contraction (Macones, et al, 2008)

12. Periodic/Episodic Changes - Decelerations Late Deceleration: • usually symmetrical • gradual decrease and return to baseline • associated with contraction • delayed in timing • nadir occurs after peak of contraction • generally, onset, nadir, and recovery occur after the beginning, peak, and end of the contraction (Macones, et al, 2008)

13. Periodic/Episodic Changes - Decelerations Variable Deceleration: • Abrupt decrease • Onset to nadir <30 seconds • Decrease is >/= 15 bpm, lasting >/= 15 seconds and < 2 minutes • If associated with contractions, onset, depth and duration commonly vary with successive contractions (Macones, et al, 2008)

14. Periodic/Episodic Changes - Decelerations Prolonged Deceleration: • Decrease from baseline >/= 15 bpm • Lasts >/= 2 minutes but < 10 minutes • Deceleration lasting > 10 minutes = baseline change Recurrent:occurring with >/= 50% contractions in any 20 minute window Intermittent: occurring with < 50% contractions in any 20 minute window (Macones, et al, 2008)

15. Uterine Activity Normal Uterine Activity: Five or fewer uterine contractions in 10 minutes, averaged over a 30 minute window Tachysystole: • More than five contractions in 10 minutes, averaged over a 30 minute period • Should always be discussed in conjunction with FHR characteristics • Terms “Hyperstimulation” & “Hypercontractility” not defined, should not be used (ACOG, 2009; AWHONN 2009)

16. Terminology Reactive and Nonreactive: apply to antepartum monitoring (non-stress test) vs. intrapartum Reassuring and Nonreassuring: Not used or addressed in new terminology. AWHONN FHM course states that one can feel reassured by a tracing, based upon the Category it is in. (AWHONN, 2009 & 2010)

17. Three Tiered System • Represents analysis of fetal acid-base status at the time assessment is made • Category I: Normal acid-base status likely – probability high that fetus is well oxygenated • Category II: Indeterminate. Fetus likely exhibiting compensatory response – has “reserves” • Category III: Abnormal fetal acid-base status likely All definitions related to categories and their description are adapted from Macones, et al, 2008.

18. Points to Emphasize • FHR patterns change over time • Clinical management individualized for each situation • Must evaluate entire clinical picture, including risk factors for both mother and baby • All interpretation and management based upon understanding of physiologic mechanisms underlying FHR tracing • Fetal monitoring is a collaborative process of continual assessment, interpretation, diagnosis, intervention, and evaluation

19. Three Tiered System for Classifying FHR Tracings

20. Category I Overview • Category I tracings are normal • Strongly predictive of normal fetal acid-base status • May be followed in routine manner

21. Category II Overview • Includes all tracings not categorized as Category I or III • Not predictive of either normal or abnormal fetal acid-base status • No evidence to categorize as either I or III • Generally require “evaluation, and continued surveillance and reevaluation, taking into account the entire associated clinical situation” (Macones 2008) • Additional tests (i.e. biophysical profile, amniotic fluid volume) may be needed to gather all information required to plan management • May require intrauterine resuscitative measures • MOST IMPORTANT: try to identify &/or address underlying physiologic mechanism which may be resulting in the characteristics of the tracing

22. Category II Overview • Communicate with care provider • Continue to evaluate and respond to tracing • Implement intrauterine resuscitative measures as needed to attempt correction of underlying mechanism of FHR pattern characteristics • Consider tocolytics if intrauterine resuscitative measures do not bring resolution

23. Category III Overview • Are abnormal • Associated with abnormal fetal acid-base balance at time of observation • Must evaluate and intervene quickly • Make efforts to resolve quickly: • Change maternal position • Discontinue labor stimulation • Administer IV fluids • Treat maternal hypotension • Provide oxygen to mother • Request tocolytics if appropriate • Mobilize team response

24. Category III Overview • If Category III tracing does not resolve relatively quickly with physiologically-based interventions, plan for expedited delivery • Medical provider should be notified immediately when tracing is a Category III

25. What does it mean for us? • “Data concerning the FHR pattern should ideally be conveyed using the definitions provided in the proceedings of the NICHD 2008 guidelines for EFM definitions, interpretation, and research” (AWHONN, 2009, p.178; Macones, et al, 2008) • Terminology should be defined in each institution’s policies (AWHONN, 2009) • “AWHONN and ACOG support use of 2008 NICHD guidelines for EFM definitions, interpretation, and research” (AHWONN, 2009, p. 182)

26. Questions

27. References American College of Obstetricians and Gynecologists. (2009b). Intrapartum fetal heart rate monitoring: Nomenclature, interpretation, and general management principles (Practice Bulletin 106). Washington, DC: Author. Association of Women’s Health, Obstetrical and Neonatal Nursing. (2010). Intermediate Fetal Monitoring Course. (5th Edition). Washington, DC: Author. Association of Women’s Health, Obstetrical and Neonatal Nursing. (2009). Fetal Heart Monitoring Principles and Practice. (4th Edition). Washington, DC: Author.

28. References (con’t) Macones, G.A., Hankins, G. D., Spong, C.Y., Hauth, J.D., & Moore, T. (2008). The 2008 National Institute of Child Health and Development workshop report on electronic fetal monitoring: Update on definitions, interpretations, and research guidelines. Obstetrics and Gynecology, 112, 661-666; and Journal of Obstetric, Gynecologic and Neonatal Nursing, 37, 510-515.