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)
And we all know how many mistakes involve communication. We also know how many times we’ve “debated” with physicians regarding a tracing. Although updates and clarifications in terminology will never end the debates completely, the panel attempted to objectify terms and place tracings into some fairly distinct categories while offering general guidance about how to manage tracings in different categories.

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)
Periodic – associated with contractions
Episodic – not associated with contractions
Include characterizing accelerations and decelerations – our charting is a bit duplicate (boxes that say periodic and with contractions – means the same thing – don’t need to chart both)
To start we’ll very quickly review basic elements of NICHD terminology, just to make sure we’re all talking from the same vantage point.
These 6 elements are included in each assessment of fetal heart rate
Not always thought through individually, but represent the overall picture of FHR. However, each element should be considered when evaluating patterns, especially concerning ones

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)
If baby very active, may be hard to get 2 contiguous minutes of baseline, but can either piece together or look previous window

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)
So no need to split hairs – onset usually “after” beginning of contraction. No need to measure exactly how far after – just after, and the lowest point in the decel is usually after the peak of the contraction. Decel gradually resolves after the end of the contraction. When auscultating, can’t characterize type of decel, but this is often the one where you’re listening through contraction and it sounds ok, but then after woman says contraction is over, you hear an audible drop in FHR. Our ears just aren’t able to immediately hear all that the eye sees on EFM, so that’s why further eval is needed if this occurs more than once successively w/auscultation.

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)
So, quickish and fastish – quick to drop to lowest point, and relatively quick to return to baseline. May have variables after contractions – no more “variables with a late component” – if they’re variables, they’re variables, and you’ll want to take action if they’re recurrent, no matter when they’re occurring in relationship to contraction

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)
Definitions for recurrent and intermittent become important when looking
@ categories

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)
Will certainly hear people say strips are reassuring, and they are. It’s just that the terminology is really not defined in most recent document. Rather, encourage us to elements of tracing and try to define according to categories. It’s not that reassuring is wrong.

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.
Three tiered system is meant to categorize tracings according to probably acid-base status of fetus AT THE TIME tracing is being interpreted, recognizing that labor is a dynamic process, that fetuses come into the process with many different risk factors and amounts of “reserve” and that tracings often can and do evolve in and out of categories throughout labor Years of research now demonstrate that much of what we thought of in the past as “a bad tracing’ may not have been associated with a “bad baby” – we’ve all seen the 9/9 apgars in the OR after running around worrying.
What this working group wanted to do was to help clinicians systematically evaluate and think through tracings, considering the entire clinical picture. They emphasize likely physiology behind tracings and evaluating and responding accordingly. Now we’ll review each category in more detail.

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
Changes over time – you may have a strip that is category II and goes back to a I with intervention, or you may have a great baby that becomes category II or III – happens all the time.
Guidelines don’t lock clinicians into any specific response in every situation – need to consider the whole clinical picture – risk factors, pre-existing status of fetus (ie. IUGR, known placental insufficiency, diabetic mother, congenital abnormalities, etc) and the mother in evaluating and making decisions re: management

19. Three Tiered System for Classifying FHR Tracings
Category I
Category II
Category III
All of the Following:
Baseline
Variability: Moderate
Late or Variable Decels: Absent
Early Decelerations:
Present or Absent
Accelerations:
Examples:
Moderate Variability with recurrent late or variable decelerations
Minimal Variability with recurrent variable decelerations
Absent Variability WITHOUT recurrent decelerations
Bradycardia with Moderate Variability
Prolonged Decelerations
Either:
Absent Variability with:
Recurrent late decels OR
Recurrent variable decels OR
Bradycardia
OR:
Sinusoidal Pattern
If you recognize characteristics necessary for category I and Category III – you’ll know what’s not either one and by default is category II. NICHD acknowledges that the bulk of our strips often fall into category II – terminology and categories have not changed this very frustrating fact. Just helps us rule out ominous from our thinking if it’s not yet ominous – but we know more clearly exactly what we’re watching for and need to communicate with increased urgency and persistence. If you’re watching a strip evolve in the wrong direction, need to say that and not feel worried about saying it – focus on systematic assessment and reporting characteristics of all elements (baseline, variability, periodic/episodic changes, etc)
Category I – must have normal baseline and moderate variability. Can’t have lates or variables. May have earlies. And may OR MAY NOT have accels.
Category III – must have ABSENT variability along with recurrent late or variable decels – OR bradycardia. If have true sinusoidal rhythm, this alone categorizes as a III. This is because of the physiology behind a true sinusoidal rhythm. Requires immediate delivery and intervention.
Things to note about category II – may have absent variability as long as you don’t have recurrent decels. If variability is moderate or minimal and you have recurrent decels, tracing is category II. SO – category II DOES NOT mean DO NOTHING.
Discuss

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
Important to be clear – we are NOT saying that category II strips don’t require intervention. They may and often do. It’s just that you’re intervening before things go further downhill. You’re trying to increase placental bloodflow and oxygen delivery to the fetus by doing things that have been shown to do this (EFM course includes great review of literature presenting research which does demonstrate measurable increases in oxygen delivery to fetus by performing “traditional” interventions – ie. Position change, IV hydration, O2 to mom, etc).
Please try your best to get an order before administering tocolytics – discuss w/MD ahead of time if you have concerns – ie. Induction, etc. There are a few MDs who don’t want terb just given, and a few situations in which you wouldn’t really want to give it (previa, mom w/underlying heart condition or cardiovascular compromise from pulmonary edema for example ) –terb not a benign drug and does present increased cardiac workload to mom. So just be clear in your communications – it’s a bit too easy to run into a room w/ terb to help w/out knowing whole clinical situation, so just be careful

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
These interventions should be intiated any time you are concerned about the well-being of the baby, even if strip is still in category II. Other interventions which may be considered are things like amnioinfusion for recurrent variables or performing a vaginal exam to check for a prolapsed cord. Remember, performing a vaginal exam to do scalp stimulation is meant to be done for a baby who appears stable but for whom you may wish to elicit an acceleration. Scalp stim should not be done during a deceleration to see if you can increase the baby’s heart rate. Why not? What sometimes happens to the fetal heart rate when you do a vag exam? Just remember to think about why you’re doing what you’re doing.

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)
General Points:
Our IView cannot have any changes made at the moment. So, if you choose to use Categories to communicate information regarding the tracing to the physician, you’ll need to make a flag annotation to say this, or use the notes section of the “OB Notified” section in the Labor Assessment band
However, what we want to emphasize is the importance of systematic assessment of FHR tracings, every time. Therefore, the most important thing that we as nurses can do is to make, document, and report our systematic assessment of FHR tracing characteristics, and then respond accordingly based upon probably physiologic mechanisms influencing the tracing. Whether or not we report the category is not the most important thing – it is whether or not we’re thinking about the physiology of FHR and what we need to do in response to a specific situation.
Not all MDs are using. Some are. Some are documenting, some are not. Dr. Heider told us on Thursday that there is now some discussion of splitting out categories II and III even further, because Category II represents such a large portion of our tracings. However, as he reminded us, these things usually take years to get into the literature and practice, so for now, these are the most up-to-date, evidence-driven guidelines we have, and for the 1st time ever, they came from both the nursing and the OB/GYN professional organization.

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, ; and Journal of Obstetric, Gynecologic and Neonatal Nursing, 37,