Fetal Heart rate assessment ch9

Question 1

Electronic fetal monitoring

Answer 1

The goal of fetal monitoring is to interpret and continually assess fetal oxygenation (Lyndon & Ali, 2015) and prevent significant fetal acidemia while minimizing unnecessary intervention and promoting a satisfying family-centered birth experience.
While it is essential in the assessment of maternal and fetal well-being in antepartal and intrapartal settings, keep in mind that other evidence-based options such as intermittent auscultation are appropriate for laboring women

Question 2

Principles of Fetal Monitoring

Answer 2

Overall Goals

● Support maternal coping and labor progress

● Maximize uterine blood flow

● Maximize umbilical blood flow

● Maximize oxygenation

● Maintain appropriate uterine activity

Nursing Actions

● Review plans/expectations with woman and her family

● Maintain calm environment

● Stay at the bedside as much as possible

● Monitor only at the level needed for this patient

● Frequent position changes; upright positioning

● Judicious use of technology

● Avoid:

● Unnecessary interventions

● Tachysystole

● Supine position

● Coached pushing

● Valsalva pushing
Nurses are expected to independently assess, interpret, and intervene based on interpretations of EFM patterns. Assessments and interactions with monitored women and their families are individualized to provide information and explanation and reduce anxiety (Box 9-2). Clear and accurate communication with care providers and the perinatal team is essential for optimizing perinatal outcomes.

Question 3

AWHONN Fetal Heart Monitoring Clinical Position Statement

Answer 3

The Association of Women’s Health, Obstetric and Neonatal Nurses (AWHONN) asserts that care by registered nurses (RNs) skilled in fetal heart monitoring (FHM) techniques, including auscultation and electronic fetal monitoring (EFM), is essential to maternal and fetal well-being during antepartum care, labor, and birth. EFM requires advanced assessment and clinical judgment. It is within the nurse’s scope of practice to implement customary interventions in response to FHM data and clinical assessment. Interprofessional policies should support the RN in making decisions regarding fetal monitoring practice, intervening independently when appropriate to maternal and/or fetal condition.

Question 4

Teamwork and Collaboration

Answer 4

• Following communication practices that minimize risks associated with EFM communication among providers.
• Appreciating the importance of intra- and interprofessional collaboration to improve patient outcomes.
• Integrating the contributions of others who play a role in helping patient and her family achieve a healthy birth.
• Respecting the centrality of the patient/family as core members of any health care team.
• Acknowledging your own potential to contribute to effective team functioning in this critical setting.

Question 5

MODES OR TYPES OF FETAL AND UTERINE MONITORING

Answer 5

Types of fetal and uterine monitoring include the following.

Auscultation
Auscultation refers to the use of the fetoscope or Doppler to listen to the FHR without the use of a paper recorder (Feinstein, Sprague, & Trepanier, 2008) (Fig. 9–1A&B). Auscultation with a fetoscope allows the practitioner to hear the sounds associated with the opening and closing of ventricular valves via bone conduction. A Doppler, by contrast, uses sound waves that are deflected from fetal heart movements similar to that used on an EFM external ultrasound transducer. This ultrasound device then converts information into a sound that represents cardiac events.

Question 6

Baseline FHR

Answer 6

FHR rounded to increments of 5 bpm during a 10-minute window. There must be at least 2 minutes of identifiable baseline segments (not necessarily contiguous). Does not include accelerations or decelerations or periods of marked variability (amplitude >25 bpm).

• Periodic: changes in baseline of FHR occur in relation to UCs.
• Episodic: changes in baseline of FHR occur independent of UCs.
• Recurrent: changes in baseline of FHR occur in greater or equal to 50% of the contractions in a 20-minute period.
• Intermittent: changes in baseline of FHR in less than 50% of the contractions in a 20-minute period.

Question 7

Baseline variability

Answer 7

Fluctuations in the baseline FHR that are irregular in amplitude and frequency. The fluctuations are visually quantified as the amplitude of the peak to trough in bpm. It is determined in a 10-minute window, excluding accelerations and decelerations. It reflects the interaction between the fetal sympathetic and parasympathetic nervous system.

• Absent: Amplitude range is undetectable.
• Minimal: Amplitude range is visually detectable ≤5 bpm.
• Moderate: Amplitude from peak to trough is 6 bpm to 25 bpm.
• Marked: Amplitude range >25 bpm.

Question 8

Indeterminant FHR

Answer 8

FHR that does not meet the criteria of baseline FHR

Question 9

Accelerations

Answer 9

Visually apparent, abrupt increase in FHR above the baseline. The peak of the acceleration is ≥15 bpm over the baseline FHR for ≥15 seconds and <2 minutes.

• Before 32 weeks’ gestation, acceleration is ≥10 beats over the baseline FHR for ≥10 seconds.

Prolonged accelerations are ≥2 minutes but ≤10 minutes.

Question 10

Deceleration

Answer 10

Transitory decrease in the FHR from the baseline.

• Early deceleration is a visually apparent gradual decrease in FHR from baseline to nadir (lowest point of the deceleration) taking more than 30 seconds. The nadir occurs at the same time as the peak of the UC. Onset, nadir, and recovery match the onset, peak, and end of the UC. It’s always periodic.
• Variable deceleration is a visually apparent abrupt decrease in the FHR from baseline to nadir taking less than 30 seconds. The decrease in FHR is greater or equal to 15 bpm and less than 2 minutes in duration. It can be periodic or intermittent.
• Late deceleration is a visually apparent gradual decrease of FHR from baseline to nadir taking more than 30 seconds. Nadir occurs at the peak of the UC. Onset, nadir, and recovery after the respective onset, peak, and end of the UC. Always periodic.
• Prolonged deceleration is a visually apparent abrupt or gradual decrease in FHR below baseline that is ≥15 bpm lasting ≥2 minutes but ≤10 minutes. It can be periodic or intermittent.

Question 11

Variation in baseline

Answer 11

Sinusoidal pattern: visually apparent smooth sine wave like undulating pattern in FHR baseline with a cycle frequency of 3-5/minutes that persists for ≥20 minutes. Benign sinusoidal patterns contain accelerations that last less than 20 minutes. A sinusoidal appearing FHR pattern can occur following maternal administration of some opioids (butorphanol and fentanyl). This undulating FHR pattern is of short duration and is also referred to as pseudosinusoidal or medication-induced sinusoidal

Question 12

Tachycardia

Answer 12

• Baseline FHR of > 160 bpm lasting 10 minutes or longer.

Question 13

Bradycardia

Answer 13

Baseline FHR of < 110 bpm lasting for 10 minutes or longer.

Question 14

Normal FHR

Answer 14

Category I (see Critical Component: Three-Tier FHR Interpretation System) reflects absence of metabolic acidemia at the time the EFM pattern is observed (AWHONN, 2015), and reflects favorable physiological response to maternal-fetal environment.

Question 15

Abnormal FHR

Answer 15

Category II and III (see Critical Component: Three-Tier FHR Interpretation System) reflects unfavorable physiological response to maternal fetal environment.

Question 16

Common Abbreviations for Electronic Fetal Monitoring

Answer 16

ED	Early deceleration
EFM	Electronic fetal monitoring
FHR	Fetal heart rate
FSE	Fetal scalp electrode
IA	Intermittent auscultation
IUPC	Intrauterine pressure catheter
LD	Late deceleration
MVU	Montevideo units
PD	Prolonged deceleration
TOCO	Tocodynamometer
VAS	Vibroacoustic stimulation
UC	Uterine contractions
US	Ultrasound
VD	Variable deceleration
VE	Vaginal examination

Question 17

Paper recorder

Answer 17

A paper recorder provides additional information on a tracing for clinician assessment, such as determining the difference between the categories in the three-tiered FHR interpretation system. This is because auscultation limits assessment data to FHR baseline, rhythm, and changes from baseline. Auscultation cannot detect certain types of decelerations and variability that can be detected by a combination of a paper recorder and ultrasound technology (part of electric monitoring).

Question 18

Recent research

Answer 18

Research evidence supports the use of structured intermittent auscultation (SIA) as a method of fetal surveillance during labor for low-risk pregnancies (Feinstein et al., 2008; Lyndon & Ali, 2015; True & Bailey, 2016). An updated position statement from ACOG supports intermittent auscultation in low risk pregnancy in labor (ACOG, 2017

Question 19

Guidelines and Procedure for Auscultation

Answer 19

1. Explain the procedure to the woman and her family.
2. Palpate the maternal abdomen to determine fetal position (Leopold’s maneuvers).
3. Place the Doppler over the area of maximum intensity of fetal heart tones, generally over the fetal back.
4. Palpate maternal radial artery to differentiate maternal heart rate from FHR.
5. Determine relationship between uterine contractions (UCs) and FHR by palpating for UCs during period of FHR auscultation.
6. Count FHR between contractions for at least 30 to 60 seconds to determine the baseline rate.
7. Determine differences between baseline FHR and fetal response to contractions by counting FHR after a UC using multiple consecutive 6- to 10-second intervals for 30 to 60 seconds (protocols may differ based on location).

Question 20

Fetoscope /doppler

Answer 20

Normal findings of SIA include normal baseline between 110 and 160 beats per minute (bpm) and regular rhythm; presence of FHR increases from baseline, and the absence of FHR decreases from baseline. To identify the baseline rate, the FHR should be auscultated and counted between contractions when the fetus is not moving for at least 30 to 60 seconds. Once the baseline is established, the FHR is then auscultated and counted while palpating maternal pulse for 15 to 60 seconds between contractions (Killion, 2015) (see Box 9–4). Successful implementation of SIA can be achieved by considering the following guidelines:

● Presence of nurses and providers experienced in auscultation and recognition of auditory changes in FHR

● Institutional policy developed to address the technique and frequency of assessment

● Clinical interventions (e.g., change to EFM) when concerning findings are present

● Nurse to laboring women ratio of 1:1

● User-friendly documentation tools for recording SIA findings

● Ready availability of auscultation devices

● Culture embracing the normalcy of childbirth and minimization of unnecessary interventions (True & Bailey, 2016)

In summary, fetoscope and Doppler obtain information differently but are both appropriate in certain auscultation clinical situations.

Question 21

Palpation of Contractions

Answer 21

● Palpation of uterine contractions is done by the nurse placing her fingertips on the fundus of the uterus and assessing the degree of tension as the contractions occur.

● The intensity of contractions is measured at the peak of the contraction and is rated as:

● Mild or 1+ feels like the tip of the nose (easily indented)

● Moderate or 2+ feels like the chin (can slightly indent)

● Strong or 3+ feels like the forehead (cannot indent uterus)

● The resting tone is measured between contractions and listed as either soft or firm uterine tone.

● Palpation is a subjective assessment and can be biased by the fat distribution on the pregnant woman’s abdomen.

Question 22

External Electronic Fetal and Uterine Monitoring

Answer 22

External electronic fetal and uterine monitoring uses an ultrasound device to detect FHR and a pressure device to assess uterine activity, which is attached to a paper recorder
● The FHR is measured via an ultrasound transducer, an external monitor.

● External EFM detects FHR baseline, variability, accelerations, and decelerations.
● External heart rate monitors receive waveforms from the fetal heart interpreted by the computer in the fetal monitor to produce audible sound and visual tracing to reflect the FHR.

● Fetal monitors average three consecutive beat-to-beat intervals and then assign the FHR
providers are instructed to take precautions against misinterpretations by verification of FHR via monitoring of maternal heart rate via palpating the maternal radial pulse and maternal pulse oximetry

Question 23

Monitoring of both fetal and maternal heart rate

Answer 23

● Today, many EFMs allow the monitoring of both the FHR and the maternal heart rate (MHR) via sensors within the tocodynamometer (TOCO), both appearing on the printout paper. MHR usually is significantly lower than the FHR and tends to increase as labor progresses and during contractions and pushing efforts.

● Location of the FHR via EFM changes in maternal position and as the fetus descends during labor, especially in the second stage (AWHONN, 2015; Lyndon et al., 2015).

● Erratic FHR recordings or gaps on a paper recorder may be caused by inadequate conduction of ultrasound signal, displacement of the transducer (may be picking up maternal heart rate), fetal or maternal movement, inadequate ultrasound gel, or fetal arrhythmia (may need to auscultate to verify).

Question 24

Measuring contractions

Answer 24

● Contractions are measured via TOCO, also an external uterine monitor.

● The relative frequency and duration of uterine contractions (UCs) and relative resting tone, which is the tone of the uterus between contractions, can be measured by this method.

● External contraction monitor, TOCO, is a strain gauge that detects skin tightness or contour changes resulting from UCs. It should be placed via palpation at the uterine fundus, during maximum uterine contraction intensity, ideally at a smooth part of the uterus where no fetal small parts are felt. Appropriate placement of the TOCO may change during labor. Also, it may be more difficult to monitor tightening of the skin with increased fat distribution around the maternal abdomen.

● External uterine monitors cannot measure pressure/intensity of contractions.

● Pressure/intensity of the contraction must be estimated by palpation of contractions.

● Contractions not recording on a paper recorder may occur when the transducer is placed away from strongest area of contraction or when resting tone is not dialed to 10 to 20 mm Hg when the uterus is relaxed.

Question 25

Internal Electronic Fetal and Uterine Monitoring

Answer 25

Internal electronic fetal monitoring uses a fetal scalp electrode (FSE)/internal scalp electrode applied to the presenting part of the fetus to directly detect FHR. Internal electronic uterine monitoring involves an intrauterine pressure catheter (IUPC) placed in the uterine cavity to directly measure uterine contractions (Fig. 9–3 and Box 9–6). Membranes must be ruptured for both methods (AWHONN, 2015).
The decisions to insert an FSE are based on the need for continuous FHR tracing when troubleshooting methods do not alter quality of tracing. A nurse or care provider certified to attach this should be aware of relative contraindications to direct methods of monitoring. These include chorioamnionitis, active maternal genital herpes, HIV, positive group B streptococcus testing (Coviden, 2012), and conditions that preclude vaginal exams (e.g., placenta previa and undiagnosed vaginal bleeding.
The contraction and resting tone intensity is a combination of pressure from myometrial muscle contraction and intrauterine hydrostatic pressure (pressure exerted from amniotic fluid above the catheter). Therefore, positioning of the patient-measuring IUPC pressures in left, right, supine, and lateral will prevent possible erroneous conclusions about induction or augmentation management.

Question 26

Guidelines for Placement of an External Electronic Fetal Monitor

Answer 26

Explain the procedure to the woman and her family.
For example: “The monitor records your baby’s heart rate and uterine contractions, and it tells us the baby’s response to uterine contractions. We place two monitors on your abdomen and secure them with belts. You can move around in bed and we will adjust the monitors.”

FHR
Use Leopold’s maneuvers to locate fetal back.

Apply ultrasound gel to FHR ultrasound transducer and place it on the woman’s abdomen at the location of the fetus’s back and move the transducer until clear signal and FHR is heard. Secure with monitor belt.

UCS
Place the uterine activity sensor (tocodynamometer) in the fundal area where the contraction feels strongest to palpation. Secure the monitor with a belt.

Question 27

Guidelines for Placement of an Internal Electronic Fetal Monitor

Answer 27

Explain the procedure to the woman and her family. For example: “The internal fetal scalp electrode allows us to directly monitor your baby’s heart rate. It is clipped on the baby’s scalp during a vaginal exam and the monitor is attached to your leg. You can still move around and go to the bathroom.

“The intrauterine pressure catheter tells us exactly how strong your contractions are. It is a direct measurement of the pressure of your contractions. It is placed in your uterus during a vaginal exam.”

FHR
Placement of the FSE requires skills and techniques of vaginal examination and EFM. There are risks, limitations, and contraindications, such as abnormal presentation, placenta previa, or preexisting infections such as herpes, HIV, or Group B streptococcus.

For placement of FSE, a vaginal exam is performed and the guide tube with the electrode is advanced and attached to the presenting part of the fetus. The membranes must be ruptured for placement and cervix dilated to 2 cm.
UCS
Placement of an IUPC is an invasive procedure where the nurse should have knowledge and understanding of indications and contraindications and risks of internal monitoring. For placement of the IUPC, the manufacturer directions are reviewed as there are several types of IUPC with different set-up guidelines. The IUPC and the guide tube are inserted in the vagina with a vaginal exam, and the catheter is advanced through the cervix into the amniotic cavity. The membranes must be ruptured for placement and cervix dilated to 2 cm.

Question 28

Internal Electronic Fetal and Uterine Monitoring(Fetal scalp electrode)

Answer 28

● FHR is measured via FSE.

● Internal EFM detects FHR baseline, variability, accelerations, decelerations, and limited information on some types of arrhythmias.

● It is attached to the presenting part of the fetus by the nurse or care provider.

Question 29

intrauterine pressure catheter (IUPC)

Answer 29

IUPC monitoring is initiated based on the clinical need for additional uterine activity information. It may be used when external monitoring is inadequate due to maternal obesity or lack of progress in labor when quantitative analysis of uterine activity is needed for clinical decision making. In addition, an IUPC may be inserted to treat a worsening Category II tracing (e.g., recurrent variable decelerations with nadir greater than 60 mm Hg from baseline) via amnioinfusion. IUPCs provide an objective measure of the frequency, duration, and intensity of contractions (as opposed to palpation, which is subjective) and resting tone, both expressed in mm Hg.
● Contractions are measured via IUPC.

● IUPC provides an objective measure of the pressure of contractions, expressed as mm Hg.

● IUPC monitoring can detect actual frequency, duration, and strength of UCs and resting tone in mm Hg.

● Uterine contraction intensity is measured using an IUPC = Peak pressure minus the baseline pressure in mm Hg.

● Contraction intensity varies during labor, from 30 mm Hg in early spontaneous labor to 70 mm Hg in transition to 70 to 90 mm Hg in the second stage.

● Peak pressure is the maximum uterine pressure during a contraction measured with an IUPC.

● Resting tone or baseline pressure is the uterine pressure between contractions and should be about 5 to 20 mm Hg.

● The contraction and resting tone intensity is a combination of pressure from myometrial muscle contraction as well as intrauterine hydrostatic pressure (pressure exerted from amniotic fluid above the catheter). Therefore, positioning of the patient—measuring IUPC pressures in left, right, supine, and lateral—will prevent possible erroneous conclusions about induction or augmentation management (AWHONN, 2015).

● Uterine contractions may also be quantified via Montevideo units (MVUs) measured by the peak pressure for each contraction in a 10-minute period. ACOG has recommended at least 200 MVUs every 10 minutes for 2 hours as adequate uterine contraction intensity for normal progress of labor (Cunningham et al., 2014).

● An IUPC can be used to perform an amnioinfusion.

● The IUPC is inserted by the care provider. Some institutions may have protocols for nurses to insert IUPCs; nurses need to check hospital policy on IUPC insertion.

Question 30

Telemetry

Answer 30

Telemetry is a type of continuous EFM that involves connecting the patient to a radio frequency transmitter that allows her to walk and take a bath without having to be connected to the monitor via cables. Nurses can oversee the fetal and uterine information as if the patient were connected directly to the monitor (Tucker et al., 2009). It can be used in all phases of labor.

Question 31

Monitor Paper Used for the Electronic Fetal Monitor

Answer 31

Monitor paper is used for EFM (Fig. 9–4). At a paper speed of 3 cm per minute (standard for the United States), each dark vertical line represents 1 minute and each lighter vertical line represents 10 seconds.
The FHR is recorded on the top grid of the paper in bpm while uterine contractions are recorded on the lower grid in mm Hg with IUPC and relative height for TOCO. Some EFM systems allow for maternal pulse to be recorded on the top grid of the paper. Maternal pulse can be obtained via a blood pressure cuff or pulse oximetry; some TOCOs now have sensors that can detect maternal pulse. Clinicians may need this additional information to distinguish between maternal and fetal heart rate. Both external and internal fetal monitors may inadvertently pick up maternal rate, which is especially critical if the fetus is not tolerating labor or has died

Question 32

AWHONN STANDARDS FOR FREQUENCY OF ASSESSMENT OF FHR

Answer 32

Frequency of FHR assessment is based on assessment of risk status, stage of labor, and ongoing clinical assessment

Question 33

Intermittent auscultation (IA

Answer 33

Intermittent auscultation (IA) (Box 9–7): Absent risk factors:

● Every 1 hour in latent phase

● Every 5 to 30 minutes in active and transition phases

Question 34

Intermittent EFM

Answer 34

● Intermittent EFM

● Latent and active phase of first stage for low-risk labors (Category I), need EFM for 10 to 30 minutes every 1 to 2.5 hours, with particular attention to noting baseline, variability, and accelerations and decelerations for 30 seconds before, during, and after a UC.

● Need continuous EFM during second stage

Question 35

● Continuous EFM

Answer 35

Continuous EFM

● Continuous fetal monitoring requiring external or internal monitoring became a part of routine maternal care during the 1970s.

● By 2002, 85% of live births (3.4 million out of 4 million) were monitored by continuous monitoring.

● This method of monitoring led to an increase in cesarean and instrumental (vacuum, forceps) vaginal births.

● A decrease in neonatal seizures is the sole benefit of this method of perinatal management (Alfirevic, Devane, Gyete, & Cuthbert, 2017).

● It is considered necessary if risk factors are present (Box 9–

Question 36

Monitoring with risk factors

Answer 36

● With risk factors, women should be monitored every 30 minutes during the latent phase, every 15 minutes during the active phase, and every 5 minutes during the second stage.

● Thick meconium upon rupture of membranes

● Rupture of membranes (greater than 24 hours at term)

● Maternal fever

● Vaginal bleeding in labor

● Intrauterine infection/chorioamnionitis

● Previous cesarean section

● Abnormal vital signs

● Fetal conditions (anomalies, anemia, intrauterine growth restriction, multiple gestation, breech presentation, prematurity, isoimmunization)

● Fetal intolerance of labor (as evidenced by late decelerations, variable decelerations, nadir below 60 bpm)

● Decreased fetal activity

● Maternal conditions (e.g., hypertensive disorders, diabetes, cholestasis, preexisting diseases, morbid obesity, labor dystocia)

● Use of uterine stimulants (misoprostol, dinoprostone, oxytocin)

● Epidural, other maternal analgesic interventions

● Preterm labor (less than 37 weeks)

● Post-term pregnancy (greater than 42 weeks)

● Category II or III upon admission to labor and delivery unit
● The frequency of assessment increases:

● When indeterminate Category II or abnormal Category III FHR characteristics are heard

● Before and after rupture of membranes or administration of medication

● When indeterminate or abnormal characteristics are heard, electronic FHR monitoring is used to:

● Clarify pattern interpretation.

● Assess baseline variability.

● Further assess fetal status.

It is common practice for all women to have a baseline EFM tracing of at least 20 minutes at the time they are first evaluated in labor. Routine continuous FHR monitoring remains controversial. Nurses may use a decision tree to manage fetal assessment.