Week 4 FHR Monitoring Flashcards by Steven Singh

Uterine Activity Assessment

Frequency
Duration
Intensity
Resting Tone

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Number of contractions in a 10 minute window averaged over 30 min

Uterine Contractions

Count from beginning of one UC or until the beginning of the next UC

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What is normal UC contractions?

< 5 uc’s in 10 min

Tachysystole is >5 uc’s in 10 min

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Characteristics of uterine contractions include

Increment
Acme
Decrement
Intensity
Duration
Frequency

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NST have accelerations of

15 bpm lasting 15 seconds with each FM
Top shows FHR and bottom shows Uterine activity

Note FHR increase at least 15 beats and remains at least 15 seconds before returning to the former baseline

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FHR Interpretation includes what?

Baseline
- Variability
-Bradycardia
Periodic changes
- Accelerations
Early, late, and variable and prolonged decelerations
Interpretation and Management

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Slowing or speeding of the FHR in response to a uterine contraction

Periodic changes

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110-160 BPM is what?

FHR Baseline

Approximate mean is FHR rounded to 5 BPM increments
- Over 10 min(min 2 min)
- Between UC’s, decels and accels

Highest early in gestation
- BL progressively lowers as PSNS matures
- PSNS dominates SNS at term

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Fluctuations or variations in baseline FHR
- Absent- Undetectable
- Minimal- <5BPM
- Moderate-6-25 BPM
- Marked->25BPM

Presence reflects an intact, oxygenated CNS
- Due to opposing effects of PSNS and SNS

Variability

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How can variability be viewed?

Over a minute externally with at least 2 fluctuating sine waves of peaks and troughs

Also measured internally with a fetal scalp electrode to detect FHR changes from one R wave to the next and is recorded

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The PSNS and SNS are pushing and pulling to the fine tune the FHR from beat to beat based on what?

fetus oxygenation needs at the moment

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What are causes of decreased or absent variability?

Fetal sleep
Drugs
Gestation < 28-32 weeks

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May be no apparent cause and may be benign

Nonreassuring if late or variable decels also present

Possible warning sign of chronic hypoxia or fetal acidosis
Place internal monitor to confirm if possible
Consider prompt delivery

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Many factors like fetal sleep or drugs may due what?

Decrease CNS activity and variability of FHR

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Name drugs that may reduce variability

CNS depressants
Barbiturates
Tranquilizers
Narcotics
Mag Sulfate
Epidural Anesthesia

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If decelerations are present in the FHR are, what is advised?

Internal Fetal Scalp Monitoring Electrodes

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Name types of Fetal Stimulation

Acoustic fetal stimulation
- Handheld buzzer or other noisemakers
close to the abdomen, as well as maternal ice chewing, are effective methods prior to labor or with closed cervix

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Once labor has begun and the cervix is dilated ….

Fetal scalp stimulation during vaginal examination gives the same result

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Severe variable decels
Late decels of any magnitude
Absent variability
Prolonged deceleration
Severe bradycardia

Nonreassuring EFM Tracings

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Maternal Causes of bradycardia include

Hypotension 2 supine position or anesthetics
Beta blockers
Acute event- PE, AFE, Uterine Rupture, ETC
Prolonged Hypoglycemia

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Metals causes of bradycardia

Mature PSNS
Umbilical cord prolapse
Hypoxia
Hypothermia
CCHB
Cardiac structural defect

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What requires assessment and interventions immediately after onset?

Bradycardia

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parasympathetic system becomes more dominate late in

Gestation

Baseline of 100 in a postmature fetus would not be cause for concern

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Cardiac Output is dependent on

FHR

As FHR slows, CO falls

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Indicates fetus may be severely compromised, especially if accompanied by decels Immediate delivery indicated if interventions ineffective

Nonreassuring

Causes of maternal tachycardia

-Fever/ infection - Hyperthyroidism - Drug response - Anemia

Fetal causes of tachycardia

- Infection - Anemia - Hypoxia - Tachyarrhythmia - Cardiac Anomaly

This occurs with loss of variability and late or severe variable decels

Nonreassuring

Identified after min of 2 minutes, but technically not official as a baseline reading until at least 10 minutes

Tachycardia Cause must be investigated and it is always abnormal

What is suspected of first causes of tachycardia?

Maternal or fetal infection

Every degree of maternal temp., what happens to FHR?

Rises 10 BPM

Medications both legal and illegal producing tachycardia in maternal and fetal include?

Terbutaline Albuterol Stimulants Decongestants Cocaine

Tachycardia may be response to______________ release due to maternal or fetal stress

Catecholamine

As sympathetic NS begins to dominate, variability may what?

Decrease due to less parasympathetic tone

What is Nonreassuring?

Tachycardia with decelerations or loss of variability May indicate hypoxia or acidosis Once find cause= Tx

Increase in fetal HR lasting>15 secs and rising >15 beats over the baseline

Accelerations

Accelerations may be less if what?

Gestational age < 32 weeks (10x10 rule)

How many accelerations should one see in 30 minute?

What are nursing actions if less than 1 accelerations?

o2, hydrate, position change

Presence of 2 accelerations in 20 minutes at least 15 bpm above the baseline and lasting at 15 seconds if >32 weeks of gestation or at least 10 BPM above the baseline and lasting at least 10 sec. if <32 weeks meet criteria for nonreactive stress test

Accelerations

Visually apparent decrease in FHR

Decelerations

Gradual onset >30 seconds from onset to nadir, nadir simultaneously with peak of uc

Early

Gradual onset >30 sec. from onset to nadir, delayed in timing-nadir after peak of uc

Late

Abrupt onset <30 seconds to nadir, lasting > 15 sec. but <2min; depth >15BPM

Variable

Decreased of FHR >15 BPM lasting>2min but<10 min

Prolonged

Early deceleration shape

Waveform consistently uniform inversely mirrors contraction Onset is just prior to or early in contraction Cause is head compression

Lowest level range and ensemble of early decelerations

Consistently at or before midpoint of contraction Range is usually within normal range of 120-160 BPM Ensemble can be single or repetitive

Shape and onset for late deceleration

Waveform is uniform shape; shape reflects contraction Onset is late Late deceleration- Uteroplacental Insufficiency

Lowest level, range, and ensemble of late decelerations?

Consistently after the midpoint of the contraction Usually within normal range of 120-130 BPM/min Occasional, consistent, gradually increase- repetitive

Shape and onset of variable deceleration

Waveform variable, generally sharp drops and returns Abrupt with fetal insult; not related to contraction

Lowest level, range, and ensemble for variable decelerations`

Variable around midpoint Not usually within normal range Variable- single or repetitive

Start when the contraction begins, ends when the contraction ends May indicate head compression Check for impending delivery If not read: -position change-O2-IV hydration

Early Decelerations

Starts at the peak of contractions after the contraction is over Caused by Uteroplacental insufficiency - Aged or damaged placenta - Maternal position ( Supine hypotension or vena cava syndrome) - Inadequate maternal blood flow (IE: hypotension from epidural anesthesia, shock, blood loss, etc)

Late Decelerations

Gradual decrease in FHR related to the time it takes for intervillous blood to reach the fetal heart and brain in the presence of a contraction

Late Deceleration

What are some interventions to improve fetal oxygenation and placental perfusion?

Position change for optimal UBF - Lateral - Knee to chest 100% O2 by mask 8-10 l/min Stop Pitocin IV fluid bolus Assess BP Vaginal Exam Inform MD/ Midwife

Variable Decelerations are reassuring if

Duration < 60 sec. Rapid return to BL Normal BL rate and variability Presence of accels

Nonreassuring variable decelerations if

Loss of variability Tachycardia or bradycardia Slow return to BL Deepening to <70 BPM Prolonged >60 sec Overshoots

Over time if variable persist and progress in depth and width, watch for

presence of accels and variability for reassuring status

__________________ is main indicator of fetal response to the decel.

Variability

Tachycardia and loss of variability with variables are correlated with

Fetal Acidosis

Interventions to improve or correct variable decels

Reposition pt- side to side or hands and knees Perform vaginal exam to r/o cord prolapse IV bolus Oxygen by 10L/ min by mask

Defined as decrease in the BL for>2minutes and <10 minutes from onset to return

Prolonged deceleration - deceleration for longer than 10 minutes is change in baseline

What are some reassuring and Nonreassuring EFM tracings ?

Reassuring - Normal baseline - Accelerations with fetal movement - Present short term variability - 3-5 cycles of long term variability per minute - Early decels may be present

Considered normal category and no need for concern

Category 1

Some abnormal components, requires close observation, some intervention may be required; provider notification and/or presence

Category II

FHR indicates fetal distress requiring immediate intervention and delivery

Category III

What testing is included in antepartum?

Biophysical profile NST CST

Score of 8-10 is normal in biophysical profile if

AFI is adequate Equivocal is 6 Abnormal is less than 4

Biophysical profile variables include ?

Fetal breathing Movements Grossbody Movements Fetal Tone Reactive NST Amniotic Fluid Index Planes

Biophysical normal includes ?

1 movement in 30 min 3 limb or body moves in 30 min 1 or more slow or extensions/ flexions episodes (active) 2 accels. 15x15 1 or more pockets More than 1 cm of fluid in 2 perpendicular planes

Abnormal in biophysical profile includes?

No moves lasting 30 sec. Less than 3 in 30 min No ext/ flex Non reactive NST Less than 1 cm fluid in 2