Week 4 FHR Monitoring Flashcards
Uterine Activity Assessment
Frequency
Duration
Intensity
Resting Tone
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
What is normal UC contractions?
< 5 uc’s in 10 min
Tachysystole is >5 uc’s in 10 min
Characteristics of uterine contractions include
Increment
Acme
Decrement
Intensity
Duration
Frequency
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
FHR Interpretation includes what?
Baseline
- Variability
-Bradycardia
Periodic changes
- Accelerations
Early, late, and variable and prolonged decelerations
Interpretation and Management
Slowing or speeding of the FHR in response to a uterine contraction
Periodic changes
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
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
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
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
What are causes of decreased or absent variability?
Fetal sleep
Drugs
Gestation < 28-32 weeks
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
Many factors like fetal sleep or drugs may due what?
Decrease CNS activity and variability of FHR
Name drugs that may reduce variability
CNS depressants
Barbiturates
Tranquilizers
Narcotics
Mag Sulfate
Epidural Anesthesia
If decelerations are present in the FHR are, what is advised?
Internal Fetal Scalp Monitoring Electrodes
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
Once labor has begun and the cervix is dilated ….
Fetal scalp stimulation during vaginal examination gives the same result
Severe variable decels
Late decels of any magnitude
Absent variability
Prolonged deceleration
Severe bradycardia
Nonreassuring EFM Tracings
Maternal Causes of bradycardia include
Hypotension 2 supine position or anesthetics
Beta blockers
Acute event- PE, AFE, Uterine Rupture, ETC
Prolonged Hypoglycemia
Metals causes of bradycardia
Mature PSNS
Umbilical cord prolapse
Hypoxia
Hypothermia
CCHB
Cardiac structural defect
What requires assessment and interventions immediately after onset?
Bradycardia
parasympathetic system becomes more dominate late in
Gestation
Baseline of 100 in a postmature fetus would not be cause for concern
Cardiac Output is dependent on
FHR
As FHR slows, CO falls
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?
1
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
