fetal monitoring (unit 1) Flashcards
continuous electronic fetal monitoring (EFM)
•widely used
•sometimes controversial b/c keeps mom bedridden sec. to sec. makes hard to implement correct intervention
-slows labor
-can’t move for pain control
Intermittent FM
- listen to FHR w/ doppler at certain times
* more common at birthing centers, home, some hospitals
tocodynameter
- measures ctx
- placed on fundus
- has “button” to detect pressure
- don’t use gel
- monitor used in combo w/ FHR monitor (uses gel)
tocolysis
•stop ctx
vibroacoustic stimulator
- vibration device strapped on mom
* stimulates baby to make sure has adequate reactivity
maternal fetal unit
- mom
- uterus
- placenta
- cord
- fetus
placenta
•connects to uterus and surrounds baby
•no blood exchanged b/t placenta and uterus
-exchange of O2 and nut. occurs in lacunae b/t placental-utero junction
*mom and fetal blood NEVER mixes (ideally)
umbilical cord
- connects placenta to fetus
* fetal supply of oxygen and nutrients
good fetal O2 depends on…
- normal maternal blood flow and volume to placenta
- normal O2 sat. of maternal blood
- functional placenta
- functional umbilical cord
- normal fetal circulation
what can happen to interrupt O2 to fetus
- changes in maternal circulating volume
- uterine activity
- placental/umbilical cord problems/compression
- abnormal fetal conditions
what causes changes in maternal circulation volume
- hypotension
- vena cava syndrome
- drop in maternal O2
cervical os
•opening into vagina
what causes hypotension in preggo
- blood loss
* dehydration (esp. morning sickness)
vena cava syndrome
•vena cava compressed when lying supine
•causes hypotensive episode
•avoided by keeping on side or prevent from completely supine
-L side most cardio-restive
diabetes and placenta
•uterus is peripheral vascular site, so poor perfusion would lead to inadequate blood flow at placenta-utero junction
nuchal cord
- umbilical cord wrapped around the neck
- more complications w/ multiple wrappings
- termed “nuchal times ___”
how often EFM monitoring during labor?
- < 4 cm- every 30 min
- 4-10 cm- every 15 min
- pushing- every 15 min
- 2nd stage of labor- every 5 min
blood flow to fetus during labor
•decreased b/c as uterus contracts, the placenta is compressed, decreasing blood flow
assessing uterine contraction
- palpate fundus to assess frequency, duration, and intensity
- can also use external or internal monitoring
fundus
- top portion of uterus
* opposite of cervix
frequency of uterine ctx
•beginning of one ctx to beginning of next
•given in rage (compare 2 counts)
•each block represents 10 sec.
-measured in minutes
duration uterine ctx
- time b/t beginning of ctx to the end of that same ctx
* measured in seconds
intensity uterine ctx
•strength of ctx at its peak
•mild, moderate, strong
•can ONLY be monitored w/ internal monitor
-if using external monitor have to palpate fundus
*tip of nose: mild
*chin: moderate
*forehead: strong
resting tone of uterine ctx
•tone of uterine muscle b/t ctx (not having ctx)
•lowest point on monitors is resting
-peak IUP is highest point
ctx greater than 90 sec or more than 5 ctx in 10 min period causes…
- insufficient time for uterine relx (less than 30 sec)
- reduces blood flow to placenta
- can cause fetal hypoxia and decreased FHR
fetal heart rate (FHR)
- normal: 110-160
- observe b/t ctx
- have to look at 10 min block to determine rate
common causes of fetal tachycardia
- maternal fever (infection in amniotic fluid)
- anxiety/fear/pain
- dehydration
- medications
common causes of fetal bradycardia
•maternal hypotension •medications (sedatives) -fld bolus prior to epidural admin to prevent hypotension •cord compression •utero-placental insufficiency (UPI)
FHR variability
- fluctuations in FHR
- broad minute to minute, so have to look at 10 min block
- find diff. b/t lowest and highest point for each minute
decreased/minimal variability
•0-5 bpm
average (WNL) variability
•6-25 bpm
marked/saltatory variability
• > 25 bpm
accelerated FHR
•usually brief, temporary
•reassuring sign indicating responsive, non-acidotic fetus
•occurs w/ fetal movement
•size, freq, occurrence increase w/ gestational age
*peaks on EFM
++ acceleration
- 15x15 sec
* up more than 15 bpm and lasted more than 15 seconds
+ acceleration
•acc. < 15 sec
0 acceleration
•none
early deceleration FHR
- cause by fetal head compression or vagal stimulation
- curved shape (mirror of ctx)
- onset at beginning of ctx (head squeezing)
- FHR returns to baseline at end of ctx
early deceleration clinical pattern
- active phase of labor (4-7 cm)
- common w/ cephalopelvic disproportion (CPD)-rare
- no tx
variable deceleration FHR
- caused by umbilical cord compression
- occurs in 50% of labors
- usually during 2nd stage (pushing)
- duration and depth vary
- abrupt onset
- FHR usually returns rapidly
variable deceleration clinical pattern
•U/V/W shape (non uniform) -QUICK drop and quick return •occurs at any time (esp. w/ ctx) •may lead to acidosis •tx: vag exam to r/o cord prolapse (comes out before baby)
variable deceleration tx
•vag exam to r/o cord prolapse -emergency- push baby head up to relieve pressure to/in OR •if no prolapse, reposition mom •O2 @ 40% w/ mask •stop Pitocin
late deceleration FHR
•caused by utero-placental insufficiency (UPI)
•consistent shape from one decal to next (repetitive)
•occurs 20-30 sec after ctx begins
•ends after ctx ends
•gradual return of FHR to baseline
*looks like early deceleration, so timing is key (base of dec. and peak of ctx don’t meet)
late deceleration FHR clinical pattern
- often seen w/ loss of variability
* due to fetal hypoxia, so uncorrected will lead to fetal acidosis
late deceleration FHR tx
- turn mom to left side
- correct hypotension w/ IVF bolus
- stop/decrease Pitocin
- stop ctx w/ tocolytic drugs (Brethine)
- O2 at 40% w/ mask
fetal scalp electrode (FSE)
- internal fetal monitor placed directly on baby’s head
- amniotic sack must be broken
- avoid in HIV+ mom or preterm infant
intrauterine pressure catheter
- internal fetal monitor that is placed on fetal head
- detects changes in pressure on uterus
- requires membrane to be ruptured and cervix to be sufficiently dilated
- used w/ induction/augmentation of labor b/c monitors for hyper stimulating of uterus
Leopold’s Maneuvers
- performing external palpations of uterus thru abdominal wall
- used to determine presentation and position of fetus
- purpose is to locate best area to hear FHTs
fetal heart tones (FHT)
- optimal at fetal PMI
- auscultated loudest on mom’s abdomen
- best heard directly over fetal back
fetal PMI in vertex presentation
•right or left lower quad. below maternal umbilicus
fetal PMI in breech presentation
•right or left upper quad. above maternal umbilicus
episodic vs. spontaneous deceleration
- episodic occurs w/ ctx- early and late
* spontaneous occurs at any time- variable
why does’t late deceleration occur after ctx begins
- msg to heart to slow down b/c not getting enough O2
* diff. than early b/c early caused by immediate vagal response, not b/c of O2 lack
early/late deceleration extra
•always have a pattern and connected w/ ctx
•early dec. base lines w/ peak of ctx
•late dec. base doesn’t line w/ peak of ctx
*if don’t line up, ALWAYS late
fetal bradycardia
•worst clinical situation for fetus •caused by -viral infection -maternal hypothermia -drugs
category I tracing
- normal
- FHR 110-160
- moderate variability
- may or may not accelerate
- early decelerations maybe
- no variable or late decelerations
category II tracing
- indeterminate
- Tachycardia
- bradycardia w/o absent variability
- minimal variability
- absent variability without recurrent decelerations
- marked variability
- absence of accelerations after stimulation
- recurrent variable decel. w/ min/mod variability
- prolonged deceleration > 2min but < 10 min
- recurrent late decelerations w/ moderate variability
category III tracing
- abnormal
- sinusoidal pattern OR
- absent variability w/ recurrent late or variable decelerations and/or bradycardia
