NRS 3016 Chapter 14 Intrapartum Fetal Surveillance

fetal oxygenation facotrs

1. sufficient maternal BF and volume to the placenta

2. normal maternal oxygen saturation

3. adequate exchange of O2 and CO2

4. open circulatory path from placenta to fetus through umbilical cord vessels

5. normal fetal circulatory and OCC

fetal oxygenation alterations: maternal cardiopulmonary

maternal hemorrhage leads to maternal hypotension

supine hypotension (compression of vena cava and aorta)

maternal HTN d/t gestational HTN

lowered oxygen level in mother’s blood (ex: anemia)

fetal oxygenation alterations: uterine activity

placental disruptions (hypertonic contractions, abuptio placentae)

fetal oxygenation alterations: fetal alterations that interrupts BF to umbilical cord

Nuchal cord → around fetal neck or entangled in fetal body parts

knot in umbilical cord

oligohydraminos → lower than normal amounts of amniotic fluid volume

inadequate Wharton’s jelly → cushions umbilical cord (decrease wharton jelly = cut off supply compression of cord)

EFM instrumentation

intermittent auscultation and transducers

uterine activity via tocodynamometer (toco)

external fetal HR obtained via doppler or US

bedside fetal monitoring and transducers: benefits

non-invasive

used during antepartum and intrapartum period (not really for labor)

used with telemetry

no known risks to woman or fetus

continuous recording of FHR and UA (uterine activity)

bedside fetal monitoring and transducers: limitation

limits maternal mobility

frequent repositioning for readable/accurate tracing

may double-count a slow FHR <60bpm or half-count a FHR >180bpm

may record maternal HR if placed over maternal arterial vessel (aorta)

unable to assess intensity of UA

difficult to monitor on obese women and preterm or multifetal gestations

external monitors for FHR/contractions

ultrasound transducer → FHR

tocotransducer (toco) → contraction pattern

internal monitors for FHR/contractions

internal scalp lead (ISL) → FHR by screwing into baby’s head

internal uterine pressure catheter (IUPC): contraction pattern

• sterile, flexible catheter that sits between wall of uterus and baby’s head, pressure measured during contraction when everything is squeezes (mmHg)

fetal scalp electrodes (FSE)

internal fetal monitoring: requires cervical dilation and ruptured membranes to directly apply electrodes to fetal presenting part (head or buttt)

internal fetal monitoring benefits

FSR: accurate fetal cardia arrhythmias & FHRs between 30-240bpm, maternal position changes does not affect reading

IUPC: only true accurate measure of UA, allows to use of amnioinfusion (give fluid back thru IUPC if cord is compressed too much)

internal fetal monitoring limitations: FSE & IUCP

FSE: vaginal lacerations, presenting part must be accessible, may record maternal HR in presence of fetal demise, fetal hair can cause inadequate ECG conduction

IUCP: uterine perforation, placental abruption, maternal position change can cause hydrostatic pressure, variations in IUPC types

Both: requires ruptured membranes, cervix must be dilated sufficiently, increased infection risk

fetal monitoring tracing

each tracing has an x & y-axis with an upper and lower graph depicting FHR and contraction pattern

uterine activity: frequency

onset of one contraction to onset of the next contraction (minutes)

uterine activity: duration

onset of one contraction to the end of another contraction (seconds)

uterine activity: intensity-strength

palpation-mild, moderate, or strong, quantitative numbers

• in the form of mmHg used only with IUPC

  • strength is ONLY measured internally or subjectively

uterine activity: resting tone

soft or relaxed when not contracting

contraction variability means

well oxygenated

FHR interpretations

baseline FHR

• normal = 110-160bpm

• bradycardia <110bpm

• tachycardia >160bpm

ideally: baseline FHR is over a 10min period of time

FHR = balance between fetus parasympathetic and sympathetic NS

FHR variability

fluctuations in the baseline FHR that irregular in amplitude and frequency

it evaluates fetal ANS, indicates fetal oxygenation, & most reliable for fetal well-being

variability classifications: absent

amplitude visually undetectable

variability classifications: minimal

amplitude range visually detectable but 5bpm or less (sleeping, relaxing drug)

• if occurs for longer than 30mins, try to wake baby

  

variability classifications: moderate

amplitude range 6-25bpm (normal)

variability classifications: marked

amplitude range >25bpm (big M)

variability classifications: sinusoidal pattern

smooth wave-like (S) appearance, rare but indicates severe fetal compromise

potential variability changes

fetal: sleep cycle (20-30mins), anemia, tachycardia, sepsis, metabolic acidosis from ongoing hypoxic injury

maternal: drug ingestion (narcotics, CNS depressants, Mg sulfate, barbiturates, tranquilizers), general anesthesia, infection

FHR interpretation: periodic

associated with uterine contractions

FHR interpretation: episodic

not associated with uterine contractions

accelerations are what FHR pattern

periodic or episodic (w/ or w/o contraction)

early head compression is what deceleration FHR pattern

periodic (w/ contraction)

late uteroplacental insufficiency is what deceleration FHR pattern

periodic (w/ contraction)

variable cord compression is what deceleration FHR pattern

periodic or episodic (w/ or w/o contraction)

prolonged deceleration is what deceleration FHR pattern

periodic or episodic (w/ or w/o contraction)

FHR accelerations

normally occur in response to fetal movement, vaginal exams, or contractions

definition: increase baseline of HR (15 beats for 15s)

indicates fetal well-being (sympathetic fetal response) & reassuring sign

early decelerations

1. fetal head compression: symmetric in shape, gradual decrease, return to FHR baseline that mirrors the uterine contractions, vagal response during head compression, benign & not associated with interruption of fetal oxygenation

2. RN: monitor progress

   

late decelerations

BAD, placental issues

visually apparent, usually symmetric in shape

gradual decrease and return of FHR baseline

drop in FHR begin after the peak of contraction

FHR returns to baseline after the contraction ends

similar to early deceleration but are shifted to the right

late deceleration

appears before loss of variability therefore indicates transient fetal hypoxia state (maternal hypotension)

one ‘late deceleration’ is a priority intervention by changing pt position

concerning: recurrent (fecurrent) when late deceleration occurs with 50% or more uterine contractions over 20 minutes

• associated with tachycardia and loss of variability therefore severe fetal hypoxia

• IMMEDIATE delivery

  

variable deceleration

caused by interruption of oxygenation at umbilical cord d/t compression

visually apparent, abrupt decreases from onset of a deceleration

most frequent type of deceleration during first-second stage of labor

RN: change maternal position

prolonged deceleration

decrease in FHR that lasts a minimum of 2-10min

reflects interruption of oxygen transfer from environment to fetus at one or more points

RN: give fluids, more than 10mins = get baby out

most common 3 deceleration patterns mneumonic

VEAL CHOP

variable → cord → reposition

early → head → okay

acceleration → ox → okay

late → placenta → not good

3 tier FHR interpretation

category I: normal fetal acid-base status

category II: indeterminate fetal acid-base uncertain (some interventions)

category III: abnormal fetal acid status (bad)

category I: normal FHR tracing

baseline FHR: 110-160bpm

variability moderate

accelerations/early decelerations absent or present

late & variable decelerations absent

category II: indeterminate FHR tracing

bradycardia w/o absent variability

tachycardia

minimal variability

absence of induced acceleration after fetal stimulation

prolonged decelerations

recurrent late decelerations with moderate variability

category III abnormal FHR tracings

absent variability

recurrent late or variable decelerations

bradycardia

sinusoidal pattern

cannot continue to labor → get to OR

how to improve placental BF and fetal oxygen supply mneumonic

P→ change position

O → administer O2 with non-rebreather

I → increase rate of IV fluids

S → perform sterile vaginal exam-prolapsed cord

O → stop oxytocin (pitocin)

N → notify MD/CNM

*always document FHR category and response to intervention)

approach to FHR management mneumonic

A → assess O2 pathway and identify FHR etiology, changes of maternal/fetal

B → begin conservative measures

C → clear obstacles to delivery

D → determine delivery plan

common FHR corrective measures

maternal repositioning

IV boluses

administering oxygen

reducing UA (stop pitocin)

correct maternal hypotension

modify second stage pushing efforts (see decel with mom pushing)

assessment frequency & documentation

ongoing maternal-fetal assessment of FHR & UA

health information technology (HIT)

improve obstetric patient centered care and safety

ongoing fetal monitoring education and competency

the nurse notes a pattern of late decelerations on the fetal monitor. the most appropriate action is to:

continue observation of this reassuring pattern

notify the physician or midwife

give the mom oxygen by face mask and place pt in side lying position (left)

place the woman in a trendelenburg position

give the mom oxygen by face mask and place pt in side lying position (left)