Fetal Monitoring BasicsNUR 134

M. Johnston, RN-BC, M.Ed.

Types of MonitoringAuscultation- listen to fetal heart rate (FHR)

Electronic Fetal Monitoring – use of instruments to record FHR and uterine contractions(U/Cs)

AuscultationDoppler - ultrasound converts sounds waves to signals of

fetal heartFetoscope - Like stethoscope, open end pressed on

abdomen, used less frequently

Electronic Fetal MonitoringMeasures response of FHR to uterine contractions (U/Cs)Intermittent or ContinuousExternal

Ultrasound transducerTocotransducer

InternalFetal Scalp ElectrodeIntrauterine Pressure Catheter

Fetal Monitoring Setup

http://www.youtube.com/watch?v=DvcDXvlCXAE&feature=player_embedded

Fetal Heart Rate CharacteristicsEvaluate to determine fetal statusNICHD terminology

Baseline RateBaseline VariabilityAccelerations (present or absent)Decelerations (present or absent)Changes or trends over time

Baseline (BL)Normal range 110-160 bpmMeasure between U/Cs for 10 min. periodTachycardia - >160 bpm for >10 minutesBradycardia - <110 bpm for >10 minutes

Classifications of FHR VariabilityFluctuations in FHR, irregular in frequency and amplitude

Absent 0-2 bpmMinimal >2 <6 bpmModerate 6 -25 bpmMarked >25 bpm

AccelerationsAbrupt increase in FHR above BLPresent or Absent< 32 wks gestation

Peak ≥ 10 bpm above BL for at least 10 sec.>32 wks gestation

Peak ≥ 15 bpm above BL for at least 15 sec.

Accel ≥ 10 min. is defined as BL change

AccelerationsAbrupt increase in FHR above BLPeak ≥ 15 bpm above BL for at least 15 sec.

Types of DecelerationsEarly – Gradual decrease and return to BL, mirrors the

U/CVariable – Abrupt (<30 sec) decrease (≥15 sec down,

lasting ≥ 15 sec and <2 min from onset to return to BL)Late – Gradual decrease (≥30 sec) and gradual return to

BL; delayed timing nadir occurs after peak of U/CProlonged – Decrease in FHR below BL ≥15 sec, lasting ≥

2 min. but <10 min.

Early DecelerationGradual decrease and return to BLMirrors the U/C

Variable DecelerationAbrupt (<30 sec) decrease (≥ 15 sec down, lasting ≥

15 sec and < 2 min. from onset to return to BL)

Late DecelerationGradual decrease (≥ 30 sec) and gradual return to BLDelayed timing, nadir occurs after peak of U/C

Prolonged DecelerationDecrease in FHR below BL ≥ 15 sec, lasting ≥ 2 min.

but < 10 min.

Fetal Heart Rate Interpretation System

Category lAssociated with normal acid base

balance

Category lllPredictive of abnormal acid base

status

Normal

Indeterminate

Abnormal

FHR InterpretationInformation about fetal oxygenation/placental functionSomewhat subjectiveAbnormal patterns may need further testing

Monitoring Uterine ContractionsAssess U/C pattern while assessing FHTs

ExternalPalpationEFM Toco measures frequency, durationNoninvasive

InternalIntrauterine pressure catheter (IUPC)Measures exact intrauterine pressure Invasive

Why Monitor?FHR changes in response to oxygenation, gestation, and

certain stimuliEFM provides more objective data than auscultationInfers information about current and ongoing fetal

oxygenation

InterventionsAbnormal FHR pattern:

Change maternal positionGive oxygen via maskIncrease IV fluidsConsider medication to relax uterus

Other Fetal SurveillanceNon-Stress Test (NST) - EFMContraction Stress Test (CST) - EFMBiophysical Profile (BPP) - U/SDoppler Flow Studies/Growth - U/SFetal Movement Count-maternal sensation/palpation