Fetal HeartRatePatternsPeriodic Fetal HeartRate ChangesThree kinds of responses to uterine contractionsDeceleration: The FHR decreasesin responseto uterine contractions.Decelerations may beearly,late,variable or mixed.All except earlydecelerations are abnormalSAAM八八EAm手0nunBn儿eamnsFigure10-3,EalydoceemNoeththedceutarts and ench with the ulesaM-NHhea
Fetal Heart Rate Patterns Periodic Fetal Heart Rate Changes Three kinds of responses to uterine contractions ◼ Deceleration: The FHR decreases in response to uterine contractions. Decelerations may be early, late, variable or mixed. All except early decelerations are abnormal
Nonreactivefetal heart rate tracingPlacing an artificial larynx with 120 dB of sound onthe maternal abdomen in the vicinity of the vertex,acousticstimulation can be used to try to induce FHR-accelerationsA response of greater than 15 bpm lasting at least 15seconds can ensures the absence of fetal acidosisThe chance of acidosis occurring in the fetus who failsto respond to such stimulation is about 5o%
Nonreactive fetal heart rate tracing ◼ Placing an artificial larynx with 120 dB of sound on the maternal abdomen in the vicinity of the vertex, acoustic stimulation can be used to try to induce FHRaccelerations ◼ A response of greater than 15 bpm lasting at least 15 seconds can ensures the absence of fetal acidosis ◼ The chance of acidosis occurring in the fetus who fails to respond to such stimulation is about 50%
Late DecelerationsChange the maternal position from supine to left orright TateralGive oxygen by face mask, this can increase fetalPoz by 5 mmHgStop any oxytocic infusionInject intravenously a bolus of tocolytic drug torelieve uterine tetary.Monitor maternal blood pressureOperative delivery should be considered for fetaldistress when fetal acidosis is present or when latedecelerations are persistent in early labor and thecervix is insufficiently dilated
Late Decelerations ◼ Change the maternal position from supine to left or right lateral ◼ Give oxygen by face mask, this can increase fetal Po2 by 5 mmHg ◼ Stop any oxytocic infusion ◼ Inject intravenously a bolus of tocolytic drug to relieve uterine tetary. ◼ Monitor maternal blood pressure ◼ Operative delivery should be considered for fetal distress when fetal acidosis is present or when late decelerations are persistent in early labor and the cervix is insufficiently dilated
Fetal Tachycardia心动过速Prolonged periods of tachycardia areusually associated with elevatedmaternal temperature or an intrauterineinfection, which should be ruled out. Theacid-base status is usually normalIn general, fetal tachycardia occurs toimprove placental circulation when thefetus is stressed
Fetal Tachycardia心动过速 ◼ Prolonged periods of tachycardia are usually associated with elevated maternal temperature or an intrauterine infection, which should be ruled out. The acid-base status is usually normal ◼ In general, fetal tachycardia occurs to improve placental circulation when the fetus is stressed
ABNORMALFETALHEARTTRACING1.Alterpositionto leftorrightside2100%0,byfacemask3Discontinueoxytocin4.Ruleoutcordprolapse5.Performfetal scalp stimulation6.ConsiderTerbutaline25mgsubcutaneouslyProlongedImprovedfetalPersistentabnormalpatternsdecelerationcondition具宝Fetal scalpbloodpHConsiderimmediateContinue monitoringdelivery(considerfetal oxygen saturationtesting-see text)pH≥7.25PH≤7.20ContinuedConsider immediatedeliverysurveillanceFigure 10-6. Algorithm for the management of an abnormal heart tracing during fetalmonitoring