MW II Prepared by Mrs. Raheegeh Awni. Fetal assessment during labor. Electronic fetal monitoring. ( EFM) is a useful tool for visualizing FHR pattern on a monitor screen or printed tracing. Basis for monitoring.
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MW II Prepared by Mrs. Raheegeh Awni
Electronic fetal monitoring • ( EFM) is a useful tool for visualizing FHR pattern on a monitor screen or printed tracing.
Basis for monitoring • Labor is a period of physiologic stress for the fetus, so frequent fetal monitoring of fetal status is part of the nursing care during labor. • Fetal oxygen supply must be maintained during labor to prevent fetal compromise and to promote newborn health after birth.
Basis for monitoring Fetal oxygen supply is decreased by: • Reduction of blood flow through maternal vessels, eg. Chronic hypertension, gestational hypertension, hemorrhage, epidural anesthesia and hypovolemia. • Reduction of oxygen content in maternal blood eg. Hemorrhage, and severe anemia.
Basis for monitoring • Alteration in fetal circulation, eg, pressure on umbilical cord, cord prolapse, placental separation, or complete abruption. • Head compression causes increased intracranial pressure, and vagal nerve stimulation accompanied by decreased FHR.
Basis for monitoring • Reduction in blood flow in intervillious space in the placenta secondary to uterine hypertonus, eg oxcytocin. • Secondary to deterioration in vasculature associated with maternal disorder, eg, hypertension or diabetes millitus.
Electronic fetal monitoring • Electronic fetal monitoring is associated with increased rates of surgical intervention and decreased perinatal mortality due to fetal hypoxia. ( Intrapartum electronic fetal heart rate monitoring versus intermittent auscultation. 2007 )
Basis for monitoring • Fetal well being during labor can be measured in labor by response of FHR to UCs.
Indications for Electronic Monitoring • Previous history of a stillborn (fetus dies in the uterus) • at 38 or more weeks’ gestation • ■ Presence of a complication of pregnancy • ■ Induction of labor • oxytocin [Pitocin]) • ■ Preterm labor (gestation less than 37 completed weeks)
■ Decreased fetal movement ■ Nonreassuring fetal status ■ Meconium staining of amniotic fluid (meconium has ■ Trial of labor following a previous cesarean birth
Reassuring FHR pattern • Baseline FHR in normal range of 110-160bpm, with no periodic changes and moderate baseline variability. • Acceleration with fetal movement.
Uterine activity Normal uterine activity is characterized by: • Occurs every 2-5 min. and lasting less than 90 seconds. • Moderate to strong intensity by palpation or less than 80 mmhg. • 30 seconds or more between the end of one contraction and the beginning of the next. • Average intra uterine pressure of 20 mmHg or less between contractions.
Fetal compromise • Non reassuring FHR patterns are associated with fetal hypoxemia. • Hypoxemia is a deficiency of oxygen in arterial blood. • Hypoxia is an inadequate supply of oxygen at the cellular level.
Nonreassuring FHR pattern • Progressive decrease or increase in baseline rate. • Tachycardia of more than 160bpm or more. • Progressive decrease in baseline variability.
Non reassuring FHR pattern • Sever variable decelerations FHR less than 60 bp/m lasting more than 30-60secondswith slow return to baseline or decreased variability. • Late decelerations especially repetitive and uncorrectable. • Absent or undetected FHR variability. • Prolonged deceleration more than 60-90 seconds. • Severe bradycardia.
Monitoring techniques • Intermittent auscultation uses listening to fetal heart sounds at periodic intervals to assess fetal heart rate using a Leff scope, DeeLee- Hillis fetoscope, and Doppler ultrasound.
Recommended practice AWHONN (2003). First stage • Active phase: every 30 min. Second stage: • every 15 min. • If risk factor: Active phase: every 15minutes • Second stage: every 5 minutes
Electronic fetal monitoring • Is ongoing assessment of fetal oxygenation. • FHR tracing is analyzed for hypoxic and nonhypoxic events.
Modes of electronic fetal monitoring • External mode, which uses external transducers. • Internal mode, uses spiral electrode.
External mode • Work by reflecting high frequency sound waves. • FHR is printed on specially formatted monitor paper. • The standard paper speed is 3cm/min. • Conductive jell is applied to the surface of the US transducer.
Internal monitor • Continuous internal monitoring allows accurate apprasial of fetal well being during labor. • Small spiral electrode attached to the presenting part shows a continuous FHR on fetal monitor strip.
Internal monitor • Membranes should be ruptured. • Cervix sufficiently dilated 2-3cm. • Presenting part low enough to allow placement of electrode.
Internal monitor • May be implemented without monitoring of UA. • A solid or fluid filled IUPC is introduced in to uterine cavity. • FHR and UA are displayed on monitor paper. • FHR in upper section and UA in lower section. Each small square represents 10 seconds. • Each larger box of six squares equals 1minute.
Base line FHR • Is the average rate during a 10 minute segment that exclude periodic or episodic changes, periods of marked variability, and segments of base line that differ by more than 25bpm.
Variability • Can be described as irregular fluctuations in the baseline of FHR. • It’s a characteristic of baseline FHR and doesn’t include accelerations or decelerations.
Variability • Variability in fetal heart rate was significantly and positively associated with child developmental performance during the third year of life. • Significant positive associations between fetal heart rate variability and developmental outcomes began at 28 weeks gestation for the developmental assessment scores and at 32 weeks for the language composite. Fetal Heart Rate and Variability: Stability and Prediction toDevelopmental Outcomes in Early Childhood.2oo7
Variability • Can be described as short term ( beat to beat ). • Long term variability rhythmic waves or cycles from base line. • In practice, both are viewed together.
Ranges of variability • Absent or undetected ( non reassuring) • Minimal ( greater than undetected but not more than 5pbm • Moderate variability (6-25pbm) • Greater variability ( more than 25pbm
Tachycardia • Is a baseline FHR greater than 160pbm. For a duration of 10 minutes or longer. • Considered early sign of fetal hypoxemia Causes: • Maternal or fetal infection such as amnionitis • Maternal hyperthyroidism (thyroid-stimulating • hormones may cross the placenta and stimulate FHR) • Fetal anemia • Drugs as atropin and methamphetine • Maternal dehydration
Bradycardia • Is a baseline FHR less than 110 bpm. For a duration of 10 minutes or more. • It can be considered a later sign of fetal hypoxia and is known to occur before fetal death.
Causes of fetal bradycardia • fetal hypoxia • ■ Maternal hypotension • ■ Prolonged umbilical cord compression • ■ Fetal arrhythmia • ■ Uterine hyperstimulation • ■ Abruptio placentae • ■ Uterine rupture • ■ Vagal stimulation in the second stage
Variability • Baseline variability: is a measure of the interplay (the push pull effect) between the sympathetic and parasympathetic nervous systems. There are two types of fetal heart variability. • Short-term variability (STV) is the beat-to-beat change in FHR. It represents fluctuations of the baseline.
STV can only be measured via internal (scalp electrode) means and is classified as either present or absent. • Long term variability (LTV) is the waviness or rhythmic fluctuations (called cycles) of the FHR tracing, which occur three to five times per minute
Fetal heart rate variability is defined as follows ■ Absent: amplitude undetectable ■ Minimal: amplitude greater than undetectable, and 5bpm or less ■ Moderate: amplitude 6 to 25 bpm ■ Marked: amplitude greater than 25 bpm
Changes in FHR • Changes from baseline are categorized as periodic or episodic. 1) periodic: are those that occur in relation to UCs. 2) episodic changes: are not associated with UCs.
Accelerations • A visually apparent abrupt increase in FHR above the baseline rate 15 bpm or more lasts 15 second or more. • Return occurs within less than 2 minutes from the beginning of acceleration.