fetal monitoring for undergraduate
DESCRIPTION
Undergraduate course lectures in PB&GYNE prepared by Dr Manal Behery ,Professor of OB&GYNE .Faculty of medicine ,Zagazig UniversityTRANSCRIPT
INTRAPARTUM FETAL MONITORING
Dr Manal Behery Professor OB&GYNE
2014
Methods available for fetal monitering in labor
Intermittent auscultation
CTG Fetal electrocardiography Scalp stimulation
Vibroacoustic stimulation
Fetal scalp sampling PH determination
Fetal pulse oximetry
Types of Intermittent Monitors
Intermittent Auscultation
The three unique risk factors for fetus during labor
Factor of uterine contraction
Factor of cord accident
Factor of head compression
Factor of uterine contraction
Oxy –Hb 0.19 micromol/100Gm of brain Cerebral O2 saturation 9%• In spite of this slightly worrying picture, Nothing
harmful effect happen if fetus is healthylabor contraction are normalPlacenta has adequate reserve
Factor of head compression
Some degree of compression is inevitable during normal labor But
Excessive compression over long period causing supermoulding as in obstructed labor may cause fetal hypoxia
Factor of cord accident
Only during labor cord prolapse ,presentation and entanglements become apparent either by compression or stretch secondary to uterine contraction
Aim of intrapertum fetal monitering
1- to detect the earliest stages of hypoxia so
therapy can be directed to prevent asphyxia and asphyxial damage( e.g Cerebral palsy)
2-To Improve perinatal morbidity & mortality
What is Cardiotocography(CTG)?
It is a paper record of the continuous FHR blotted simultaneously with a record of uterine activity
Ultrasound (cardio) transducer
Tocotransducer
CTG records
Non stress test without uterine contractionStress test
in correlation to uterine contraction
External monitoring
Internal monitoring
Intrapartum Fetal monitoring CTG
FHR trace(4 components)
Base line FHR
Baseline variability
Accelerations
Decelerations
Baseline FHR
The dominant reading taken ≥10 min
Normal baseline FHR 110-160(pbm)
Controlled by atrial pacemaker
Baseline FHR
Tachycardia FHR>160 bpm
Baseline bradycardia FHR<110bpm
Baseline varibility
The Oscaltatory pattern of FHR when recorded on a graph.
Short term(beat t0 beat) is the fluctuation of HR over short interval
Long term is the fluctuation over long interval(≥2 min) Indicates mature fetal neurologic system
Baseline varibility
Short term variability (scalp electrode)
Long term variabilitydefined as 3-5 cycle/min
Baseline varibility
No variability (0-2 ครั้��ง/นาที)
Mark variability (>25 ครั้��ง/นาที)
Moderate variability (11-25 ครั้��ง/นาที)
No variability (0-2 ครั้��ง/นาที)
Moderate variability (11-25 ครั้��ง/นาที)
Minimal variability (3-4 ครั้��ง/นาที)
Accelaration
Increase in FHR with contraction or with other activities
Increase15pbm lasting 15 sec
Return to base line <2 min
Accelaration
Decelerations Decelerations
Transient slowing of FHR below The baseline level> 15 bpm
and lasting for 15 sec. or more.
Early Decelerations
Uniform
Synchronous with contraction (mirror image) Rarely fall below 110 (pbm) Due to head compression
Should not be disregarded if they appear early in labor or Antenatal.
Early Decelerations
Late Deceleration
Uniform
Start after peak of contractionAssociated with decreased Variability
Reflect a baroreceptor responseIndicate fetal hypoxia
Late Deceleration
Repetitive late decelration
increases risk ofUmbilical artery acidosis
Apgar score < 7 at 5 ms
Cerebral palsy If associated with
decrease or loss ofvariability
Variable Deceleration (the most common type)
Varible in appearance and Timing.May be assoicated with increased variability .
Reflect umbilical cord compression
• Of no clinical significance if non recurrent
.
Variable Deceleration
Tyes of decleration
Prolonged Deceleration deceleration
A deceleration that lasts more than 90 seconds (but less than 10 minutes)
Drop in FHR of 30 bpm or More
Reduction in O2 transfer to placenta.
Associated with poor neonatal outcome
Prolonged Deceleration
What are the features of a normal tracing?
Baseline FHR 110-160 BPM
Baseline Variability > 5 pbm (10-25)
2 Accelerations > 15 BPM > 15 sec / 20 min trace
No decelrations
Normal -Reassuring CTG
Interpertation of CTG
Normal -Reassuring(R)- CTG with all 4 Features
Suspicious (equivocal)- one non reassuring category and reminder are reassuring
Abnormsal -Non reasurring (NR) - 2 or more non-reassuring categories or one or more abnormal categories.
Interpertation of CTG
Consider Intrapartum / antepartum trace.Stage of labourGestationFetal presentation.Any augmentationMedications
Is Normal CTGs always Reassuring?
With normal CTC the chance of fetus to develop hypoxia is 1.5% due to unpredictable acute events
So a normal CTG is always Reassuring
Is NR CTGs always worrisome ?
60% CTG in Labour have 1 abnormal feature
Only 15-20% of NR CTGs are pathological.
High false positive rate with unnecessary operative intervention for fetal distress.
Thus NR CTG is not always worrisome.
?? To reduce CS….
Consider these factors with abnormal CTG
Maturity of the fetus Reduced variability and baseline tachycardia is
conmen in preterm
State of maternal pulseDrugs may cause maternal and fetal tachycaedia
Check blood pressure for hypotension in patients on epidural.
Consider these factors with abnormal CTG
Posture of patient during CTGo Supine position give abnormal tracing o Some cord compression can get released by
change posture and must be tried with variable deceleration
Congenital fetal malformation Color Doppler of fetal heart to exclude congenital
heart block
Correct reversible causes
Change mother position from supine to left lateral position-----increase uterine blood flow
Improve maternal oxygenation—100% O2 by masK
Correct maternal hypotension –IV fluid
Decrease or stop any oxytocin infusion
Remove vaginal prostaglandins
Secondary tests of fetal well-being
Vibro-acoustic stimulation
Used as a substitute for scalp sampling when CTG –is NR
Normal ----------if FHR acceleration > 15 bpm for 15 seconds within 15 seconds after the stimulation with prolonged fetal movements.
Abnormal ----Only 50% have acidotic PH
Fetal blood sampling
If the pH >7.25 --- observe. If the pH 7.2 and 7.25---repeated within 30 minutes.
If the pH <7.2----repeat immediately
If pH still low -- Prompt delivery
Scalp stimulation. Firm digital pressure
Gentile pinch by atramatic Allis forceps
Fetal pulse oximetry.
THANK YOU