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Intrapartum fetal monitoring for undergraduate

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Undergraduate course lectuers in OB&GYNE PREPARED BY dr manal behery ,faculty of medicine ,Zagazig University – PowerPoint PPT presentation

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Title: Intrapartum fetal monitoring for undergraduate


1
INTRAPARTUM FETAL MONITORING
  • DR MANAL BEHERY
  • Zagazig University, EGYPT

2
The three unique risk factors for fetus during
labor
  • Factor of uterine contraction
  • Factor of cord accident
  • Factor of head compression

3
Factor of uterine contraction
  • Let us see what happen to oxygenation and blood
    supply of the fetal brain during a uterine
    contraction?

4
  • De-oxy-Hb 0.79micromol/100Gm of brain
  • Oxy Hb 0.19 micromol/100Gm of brain
  • CerebralO2 saturation 9
  • Cerebral blood volume 0.33 ml/100Gm of
  • In spite of this slightly worrying picture,
  • Nothing harmful effect happen if
  • fetus is healthy
  • labor contraction are normal
  • Placenta has adequate reserve



5
Fetal distress, birth asphxia are likely to
occur if
  • The fetus is already compromised
    antenatally---even with normal uterine
    contraction
  • The uterine contraction are exaggerated------even
    with healthy fetus and adequate placental reserve

6
Factor of cord accident
  • Only during labor cord prolapse ,presentation
    and entanglements become apparent either by
    compression or stretch secondary to uterine
    contraction

7
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

8
Methods available for fetal monitering in
labor
  • Intermittent auscultation
  • CTG Fetal electrocardiography
  • Scalp stimulation
  • Vibroacoustic stimulation
  • Fetal scalp sampling ? PH determination
  • Fetal pulse oximetry

9
Important definations
  • Hypoxia Decreased po2 level in tissues.
  • Hypoxima Decreased po2 level in blood.
  • Acidosis Decreased PH in tissues.
  • Acidemia Decreased PH in blood.
  • Ashyxia Hypoxia with metabolic acidosis.

10
Aim of intrapertum fetal monitering
  • 1- to detect the earliest stages of hypoxia or
    even (hypoxic acidemia ) so therapy can be
    directed to prevent asphyxia and asphyxial
    damage( e.g Cerebral palsy)
  • 2-To Improve perinatal morbidity mortality

11
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

12
External monitoring
  • Doppler ultrasound transducer
  • FHR
  • Tocotransducer(contraction)

13
Internal monitoring
14
What is Admission test ?
  • Ideally every fetus every fetus should be
    screened by CTG for a short period (20 min) right
    on admission in labor.
  • From nature of the trace determine
  • Intensity of monitoring Whether the case should
    be monitored clinically or by CTG
  • Duration and frequency of monitoring Whether the
    case should be covered by CTG continuously or
    intermittently

15
Interpreting FHR trace
  • 4 components
  • Base line FHR
  • Baseline variability
  • Accelerations
  • Decelerations

16
Baseline FHR
  • The dominant reading taken 10 min
  • Normal baseline FHR 110-160(pbm)
  • Controlled by
  • atrial
  • pacemaker

17
Tachycardia FHRgt160 bpm
18
Baseline bradycardia FHRlt110bpm
19
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

20
Baseline varibility
  • Short term variability
  • (scalp electrode)
  • Long term variability
  • defined as 3-5 cycle/min

21
Baseline varibility
22
No variability (0-2 ?????/????)
No variability (0-2 ?????/????)
Minimal variability (3-4 ?????/????)
Moderate variability (11-25 ?????/????)
Moderate variability (11-25 ?????/????)
Mark variability (gt25 ?????/????)
23
Changes in fetal HR
  • Peroidic changes Occur with contraction
  • Episodic changes (non peroidic)do not occur with
    contraction

24
Accelaration
  • Increase in FHR with contraction or with other
    activities
  • Can be periodic or episodic
  • Increase15pbm
  • lasting 15 sec
  • Return to base line lt2 min

25
Accelaration
26
Decelerations Decelerations
  • Transient slowing of
  • FHR below the
  • baseline level
  • more than 15 bpm
  • and lasting for 15 sec.
  • or more.

27
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.

28
Early Decelerations
29
Late Deceleration
  • Uniform
  • Start after peak of contraction
  • Associated with decreased
  • Variability
  • Reflect a baroreceptor
  • response
  • Indicate fetal hypoxia

30
Late Deceleration
31
Repetitive late decelration
  • increases risk of
  • Umbilical artery acidosis
  • Apgar score lt 7 at 5 ms
  • Cerebral palsy
  • If associated with
  • decrease or loss of
  • variability

32
Variable Deceleration (the most common type)
  • Varible in appearance and Timing.
  • May be assoicated with
  • increased variability .
  • Reflect umbilical cord compres
  • Observed in up to 50 of NSTs compression
  • Of no clinical significance
  • if non recurrent
  • .

33
Variable Deceleration
34
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

35
Prolonged Deceleration
36
Sinusoidal pattern
  • Regular Oscillation of the Baseline long-term
    Variability resembling a Sine wave ,with no beat
    to -beat Variability.
  • Has fixed cycle of 3-5 pbm with amplitude of
    5-15 bpm and above but not below the baseline.
  • Should be viewed with suspicion as poor
    outcome has been seen (eg Feto-maternal
    haemorrhage)

37
Sinusoidal pattern
38
What are the features of a normal tracing?
  • Baseline FHR 110-160 BPM
  • Baseline Variability gt 5 pbm (10-25)
  • 2 Accelerations gt 15 BPM gt 15 sec / 20 min trace
  • No decelrations

39
Normal -Reassuring CTG
40
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.

41
Interpertation of CTG
42
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

43
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.

44
?? To reduce CS.
45
Consider these factors with abnormal CTG
  • Clinical indication of doing CTG
  • Abnormal patch of tracing from high risk case
    differ that from no risk case
  • Maturity of the fetus
  • Reduced variability and baseline tachycardia is
    conmen in preterm
  • State of maternal pulse
  • Drugs may cause maternal and fetal tachycaedia
  • Check blood pressure for hypotension in patients
    on epidural.

46
Consider these factors with abnormal CTG
In case of abnormal trace consider these fectots
  • Posture of patient during CTG
  • Supine position give abnormal tracing
  • 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
  • Stage of labor and expected time of delivery
    Wether to deliver immediate or give sometime
    under close observation

47
Suspicious (Equivocal)CTG
  • Do continuous monitoring for further development
    towards better or worse trace while instituting
    the corrective measures.
  • Ideally check condition of fetus by FAS or FBS or
    scalp stimulation test.
  • However ,if liquor is meconium stained ---Deliver
    immediately

48
Correct reversible causes
  • Change mother position from supine to left
    lateral position-----increase uterine blood flow
  • Improve maternal oxygenation100 O2 by masK
  • Correct maternal hypotension IV fluid
  • Decrease or stop any oxytocin infusion
  • Remove vaginal prostaglandins

49
Secondary tests of fetal well-being
  • Vibro-acoustic stimulation
  • Used as a substitute for scalp sampling when CTG
    is NR
  • Normal ----------if FHR acceleration gt 15 bpm
    for 15 seconds within 15 seconds after the
    stimulation with prolonged fetal movements.
  • Abnormal ----Only 50 have acidotic PH

50
Fetal blood sampling
  • If the pH gt7.25 --- observe.
  • If the pH 7.2 and 7.25---repeated
  • within 30 minutes.
  • If the pH lt7.2----repeat immediately
  • If pH still low -- Prompt delivery

51
  • Scalp stimulation.
  • Firm digital pressure
  • Gentile pinch by atramatic Allis forceps
  • Fetal pulse oximetry.

52
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