intrapartum fetal monitoring for undergraduate


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Undergraduate course lectuers in Obstetrics&Gynecology
Prepared by DR Manal Behery
Assistant Professor in OB&GYNE ,Faculty of medicine,Zagazig University

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intrapartum fetal monitoring for undergraduate

  2. 2. The three unique risk factors for fetus during laborFactor of uterine contractionFactor of cord accidentFactor of head compression
  3. 3. Factor of uterine contraction Let us see what happen to oxygenation and blood supply of the fetal brain during a uterine contraction?
  4. 4.  De-oxy-Hb 0.79micromol/100Gm of brain Oxy –Hb 0.19 0.79micromol/100Gm of brain CerebralO2 saturation 9% Cerebral blood volume 0.33 ml/100Gm ofIn spite of this slightly worrying picture,Nothing harmful effect happen if fetus is healthy labor contraction are normal Placenta has adequate reserve
  5. 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. 6. Factor of cord accident Only during labor cord prolaps ,presentation and entanglements (occult or overt) become apparent either by compression or stretch secondary to uterine contraction
  7. 7. Factor of head compression Some degree of compression is inevitable during normal labor But Excessive compression over long period causing supermouldingas in obstructed labor may cause fetal hypoxia
  8. 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. 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 acidosis.
  10. 10. Aim of intrapertum fetal monitering 1- to detect the earliest stages of hypoxia or (hypoxic acidemia ) so therapy can be directed to prevent asphyxia and asphyxial damage 2-To Improve perinatal morbidity & mortality
  11. 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. 12. External monitoringDoppler ultrasound transducer FHRTocotransducer(contraction)
  13. 13. Internal monitoring
  14. 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. 15. Interpreting FHR trace 4 components  Base line FHR  Baseline variability  Accelerations  Decelerations
  16. 16. Baseline FHR The dominant reading taken ≥10 min Normal baseline FHR 110-160(pbm) Controlled byatrialpacemaker
  17. 17. Tachycardia FHR>160 bpm
  18. 18. Baseline bradycardia FHR<110bpm
  19. 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. 20. Baseline varibility Short term variability(scalp electrode) Long term variability defined as 3-5 cycle/min
  21. 21. Baseline varibility
  22. 22. No variability (0-2 / ) Minimal variability (3-4 / )Moderate variability (11-25 / )Mark variability (>25 / )
  23. 23. Changes in fetal HRPeroidic changes: Occur with contractionEpisodic changes (non peroidic):do not occur with contraction
  24. 24. Accelaration Increase in FHR with contraction or with other activities Can be periodic or episodic Increase15pbm lasting 15 sec Return to base line <2 min
  25. 25. Accelaration
  26. 26. Decelerations DecelerationsTransient slowing ofFHR below thebaseline levelmore than 15 bpmand lasting for 15 sec.or more.
  27. 27. Early Decelerations Uniform Synchronous with contraction (mirror image) Rarely fall below 110 (pbm) Due to head compression Should not be disregardedif they appear early in labor or Antenatal.
  28. 28. Early Decelerations
  29. 29. Late Deceleration Uniform Start after peak of contraction Associated with decreasedVariability Reflect a baroreceptorresponse Indicate fetal hypoxia
  30. 30. Late Deceleration
  31. 31. Repetitive late decelrationincreases risk of Umbilical artery acidosis Apgar score < 7 at 5 ms Cerebral palsy If associated withdecrease or loss of variability
  32. 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. 33. Variable Deceleration
  34. 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. 35. Prolonged Deceleration
  36. 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. 37. Sinusoidal pattern
  38. 38. 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
  39. 39. Normal -Reassuring CTG
  40. 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. 41. 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
  42. 42. 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.
  43. 43. ?? To reduce CS….
  44. 44. 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 pulseDrugs may cause maternal tachycardia– fetal tachycaedia Check blood pressure for hypotension in patients on Epidural
  45. 45. Consider these factors with abnormal CTG Posture of patient during CTGo Supine position give abnormal tracingo Some cord compression can get released by change posture and must be tried with variable deceleration Congenital fetal malformationColor 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
  46. 46. 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
  47. 47. Correct reversible causes Change mother position from supine to left lateral position-----increase uterine blood flow Improve maternal oxygenation—100% O2 by masKCorrect maternal hypotension –IV fluid Decrease or stop any oxytocin infusion Remove vaginal prostaglandins
  48. 48. 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
  49. 49. Fetal blood sampling If the pH >7.25 --- observe. If the pH 7.2 and 7.25---repeatedwithin 30 minutes. If the pH <7.2----repeat immediately If pH still low -- Prompt delivery
  50. 50.  Scalp stimulation. Firm digital pressure Gentile pinch by atramatic Allis forceps Fetal pulse oximetry.
  51. 51. THANK YOU