Intrapartum fetal survellence

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  • 1. DR. Mohit Satodia DR.BHARTI GOEL
  • 2. GOAL  The timely identification and rescue of the fetus at risk of neonatal and long term morbidity from intrapartum hypoxic insult
  • 3. Intrapartum monitoring  FHR monitoring –  Intermittent auscultation(IA)  Electronic fetal monitoring(EFM)  Fetal Scalp pH  Fetal Pulse oximetry  Fetal scalp lactate testing  ST waveform analysis
  • 4. FETAL HEART RATE MONITORING  External FHR monitoring-  Hand-held Doppler ultrasound probe  External transducer
  • 5. External FHR monitoring-
  • 6. TECHNICAL CONSIDERATIONS  Basis for FHR monitoring is beat to beat recording  For practical purposes ,this is possible only when direct fetal electrocardiograms are recorded with a scalp electrode.  Paper speed is important. Commonly used are 1,2 or 3 cm/min.  1 cm/min –a) good records for clinical purposes and limiting the cost and amount of paper b)crowding together of the record making baseline variability difficult to interpret.
  • 7. Contd…  3 cm/min- a) useful when record is difficult to interpret at slow speed i.e. during second stage of labor b) waste of paper more
  • 8. Internal FHR monitoring Spiral electrode attatched to the fetal scalp with a connection to FHR monitor.  The fetal membranes must be ruptured, and the cervix must be at least partially dilated before the electrode may be placed on the fetal scalp.
  • 9. Intermittent auscultation  In uncomplicated pregnancies .  Doppler better than stethoscope.  Every 15 - 30 minutes in active phase of first stage and every 5 minutes in second stage  Listen in the absence of active pushing and toward the end of the contraction and at least for 30seconds after each contraction ACOG JUlY 2009 CONTINUOUS EFM  No benefit in low risk  Continuous EFM -when risk factors for present  Every 15 minutes in first stage and every 5 minutes during the second stage.
  • 10. Fetal Assessment : IA & EFM Surveillence Low-Risk High-Risk Pregnancies Pregnancies Acceptable methods Intermittent Auscultation* Yes Yes (a) Continuous Electronic Fetal Monitoring (EFM) Yes Yes (b) First-stage Labour 30 min 15 min (a,b) Second –stage labour 15 min 5 min (a,c) Evaluation Intervals •a- before, during and especially after a contraction for 60 sec •b- includes evaluation of tracing every 15 min • c- evaluation of tracing every 5 min (ACOG & AAP 2007)
  • 11. INDICATIONS FOR CONTINUOUS EFM Antepartum risk factors          Abnormal Doppler umbilical artery velocimetry Suspected IUGR APH HTN / preeclampsia (current pregnancy) DM Multiple pregnancy Uterine scar / previous CS Iso-immunisation Oligohydramnios / polyhydramnios Maternal medical conditions(including severe anaemia, cardiac disease, hyperthyroidism, vascular disease, renal disease)
  • 12. Risk factors during labour Prolonged rupture of membranes (> 24 hours)  Meconium-stained or blood-stained liquor  Fetal bradycardia  Fetal tachycardia  Maternal pyrexia > 38 ˚C  Chorioamnionitis  Vaginal bleeding in labour  Prolonged active first stage of labour (> 12 hours regular uterine contractions with cervical dilatation>3cm)  Prolonged second stage of labour .
  • 13. Other indications  Any use of oxytocin whether for induction or for augmentation of labour  Before and for at least 20 minutes after administration of prostaglandin  Epidural analgesia (immediately after inserting an epidural block)
  • 14. Benefits of EFM over IA Reduced risk of neonatal seizures(RR 0.50) No benefit over IA did not reduce perinatal mortality(RR, 0.85)  did not reduce the risk of cerebral palsy (RR, 1.74) Risks of EFM High false-positive results.  Increased rates of surgical intervention  High interobserver and intraobserver variability COCHRANE 2006
  • 15. Electronic fetal monitoring  Various components include -Baseline -Variability -Accelerations -Decelerations
  • 16. External fetal monitoring BASELINE The mean FHR rounded to increments of 5 bpm during a 10minute segment, excluding: —Periodic or episodic changes —Periods of marked FHR variability —Segments of baseline that differ by more than 25 bpm  The baseline must be for a minimum of 2 minutes in any 10-minute segment  Normal : 110–160 bpm  Tachycardia: > 160 bpm  Bradycardia: <110 bpm
  • 17. FETAL HEART RATE MONITORING  Baseline Variability  Fluctuations in the baseline FHR that are irregular in amplitude and frequency  Visually quantitated as the amplitude of peak-totrough in bpm. Absent—amplitude range undetectable Minimal—0 to5 bpm Moderate (normal) — 6to25 bpm Marked—> 25 bpm
  • 18.  Short term variability – small changes in fetal beat to beat intervals under physiological conditions  Long term variability- certain periodicity in the direction and size of these changes causes oscillations of fetal heart rate around mean level  In FHR tracings short term variability is superimposed over long term variability as minimal deflexions, not interpreted by naked eye, therefore in clinical practice variability means long term variability
  • 19.  Long term variability characterized by – frequency and amplitude  Frequency is difficult to assess correctly  Therefore , variability is usually quantitated by amplitude of the oscillations around baseline heart rate.
  • 20.  The tracing shows an amplitude range of ~ 10 BPM (moderate variability ).
  • 21. Factors affecting variability  Normal variability : 98% fetuses not acidotic  Decreased variability: Fetal metabolic acidosis , CNS depressants, fetal sleep cycles, congenital anomalies, prematurity, fetal tachycardia, preexisting neurologic abnormality, betamethasone.  Increased variability (saltatory pattern):Acute hypoxia or cord compression, eg 2nd Stage
  • 22. ACCELERATION  A visually apparent abrupt increase in the FHR  <32 weeks: >10 BPM above baseline for >10 sec  >32 weeks: >15 BPM above baseline for > 15 sec  Prolonged acceleration lasts >2 min but <10 min in duration.  If an acceleration lasts 10 min or longer, it is a baseline change
  • 23. Early Deceleration  Symmetrical gradual decrease and return of the FHR associated with a uterine contraction  The nadir of the deceleration occurs at the same time as the peak of the contraction.  In most cases the onset, nadir, and recovery of the deceleration are coincident with the beginning, peak, and ending of the contraction, respectively
  • 24. Caused by fetal head compression by uterine cervix Usually seen between 4 and 6 cm of dilation
  • 25. Late Deceleration  Symmetrical gradual decrease and return of the FHR associated with a uterine contraction  The deceleration is delayed in timing, with the nadir of the deceleration occurring after the peak of the contraction.  In most cases, the onset, nadir, and recovery of the deceleration occur after the beginning, peak, and ending of the contraction, respectively
  • 26. Associated with uteroplacental insufficiency Causes -Maternal hypotension,postmaturity, DM,HTN
  • 27. Variable Deceleration  Visually apparent abrupt decrease in FHR  The decrease in FHR is ≥ 15 bpm , lasting ≥ 15 sec, and <2 minutes in duration.  When variable decelerations are associated with uterine contractions, their onset, depth, and duration commonly vary with successive uterine contractions.
  • 28. Caused by compression of the umbilical cord. If appearing early in labour-often caused by oligohydramnios
  • 29. TYPES  Typical  Atypical  Loss of shoulders  Slow return to baseline  Prolonged secondary rise in baseline  Loss of variability during deceleration  Continuation at lower baseline
  • 30. Classification of the severity of variable deceleration  MILD- Deceleration of a duration of <30sec , regardless of depth Deceleration not below 80bpm , regardless of duration  MODERATE- Deceleration with a level <80bpm  SEVERE- Deceleration to a level <70bpm for >60sec
  • 31. Prolonged Deceleration  Decrease from baseline that is 15 bpm or more, lasting ≥ 2 min but <10 min  If lasts 10 minutes or longer, it is a baseline change  Causes-prolonged cord compression,prolonged uterine hyperstimulation,severe degree of abruptio,eclamptic seizure,following conduction anaesthesia
  • 32. SINUSOIDAL PATTERN  Visually apparent, smooth, sine wave-like undulating pattern in FHR baseline with a cycle frequency of 3–5 per minute which persists for 20 min or more.  Indicates severe fetal anemia as occurs in  Rh isoimmunization  Feto maternal hemorrhage  Twin twin transfusion syndrome severe hypoxia
  • 33. A
  • 34. Three-Tiered Fetal Heart Rate Interpretation System Category I- NORMAL acid base status • Baseline rate: 110–160 bpm • Moderate Baseline FHR variability • No Late or variable decelerations • Early decelerations: • Accelerations: Category II-INDETERMINATE not categorized as Category I or III. Category III-ABNORMAL acid base status-Intervention • Absent baseline FHR variability and any of the following: —Recurrent late decelerations —Recurrent variable decelerations —Bradycardia • Sinusoidal pattern
  • 35. RCOG CLASSIFICATION BASELINE VARIABILITY DECELERATIO N REASSURING 110-160 ≥ 5 bpm None NON REASSURING 100-109 161-180 < 5 for ≥40 min but <90 min Early decel; typical variable; single prolonged ≤ 3min ABNORMAL <100 >180 sinusoidal ≥ 10 min < 5 for ≥90 min Late decel; atypical variable; single prolonged > 3min ACCELERATIO N present
  • 36.  Ancillary tests that can aid in the management of Category II or Category III FHR tracings Four techniques are available to stimulate the fetus: 1)fetal scalp sampling, 2) Allis clamp scalp stimulation, 3) vibroacoustic stimulation, and 4) digital scalp stimulation
  • 37.  A Cochrane review of three trials concluded that manual fetal manipulation did not decrease NRFS and it is not recommended.  Cochrane review of two trials concluded that antenatal maternal glucose administration did not decrease the incidence of NRFS and it is not recommended.
  • 38. Standard interventions for NRFS Supplemental oxygen Discontinuation of any labor stimulating agent Changing maternal position Resolution of maternal hypotension-hydration. P/V to determine umbilical cord prolapse, rapid cervical dilation, or descent of the fetal head,ARM Assessment of uterine contraction . Tocolytics-in tachysystole with associated FHR changes. When the FHR tracing includes recurrent variable decelerations -Amnioinfusion
  • 39. MANAGMENT Suspicious CTG If inadequate quality-check contact and connections  If hypercontractility-discontinue oxytocin, consider tocolytics  Maternal tachycardia,pyrexia,dehydration, hypotension  Supine? Epidural? sedation? drugs?  i/v crystalloid bolus; 10 L/min O2 If persistent → do ancillary tests Pathological CTG  FBS if feasible  If not feasible-expedite delivery (within 30 min)
  • 40. Effects of Medications on FHR Patterns Narcotics decreased variability and accelerations Corticosteroids Decreased variability (with beta-methasone but not dexamethasone) Magnesium sulfate A significant decrease in short-term variability, clinically insignificant decrease in FHR inhibits the increase in accelerations with advancing gestational age Epidural analgesia decreased variability and accelerations Terbutaline Increase in baseline FHR
  • 41. FETAL SCALP PH  In women with "abnormal“ fetal heart rate tracings .  Cervix needs to be 4-5cm dilated and Vx at -1 st or     below pH <7.20 –fetal acidosis: deliver pH 7.20-7.25 – borderline, repeat in 30 min or deliver if rapid fall pH > 7.25 – reassuring, repeat if FH abnormality persists Greater utility of scalp pH is in its high negative predictive value (97–99%).
  • 42.  Contraindications  Maternal infection (HIV, hepatitis, HSV)  Fetal bleeding disorders (e.g. haemophilia)  Prematurity < 34 weeks  Face presentation
  • 43. FETAL PULSE OXIMETRY  Acidosis: O2 sat. <30% for >2min  Approved by FDA for use in fetuses with NRFS in May 2000  The ACOG currently recommends against its use until further studies are available to confirm its efficacy and safety  Insufficient evidence for its use as an adjunct or independent of electronic fetal surveillance.
  • 44. FETAL SCALP LACTATE TESTING  Higher sensitivity and specificity than scalp pH  > 4.8 mmol/L : acidosis  Clinical trial that compared the use of scalp pH to scalp lactate level did not demonstrate a difference in the rate of acidemia at birth, Apgar scores, or neonatal intensive care unit admissions  Not recommended for routine use
  • 45. ST WAVEFORM ANALYSIS  Method: STAN S31 fetal heart monitor(USFDA) Scalp electrodes  The electrical fetal cardiac signal – P wave, QRS complex, and T wave – is amplified and fed into a cardiotachometer for heart rate calculation
  • 46.  Restrict fetal ST waveform analysis to those with non reassuring fetal status on EFM  The use of ST waveform analysis for the intrapartum assessment of the compromised fetus is not recommended for routine use at this time.
  • 47. THANK YOU