Updated intrapartum monitoring

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

2. The three unique risk factors for fetusduring laborFactor of uterine contractionFactor of cord accidentFactor 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 0.79micromol/100Gm of brain CerebralO2 saturation9% Cerebral blood volume0.33 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. 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 prolaps ,presentation and entanglements (occult or overt) become apparent either by compression or stretch secondary to uterine contraction 7. Factor of head compression Some degree of compression is inevitableduring normal labor But Excessive compression over long periodcausing supermouldingas in obstructed labor may cause fetal hypoxia 8. Methods available for fetal moniteringin labor Intermittent auscultation CTG Fetal electrocardiography Scalp stimulation Vibroacoustic stimulation Fetal scalp sampling PH determination Fetal pulse oximetry 9. Importantdefinations 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. 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. 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 monitoringDoppler ultrasound transducer FHRTocotransducer(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 Whetherthe case should be monitored clinically or by CTGDuration 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 byatrialpacemaker 17. Tachycardia FHR>160 bpm 18. Baseline bradycardia FHR25 / ) 23. Changes in fetal HRPeroidic changes: Occur with contractionEpisodic changes (non peroidic):do not occur with contraction 24. Accelaration Increase in FHR with contraction orwith other activities Can be periodic or episodic Increase15pbm lasting 15 sec Return to base line 5 pbm (10-25) 2 Accelerations > 15 BPM > 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. 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. Is NR CTGs always worrisome ?60% CTG in Labour have 1 abnormal featureOnly 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. ?? To reduce CS. 44. Consider these factors with abnormal CTG Clinical indication of doing CTG Abnormal patch of tracing from high risk case differthat from no risk case Maturity of the fetus Reduced variability and baseline tachycardia isconmen in preterm State of maternal pulseDrugs may cause maternal tachycardia fetaltachycaedia Check blood pressure for hypotension in patientson Epidural 45. Consider these factors with abnormal CTG Posture of patient during CTGo Supine position give abnormal tracingo Some cord compression can get released by changeposture and must be tried with variable deceleration Congenital fetal malformationColor Doppler of fetal heart to exclude congenitalheart blockStage of labor and expected time of delivery Wether to deliver immediate or give sometime under close observation 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. Correct reversible causes Change mother position from supine to left lateral position-----increase uterine blood flow Improve maternal oxygenation100% O2 by masKCorrect maternal hypotension IV fluid Decrease or stop any oxytocin infusion Remove vaginal prostaglandins 48. Secondary tests of fetal well-being Vibro-acoustic stimulation Used as a substitute for scalp sampling whenCTG is NR Normal ----------if FHR acceleration > 15bpm for 15 seconds within 15 seconds afterthe stimulation with prolonged fetalmovements. Abnormal ----Only 50% have acidotic PH 49. Fetal blood sampling If the pH >7.25 --- observe. If the pH 7.2 and 7.25---repeatedwithin 30 minutes. If the pH