CTG Interpretation .pptx

CTG Interpretation, evidence based approach
Cardiotocography (CTG) or electronic fetal monitoring (EFM) is the most widely used technique for assessing fetal wellbeing in labour in the developed world. The primary purpose of fetal surveillance by CTG is to prevent adverse fetal outcomes. Continuous electronic foetal monitoring is recommended to assure fetal wellbeing in labour in high risk pregnant women. Understanding pathophysiology of fetal heart rate variation will help appropriate interpretation of the CTG.
Features & classification of CTG according to RCOG will be demonstrated in this presentation with sufficient trace demonstration.

1. CTG Interpretation Wafaa Benjamin Basta Consultant Ob/ Gyn Mataria Teaching Hospital MRCOG –ERC Member Egyptian Board of Ob/ Gyn Meeting - March 201 9

2. Foetal Physiology Fetus designed to cope with labour Every fetus will have his/hers own unique physiological reserve all modified by his /hers antenatal and intra-partum risk factors. Fetal physiology in labour will make all efforts to protect the myocardium

3. Control of Baseline Fetal Heart Rate and Variability Pacemaker in SA node , Conduction bundle , AV node CNS Brain stem centre Chemoreceptor and baroreceptor Sympathetic and parasympathetic systems • Baseline heart rate – sum result of these factors • Baseline variability – integration of sympathetic and parasympathetic input • Gestation

4. Control of Baseline Fetal Heart Rate and Variability CNS activity - increase activity leads to increased variability of heart rate Chemoreceptors – hypoxia / hypercapnia → bradycardia Baroreceptors - ↑ arterial pressure → bradycardia Sympathetic system – adrenal medulla → epinephrine and nor-epinephrine Parasympathetic system – vagal effect on SA node and AV node → decreased FHR

5. The well oxygenated fetus demonstrates a stable baseline and variability

6. Chemical ( Chemo-receptors) Responsive to ↑ in H+ CO2 ↓ Po2 Stimulate parasympathetic nervous system to decrease FH Gradual fall from baseline and delayed recovery. Take longer to recovery to baseline Mechanical Baro -receptors Compression of umbilical artery Increase in fetal systemic BP Stimulates Baro -receptor to send impulse to cardiac inhibitory centre FH slows Sharp drop Usually 30 -60 seconds Recovery to baseline Not of concern if Baseline and Variability are reassuring.

7. A Normal Antenatal CTG

8. Features of a CTG Baseline Rate bpm Baseline variability bpm Accelerations Decelerations Response to stimuli Contractions Fetal movements Other

9. Features of a CTG Baseline Rate bpm Baseline variability bpm Accelerations Decelerations Response to stimuli Contractions Fetal movements Other Classified into : Reassuring Non-reassuring Abnormal

10. RCOG Classification of CTGs Normal CTG = all Three features are reassuring Suspicious CTG = One non reassuring feature and two reassuring Pathological CTG = One abnormal or Two non reassuring features

11. Features of CTG Fetal Heart rate feature classification Baseline (bpm) Variability (bpm) Decelerations Accelerations Reassuring 110 - 160 ≥5 None Present Absence of accelerations with otherwise normal CTG is of uncertain significance Non-reassuring 100 – 109 110 - 160 <5 for ≥40 but <90 min early Variable Single prolonged for up to 3 minutes Abnormal <100 >180 Sinusoidal pattern for ≥10 minutes <5 for >90 minututes atypical Late Single prolonged for >3 minutes

12. Baseline Fetal Heart Rate {FHR} Mean level of FHR when this is stable, excluding Accelerations and Decelerations -Tachycardia - Bradycardia Reassuring : 110 to 160 bpm at term Non-reassuring : 100-109 bpm / 161-180 bpm Abnormal: less than 100/ more than 180 bpm Tachycardia with reduced STV = early hypoxia

13. BaselineTachycardia Hypoxia Chorio-amnionitis Sepsis Maternal fever Maternal Anxiety Maternal thyrotoxicosis B-Mimetic drugs Fetal anaemia Heart failure Arrhythmias Prematurity

14. Baseline Bradycardia Postdates Drugs Idiopathic Arrhythmia's Hypothermia. Cord compression Acute Hypoxia Congenital heart

15. Baseline variability The minor fluctuations on baseline FHR at 3-5 cycles bpm produces Baseline variability. Examine imin segment and estimate highest peak and lowest trough . Reassuring : 5-25 bpm – this indicates Normal-CNS. Non-reassuring : > 5 bpm for 3 -5 0 minutes < 25 bpm for 15-25 minutes Abnormal : > 5 bpm for < 5 0 minutes < 25 bpm for < 25 minutes

16. Baseline Variability Para-Sympathetic affects short term variability whilst Long Term is more Symp . CNS ,Drugs reduce Variability High gestation increases variability Mild Hypoxia may cause both S and para S stimulation

17. Reduced Variability Hypoxia Drugs Extreme prematurity Sleep CNS abnormality.

18. Variability less than 5 bpm for 30-50 minutes

19. Accelerations Must be >15 bpm and >15 sec above baseline Should be >2 per 15 min period Always reassuring when present May not occur when fetus is “sleeping” Should occur in response to fetal movements or fetal stimulation Non reactive periods usually do not exceed 45 min (>90 min and no accelerations is worrying)

20. Acceleration

21. Decelerations Transient slowing of FHR below the baseline level of more than 15 bpm and lasting for 15 sec. Or more.

22. Deceleration Reassuring : Non Early deceleration Variable dec ,no concerning characteristic > 9 minutes Non-reassuring Variable dec ,no concerning characteristic < 9 0 minutes Variable dec , with any concerning characteristic : < 50% of contractions for more than 30 minutes or more > 50% contractions for less than 30 minutes Late deceleration in >50% contractions for less than 30 minutes {no maternal or fetal risk factors}

23. Deceleration Abnormal : Variable dec , with any concerning characteristic >50% contractions for more than 30 minutes {or less if fetal or maternal risk factors} Late deceleration for more than 30 minutes {or less if maternal or fetal risk factors } Bradycardia or a single deceleration over 3 minutes

24. Early Deceleration mirrors the contraction. = Head Compression Typically occurs as the head enters the pelvis and is compressed, i.e. it is a vagal response

25. Late Deceleration Follows every contraction and exhibits a slow return to baseline. = Fetal Hypoxia Is the response of a hypoxic myocardium

26. Variable Deceleration Show no relationship to contractions. = Cord Compression If frequent lead to hypoxia Without concerning features With concerning features

27. Non-reassuring – variable decelerations Concerning features Biphasic or W shaped Lasting >60 seconds Failure to return to baseline No shouldering Reduced variability within the deceleration Variable decels with concerning features: <50% of contractions for more than 30 minutes >50% contractions for less than 30 minutes

28. Biphasic or W shaped

29. Lasting > 60 seconds

30. Reduced variability within the deceleration

31. Failure to return to the baseline

32. No shouldering

33. Decelerations that become “Longer, later and deeper” are a worrying sign

34. Sinusoidal

35. Saltatory Pattern

36. Normal CTG Variable decelerations with no concerning features are very common They can be normal if there are no other non-reassuring features They become non-reassuring if they persist for more than 90 minutes

37. Non reassuring CTG

38. Pathologic CTG

39. TAKE ACTION Suspicious Pathological Inform Senior MW and doctor Exclude acute events Cord prolapse Uterine rupture Abruption Think about MOTHERS Start conservative measures Investigate

40. Pathological CTG If CTG remains pathological: Perform scalp stimulation If this leads to an acceleration, regard this as a sign the baby is healthy Only continue with FBS if the CTG remains pathological If there is no acceleration, consider FBS Or Expediting birth

41. Conservative measures Left lateral / mobilise Consider iv fluids Reduce contractions: Reduce/stop synto Terbutaline Paracetamol if temp/pulse raised

42. Remember….

43. MOTHERS Risk factors

44. Bradycardia 3 6 9 3 minutes Call obs reg , anaesthetist, theatre team Start Conservative measures Ask for terbutaline 6 minutes Prepare woman for theatre / instrumental Continue conservative measures 9 minutes Transfer to theatre and expedite birth 95 % of babies will recover before 9 minutes in the absence of cord prolapse, abruption, uterine rupture If cord prolapse, abruption or rupture – expedite birth immediately

45. Prolonged deceleration

46. Decompensation of the CNS

47. Thank you Any questions ?!