Electronic fetal monitoring vs intermittent auscultation Dr .Pradeep.S Prof in OBG PESIMSR

Place for CTG ? No admission CTG for low risk cases Only Intermittent auscultation for low risk cases in labor If on auscutation fetal heart is abnormal , connect CTG Once the CTG becomes normal and no further risk, can switch to intermittent auscultation.

Frequency of IA Auscultate for one whole minute 1st Stage 2nd Stage ACOG q15 mins q5 mins NICE q15mins q5mins/ after every contraction

CONTINUOUS ELECTRONIC FETAL MONITORING Benefits: ▶ Can identify early signs of developing hypoxia ▶ Allows closer monitoring of high risk patients ▶ Excellent predictor of a normally oxygenated fetus ▶ Records FHR & uterine contractions simultaneously

THE PROBLEM WITH EFM IS… ▶ Over use in low-risk women ▶ Over reliance on a poor screening tool ▶ 30% false positive rate ▶ Increased rate of interventions with significant increase in morbidity and mortality for women and babies ▶ Difficulty in legal cases due to interpretation disputes Reduced mobility and lack of support in labour may affect the woman's ability to control and cope with labour pain

What does evidence say?

NICE guidance NICE advocate the use of continuous EFM in high-risk labours.

COCHRANE REVIEW (2006, 2013) ▶ No difference in incidence of CP between IA & EFM ▶ EFM was associated with a significant increase in C-Sections (1.7times) & instrumental vaginal deliveries

Clinical Decision-making Based on Auscultation Findings Continue Individualized Assessment and Care Assess with IA & palpation per pt/care provider preferences, guidelines, & availability Promote maternal comfort & continued fetal oxygenation(position change; anxiety reduction measures Notify Auscultate Interpretation Yes Reassuring FHR Pattern? Baseline rate 110-160 Regular rhythm Absence of decrease from baseline No

Non-Reassuring FHR Pattern Baseline <110 pbm Baseline >160 bpm (unexplained persistent tachycardia for > 3 contractions or > 10-15 minutes Irregular rhythm FHR during & 30 seconds after contractions Gradual or abrupt change in FHR Intervention/Management  frequency of Intermittent auscultation Assess potential cause of FHR characteristics Attempt to remove problem(s)/cause Intervene to promote 5 physiologic goals: Improve uterine blood flow Improve umbilical blood flow Improve oxygenation  uterine activity (e.g. position change, hydration)

Continue interventions Problem Solved ?? YES—Return to Continued Individualized Assessment & Care No FHR Pattern Persists? Continue interventions Apply EFM to clarify pattern interpretation, assess variability, to further assess fetal status Consider additional assessments (e.g. fetal scalp stimulation; fetal acoustic stimulation)

Indications for electronic fetal monitoring Antenatal indications: maternal Antenatal indications: fetal Hypertension Diabetes APH Maternal diseases : cardiac, anemia, renal Maternal trauma Morbid obesity IUGR Prematurity Oligohydramnios Abnormal umblical artery doppler Isoimmunisation Intrapartum indications: maternal Intrapartum indications: fetal Excess vaginal bleeding Chorioamnionitis TOLAC Induced labor Augmented labor Hypertonic uterus Prolonged pregnancy Meconium stained liquor Abnormal fetal heart rate on auscultation

Indications for internal fetal monitoring Obese women where external monitoring is not possible

FETAL ELECTROCARDIOGRAM (ECG) OR ST ANALYSIS (STAN)

STAN ST analysis (STAN) involves a combination of fetal heart rate interpretation and analysis of the fetal electrocardiogram. STAN aims to reduce the incidence of fetal acidaemia and hypoxia by identifying these earlier and with greater sensitivity than cardiotocography (CTG) alone.

BASIS FOR STAN During oxygen deficiency, anaerobic metabolism is used by cardiac myocytes to maintain an energy supply. The breakdown of glycogen releases potassium ions that can cause an increase in the height of the T wave. Cardiac hypoxia and ischemia can cause ST depression and inversion of the T wave The STAN software is able to detect all such changes and prompts the clinician that such changes have occurred.

The STAN software analyses the average waveform of the fetal ECG signal over 30 consecutive heartbeats. It then compares this waveform with the average of each of the subsequent 30 complexes. STAN should not be started if there is a total loss of fetal heart rate variability. a spiral fetal scalp electrode (FSE) is attached to the fetal scalp during a vaginal examination. A skin reference electrode is placed on the mother’s thigh; this attaches both to the FSE and to the STAN monitor. An abdominal toco is used as in CTG monitoring.

A normal ECG complex

ST events shown on STAN monitor The ST analysis is displayed by crosses at the bottom of the screen Each cross represents an episode of ST analysis of the ECG complexes of 20 beats Significant changes are displayed as an ST event with a black box to mark the time on the trace

There are three types of ST event that can be noted

Episodic T/QRS rise. Increase in the T/QRS ratio that lasts for less than 10 minutes. An episodic T/QRS rise usually indicates a period in which the fetus had to utilize anaerobic metabolism but has now recovered. The magnitude of rise is given in the event log as 0.11 or greater

Baseline T/QRS rise. an increase in the T/QRS ratio that has lasted more than 10 minutes. magnitude of the rise is given in the event log as 0.06 or greater A baseline T/QRS rise usually indicates that the fetus is utilizing anaerobic metabolism for an extended period of time.

Biphasic events Reflects a downward-sloping ST segment indicate a situation where hypoxia is occurring but the fetus either has not yet had time to respond with anaerobic metabolism or cannot respond.

Grade 1 biphasic event The ST segment is sloping downwards but the entire segment remains above the baseline

Grade 2 biphasic event The ST segment is sloping downwards but it crosses the ECG baseline and is not fully below it.

Grade 3 biphasic event The ST segment is sloping downwards and the entire segment is below the ECG baseline

INTERPRETATION OF THE RESULTS If the CTG is normal then no action is required with any STAN event – this represents an adrenaline surge in a healthy fetus. If the CTG is classified as preterminal then the fetus should be delivered regardless of the type and magnitude of any STAN events, and even in their absence.

The basic principle is if the CTG is more concerning even with smaller ST event it needs intervention. If the CTG is classified as intermediary or abnormal then the type and magnitude of STAN event should be noted.

Limitations to the use of STAN: already hypoxic fetus Intrauterine infection Breech presentation: breech mode Fetal heart rate >170 bpm Recording the maternal ECG Fetal cardiac abnormalities

Fetal pulse oximetry (FPO) Measures fetal oxyhemgolobin saturation by placing a sensor against fetal cheek transcervically after membranes have ruptured

Near infrared spectroscopy (NIRS) When light is passed through detectors placed on the fetal head, it will be reflected back depending on the oxygenation and the amount of blood flow through the fetal head