This presentation explains the basic concepts involved in CTG such as how to read it and how it works and the terms associated with it and a machine manufacture by Philips known as the Avalon FM30 : Fetal monitor

1. Cardiotocography
By Mohit Shukla & Samiran Tripathi

2. What is cardiotocography?
• Cardiotocography (CTG) is used during
pregnancy to monitor both the foetal
heart and the contractions of the
uterus.
• It is usually only used in the 3rd
trimester. It’s purpose is to monitor
foetal well-being and allow early
detection of foetal distress.
• An abnormal CTG indicates the need
for more invasive investigations and
may lead to the need for emergency
caesarian section.

3. How it works
• The device used in cardiotocography is known as a cardiotocograph.
• It involves the placement of 2 transducers onto the abdomen of a
pregnant women.
• One transducer records the foetal heart rate using ultrasound.
• The other transducer monitors the contractions of the uterus.
• It does this by measuring the tension of the maternal abdominal wall.
• This provides an indirect indication of intrauterine pressure.
• The CTG is then assessed by the midwife and obstetric medical team.

4. How to read a CTG
• To interpret a CTG you need a structured method of assessing its
various characteristics.
• The most popular structure can be remembered using the acronym
DR C BRAVADO
• DR – Define Risk
• C – Contractions
• B Ra – Baseline Rate
• V – Variability
• A – Accelerations
• D – Decelerations
• O – Overall impression

5. Risk
• You first need to assess if this pregnancy is high or low risk.
• This is important as it gives more context to the CTG reading – e.g. If
the pregnancy is high risk, your threshold for intervening maybe
lowered.

6. Reasons a pregnancy may be considered high risk
• Maternal medical illness
• Gestational diabetes
• Hypertension
• Asthma
• Obstetric complications
• Multiple gestation
• Post-date gestation
• Previous caesarean section
• Intrauterine growth restriction
• Premature rupture of membranes
• Congenital malformations
• Oxytocin induction/augmentation of labour

7. Other risk factors
• Absence of prenatal care
• Smoking
• Drug abuse

8. Contractions

9. Contractions
• Record the number of contractions present in a 10 minute period –
e.g. 3 in 10
• Each big square is equal to 1 minute, so look at how many
contractions occurred within 10 squares.
• Individual contractions are seen as peaks on the part of the CTG
monitoring uterine activity.
• You should assess contractions for the following:
• Duration – how long do the contractions last?
• Intensity – how strong are the contractions? (assessed using
palpation)

10. Baseline rate of the foetal heart

11. Baseline rate of the foetal heart
• The baseline rate is the average heart rate of the foetus within a 10
minute window.
• Look at the CTG and assess what the average heart rate has been over
the last 10 minutes.
• Ignore any accelerations or decelerations.
• A normal foetal heart rate is between 110-150 bpm.

12. Foetal Tachycardia & Bradycardia
• Foetal tachycardia is defined as a
baseline heart rate greater than
160 bpm.
• It can be caused by:
• Foetal hypoxia
• Chorioamnionitis – if maternal fever
also present
• Hyperthyroidism
• Foetal or maternal anaemia
• Foetal tachyarrhythmia
• Foetal bradycardia is defined as a
baseline heart rate less than 120
bpm.
• Mild bradycardia of between 100-
120bpm is common in the
following situations:
• Post-date gestation
• Occiput posterior or transverse
presentations
• Severe prolonged bradycardia (<
80 bpm for > 3 minutes) indicates
severe hypoxia

13. Variability
• It refers to the variation of foetal heart rate from one beat to the next.
• Variability occurs as a result of the interaction between the nervous
system, chemoreceptors, baroreceptors and cardiac responsiveness.
• Therefore, it is a good indicator of how healthy the foetus is at that
particular moment in time.
• Normal variability is between 10-25 bpm.
• To calculate variability you look at how much the peaks and troughs
of the heart rate deviate from the baseline rate (in bpm).

14. Variability can be categorized as:
• Reassuring – ≥ 5 bpm
• Non-reassuring – <
5bpm for between
40-90 minutes
• Abnormal – < 5bpm
for >90 minutes

15. Accelerations
• They are an abrupt increase in baseline
heart rate of >15 bpm for >15 seconds.
• The presence of accelerations is reassuring.
• Antenatally there should be at least 2
accelerations every 15 minutes.
• Accelerations occurring alongside uterine
contractions is a sign of a healthy foetus.
• However the absence of accelerations with
an otherwise normal CTG is of uncertain
significance.
• Decelerations are an abrupt decrease in
baseline heart rate of >15 bpm for >15
seconds.

16. Type of Deceleration with Significance:
1. Early deceleration
• Starts when uterine contraction begins and recovers when uterine
contraction stops.
• This type of deceleration is therefore considered to be physiological and not
pathological.

17. 2. Variable deceleration
• Observed as a rapid fall in baseline rate with a variable recovery phase.
• They are variable in their duration and may not have any relationship to
uterine contractions.
• Most often seen during labour and in patients with reduced amniotic fluid
volume.
• Variable decelerations are usually caused by umbilical cord compression.
• Variable decelerations can sometimes resolve if the mother changes
position.
• The presence of persistent variable decelerations indicates the need for
close monitoring.
• Variable decelerations without the shoulders is more worrying as it
suggests the foetus is hypoxic.

18. 3. Late deceleration
• Late decelerations begin at the peak of uterine contraction and recover after the
contraction ends.
• This type of deceleration indicates there is insufficient blood flow through the uterus
and placenta.
• As a result blood flow to the foetus is significantly reduced causing foetal hypoxia and
acidosis.
• Reduced utero-placental blood flow can be caused by:
• Maternal hypotension
• Pre-eclampsia
• Uterine hyper-stimulation
• The presence of late decelerations is taken seriously and foetal blood sampling for pH
is indicated.
• If foetal blood pH is acidotic it indicates significant foetal hypoxia and the need for
emergency C-section.

19. 4. Prolonged deceleration
• A deceleration that last more than 2 minutes.
• If it lasts between 2-3 minutes it is classed as non-reassuring.
• If it lasts longer than 3 minutes it is immediately classed as abnormal.
• Action must be taken quickly – e.g. foetal blood sampling / emergency
C-section

20. 5. Sinusoidal pattern
• This type of pattern is rare, however if present it is very serious.
• It is associated with high rates of foetal morbidity & mortality.
• It is described as:
• A smooth, regular, wave-like pattern
• Frequency of around 2-5 cycles a minute
• Stable baseline rate around 120-160 bpm
• No beat to beat variability
• A sinusoidal pattern indicates:
• Severe foetal hypoxia
• Severe foetal anemia
• Foetal/maternal hemorrhage
• Immediate C-section is indicated for this kind of pattern.

21. Overall Impression
• The overall impression can be described as either:
• Reassuring
• Suspicious
• Pathological
• The overall impression is determined by how many of the CTG
features were either reassuring, non-reassuring or abnormal. It is
classified as how to decide which category a CTG falls into.

23. Philips Avalon FM30 : Fetal monitor
• Product number: 862199
• Avalon FM fetal and maternal
monitors are Philips' first and
only to offer automated
coincidence detection (cross-
channel verification) using
Smart Pulse, measuring fetal &
maternal heart rates
separately to enhance
diagnostic confidence.

24. • Extensive fetal parameters when more information is needed For complex cases, the Avalon
FM30 fetal monitor offers external and internal fetal parameters. These include ultrasound, fetal
movement, direct fetal heart rate, Toco and intrauterine pressure, as well as maternal pulse rate,
and ECG, with optional SpO2 and blood pressure.
• Smart Pulse for automated coincidence detection Smart Pulse provides cross-channel
verification. It continuously compares all fetal and maternal heart rates, enhancing caregiver
confidence that each is measured separately.
• Variety of readings for comprehensive understanding This antepartum and intrapartum monitor
provides a wide range of readings. These include separate maternal pulse measurement;
integrated monitoring of maternal pulse rate and blood pressure (optional); external monitoring
of fetal heart rates, uterine activity, and fetal movement; an extensive set of internal fetal
parameters such as direct fetal heart rate and uterine pressure; and optional maternal SpO2
monitoring.
• Avalon CTS for freedom of movement When connected to the Avalon Cordless Transducer
System (CTS), mothers can freely move up to 100 meters from the CTS base station during
continuous monitoring by the care team. The CTS also transmits data to the IntelliSpace Perinatal
information system to add to the overall patient record.
• Triplet monitoring option expands capabilities Only the Avalon FM series can monitor triplets on
a single monitor using the same ultrasound frequency. This allows one monitor to be used for a
wide range of clinical needs.
Features

25. Features
• External touch display option for flexibility The optional external touch display gives caregivers
enhanced flexibility in placing the monitor where it can be easily viewed by family members and
caregivers.
• IntelliSpace Perinatal connectivity for continuous care The Avalon FM30 fetal monitor connects
to IntelliSpace Perinatal, Philips obstetrical surveillance and information management system.
This supports the continuum of care from the first antepartum visit to delivery, postpartum, and
newborn nursery, discharge and postpartum follow-up visits.
• Reliability features allow uninterrupted operation With the Avalon FM series, you have the
confidence of an uninterrupted flow of information. The optional battery allows continuous
monitoring during maternal transport in healthcare facilities. It also features a backup memory
and LAN interface.
• Large, intuitive color display clearly shows status The luminous color display has large numeric
and graphs so you can easily view maternal and fetal ECG waves.
• Smart transducers to simplify operation The smart transducers have auto-recognition and
"Finder LED" that automatically recognize which transducer is plugged in. When the transducer is
plugged in, the screen layout automatically displays data in the correct format. This simplifies
operation for caregivers.

26. Specifications
• General
• Care stage Intrapartum
• Patient type Fetal and maternal
• Parameters
• External foetal parameters US / Toco
• Twin capability Standard
• Triplets capability Optional
• Internal foetal parameters DECG, IUP
• Smart Pulse technology Standard
• Cross channel verification Standard
• Foetal movement profile Standard

27. Specifications
• Interfaces
• System interface (optional) Serial, LAN
• PS/2 interfaces Optional
• Display
Monitor screen display 6.5 in/16.51 cm
Touchscreen operation Standard

28. Specifications
• Readings
• NST hours Standard
• NST trace interpretation (optional) Up to three Fetal Heart Rates (FHR)
• Data storage
• Data buffer Up to one hour
• Battery
• Operating time (optional) Up to four hours
• Weight
• Weight without battery option 5.1 kilogram
• Weight with battery option 5.3 kilogram

29. Terms
• Shoulders of Deceleration- Accelerations before and after a variable deceleration. Their presence
indicates the foetus is not yet hypoxic and is adapting to the reduced blood flow.
• Antenatal- during or relating to pregnancy.
• Pre Eclampsia- a condition in pregnancy characterized by high blood pressure, sometimes with
fluid retention and proteinuria.
• Chorioamnionitis: Inflammation of the chorion and the amnion, the membranes that surround
the fetus. Chorioamnionitis usually is associated with a bacterial infection. This may be due to
bacteria ascending from the mother's genital tract into the uterus to infect the membranes and
the amniotic fluid. Chorioamnionitis is dangerous to the mother and child.
• Occiput Posterior: The most common position for a baby during labor is head down with the back
of the head (occiput) facing the front of the mother (anterior). When the back of the head is
facing the back of the mother (posterior) the baby's position is called Occiput Posterior. This
occurs in 15-30% of labors. A baby who does not rotate into an anterior position during labor is
considered a "persistent posterior."

30. Terms
• Toco: A tocodynamometer, or toco for short, is a transducer pressure-sensing device that can
detect the changes in your abdomen as your uterus tightens during a contraction. It marks how
often contractions occur and the length of each, producing a graph that looks like a series of hills
rolling across the bottom of the printout.
• Intrapartum: occurring during labour or delivery.
• Antepartum: occurring before childbirth.

31. References
• http://www.aafp.org/afp/990501ap/2487.html
• http://www.fastbleep.com/medical-notes/o-g-and-paeds/16/34/449
• Clinical obstetrics & gynaecology. 2nd Edition. 2009. B.Magowan,
Philip Owen, James Drife
• http://www.nice.org.uk/nicemedia/live/11837/36273/36273.pdf
• http://www.brooksidepress.org/Products/Military_OBGYN/Textbook/
LaborandDelivery/electronic_fetal_heart
• http://www.philips.co.in/healthcare/product/HC862199/avalon-
fm30-fetal-monitor#

32. Thank You!