CTG Flashcards
What is cardiotocography?
Continuous foetal heart rate monitoring (also known as electronic foetal monitoring)
What are maternal antenatal risk factors that should prompt recommendation of EFM in labour?
- Previous CS
- Cardiac Problems
- Pre-eclampsia
- Prolonged pregnancy > 42 weeks
- Prelabour rupture of membranes
- Induction of labour
- Diabetes
- Antepartum haemorrhage
What are foetal antenatal risk factors that should prompt recommendation of EFM?
- IUGR
- Prematurity
- Oligohydramnios
- Abnormal doppler velocimetry
- Multiple pregnancy
- Meconium stained liquor
- Breech presentation
What are intrapartum risks which require CTG?
- Oxytocin augmentation
- Epidural analgesia
- Intrapartum vaginal bleeding
- Pyrexia >37.5oC
- Fresh meconium staining of liquor
- Abnormal FHR on intermittent auscultation
- Prolonged labour
What does the term baseline rate mean when decribing features of CTG?
Mean level of the FHR when this is stable and after exclusion of accelerations and decelerations
What does the term baseline variability mean when refering to CTG reading/
Degree to which the baseline varies:
- 0-5 beats/min = reduced
- 5-25 beats/min = normal
- >25 beats/min = saltatory
What is meant by acceleration when referring to CTG readings?
Transient rise in FHR by at least 15 beats over the baseline lasting for >/= 15 secoonds
What is meant by the term deceleration when referring to CTG readings?
A reduction in the baseline of 15 beats or more for more than 15s
What is a bradycardia defined as on CTG?
FHR <110 bpm
What are causes of decreased baseline variability on CTG?
- Foetal hypoxia
- Foetal sleep cyce
- Foetal malformation
- Drug administration
- Severe prematurity
- Foetal heart block
- Foetal abnormalities
What is regarded as tachycardia on CTG?
>160 bpm
What are maternal factors which can contribute to an abnormal CTG?
- Woman’s position
- Hypotension
- Vaginal examination
- Emptying bladder or bowels
- Vomiting
- Vasovagal episodes
What approach could you use for assessing a CTG?
DR C BRAVADO
- Define Risk
- Contrations
- Baseline RAte
- Variability
- Accelerations
- Decelerations
- Overall impression
How would you define risk in someone with CTG?
- Maternal medical issues - hypertension, diabetes, asthma
- Obstetric complications - Multiple, Post-term delivery, Previous CS, IUGR, premature membrane rupture, oxytocin induction, pre-eclampsia
- Other - Absence or prenatal care, smoking, drug abuse
How would you assess contrations as part of the DR C BRAVADO mnemonic?
- Number of contractions in 10 minutes - within 10 big squares on CTG
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Record the following:
- Duration
- Intensity
How would you assess baseline rate of CTG as part of you DR C BRAVADO mnemonic?
- Average heart rate of the fetus within a 10-minute window.
- Ignore any accelerations or decelerations.
- A normal fetal heart rate is between 110-150 bpm
What are causes of foetal tachycardia?
- Foetal hypoxia
- Chorioamnionitis
- Hyperthyroidism
- Foetal/maternal anaemia
- Foetal tachyarrhythmias
What are causes of mild foetal bradycardia?
- Postdate gestation
- OP/ROT/LOT presentation
What are causes of prolonged severe foetal bradycardia?
Severe hypoxia:
- Prolonged cord compression
- Cord collapse
- EPidural/spinal anaesthesia
- Maternal seizures
- Rapid foteral descent
Why does baseline variability occur?
Variability occurs as a result of the interaction between the nervous system, chemoreceptors, baroreceptors and cardiac responsiveness.
What is regarded as non-reassuring variability?
- Less than 5bpm for between 30-50 minutes
- More than 25bpm for 15-25 minutes
What is regarded as abnormal variability?
- Less than 5bpm for more than 50 minutes
- More than 25bpm for more than 25 minutes
- Sinusoidal
How are accelerations in FHR on CTG interpreted?
Presence of accelerations is reassuring - presence alongside uterine contractions is a sign of a healthy foetus
What is early deceleration indicative of?
Normal physiological response - due to increased foetal ICP due to uterine contractions; ends when contraction ends
