Cardiotocography (CTG) Flashcards
What are the indications of continuous CTG? (8)
Sepsis
Maternal tachycardia (> 120)
Significant meconium
Pre-eclampsia (particularly blood pressure > 160 / 110)
Fresh antepartum haemorrhage
Delay in labour
Use of oxytocin
Disproportionate maternal pain
Key features of CTG (5)
Contractions – the number of uterine contractions per 10 minutes
Baseline rate – the baseline fetal heart rate
Variability – how the fetal heart rate varies up and down around the baseline
Accelerations – periods where the fetal heart rate spikes
Decelerations – periods where the fetal heart rate drops
Why are contractions monitored?
Used to gauge the activity of labour
Too few contractions indicate labour is not progressing
Too many contractions can mean uterine hyperstimulation - can lead to fetal compromise
Important to interpret the fetal heart rate in the context of the uterine contractions.
Why are accelerations monitored?
Generally a good sign that the fetus is healthy (paticularly during contractions)
How is baseline rate and variability described?
Reassuring
(HR 110-160, V 5-25)
Non-reassuring
(HR 100-109 or 161-180, V Less than 5 for 30 – 50 minutes or More than 25 for 15 – 25 minutes)
Abnormal
(HR Below 100 or above 180, V Less than 5 for over 50 minutes or More than 25 for over 25 minutes)
Why are decelerations monitored?
Concerning finding
Fetal heart rate drops in response to hypoxia
Fetal heart rate is slowing to conserve oxygen for the vital organs
What are the 4 types of decelerations?
Early decelerations
Late decelerations
Variable decelerations
Prolonged decelerations
What are Early decelerations?
Gradual dips and recoveries in heart rate that correspond with uterine contractions
Lowest point of the declaration corresponds to the peak of the contraction
Normal and not considered pathological
Caused by the uterus compressing the head the fetus, stimulating the vagus nerve, slowing HR
What are Late decelerations?
Gradual falls in heart rate that starts after the uterine contraction has already begun
Delay between the uterine contraction and the deceleration
Lowest point of the declaration occurs after the peak of the contraction
Caused by hypoxia in the fetus - may be caused by:
Excessive uterine contractions
Maternal hypotension
Maternal hypoxia
What are Variable decelerations?
Abrupt decelerations that may be unrelated to uterine contractions
Fall of more than 15 bpm from the baseline
Deceleration lasts less than 2 minutes in total
Often indicate intermittent compression of the umbilical cord, causing fetal hypoxia
Brief accelerations before/after ‘shoulders’
What are prolonged decelerations?
Last between 2 and 10 minutes with a drop of more than 15 bpm from baseline
often indicates compression of the umbilical cord, causing fetal hypoxia
abnormal and concerning
How are decelerations described?
Reassuring - no decelerations, early decelerations or less than 90 minutes of variable decelerations with no concerning features
Non reassuring/abnormal - Regular variable decelerations and late decelerations
Prolonged always abnormal
Assessing CTG
Normal
Suspicious: a single non-reassuring feature
Pathological: two non-reassuring features or a single abnormal feature
Need for urgent intervention: acute bradycardia or prolonged deceleration of more than 3 minutes
How to manage fetal bradycardia
3 minutes – call for help
6 minutes – move to theatre
9 minutes – prepare for delivery
12 minutes – deliver the baby (by 15 minutes)
What is DR C BRaVADO?
DR – Define Risk (define the risk based on the individual woman and pregnancy before assessing the CTG)
C – Contractions
BRa – Baseline Rate
V – Variability
A – Accelerations
D – Decelerations
O – Overall impression (given an overall impression of the CTG and clinical picture)
