Foetal Monitoring Flashcards
(50 cards)
What speed should the CTG paper be set at?
1cm/min
What are some adverse effects of using cEFM?
- High false positive rate
- Increased risk of instrumental delivery/CS
- Increased anxiety
What does mothers stand for?
Beware of: Meconium Oxytocin Temperature Hyperstimulation/haemorrhage Epidural Rate of progress Scar (VBAC)
What does DR C BRAVADO stand for?
DR = define risk C = contractions BRA = baseline rate V = variability A = accelerations D = decelerations O = overall
How is the overall CTG categorised?
Normal, Suspicious, Pathological
How are the individual elements categorised?
Reassuring, Non-reassuring, Abnormal
What makes a CTG suspicious?
1 non-reassuring feature
What makes a CTG pathological?
1 abnormal or 2 non-reassuring features
What are the categories for baseline rate?
Reassuring = 110-160 Non-reassuring = 100-109 or 161-180 Abnormal = >180 or <100
Give some causes of a bradycardic baseline
- Maternal hypotension
- Hypertonic uterus
- Placental abruption
- Cord prolapse
- Drugs (e.g. pethidine)
Give some causes of a tachycardic baseline
- Prematurity
- FM
- Hypoxia
- Anaemia/ hypovolaemia
- Maternal pyrexia/tachycardia
- Maternal dehydration
- Drugs (e.g. nicotine)
What causes variability?
Interplay between sympathetic and parasympathetic NS
What is cycling?
Periods of reduced variability, usually while the baby is sleeping - these are normal if under 30 mins
What are the categories for variability?
Reassuring = 5-25 or <5 for <30 mins Non-reassuring = <5 for 30-50 mins or >25 for 15-25 mins Abnormal = <5 for >50 mins or >25 for >25 mins
What factors may reduce variability?
- Cycling
- Opiates (e.g. pethidine, morphine)
- Hypoxia
- Brain damage
- Cardiac arrythmia
What kind of variability always has a pathological cause?
Sinusoidal (baseline 120-160 with regular sine waves)
What are the signs of foetal hypoxia?
Reduced variability + Tachycardia + Decelerations
What are accelerations?
Increase of at least 15 beats for at least 15 secs
What are decelerations?
Decrease of at least 15 beats for at least 15 secs
What are decelerations mediated by?
Baroreceptors and chemoreceptors
How do baroreceptors work?
- Detect raised BP
- Located in carotid artery and aortic arch
- Cause early/variable decels
How do chemoreceptors work?
- Detect change in pH of blood
- Located in carotid bodies, aortic arch and brain stem
- Cause late decels
Describe early decelerations
- Very rare (2% of decels)
- In line with contractions
- Head compression = raised BP = baroreceptors stimulate parasympathetic NS = vagus nerve releases acetylcholine = decreased FHR
How are late decelerations categorised?
> 50% for <30 mins = non-reassuring
>50% for >30 mins = abnormal
