Fetal Monitoring Flashcards
What is the correct baseline rate of a foetal tachycardia? What are the causes?
160bpm Foetal hypoxia Chorioamnionitis – if maternal fever also present Hyperthyroidism Foetal or maternal anaemia Foetal tachyarrhythmia
What is the definition of a prolonged deceleration on CTG?
Deceleration that lasts more than 2 minutes
Prolonged deceleration/bradycardia: Baseline <90bpm indicates impending demise- ACT!
What is common method used to monitor a foetus in utero?
CTG (not usually done before 26weeks)
Confidently used after 32weeks
What do the different lines (from top to bottom) correspond to?
1: Fetal heart beat
2: Mother presses for fatal movement
3: Actual fetal movement
4: Contraction
What is a CTG acceleration defined as?
Rise of >15bpm for 15secs
What is a CTG deceleration defined as?
Drop of >15bpm for 15secs
What is the number of normal variability?
5bpm
Find a squiggly bit on the fetal HR and measure the distance between the peak & trough
What are the normal rate of contractions during labour?
4-5/ 10mins
What is a normal fetal heart rate?
100-160bpm
What does the contractions line on a CTG show?
Frequency & duration
NOT intensity
Is the absence of accelerations a bad thing?
Not necessarily
Babies in utero sleep
What are the types of decelerations?
Early: Occur with the beginning of a contraction and normalise by the end of the contraction
Late: Occur with the end of a contraction and normalise after the contraction
Early & Late: Uniform in shape, depth & length
Variable: typical (vary in shape & timing related to contraction) & atypical
How are early & late decelerations defined?
E: HR dip always before uterine contraction peak
L: HR dip always after uterine contraction peak
What can be done with a worrying CTG?
- Change to maternal left lateral position
- Give fluids (dehydrated)
- Fetal scalp stimulation
- Fetal blood sample
- Delivery
When should a fatal blood sample be taken?
Worried about CTG but delivery not imminent
At least 3cm dilated
Measurement of fetal pH
What are the different parameters you should cover on a CTG?
DR C BRAVADO Determine risk Contractions Baseline Variability Accelerations Decelerations Overall impression (normal, reassuring, abnormal)
What are the indications for CTG monitoring?
Maternal: Pain, pre-eclampsia, DM, APH
Fetal: IUGR, Prematurity, oligohydramnios, multiple, breech
Intrapartum: IOL, Oxytocin infusion
What can cause sustained tachycardia on a CTG?
Prematurity Hypoxia Fetal distress Maternal pyrexia Exogenous beta agonist use (Salbutamol)
What might baseline bradycardia on a CTG suggest?
Severe fetal distress
?Due to: Abruption, uterine rupture, hypotension, maternal sedation, hypoxia, postmaturity
When can reduced variability be commonly seen?
Fetal sleep cycles
Safely last up to 40mins
>90mins = abnormal
Drugs: Opiates, benzos
Is prolonged reduced variability okay?
Sign of acute fetal distress!
What are the causes of typical variable decelerations?
Cord compression especially in oligohydramnios
What is shouldering?
Sign fetus is comping well with compression
Small acceleration before & after a deceleration
If present >50% of contractions for >90mins become non-reassuring
What are the different managements for each result of a fetal blood sample?
Normal: pH >7.25= labour continues
Borderline: pH 7.20-7.25= Repeat pH needed in 30-60mins
Abnormal: pH <7.20= fetal compromise- DELIVER
What is a sinusoidal trace?
Smooth undulating sine wave No variability Patterns lasts >10mins Amplitude 5-15bpm Cause: Physiological or fetal anaemia, hypoxia Serious until proven otherwise
