interpreting CTG Flashcards

1
Q

what is the acronym for CTG?

A
DR: Define risk
C: Contractions
BRa: Baseline rate
V: Variability
A: Accelerations
D: Decelerations
O: Overall impression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are maternal factors that make a CTG high risk?

A

Gestational diabetes
Hypertension
Asthma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are obstetric complications of that make a CTG high risk?

A
Multiple gestation
Post-date gestation
Previous cesarean section
Intrauterine growth restriction
Premature rupture of membranes
Congenital malformations
Oxytocin induction/augmentation of labour
Pre-eclampsia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the base rate for fetal heart rate?

A

110-160 bpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is considered fetal tachycardia?

A

baseline heart rate >160

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are causes of fetal tachycardia?

A
  • fetal hypoxia
  • chorioamnionitis
  • hyperthyroidism
  • fetal or maternal anaemia
  • fetal tachyarrhythmia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is defined as fetal bradycardia?

A
  • baseline heart rate of <100
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which situations is it common to have baseline HR between 100-120 bpm?

A
  • post-date gestation

- occiput posterior or transverse position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what values would be seen for severe bradycardia on CTG?

A
  • 80bpm >3minutes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are causes of prolonged severe bradycardia?

A
  • prolonged cord compression
  • cord prolapse
  • epidural and spinal anasthaesia
  • maternal seizures
  • rapid fetal descent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is reassuring baseline variability?

A

5-25 bpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is non reassuring baseline variability?

A

<5bpm for 30-50 mins

>25bpm for 15-25 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is abnormal variability?

A

<5bpm >50 mins
>25bpm >25 mins
sinusoidal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the most common cause of reduced variability in the CTG?

A

fetal sleeping-> no longer than 40 mins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are worrying causes of reduced CTG variability?

A
  • fetal acidosis due to hypoxia
  • drugs: benzodiazepines, methyldopa and magnesium sulphate
  • prematurity- variability is reduced at low gestational ages <28 weeks
  • congenital heart abnormalities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are decelerations?

A

> 15bpm decrease in heart rate >15 seconds

17
Q

what is the cause of early decelerations?

A

they begin and recover with uterine contractions
and they are due to increased fetal intracranial pressure

they are physiological not pathological

18
Q

what is the cause of variable decelerations?

A
  • they don’t correlate to the uterine contractions often seen in patients with reduced amniotic fluid
  • accelerations before and after the deceleration are called shouldering
  • variable decelerations occur when the cord is compressed- umbilical vein occlusion causes the acceleration and artery occlusion causes the rapid deceleration
19
Q

when is variable decelerations worrying?

A

if there is no shouldering it is worrying as the foetus can become hypoxic

20
Q

what do late decelerations indicate?

A

there is insufficient blood flow to the uterus and the placenta

21
Q

how do late decelerations appear on the CTG?

A

peak during uterine contraction and recover after the contraction

22
Q

what are causes of reduced uropplacental blood flow causing late decelerations?

A
  • maternal hypotension
  • pre-eclampsia
  • uterine hyperstimulation
23
Q

what is considered a prolonged deceleration?

A

> 2 mins

> 3mins-> immediately classed as abnormal

24
Q

a sinusoidal pattern is very concerning, what could it suggest?

A

Severe fetal hypoxia
Severe fetal anaemia
Fetal/maternal haemorrhage