CTG Flashcards
How much rest is needed between contractions to prevent hypoxia?
60-90seconds
How many contractions per 10 minute period is optimal?
3-4 per 10 mins.
How does maternal HTN cause hypoxia?
Vasoconstriction leads to reduced uterine blood flow which results in placental damage and the fetus’ metabolic needs not being met.
What does maternal hypotension do to the fetus?
Reduces 02 available to the fetus and results in hypoxia.
What is the baby’s “oxygen tank”?
intervillous space.
What happens when there are too many contractions or the contractions last too long?
The fetus’ energy reserves are depleted.
What are the 4 components of a normal AN CTG?
- Baseline 110-160bpm
- Normal baseline variability (6-25bpm amplitude)
- 2 accelerations within 20mins (15 up and across)
- No decelerations
Where on a CTG do you measure baseline?
In the absence of movement, contraction or during a sleep cycle.
What are the 4 signs of a normal intrapartum CTG?
- Baseline 110-160bpm
- Normal baseline variability (6-25bpm amplitude)
- Accelerations (15 up and across)
- No decelerations
How long is a fetal sleep cycle usually? Why do you not measure baseline during sleep/
Around 20mins.
HR is slightly increased due to the parasympathetic input being withdrawn.
Are premis sympathetically or parasympathetically dominent?
Sympathetically.
What does variability represent?
The upstroke represents symp input and the downstroke represents para input.
What is the difference between increased, normal, reduced and absent variability?
Increased - >25bpm
Normal - 6-25bpm
Reduced - 3-5bpm
Absent - <3bpm almost straight line.
What is an acceleration?
15bpm above baseline for 15+ seconds.
Response to stimulation.
Increased sympathetic stimulation - Increased CO & 02 demands.
What is tachysystole?
More than 5 contractions in 10mins, without fetal heart rate abnormalities.
What is uterine hypertonus?
Contractions that last more than 2 mins OR occur within 60 secs of each other, without fetal abnormalities.
What is uterine hyperstimulation?
Tachysystole OR uterine hypertonus WITH FHR abnormalities.
What does this CTG show in regards to the uterine activity?
Tachysystole. It could be classed as
What uterine activity does this CTG show?
Tachysystole, due to the amount of contractions there is not enough rest to adequately oxygenate the fetus. The CTG shows the fetus is well oxygenated but if those contractions continue the fetus will be compromised.
What uterine activity does this CTG represent?
Uterine hypertonus. Each contraction is lasting 2-3 minutes. The fetus is doing well at that point but is at risk.
What does this CTG show?
Uterine Hyperstimulation. 5+ contractions in a 10minute period. Fetus is showing prolonged decelerations and bradycardia.
What does this CTG show?
A acutely hypoxic fetus. Tachycardic with prolonged and late decelerations. With absent baseline variability.
What is fetal bradycardia?
A fall in baseline for more than 5mins.
