Fetal Heart Rate Monitoring Flashcards
When looking at a FHR tracing and trying to determine the baseline heart rate, what areas on the graph are ignored?
Anything where there is a drop or rise in the heart rate by 25 bpm or more. In other words, when there is craziness happening and deviation from the baseline.
What are the components of a FHR tracing that we care about, in order?
-Baseline heart rate
-Degree of variability
-Presence and frequency of accelerations vs decelerations (early vs late vs variable)
-Frequency of Contractions
What are baseline changes in the FHR tracing?
Changes in the baseline heart rate for ten minutes (entire strip) or more.
What is the cut off for tachycardia and bradycardia to a fetus during FHR monitoring?
Bradycardia: <110 bpm
Tachycardia: over 160 bpm
What range of bradycardia is okay for a fetus?
100-110 is okay for a fetus, so long as this is an isolated finding.
What typically causes bradycardia in a fetus?
Heart block (no variability)
When is a little bit of tachycardia okay for a fetus?
Tachycardia not above 170 is okay if there is moderate or marked variability.
What typically causes tachycardia in a fetus?
Maternal infection, mild fetal anemia, fetal heart failure, fetal hypoxia, beta sympathomimetics (Albuterol?)
Besides bradycardia, what sign tells us that a fetus has a heart block?
When a low baseline HR is coupled with little to no variability.
What are the cutoffs for the different types of variability?
-minimal: under 5 bpm
-moderate: 6-25 bpm ✅
-marked: over 25 bpm ✅
What is the variability of a sinusoidal wave pattern on a FHR tracing?
There is no/minimal variability for a sinusoidal pattern.
What does the sinusoidal wave pattern mean on a FHR tracing?
It tells us that there is severe fetal anemia! We need to deliver that baby soon.
If the fetal heart rate is normal, but the variability changed from moderate to minimal, what could be going on? Is there cause for alarm?
The baby could be having a sleep cycle.
No cause for alarm :/
Only worry if there is bradycardia too. (Sign of heart block)
What is an adequate acceleration? What age of gestation determines that?
How frequent must they occur?
What is a prolonged acceleration?
-Raise in FHR over 10 bpm or 15 bpm, if under or over 32 weeks, respectively. They must go from baseline to peak before 30 seconds. The entire thing (from baseline to baseline) must not exceed 2 minutes (2 big boxes).
-at least 2 in 20 minutes to be considered actual accelerations.
-A prolonged acceleration is an acceleration that lasts longer than 2 minutes but does not exceed 10 minutes.
When do we add fetal scalp stimulation?
What happens when the fetus does not respond to fetal scalp stimulation?
When there has not been a single acceleration for an hour and 20 minutes.
There is a higher rate of mortality, and there is probably acidosis going on if the fetus does not respond to fetal scalp stimulation.