FHR tracings Flashcards
mean FHR rounded to increments of 5 bpm during a 10 min segment, excluding periodic / episodic changes or segments that differ by more than 25 bpm
baseline
baseline must be for a minimum of __ in any __ segment, or the baseline is indeterminate
2 minutes
10 minute
normal FHR baseline
110-160 bpm
tachycardia
> 160
bradycardia
< 110
fluctuations in the baseline FHR that are irregular in amplitude and frequency
baseline variability
variability is visually quantitated as what?
the amplitude of peak-to-trough in bpm
absent variability
amplitude range undetectable
minimal variability
amplitude range detectable but 5 bpm or fewer
moderate (normal) variability
amplitude range 6-25 bpm
marked variability
amplitude range greater than 25 bpm
a visually apparent abrupt increase in the FHR
acceleration
(onset to peak in less than 30 seconds)
at 32 + weeks gestation, an acceleration has a peak of __ + above baseline, with a duration of __ + but less than __ from onset to return
15 bpm
15 seconds
2 minutes
before 32 weeks gestation, an acceleration has a peak of __ + above baseline, with a duration of __ + but less than __ from onset to return
10 bpm
10 seconds
2 minutes
prolonged acceleration lasts between
2-10 min
if an acceleration lasts 10 min or longer, it is a __ ?
baseline change
visually apparent usually symmetrical gradual decrease and return of FHR associated with a uterine contraction
deceleration
a gradual FHR decrease is defined as ?
from the onset to the FHR nadir of 30 seconds or more
the decrease in FHR is calculated from ?
the onset to the nadir of the deceleration
the nadir of the deceleration occurs at the same time as the peak of the contraction
early deceleration
for an early deceleration, in most cases, the onset / nadir / recovery of the deceleration occur?
coincident with the beginning / peak / ending of the contraction
the deceleration is delayed in timing, with the nadir of the deceleration occurring after the peak of the contraction
late deceleration
for a late deceleration, in most cases, the onset / nadir / recovery of the deceleration occur?
after the beginning / peak / ending of the contraction
visually apparent abrupt decrease in FHR
variable deceleration
an abrupt decrease is defined as from __ to __ of less than __ ?
the onset of the deceleration
the nadir
30 seconds
with a variable deceleration, the decrease in FHR is __ or greater, lasting __ or greater, and less than __ in duration
15 beats
15 seconds
2 minutes
when __ decelerations are a/w uterine contractions, their onset, depth, and duration commonly vary with successive uterine contractions
variable
visually apparent decrease in the FHR below baseline
prolonged deceleration
prolonged deceleration = decrease in FHR from baseline that is __ or more, lasting __ or more, but less than __ in duration
15 bpm
2 minutes
10 minutes
if a deceleration lasts 10 min or longer, it is a __ ?
baseline change
visually apparent, smooth, sine wave-like undulating pattern in FHR baseline
sinusoidal pattern
sinusoidal pattern typically has a cycle frequency of __ which persists for __ or more
3-5 / minute
20 minutes
EFM =
electronic fetal monitoring
how often should the FHR tracing be reviewed during the first stage of labor?
every 30 minutes
how often should the FHR tracing be reviewed during the second stage of labor?
every 15 minutes
category I FHR tracing
4
- baseline rate 110-160 bpm
- moderate variability
- absent late / variable decelerations
- present or absent early decelerations / accelerations
category II FHR tracing
all FHR tracings not categorized at category I or III
category III FHR tracing
- absent baseline FHR variability + recurrent late decelerations / recurrent variable decelerations / bradycardia
- sinusoidal pattern
what type of variable decelerations occur with less than 50% of contractions?
intermittent
what type of variable decelerations occur with more than 50% of contractions?
recurrent
common causes of recurrent late decelerations
transient or chronic uteroplacental insufficiency - maternal hypotension, uterine tachysystole, maternal hypoxia
management of recurrent late decelerations
maternal lateral positioning, IV fluid bolus, maternal oxygen administration, eval for tachysystole
for minimal FHR variability thought to be due to recent maternal opioid admin, variability often improves / returns to moderate variability within what time frame
1-2 hours
how long does a fetal sleep cycle generally last
20 min
but can persist up to 60
what is considered tachysystole
> 5 contractions in 10 minutes, averaged over 30 minutes
