Fetal heart rate monitoring Flashcards
How are uterine contractions monitored?
of ctx in 10 minute window averaged 30 minutes
Normal uterine activity
5 ctxs or less in 10 minutes averaged over 30 minutes
Tachysystole uterine activity
more than 5 ctxs in 10 minutes averaged over 30 minutes
Category 1 are strongly predictive of normal _______.
acid-base status
Baseline FHR
mean FHR rounded to increments of 5 bpminute during a 10 minute segment excluding periodic/episodic changes, periods of marked variability, segments of baseline that differ by more than 25 bpm
minimal baseline variability
range detectable but 5 bpm or fewer
moderate baseline variability
amplitude range6-25 bpm
Define acceleration
visually apparent increase in FHR w/ onset to peak less than 30 seconds. If it lasts 10 minutes or longer, then it is a baseline change
Define acceleration at 32 wga and beyond
peak of 15 bpm or more above baseline w/ a duration of 15 seconds or more but less than 2 minutes
Define acceleration before 32 wga
peak of 10 bpm above baseline w/ a duration of 10 seconds or more but less than 2 minutes
Define prolonged acceleration
2min>FHT<10 min
Define early decel
symmetrical gradual decrease and return of FHR w/ ctx/ Peak of nadir=peak of ctx.
Late decel
nadir occurs after peak of ctx.
Define variable decel
abrupt decrease is defined as from the onset of decel to beginning of FHR nadir of less than 30s. 15 bpm lasting 15 seconds to 2 minutes.
prolonged decel
decrease from baseline that is 15 bpm or more lasting 2-10 minutes.
Category 1 tracing
no late or variable decels
Category 3 tracing
absent variability and any of the following: recurrent late decels, recurrent variable decels, bradycardia, sinusoidal.
How often should pt w/o complications be monitored?
1st stage: 30 minutes. 2nd stage: 15 min
The use of EFM decreases the risk of ____
neonatal seizures
___% of encephalopathy occurs during IP period
4
T or F moderate variability is strongly associated w/ arterial umbilical cord pH >7.15
true
What is decreased variability associated with?
fetal hypoxia, acidemia, drugs, fetal tachycardia, CNS/cardiac anomalies, prolonged contractions, prematurity, fetal sleep, betamethasone
Cause of early decel
pressure on fetal head. physiologic
Cause of late decel
repititve (>50% in 20 minutes) are associated w/ uteroplacental insufficiency
causes of variable decels
umbilical cord compression, oligohydramnios
Absence of accelerations for ___ minutes correlates w/ increased neonatal morbidity
80
Define reactivity
An increase of 15 BPM above baseline for 15 second duration (from baseline to baseline) twice in a 20 minute period.
Decel etiology
Etiologies: Maternal hypotension [18] , uterine hyperactivity, cord prolapse, cord compression, abruption, artifact (maternal heart rate) , maternal seizure [19]
How are late decels managed
Place patient on side [23,24]
Discontinue oxytocin.
Correct any hypotension
IV hydration.
If decelerations are associated with tachysystole consider terbutaline 0.25 mg SC [26,27]
Administer O2 by tight face mask [25, 40]
If late decelerations persist for more than 30 minutes despite the above maneuvers, fetal scalp pH is indicated.
Scalp pH > 7.25 is reassuring, pH 7.2-7.25 may be repeated in 30 minutes.
Deliver for pH < 7.2 or minimal baseline variability with late or prolonged decelerations and inability to obtain fetal scalp pH
How are variable decels managed
Change position to where FHR pattern is most improved. Trendelenburg may be helpful.
Discontinue oxytocin.
Check for cord prolapse or imminent delivery by vaginal exam.
Consider amnioinfusion[35-37]
Administer 100% O2 by tight face mask [4].
