Intrapartum Fetal Surveillance Flashcards
What are some indications for Electronic Fetal Monitoring?
Any High risk condition:
- maternal medical conditions: DM, HTN, etc
- Maternal obstetric complications: hx of prior c-sections, 42+ weeks, preeclampsia, gestational DM
- intrapartum complications
- epidural use
- known or suspected fetal conditions
What functions do each of the two transducers perform with electronic fetal monitoring?
- uterine contractions
2. fetal heart rate
If you use structured intermittent auscultation, how often should you listen?
every 15-30 minutes in active first stage of labor and every 5-15 minutes in second stage of labor
What pnemonic describes interpreting continuous electronic fetal monitoring?
DR C BRAVADO
What does DR C BRAVADO stand for?
Determine Risk Contractions Baseline RAte Accelerations Decelerations Overall Assessment
What are 3 ways to monitor contractions?
- palpation
- external transducer
- intrauterine pressure catheter
What is considered a normal number of contractions?
= 5 contractions in 10 minutes averaged over 30 minutes
What is considered tachysystole with regards to contractions?
> 5 contractions in 10 minutes averaged over 30 minutes
How is the Baseline RAte defined?
Mean fetal heart rate rounded to increments of 5 BPM during a 10-minute segment
How is baseline bradycardia defined?
Baseline <110 BPM for greater than 10 minutes
What are 7 maternal causes of baseline bradycardia?
- supine positioning
- hypotension
- connective tissue disease, ie lupus
- hypothermia
- hypoglycemia
- excessive vagal stimulation
- tachysystole
What are 4 fetal causes of Baseline Bradycardia?
- prolonged cord occlusion/cord prolapse
- fetal hypoxia
- cardiac conduction or anatomic defects
- Post dates >42 0/7 weeks
How is baseline Tachycardia defined?
Baseline >160 BPM for greater than 10 minutes
How is variability defined?
Fluctuations in baseline FHR that are irregular in amplitude and frequency
What are the 4 ways variability can be characterized?
- absent: undetectable
- minimal: AMPLITUDE range detectable but = 5 BPM
- Moderate: 6 to 25 BPM
- Marked: >25 BPM
What are 6 maternal causes of Decreased Variability?
- fever
- CNS depressants (ie opioids, benzos, MgSO4)
- general anesthesia
- Alcohol
- Corticosteroids
- Anticholinergics/parasympathetics
What are 6 fetal causes of decreased variability?
- fetal sleep cycles (20- to 40-minute duration)
- prematurity
- cardiac anomalies
- fetal tachycardia
- hypoxia/acidosis
- CNS anomalies
How are accelerations defined?
visually apparent, abrupt increase in FHR above baseline
- onset to peak in <30 seconds
Peak must be >/= 15 BPM above baseline
(or =10 sec if <32 weeks gestation)
Must last >/=15 seconds
(or >/=10 seconds if <32 weeks gestation)
Must return to baseline within 2 minutes
What are the 3 classifications of Decelerations?
- Early
- Variable
- Late
How are decelerations defined?
by their rate of onset (abrupt or gradual) and their timing in relation to the contraction
How are early decelerations defined?
visually apparent, gradual decrease in FHR with return to baseline in association with a uterine contraction
- nadir coincides with the peak of contraction
- onset to nadir >/= 30 seconds (gradual in onset)
What is the physiology of early decelerations?
Fetal head compression –> local changes in cerebral blood flow –> stimulation of vagal centers in the fetus –> decelerations of FHR
How are variable decelerations defined?
visually apparent, abrupt decrease in FHR below baseline
- onset to nadir <30 seconds
- decrease in FHR is >/= 15 BPM, with duration of >/=15 seconds (but less than 2 minutes)
What is the physiology behind variable decelerations?
cord compression
–> rise in fetal peripheral resistance –> sudden fetal HTN –> parasympathetic outflow –> slowing of fetal atrial pacemaker –> variable FHR deceleration
