late decelerations

Question 1

20 year old with preeclampsia is induced and later noted to have late decelerations on FHR tracing. how would you describe tracing? (see book)

Answer 1

distinct decelerations are beginning within 10-30 seconds of initiation of uterine contraction and resolving within 10-30 seconds of the end of each contraction. this equates to late decelerations. moreover, although the FHR is normal (110-160 bpm), there appear to be minimal (less than 5 bpm) fluctuations of FHR.

reduced FHR variability can occur as result of magnesium sulfate-induced CNS depression, however it is most likely a non-reassuring tracing and may indicate fetal distress.

Question 2

what is normal fetal heart rate variability and what is the significants of normal and abnormal?

Answer 2

baseline variability: fluctuations of HR by >5 bpm of more than 2 cycles per minute.

normal suggests functioning autonomic nervous system and fetal well-being

absence appears to be the most significant intrapartum sign of fetal compromise (hypoxia, fetal sleep state, prematurity, fetal neurologic abnormalities, tachycardia, betamethasone administration, congenital anomalies, CNS depressants)

Question 3

what are the types of FHR decelerations?

Answer 3

early (type 1): uniform FHR less than 20 bpm below baseline and coincide with onset/offset of contractions. represent vagal response to mild hypoxia or transient increase in ICP (uterine compression of head)

late (type 2): gradual, uniform FHR decelerations, onset/recovery occur around 10-30 seconds after onset/recovery of uterine contraction.

• reflex late (maternal hypotension, reduced uterine BF, fetal hypoxia, increased fetal vagal tone, FHR decal). usually maternal hypotension, good variability
• nonreflex late (fetal hypoxia, myocardial decompensation, increased vagal tone, FHR deceleration). usually uteroplacental insufficiency, IUGR, prolonged hypoxia, decreased/absent variability

variable (type 3): non-uniform shape/duration with variable occurrence in relation to contractions. mild, moderate or severe based on degree/duration. result from increased vagal activity secondary to complete/partial cord occlusion. dural stimulation from the compression of the head may lead to increased vagal activity as well. mild to moderate decelerations (>80 bpm) well tolerated. severe (

Question 4

if this is late decelerations, how would you treat the patient?

Answer 4

1. inform OB
2. provide supplemental O2
3. ensure LUD
4. discontinue oxytocin
5. begin fluid bolus
6. optimize maternal hemodynamics
7. careful H&P focusing on airway, coagulation status, comorbidities, complications of preeclampsia
8. discuss plan with OB
9. assuming no contraindication, recommend early initiation of epidural as to avoid need for general anesthesia if crash section necessary later