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Difficulty: MediumLabor, Delivery, and Puerperium

Following an uncomplicated term pregnancy, a patient is admitted to the labor unit in the active phase of the first stage of labor. After receiving epidural anesthesia for pain management, she begins to complain of dizziness and nausea. Her current vital signs show a blood pressure of 82/4882/48 mmHg and a heart rate of 110110/min. Continuous electronic fetal monitoring reveals a baseline heart rate of 130130/min with moderate variability. The tracing also demonstrates recurrent, gradual, and symmetric decreases in the fetal heart rate that begin after the peak of each uterine contraction and resolve only after the contraction has completely finished. Which of the following is the most appropriate initial management step?

  1. Rapid infusion of isotonic crystalloid solutionsAnswer
  2. B
    Transfer to the operating room for emergent delivery
  3. C
    Transcervical instillation of isotonic saline
  4. D
    Subcutaneous injection of terbutaline
  5. E
    Placement of a fetal scalp electrode

Answer

Rapid infusion of isotonic crystalloid solutions
The patient is experiencing epidural-induced sympathectomy, a common complication of neuraxial anesthesia that leads to peripheral vasodilation and maternal hypotension. This acute drop in blood pressure decreases uteroplacental perfusion, resulting in transient fetal hypoxia. On the fetal monitor, this presents as recurrent late decelerations (gradual, symmetric decreases in the fetal heart rate that reach their nadir after the peak of the uterine contraction). The most appropriate initial step is to perform intrauterine resuscitation aimed at improving placental blood flow. This fundamentally requires correcting the maternal hypotension through the rapid infusion of isotonic crystalloid solutions to increase intravascular volume. Ancillary resuscitative measures include maternal lateral positioning (to relieve aortocaval compression) and oxygen administration. If these steps fail, intravenous vasopressors (e.g., ephedrine or phenylephrine) should be administered.

Step-by-Step Solution

1
Identify the cause of the maternal symptoms and altered vital signs.
The patient has dizziness, nausea, and a blood pressure of 82/4882/48 mmHg shortly after receiving epidural anesthesia, indicating epidural-induced sympathetic blockade and resulting vasodilation/hypotension.
Recognizing the iatrogenic cause of hypotension is crucial for selecting the appropriate targeted therapy.
2
Interpret the continuous electronic fetal monitoring tracing.
The tracing shows recurrent late decelerations (symmetric decreases starting after the contraction peak), which are a direct result of uteroplacental insufficiency.
Maternal hypotension decreases blood flow to the intervillous space, causing transient fetal hypoxia during contractions.
3
Determine the most appropriate initial management step.
Initiate intrauterine resuscitation to correct the maternal hypotension by administering a rapid intravenous fluid bolus.
Restoring maternal intravascular volume and blood pressure will improve placental perfusion and resolve the late decelerations. Other immediate steps include maternal lateral repositioning and, if refractory, vasopressors.

Key Concept

Intrauterine resuscitation for late decelerations caused by maternal hypotension
Estimated Time:1m 0s
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Topics

Labor, Delivery, and Puerperium

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