EDAIC Obstetric Anesthesia and Analgesia 4 — Questions and Answers
Question 1: Which local anesthetic is ABSOLUTELY CONTRAINDICATED for epidural use in obstetrics due to cardiac toxicity?
- Ropivacaine 0.5%
- Bupivacaine 0.75% (Correct answer)
- Levobupivacaine 0.5%
- Chloroprocaine 3%
Correct answer: Bupivacaine 0.75%
Bupivacaine 0.75% is absolutely contraindicated for epidural use after multiple maternal cardiac arrests; the lower concentrations remain acceptable.
Question 2: What is the Apgar score component affected FIRST by opioid-induced neonatal depression?
- Heart rate
- Respiratory effort (Correct answer)
- Muscle tone
- Reflex irritability
Correct answer: Respiratory effort
Respiratory effort is the most sensitive Apgar component to neonatal opioid depression, appearing as slow, irregular, or absent breathing.
Question 3: A patient with known mitral stenosis presents for labor. Which hemodynamic goal is MOST important during labor analgesia?
- Maintain tachycardia to increase cardiac output
- Avoid tachycardia and maintain sinus rhythm (Correct answer)
- Aggressive fluid loading to increase preload
- Allow significant preload reduction
Correct answer: Avoid tachycardia and maintain sinus rhythm
In mitral stenosis, tachycardia reduces diastolic filling time across the stenotic valve, precipitating pulmonary edema; maintaining sinus rhythm and controlled heart rate is critical.
Question 4: Which drug should be immediately available when performing test dose confirmation of epidural catheter placement?
- Epinephrine to detect intravascular placement (Correct answer)
- Atropine for bradycardia treatment
- Phenylephrine for hypotension
- Naloxone for opioid reversal
Correct answer: Epinephrine to detect intravascular placement
Epidural test dose contains epinephrine 15 mcg; intravascular injection causes a transient heart rate increase >20 bpm, confirming misplacement.
Question 5: At what gestational age does the lower esophageal sphincter pressure decrease sufficiently to significantly increase aspiration risk?
- 8-10 weeks
- 14-16 weeks
- 18-20 weeks (Correct answer)
- 28-30 weeks
Correct answer: 18-20 weeks
By 18-20 weeks gestation, progesterone-mediated LES relaxation combined with upward gastric displacement significantly increases aspiration risk, justifying aspiration prophylaxis.
Question 6: Combined spinal-epidural (CSE) analgesia offers which advantage over epidural-only technique for labor analgesia?
- Lower incidence of fetal bradycardia
- Faster onset of analgesia with the spinal component (Correct answer)
- Eliminates need for subsequent epidural dosing
- Provides better sacral coverage for second stage
Correct answer: Faster onset of analgesia with the spinal component
The intrathecal component of CSE provides rapid-onset analgesia within minutes, compared to the 15-20 minute onset of epidural alone.
Question 7: Which mechanism explains why parturients have increased sensitivity to local anesthetics for neuraxial blockade?
- Increased nerve myelination during pregnancy
- Elevated progesterone increasing nerve membrane sensitivity (Correct answer)
- Alkaline CSF pH enhancing ionized fraction
- Decreased plasma protein binding increasing free drug
Correct answer: Elevated progesterone increasing nerve membrane sensitivity
Progesterone increases nerve membrane sensitivity to local anesthetics, reducing the dose required for equivalent neuraxial block compared to non-pregnant patients.
EDAIC Obstetric Anesthesia and Analgesia 4
Which local anesthetic is ABSOLUTELY CONTRAINDICATED for epidural use in obstetrics due to cardiac toxicity?