BCA Obstetric Anesthesia & Analgesia 3 — Questions and Answers
Question 1: A patient with severe preeclampsia receives magnesium sulfate and epidural analgesia. Which complication is MOST likely if epidural bupivacaine dose is not adjusted?
- Hypertensive crisis from sympathetic rebound
- Enhanced neuromuscular blockade and profound hypotension (Correct answer)
- Seizure due to reduced seizure threshold
- Accelerated platelet consumption
Correct answer: Enhanced neuromuscular blockade and profound hypotension
Magnesium potentiates the vasodilatory and neuromuscular effects of local anesthetics, increasing the risk of hypotension and potentially enhancing motor block.
Question 2: The recommended fasting guideline for clear liquids in laboring patients without additional risk factors per ASA is:
- 4 hours before any anesthetic
- 2 hours before neuraxial procedures (Correct answer)
- 6 hours before all obstetric procedures
- 8 hours before emergency procedures
Correct answer: 2 hours before neuraxial procedures
The ASA recommends laboring patients may consume clear liquids up to 2 hours before neuraxial anesthesia, balancing aspiration risk with hydration needs.
Question 3: During cesarean delivery under spinal anesthesia, the patient complains of nausea immediately after uterine delivery. The MOST likely cause is:
- Systemic absorption of oxytocin
- Hypotension from aortocaval compression
- Peritoneal traction causing vagal response (Correct answer)
- Intrathecal morphine-induced emesis
Correct answer: Peritoneal traction causing vagal response
Peritoneal traction during uterine exteriorization stimulates vagal afferents causing nausea and bradycardia, a common intraoperative event during cesarean delivery.
Question 4: Which coagulation threshold is generally accepted as safe for neuraxial block placement in obstetric patients with thrombocytopenia?
- Platelet count ≥ 50,000/μL with normal PT/aPTT
- Platelet count ≥ 70,000/μL with normal PT/aPTT (Correct answer)
- Platelet count ≥ 80,000/μL regardless of trend
- Platelet count ≥ 100,000/μL
Correct answer: Platelet count ≥ 70,000/μL with normal PT/aPTT
Most obstetric anesthesia societies accept a platelet count ≥ 70,000–80,000/μL with stable trend and normal coagulation studies as sufficient for neuraxial procedures.
Question 5: A patient with a prior uterine scar presents for trial of labor. Which anesthetic consideration is most important regarding epidural analgesia?
- Epidural should be withheld to detect uterine rupture pain
- Epidural analgesia does not mask the pain of uterine rupture and can be placed (Correct answer)
- Higher concentrations of local anesthetic are required to cover rupture pain
- Spinal-epidural is contraindicated in uterine scar patients
Correct answer: Epidural analgesia does not mask the pain of uterine rupture and can be placed
Current evidence shows epidural analgesia does not mask the signs of uterine rupture (fetal heart rate changes, hemodynamic instability) and is safe in TOLAC patients.
Question 6: The transfer of local anesthetics across the placenta is MOST dependent on which property?
- Protein binding and pKa (Correct answer)
- Molecular weight alone
- Lipid solubility only
- pH of the local anesthetic solution
Correct answer: Protein binding and pKa
Placental transfer is governed by protein binding (less free drug crosses) and pKa (determines ionized fraction at physiologic pH); bupivacaine's high protein binding limits fetal transfer.
Question 7: Intraoperative awareness is most likely during general anesthesia for cesarean delivery because:
- Volatile agents are reduced to avoid neonatal depression (Correct answer)
- Muscle relaxants mask signs of awareness in obstetric patients
- Opioids are withheld pre-delivery to prevent neonatal respiratory depression
- Benzodiazepines are contraindicated in pregnancy
Correct answer: Volatile agents are reduced to avoid neonatal depression
Anesthesiologists often reduce volatile anesthetic concentrations pre-delivery to minimize neonatal depression, increasing the risk of maternal intraoperative awareness.
BCA Obstetric Anesthesia & Analgesia 3
A patient with severe preeclampsia receives magnesium sulfate and epidural analgesia.
Which complication is MOST likely if epidural bupivacaine dose is not adjusted?