ABA ABA Regional & Neuraxial Anesthesia 2 — Questions and Answers
Question 1: Epidural analgesia for labor uses which nerve roots as the PRIMARY target for pain relief during the first stage of labor?
- S2-S4
- T10-L1 (Correct answer)
- L2-L4
- T6-T10
Correct answer: T10-L1
First-stage labor pain from uterine contractions and cervical dilation is transmitted via T10-L1 visceral afferents; second-stage pain also involves S2-S4.
Question 2: Which complication is associated with unintentional intravascular injection during an interscalene brachial plexus block?
- Pneumothorax only
- Vertebral artery injection causing seizures (Correct answer)
- Recurrent laryngeal nerve palsy only
- Horner syndrome only
Correct answer: Vertebral artery injection causing seizures
The interscalene block is performed adjacent to the vertebral artery; even 1 mL of local anesthetic injected intra-arterially can cause immediate seizures.
Question 3: Continuous epidural infusion for postoperative analgesia typically combines a local anesthetic with an opioid. The PRIMARY benefit of this combination is:
- Reducing total opioid requirements with synergistic analgesia at lower individual drug doses (Correct answer)
- Allowing higher concentrations of local anesthetic without motor block
- Eliminating the need for monitoring hemodynamics
- Preventing urinary retention
Correct answer: Reducing total opioid requirements with synergistic analgesia at lower individual drug doses
Combining low-dose local anesthetic with epidural opioid exploits synergy at spinal opioid receptors, achieving better analgesia at lower doses of each drug.
Question 4: Horner syndrome (ptosis, miosis, anhidrosis) after a regional block indicates blockade of the:
- Vagus nerve
- Cervical sympathetic chain (stellate ganglion) (Correct answer)
- Phrenic nerve
- Recurrent laryngeal nerve
Correct answer: Cervical sympathetic chain (stellate ganglion)
Horner syndrome results from blockade of the cervical sympathetic trunk or stellate ganglion, commonly seen after interscalene or stellate ganglion blocks.
Question 5: An absolute contraindication to neuraxial anesthesia is:
- Mild thrombocytopenia (platelet count 90,000)
- Patient refusal (Correct answer)
- Prior back surgery without hardware
- Obesity
Correct answer: Patient refusal
Patient refusal is an absolute contraindication to any anesthetic technique; informed consent is a fundamental ethical and legal requirement.
Question 6: The safest minimum time interval to perform neuraxial block after the LAST dose of low-molecular-weight heparin (LMWH) prophylaxis is:
- 4 hours
- 8 hours
- 12 hours (Correct answer)
- 24 hours
Correct answer: 12 hours
ASRA guidelines recommend waiting at least 12 hours after prophylactic LMWH (e.g., enoxaparin 40 mg daily) before neuraxial procedures to minimize epidural hematoma risk.
ABA ABA Regional & Neuraxial Anesthesia 2
Epidural analgesia for labor uses which nerve roots as the PRIMARY target for pain relief during the first stage of labor?