MAC Regional Anesthesia & Pain Management 1 — Questions and Answers
Question 1: Which nerve block provides the broadest analgesia for hip replacement surgery?
- Femoral nerve block
- Sciatic nerve block only
- Fascia iliaca compartment block (Correct answer)
- Saphenous nerve block
Correct answer: Fascia iliaca compartment block
The fascia iliaca compartment block covers the femoral, lateral femoral cutaneous, and often obturator nerves, providing effective multi-nerve hip analgesia.
Question 2: What is the maximum safe dose of plain bupivacaine for peripheral nerve block in an adult?
- 2.5 mg/kg (Correct answer)
- 3 mg/kg
- 4 mg/kg
- 7 mg/kg
Correct answer: 2.5 mg/kg
The maximum safe dose of plain bupivacaine is 2.5 mg/kg due to its high cardiotoxicity risk compared to other local anesthetics.
Question 3: What is the first-line treatment for local anesthetic systemic toxicity (LAST)?
- Epinephrine 1 mg IV bolus
- Intralipid 20% emulsion IV (Correct answer)
- Atropine 0.5 mg IV
- Sodium bicarbonate IV
Correct answer: Intralipid 20% emulsion IV
Intravenous lipid emulsion (Intralipid 20%) is the specific antidote for LAST by acting as a lipid sink to sequester the local anesthetic.
Question 4: Which structure provides the loss of resistance during epidural needle placement?
- Dura mater
- Ligamentum flavum (Correct answer)
- Supraspinous ligament
- Posterior longitudinal ligament
Correct answer: Ligamentum flavum
Loss of resistance occurs as the needle passes through the dense ligamentum flavum into the epidural space.
Question 5: A spinal block that ascends to T4 may block which critical physiologic response?
- Knee-jerk reflex
- Cardiac accelerator fibers (Correct answer)
- Pupillary reflex
- Gag reflex
Correct answer: Cardiac accelerator fibers
Cardiac accelerator fibers originate from T1-T4; a spinal block to this level can cause significant bradycardia and hypotension.
Question 6: What is the primary advantage of ultrasound guidance for peripheral nerve blocks?
- Faster procedure time always
- Reduced local anesthetic volume and improved block accuracy (Correct answer)
- Eliminates need for sterile technique
- Allows full patient cooperation without sedation
Correct answer: Reduced local anesthetic volume and improved block accuracy
Ultrasound guidance allows real-time visualization of needle and nerve, reducing required local anesthetic volume and improving block success rates.
MAC Regional Anesthesia & Pain Management 1
Which nerve block provides the broadest analgesia for hip replacement surgery?