CRNA Regional Anesthesia and Nerve Blocks

Question 1

What dermatomal level of spinal anesthesia is typically required for a cesarean section?

Accepted Answer

T4

Answer

A sensory block to T4 (nipple level) is required for cesarean section to ensure adequate coverage of the uterus, peritoneum, and any diaphragmatic irritation.

Question 2

Which of the following is an absolute contraindication to neuraxial anesthesia?

Accepted Answer

Infection at the intended injection site

Answer

Infection at the injection site is an absolute contraindication because introducing a needle through infected tissue risks seeding bacteria into the subarachnoid or epidural space, potentially causing meningitis or epidural abscess.

Question 3

Which local anesthetic is MOST associated with refractory cardiac toxicity and is therefore used at lower concentrations for epidural anesthesia?

Accepted Answer

Bupivacaine

Answer

Bupivacaine has high affinity for cardiac sodium channels and dissociates very slowly ('fast-in, slow-out'), making accidental intravascular injection prone to causing refractory cardiac arrest.

Question 4

The standard epidural test dose detects which two complications?

Accepted Answer

Intravascular injection and subarachnoid injection

Answer

The test dose (typically 3 mL of 1.5% lidocaine with 1:200,000 epinephrine) detects intravascular placement via epinephrine-induced tachycardia and subarachnoid placement via rapid dense motor block.

Question 5

Which order correctly describes the sequence of nerve fiber blockade by local anesthetics from first to last?

Accepted Answer

Sympathetic → sensory → motor

Answer

Smaller, unmyelinated sympathetic B fibers are blocked first, followed by small sensory C and Aδ fibers, then the larger myelinated motor Aα fibers are blocked last.

CRNA - Certified Registered Nurse Anesthetist Practice Test

CRNA - Certified Registered Nurse Anesthetist Practice Test

CRNA Regional Anesthesia and Nerve Blocks