NBCRNA Regional Anesthesia 1

Question 1

In spinal anesthesia, which factor most influences the spread of local anesthetic in the intrathecal space?

Accepted Answer

Baricity of the local anesthetic solution relative to CSF

Answer

Baricity (density relative to CSF) determines whether the solution is hyperbaric (sinks), hypobaric (rises), or isobaric (stays), making patient positioning and baricity the primary determinants of block spread.

Question 2

The classic presentation of a 'high spinal' or 'total spinal' includes which combination of findings?

Accepted Answer

Severe hypotension, bradycardia, and respiratory arrest

Answer

When local anesthetic spreads to high thoracic/cervical levels, it blocks cardiac accelerator fibers (T1–T4) and the respiratory muscles (including the diaphragm at C3–C5), causing cardiovascular collapse and apnea.

Question 3

During epidural anesthesia, a test dose of 3 mL of 1.5% lidocaine with 1:200,000 epinephrine is used to detect what?

Accepted Answer

Intravascular catheter placement (tachycardia) and intrathecal placement (rapid spinal block)

Answer

The epinephrine component causes a 20+ bpm heart rate increase if injected intravascularly, while the lidocaine dose would produce a rapid dense spinal block if injected intrathecally.

Question 4

Interscalene brachial plexus block provides the best anesthesia for surgery on which area?

Accepted Answer

Shoulder and proximal humerus

Answer

The interscalene approach targets the brachial plexus at the C5–C7 roots, providing excellent coverage of the shoulder, clavicle, and proximal humerus while often missing the ulnar nerve (C8–T1).

Question 5

What is the most serious complication specific to interscalene brachial plexus block?

Accepted Answer

Ipsilateral phrenic nerve palsy causing hemidiaphragm paralysis

Answer

Ipsilateral phrenic nerve block occurs in nearly 100% of interscalene blocks, reducing pulmonary function by about 25%, which is contraindicated in patients with severe respiratory disease.

NBCRNA - National Board of Certification and Recertification for Nurse Anesthetists Practice Test

NBCRNA - National Board of Certification and Recertification for Nurse Anesthetists Practice Test

NBCRNA Regional Anesthesia 1