CRNA Regional Anesthesia and Nerve Blocks 3

Question 1

What is the first-line treatment for local anesthetic systemic toxicity (LAST) presenting with cardiovascular collapse?

Accepted Answer

20% lipid emulsion (Intralipid) IV

Answer

20% lipid emulsion acts as a 'lipid sink' to sequester the lipophilic local anesthetic from cardiac tissues and is the definitive pharmacologic treatment for LAST with cardiovascular collapse, per ASRA guidelines.

Question 2

Following an epidural top-up dose, a patient develops rapid onset of apnea, unconsciousness, and cardiovascular collapse. What has most likely occurred?

Accepted Answer

Total spinal anesthesia from inadvertent subarachnoid injection

Answer

Total spinal anesthesia from inadvertent intrathecal injection of an epidural dose causes rapid cephalad spread, blocking respiratory muscles and cardioaccelerator fibers, resulting in apnea and cardiovascular collapse requiring immediate airway management.

Question 3

Which brachial plexus approach carries the highest risk of pneumothorax?

Accepted Answer

Supraclavicular

Answer

The supraclavicular block is performed directly above the clavicle at the apex of the lung (historically called the 'bloody corner'), and pneumothorax occurs in up to 6% of cases without ultrasound guidance.

Question 4

According to ASRA guidelines, what is the minimum time to wait after the last prophylactic dose of LMWH (e.g., enoxaparin 40 mg daily) before performing neuraxial anesthesia?

Accepted Answer

12 hours

Answer

ASRA recommends a minimum 12-hour interval after the last prophylactic LMWH dose before neuraxial needle placement to reduce the risk of epidural hematoma.

Question 5

Ipsilateral Horner syndrome (ptosis, miosis, anhidrosis) following an interscalene block is caused by inadvertent blockade of which structure?

Accepted Answer

Stellate (cervicothoracic) ganglion

Answer

The stellate ganglion, which provides sympathetic innervation to the ipsilateral head and neck, lies adjacent to the brachial plexus at the interscalene level and is frequently blocked, producing the classic Horner triad.

CRNA - Certified Registered Nurse Anesthetist Practice Test

CRNA - Certified Registered Nurse Anesthetist Practice Test

CRNA Regional Anesthesia and Nerve Blocks 3