Regional Anesthesia and Pain Management Flashcards

What is the primary advantage of ropivacaine over bupivacaine for continuous peripheral nerve blocks?

Answer: Greater motor sparing at equivalent analgesic concentrations

Ropivacaine has less lipid solubility than bupivacaine, resulting in more differential sensory-motor block and a significantly lower risk of cardiotoxicity with accidental intravascular injection.

In ultrasound-guided femoral nerve block, where is the nerve typically located relative to the femoral artery?

Answer: Lateral to the femoral artery, beneath the fascia iliaca

The femoral nerve lies lateral to the femoral artery and deep to the fascia iliaca (but outside the femoral sheath) at the inguinal level.

Which opioid is most appropriate for a patient with severe renal impairment requiring analgesia?

Answer: Fentanyl

Fentanyl has no active renally-cleared metabolites, making it the preferred opioid in renal failure; morphine-6-glucuronide accumulates in renal failure and can cause profound sedation.

The erector spinae plane (ESP) block deposits local anesthetic in which anatomical location?

Answer: Between the erector spinae muscle and the transverse process

The ESP block injects local anesthetic into the fascial plane between the erector spinae muscles (multifidus/longissimus) and the tip of the transverse process, where it can spread to block dorsal and ventral rami.

A patient develops ringing in the ears, perioral numbness, and metallic taste during a scalp nerve block. What is the immediate management priority?

Answer: Stop injection, administer IV lipid emulsion if seizures develop

These are early CNS signs of local anesthetic systemic toxicity (LAST); injection should be stopped immediately and 20% lipid emulsion (1.5 mL/kg bolus) should be prepared for administration if cardiovascular or neurological deterioration occurs.

Which mechanism explains the analgesic effect of intrathecal clonidine?

Answer: Alpha-2 adrenergic receptor activation inhibiting substance P release in the spinal cord

Clonidine activates spinal alpha-2 adrenergic receptors on presynaptic C-fiber terminals, inhibiting substance P and glutamate release, and on postsynaptic dorsal horn neurons, producing hyperpolarization and analgesia.

What is the correct definition of 'chronic pain' according to the International Association for the Study of Pain (IASP)?

Answer: Pain persisting for more than 6 months or beyond expected healing time

The IASP defines chronic pain as pain that persists beyond normal tissue healing time (usually 3 months) or recurs over more than 3-6 months, often reclassified to >3 months in updated criteria.