Regional Anesthesia and Pain Management Flashcards

Which ultrasound finding confirms correct needle placement for an adductor canal block?

Answer: Local anesthetic spread surrounding the saphenous nerve between the sartorius and adductor longus muscles

The adductor canal contains the saphenous nerve alongside the superficial femoral artery deep to the sartorius muscle; correct placement shows LA spreading around these structures.

What is the mechanism of action of ketamine in pain management?

Answer: NMDA receptor antagonism

Ketamine is an NMDA receptor antagonist that blocks central sensitization and 'wind-up' phenomena, making it effective for opioid-resistant and neuropathic pain.

A patient has a suspected intravascular injection during an epidural test dose with epinephrine. Which response confirms intravascular placement?

Answer: Heart rate increase >20 bpm within 60 seconds

The classic epidural test dose uses 3 mL of 1.5% lidocaine with 1:200,000 epinephrine; intravascular injection causes a heart rate increase of >20 bpm within 60 seconds.

Which nerve root primarily supplies sensation to the medial aspect of the ankle and foot?

Answer: L4 via saphenous nerve

The saphenous nerve (terminal branch of the femoral nerve, L2-L4, predominantly L4) supplies sensation to the medial leg, ankle, and foot.

The WHO analgesic ladder for cancer pain recommends which sequence of analgesic approach?

Answer: Non-opioids → weak opioids → strong opioids, with adjuvants at each step

The WHO three-step ladder starts with non-opioids (Step 1), adds weak opioids for mild-to-moderate pain (Step 2), and escalates to strong opioids for moderate-to-severe pain (Step 3), with adjuvants at all steps.

During a stellate ganglion block, Horner's syndrome confirms successful blockade. Which triad of signs characterizes Horner's syndrome?

Answer: Ptosis, miosis, and anhidrosis

Horner's syndrome results from sympathetic blockade and manifests as ptosis (drooping eyelid), miosis (pupillary constriction), and anhidrosis (loss of sweating) on the ipsilateral face.

Which type of pain is best characterized by allodynia and hyperalgesia?

Answer: Neuropathic pain

Neuropathic pain arises from nervous system injury or dysfunction and characteristically includes allodynia (pain from non-painful stimuli) and hyperalgesia (exaggerated pain response to painful stimuli).