Regional Anesthesia/Analgesia

Question 1

Why is regional anesthesia used with general anesthesia?

Answer 1

• Decreased requirement for inhalation anesthetics
• improved muscle relaxation
• Preemptive analgesia

Question 2

How does local anesthesia provide pre-emptive analgesia?

Answer 2

• Prevents transmission of noxious stimuli to spinal cord
• Prevents excitation of interneurons in the dorsal horn

Question 3

What is the MOA of local anesthetics?

Answer 3

• Prevent influx of Na⁺ into nerve axons
• Prevents depolarization or propagation of action potential

Question 4

nerve block

Question 5

What determines the efficacy of a nerve block?

Answer 5

• Concentration of molecules at the site of action
• Volume
• Proximity

Question 6

What are the possible toxicities with Local anesthetics?

Answer 6

• Systemic:
  
  • CNS
  • Cardiovascular
  • Methemoglobinemia
• Allergic Reactions (extremely rare)
  
  • Localized vs systemic
  • Esters
• Local tissue toxicity

Question 7

What are the options for forelimb nerve blocks? medications used?

Answer 7

• Use Lidocaine (0.2-0.3 ml /site)
• Radial
• Ulnar
• Median