Regional Nerve Blocks

Josh MajorAnesthesia Clerkship

History of Peripheral Nerve Block

• 1880’s: William Stewart Halstad and Richard John Hall describe injecting cocaine into peripheral sites during minor surgery

• 1914: Heinrich Braun describes techniques for every region of the body.

• 1922: Regional Anesthesia: It’s Technic and clinical Application written by Gaston Labot at the Mayo Clinic– Definitive regional anesthesia textbook for 30 years.

Indications for Regional Nerve Block

• Pain control post-op associated with surgical procedures– Improved patient satisfaction due to decreased

pain, opioid use and side effects and decreased incidence of sleep disturbance

• Useful in patients in whom general anesthesia is contraindicated or prevent undesired effects

Contraindications

• Absolute Contraindications:– Infection at site of block– Patient refusal– Allergy to local anesthetic

• Relative Contraindications:– Medical anticoagulation or coagulopathy in

deeper nerve blocks

Types of Nerve Blocks

• Single Shot: one time injection of local anesthetic to target nerve

• Continuous Perineural Blockade: percutaneous insertion of a catheter directly adjacent to target nerves

Upper Extremity Blocks

Upper Extremity Blocks

• Interscalene Block – Indication: Surgery or manipulation of the shoulder

• Supraclavicular Block – Indication: Elbow, forearm and hand surgery

• Infraclavicular Block – Indication: Provide anesthesia to the arm and hand

• Axillary Block – Forearm and hand surgery

Lower Extremity Blocks

Lower Extremity Blocks

• Femoral Nerve Block – Indication: Knee arthroscopy, femoral shaft fractures, total knee repair and ACL reconstruction

• Obturator Nerve Block – Indication: Knee surgery, rarely blocked on it’s own

• Sciatic Nerve Block – Indication: Can be used together with a femoral or saphenous block for any procedure below the knee that doesn’t need a thigh tourniquet

Choices of Local Anesthetic

• Depends primarily on required duration of anesthesia

• Different anesthetic drugs have varying durations

• Blockade may last up to 24 hours• Epinephrine can be added to improve onset of

action and prolong drug action

Major Nerve Block Drugs

Drug with Epinephrine 1 : 200,000

Usual Concentration (%)

Usual Volume (mL)

Maximal Dose (mg)

Usual Onset (min)

Usual Duration (min)

Lidocaine 1-2 30-50 500 10-20 120-240Mepivacaine 1-1.5 30-50 500 10-20 180-300Prilocaine 1-2 30-50 600 10-20 180-300Bupivacaine 0.25-0.5 30-50 225 20-30 360-720Levobupivacaine 0.25-0.5 30-50 225 20-30 360-720

Ropivacaine 0.2-0.5 30-50 250 20-30 360-720

Major Nerve Blocks

Ultrasound Guidance

• Allows direct visualization of the nerve, needle, and anesthetic distribution

• Commonly used as an adjunct to regional anesthesia techniques

• Can be useful in decreasing complications• Facilitates placement of blocks in patients with

challenging anatomy

Complications

• Block Failure• Perineural Hematoma• Infection• Nerve Injury• Intravascular Injection• Intraneural Injection• Excessively Dense Block

References• Miller, M.D., Eriksson, L.I., et al. (eds.). Miller’s Anesthesia, 7th Edition. Philidelphia: Churchill Livingston

2009.