Bernie Miller, MD, CA3 OHSU APOM Regional Anesthesia Bernie Miller, MD, CA3 OHSU APOM

Regional Anesthesia Rendering a specific area of the body insensate to stimulus of surgery or other instrumentation

Advantages Major Intra-abdominal surgery Ambulatory Surgery Cardiac disease Vascular surgery Pulmonary resection/rib fractures Obstetric Patients Chronic Pain Oncologic Surgery?

Types of Regional Anesthesia Topical Local/Field IV block- “Bier Block” Peripheral Nerve block (named after the nerve) Plexus block (eg lumbar, brachial) Central Neuraxial (spinal, epidural)

Topical Anesthesia Application of local anesthetic to mucous membrane Uses Awake oral or nasal intubation Superficial surgical procedure Advantage Easy to do Disadvantage Potential for large doses leading to toxicity

Airway blocks Injection of LA to block airway nerves Uses: facilitation of awake intubation Advantage: complete lack of sensation in the airway, blunting of airway reflexes Disadvantage: Potential for injury/injection of surrounding major vascular structures or CSF More invasive than topicalization

Glossopharyngeal Nerve Block

Superior Laryngeal Block (sensory branch)

(recurrent laryngeal) Transtracheal block (recurrent laryngeal)

Local/Field Anesthesia Application of local subcutaneously to anesthetize distal nerve endings (small local area or field) Uses: Suturing, minor superficial surgery, line placement Advantages: minimal equipment, technically easy, rapid onset Disadvantages: potential for toxicity if large field

“IV” Block – “Bier” Block Injection of local anesthetic IV for anesthesia of an extremity Uses Any short surgical procedure on a distal extremity Advantages Technically simple, minimal equipment, rapid Disadvantages Duration limited by tolerance of tourniquet pain, toxicity

Peripheral/Plexus Nerve Block Injecting local anesthetic near the course of a named nerve or plexus Uses: Surgical procedures in the distribution of the blocked nerve Pain control of a specific area Advantages: More bang for your buck (more coverage with less LA) Less narcotic Patient can either be sedated or fully awake and functional Limb specific Disadvantages: technical complexity, neuropathy

Single shot vs Catheter Fast placement Smaller introducing needle More complex placement- two step process Duration of anesthetic not limited to duration of drug action

Setup/method Often in a designated “block” room or space with dedicated team Supplies Monitor vitals Sedation Can use ultrasound guidance or nerve stimulation Positioning! Localize nerve based on anatomy, confirm location with device Communicate with patient Inject and/or or thread catheter Test dose

Nerve stimulator Provides short, low frequency electric impulse to elicit defined muscle response Based on known innervation of nerve Can use transcutaneously to plan approach Can use with needle during block Good response at low output indicates close proximity to the nerve Inject local Should lose response as conduction blocked

Ultrasound vs Stimulator US Stimulator Benefit Direct visualization Real-time visualization Hard-to-find landmarks Drawback Osseous or gas-filled structures impede signal Takes up an extra hand Can be misleading (need to see tip) Benefit Confirm correct nerve function Attaches to needle in use Drawback No visualization of neighboring structures Requires assistant’s hands Discomfort Unreliable in neuropathy

Peripheral/Plexus Block Upper Extremity Brachial plexus interscalene supraclavicular Infraclavicular Axillary Median Ulnar Radial Lower Extremity Femoral Sciatic Obturator Saphenous Tibial Ankle Lumbar plexus Others: TAP block, paravertebral block

Upper Extremity Plexi Cervical Plexus Brachial Plexus Ventral Rami of C1-C4 Located deep to the SCM in the neck Advanced regional technique Brachial Plexus Ventral rami of C5-T1 Responsible for cutaneous and muscular innervation of upper limb

Brachial plexus blocks Level Potential Drawback Uses Interscalene Roots, Trunks Spares inferior trunk Shoulder, upper arm Supraclavicular Trunks, Divisions Risk for pneumo Entire arm, including hand Infraclavicular Cords Pectoral discomfort Entire arm, good for catheter

Interscalene Block Patient position Anatomical landmarks Supine with head rotated 30 degrees to C/L side Anatomical landmarks Determine interscalene groove (AS & MS) at the level of C6 where the nerves emerge from behind the scalene muscles (be careful of the EJ!). Do not confuse the interscalene groove with the AS/SCM groove.

Casualty nerves: phrenic – hemidiaphragmatic paralysis sympathetic chain – Horner’s recurrent laryngeal - hoarseness

Supraclavicular

Infraclavicular

Axillary Nerve Block Advantages Provides anesthesia for forearm & wrist Fewer complications than a supraclavicular block Limitations Not for shoulder or upper arm surgery Musculocutaneous nerve lies outside of the sheath and must be blocked separately Complications Intravascular injection Elevated bleeding time increases risk for hematoma

Axillary Block Position Head turned away from arm being blocked Abduct to 90º Forearm is flexed to 90º Palpate brachial artery for pulse

Axillary Nerve Block

Axillary Nerve Block

Femoral Nerve Block (L2-L4) Uses: Knee arthroscopy in combination with intra- articular local anesthetic Good for femoral shaft fractures, ACL, TKA with multimodal regimen Limitations: Not reliable for posterior knee, lower leg or upper thigh Complications: Arterial puncture Abdominal cavity puncture

Femoral block landmarks “NAVL” Draw a line between the ASIS and the pubic tubercle Determine location of femoral artery Introduce needle one cm lateral to artery

Sciatic Nerve Block (L4-5, S1-3) Uses: Nearly complete blockade of the foot and ankle What does the sciatic nerve turn into? Limitations: Not a good block for upper thigh or hip Advantages: Easy to palpate anatomic landmarks No major vessels near the nerve

Popliteal nerve block Uses : Lower 2/3 of leg Does not cover medial (saphenous) Objective Find the sciatic bifurcation Anesthetize both branches Tibial Common peroneal

Posterior Approach

Finding the bifurcation Proximal Distal

Ankle Block Five nerves Tibial Superficial peroneal Saphenous Sural Deep peroneal

Ankle block

Lower Plexus Blocks Lumbar Plexus L2-L4 Form the obturator, lateral femoral cutaneous, and femoral nerves Provides sensory and motor innervation to anterior lower extremity Lumbosacral plexus L4-L5, S1-S3 Primarily forms the sciatic nerve Provides motor and sensory innervation to posterior lower extremity Rarely done

L2-L4

Lumbar Plexus block Uses: Disadvantages Potential complications Obturator, femoral, and lateral femoral cutaneous nerves in the belly of the psoas muscle Knee, thigh and hip Catheter frequently used to extend block Disadvantages Not useful for lower leg or foot Cannot use real-time ultrasound Potential complications Bleeding from psoas muscle bed Increased systemic absorption of local anesthetic from increased vascularity

Lumbar plexus Positioning Lateral decubitus positioning with the blocked side up Foot of the side being blocked should be over the dependent leg so the twitches of the patella can be seen.

Lumbar plexus Landmarks Locate both iliac crests and and draw a line between them, this is usually the location of L4 (Tuffier’s) Generally, the plexus will be 4cm lateral to the spinous process along this line.

TAP block Transversus abdominis plane block Good for abdominal surgery Single shot (less frequently catheter) Can be used as rescue LA spread between internal oblique and transversus abdominus muscles Anesthetize anterior rami of T7-L1

TAP block

Paravertebral block Anesthetize thoracic spinal nerves within paravertebral space above L1 Thoracic, chest wall, breast, rib fx Unilateral or bilateral Usually single shot, catheter possible Landmark or ultrasound Complications?

In-line approach

Neuraxial anesthesia

Epidural Injection of local anesthetic +/- adjunct into the epidural space (lumbar, thoracic, caudal) Usually catheter is left in place for continued infusion Useful for intraoperative and post-operative pain control as well as labor analgesia Benefits: decreased ileus, pain control without respiratory depression, improved perfusion Potential drawbacks: hypotension (sympathectomy), pruritis, possible wet tap, potential for epidural hematoma or vascular injection, one-sided or patchy block

Thoracic epidural catheter

Spinal Injection of local anesthetic +/- adjunct into spinal space Usually single shot procedure Can combine with epidural (CSE) Lumbar ONLY Complete motor and sensory block Fast to perform, quick onset, relatively short duration depending on choice of anesthetic, rarely fails More pronounced hypotension, possible spinal HA, possible high spinal

Spinal via introducer

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