Perioperative Regional Anesthesia A practical approach November 7, 2015 Gareth Nakasone, MD

Types of Regional Anesthesia Neuraxial Neuraxial Spinal Spinal Epidural Epidural Peripheral Nerve Blocks Peripheral Nerve Blocks Plexus Blocks Plexus Blocks Selective Peripheral Nerve Blocks (PNB) Selective Peripheral Nerve Blocks (PNB) Bier Block Bier Block

Duration of Action Neuraxial Neuraxial Spinal: minutes Spinal: minutes Epidural: minutes Epidural: minutes Peripheral Nerve Blocks Peripheral Nerve Blocks Plexus Blocks: 1.5–18+ hours Plexus Blocks: 1.5–18+ hours Peripheral Nerve Blocks: hours Peripheral Nerve Blocks: hours Bier Block: minutes Bier Block: minutes

Why Use PNB’s? Superb analgesia Superb analgesia Long Duration of Action Long Duration of Action Decreased Intraop Anesthesia Needs Decreased Intraop Anesthesia Needs Decreased Incidence of PONV Decreased Incidence of PONV Excellent Risk Profile Excellent Risk Profile Pt can be discharged with block intact Pt can be discharged with block intact

Medicines Used for PNBs Chloroprocaine Chloroprocaine Mepivacaine Mepivacaine Lidocaine Lidocaine Ropivacaine Ropivacaine Bupivacaine Bupivacaine Shorter Acting ↓ Longer Acting

Medicines Used for PNBs Chloroprocaine Chloroprocaine Shortest acting of the common anesthetics Shortest acting of the common anesthetics Duration measured in minutes (30-120) rather than hours Duration measured in minutes (30-120) rather than hours Very safe Very safe Toxic levels rarely occur, even with large doses Toxic levels rarely occur, even with large doses Typically used for short procedures where long- lasting analgesia is not required Typically used for short procedures where long- lasting analgesia is not required

Medicines Used for PNBs Lidocaine Short-Intermediate acting Lasts 2-8 hours Epinephrine significantly increases duration Low-Moderate risk of toxicity Very commonly used Most people feel comfortable with it

Medicines Used for PNBs Mepivacaine (Polocaine) Mepivacaine (Polocaine) Faster onset than Lidocaine Faster onset than Lidocaine Slightly longer duration of action than Lidocaine (2- 8+ hours) Slightly longer duration of action than Lidocaine (2- 8+ hours) Causes less vasodilation, so less absorption Causes less vasodilation, so less absorption

Medicines Used for PNBs Ropivacaine (Naropin) Very similar to Bupivacaine, but better risk profile Much less cardiotoxic, and easier to metabolize Provides sensory>motor blockade

Medicines Used for PNBs Bupivacaine (Marcaine) Bupivacaine (Marcaine) Most commonly % Most commonly % Gives the longest lasting, most dense block Gives the longest lasting, most dense block Highest risk of cardiovascular complications Highest risk of cardiovascular complications Cheap and commonly used Cheap and commonly used

Medicines Used for PNBs Epinephrine Significantly prolongs block effect Provides earlier indication of systemic toxicity Sodium Bicarbonate Increases pH of anesthetics Speeds onset of block

Types of Peripheral Nerve Blocks Upper Body Upper Body Brachial Plexus Brachial Plexus Interscalene Interscalene Supraclavicular Supraclavicular Infraclavicular Infraclavicular Axillary Axillary Bier Block Bier Block

Types of Peripheral Nerve Blocks Lower Body Lower Body Upper and Front of Leg Upper and Front of Leg Lumbar Plexus Lumbar Plexus Femoral Nerve Block Femoral Nerve Block Lower and Back of Leg Lower and Back of Leg Sacral Plexus Sacral Plexus Sciatic Nerve Block Sciatic Nerve Block Popliteal Nerve Block Popliteal Nerve Block

Brachial Plexus Blocks

Types of Peripheral Nerve Blocks Brachial Plexus Blocks Brachial Plexus Blocks The closer to the neck, the higher on the arm The closer to the neck, the higher on the arm All of these blocks hit the same nerves, but to different extent All of these blocks hit the same nerves, but to different extent The medial portion of the upper arm is not covered (intercostobrachial nerve) The medial portion of the upper arm is not covered (intercostobrachial nerve) Complications are rare, and usually occur early after injection Complications are rare, and usually occur early after injection

Bier Block Arm is exsanguinated Arm is exsanguinated Tourniquet inflated Tourniquet inflated Lidocaine 0.5% infused via small IV in hand Lidocaine 0.5% infused via small IV in hand Lasts minutes Lasts minutes Resolves very quickly Resolves very quickly Complications dealt with prior to PACU Complications dealt with prior to PACU

Lumbar Plexus/Femoral N Block

Types of Peripheral Nerve Blocks Lumbar Plexus and Femoral Nerve Block Basically the same block, done at two different sites Lumbar Plexus also covers Lateral Femoral Cutaneous n. and Obturator n. Covers only front half of upper leg and a strip of skin from the medial knee to the medial ankle

Sacral Plexus & Sciatic Nerve Block

Sciatic Nerve/Sacral Plexus Block Covers the posterior portion of the upper leg and (almost) the entire lower leg Covers the posterior portion of the upper leg and (almost) the entire lower leg Except that strip of skin on the inside of the lower leg mentioned earlier Except that strip of skin on the inside of the lower leg mentioned earlier This is a very long lasting block, up to 30+ hours This is a very long lasting block, up to 30+ hours A Popliteal Block is simply a Sciatic N. block done at the knee A Popliteal Block is simply a Sciatic N. block done at the knee

Risks of Nerve Blocks Infection Infection Late complication, rarely seen when aseptic technique is used Late complication, rarely seen when aseptic technique is used Bruising Bruising Quite common, usually small and self-limited Quite common, usually small and self-limited Hematoma Hematoma Usually results from inadvertent vascular puncture Usually results from inadvertent vascular puncture Treat with direct pressure Treat with direct pressure

Risks of Nerve Blocks Secondary injury to blocked area Secondary injury to blocked area Pressure injury Pressure injury Patient can’t feel pressure points Patient can’t feel pressure points Place a pillow between extremity and gurney Place a pillow between extremity and gurney Unintentional self-inflicted injury Unintentional self-inflicted injury Motor returns before sensory Motor returns before sensory Warn outpatients not to cook, chop, or touch hot objects until “tomorrow” Warn outpatients not to cook, chop, or touch hot objects until “tomorrow”

Risks of Nerve Blocks Spinal/Epidural injection Occurs most commonly with interscalene block Occurs very soon after block placement Very rare Treatment is supportive, intubation and vasopressors may be needed Remember the ABCs

Risks of Nerve Blocks Pneumothorax Pneumothorax Seen most frequently with Supraclavicular blocks (~5%) and rarely with other brachial plexus blocks Seen most frequently with Supraclavicular blocks (~5%) and rarely with other brachial plexus blocks Usually small and require no treatment Usually small and require no treatment Chest X-rays are not usually ordered Chest X-rays are not usually ordered An elevated hemidiaphragm is normal after interscalene blocks An elevated hemidiaphragm is normal after interscalene blocks

Risks of Nerve Blocks Seizure Results from intravascular injection or (rarely) systemic uptake Seizures may indicate cardiac arrest is coming STAT page the anesthesiologist Treatment: Remember the ABC’s Get help

Risks of Nerve Blocks Seizure treatment, cont. Seizure treatment, cont. Drugs to help stop the seizure: Drugs to help stop the seizure: Benzodiazepines Benzodiazepines Versed 2-5 mg Versed 2-5 mg Thiopental Thiopental mg mg Propofol Propofol mg mg Again, prepare for hypotension/cardiac arrest Again, prepare for hypotension/cardiac arrest

Risks of Nerve Blocks Cardiovascular Collapse Cardiovascular Collapse Most commonly seen when Bupivacaine is injected intravascularly Most commonly seen when Bupivacaine is injected intravascularly Occurs only rarely Occurs only rarely Usually seen immediately during placement of the block Usually seen immediately during placement of the block Can be very long-lasting and very hard to treat Can be very long-lasting and very hard to treat

Risks of Nerve Blocks Treatment of Cardiovascular Collapse Treatment of Cardiovascular Collapse Airway Management Airway Management Hypoxia, Hypercapnia, and Acidosis make it more difficult to treat Hypoxia, Hypercapnia, and Acidosis make it more difficult to treat CPR, CPR, CPR CPR, CPR, CPR Follow basic ACLS protocols, and consider: Follow basic ACLS protocols, and consider: Amiodarone is the drug of choice for arrythmias ( mg IV push) Amiodarone is the drug of choice for arrythmias ( mg IV push) Vasopressin for hypotension (40u IV push) Vasopressin for hypotension (40u IV push) Try to avoid epinepherine as a first-line drug Try to avoid epinepherine as a first-line drug But it may be needed later in the code But it may be needed later in the code It can potentiate arrythmias from local anesthetics It can potentiate arrythmias from local anesthetics

Epinephrine Controversy September 2009 Hiller et al, Anesthesiology and an editorial by Cave and Martyn. This paper shows by dose-response that a single dose of epinephrine above a certain threshold (~10mcg/kg) given along with lipid infusion profoundly inhibits successful recovery from bupivacaine overdose (20mg/kg) compared with lipid alone. The potential clinical implication is that higher dose epinephrine is potentially harmful to patients with drug-induced cardiac arrest.

Risks of Nerve Blocks Treatment of Cardiovascular Collapse Treatment of Cardiovascular Collapse Intralipid (20% lipid emulsion) may be helpful Intralipid (20% lipid emulsion) may be helpful 1 mL/kg bolus (May be repeated twice) 1 mL/kg bolus (May be repeated twice) Infusion of 0.25 mL/kg/min for 10 min Infusion of 0.25 mL/kg/min for 10 min Cardiopulmonary Bypass may be indicated in refractory cases Cardiopulmonary Bypass may be indicated in refractory cases (Wow, that’s scary…) (Wow, that’s scary…)

Helping with Block Placement PNBs may be placed in pre-op and occasionally in PACU PNBs may be placed in pre-op and occasionally in PACU Don’t Panic! Don’t Panic! Assisting should be very easy Assisting should be very easy

Nerve Block Set-Up Anesthesiologist will set up most equipment Anesthesiologist will set up most equipment Sterile technique is used on the field, but the stimulator and syringes are not sterile Sterile technique is used on the field, but the stimulator and syringes are not sterile

Block Placement Remember, this is easy Remember, this is easy Use continuous negative aspiration Use continuous negative aspiration Do not inject until requested Do not inject until requested Turn stimulator slowly down from 1.0 mA to 0.3 mA when requested Turn stimulator slowly down from 1.0 mA to 0.3 mA when requested

Block Placement Inject 1cc (test dose) Aspirate Inject 3-5 cc slowly Aspirate Repeat Injection & Aspiration until done Expect your hands to be a little tired

Key Points: Nerve Blocks are generally safe and well tolerated Nerve Blocks are generally safe and well tolerated Complications are rare, but need to be treated immediately if detected Complications are rare, but need to be treated immediately if detected Common sense prevails –just treat the extremity like it’s numb, cuz it is! Common sense prevails –just treat the extremity like it’s numb, cuz it is! Don’t be afraid to ask questions –most folks who place blocks like to talk about them Don’t be afraid to ask questions –most folks who place blocks like to talk about them

Barriers to Regional Anesthesia Absolute contraindications Absolute contraindications Patient refusal Patient refusal Infection at site of injection Infection at site of injection Allergy Allergy Relative contraindications Relative contraindications Coagulopathy Coagulopathy Indeterminate neurologic disease Indeterminate neurologic disease Unknown duration of surgery Unknown duration of surgery

Questions?