Local Anesthetic Toxicity Chuck Magich, MS, CRNA Staff Nurse Anesthetist R Adams Cowley, Shock Trauma Center Baltimore, MD October 2013 Used in epidural catheters & peripheral nerve block catheters. “caine” family: Lidocaine Bupivicaine Physiology Local anesthetics block Na+ channels to prevent impulse transmission. Meant for perineuronal injection, not IV! Can bind to other receptors, especially cardiac. More about Locals • Bolus at insertion 20-40 cc’s • Infusion rates 5-10cc’s /hr • Epi used in local to detect intravascular injection (HTN, tachy) • Epi also used to prolong duration of action by causing vasoconstriction to area infiltrated • Always aspirate before injecting • Small incremental injections Signs & symptoms of toxicity CNS Dizziness Circumoral numbness Tinnitus Metallic taste Confusion Seizure Coma Cardiovacular Hypotension Bradycardia Heart Block Vent Arrythmias V-tach V-Fib Asystole Traditional Management of Toxicity BLS ACLS CPB Often prolonged resus w/poor outcomes History of Lipid Rescue First discovered in 1998 by Weinberg First used to successfully treat patient in 2006 (Rosenblatt) Now being shown to be effective for other types of OD’s: TCA’s, beta blockers, calcium channel blockers Rat Experiment http://youtu.be/b70Li9r3pL8 http://youtu.be/B3au3aKU4oE Lipid Rescue Protocol Calculations 70 Kg patient: 1. Bolus dose? 2. Infusion rate (cc/hr)? 105 cc’s IV push 1050 cc/hr “Rule of 15:” Bolus = 1.5 0.25ml/kg/min = 15 X wt(kg) = cc/hr Notify pharmacy ASAP! How it works “Partitioning”: • Lipid Sink • Lipid Pool • Lipid Sponge Location Currently in large omnicell just outside New TOR entrance Available at all satellite pharmacy windows: • GOR • 3rd floor old trauma building Hospital-wide date TBA Once hospital wide, only in key omnicells, not every one. Contents: 1. 20% Intralipid (500ml) 2. A l a r i s p u m p t u b i n g 3. C o p y o f p r o t o c o l Case Study • 84 y/o, ASA 2, 70 kg • Femoral neck fx • Block w/ 30cc 0.25% Bupivicaine • Neg asp after every 5 cc • c/o feeling “funny” 1 min after block • Became unresponsive followed by seizure • Developed PEA arrest • Intubated & CPR started • 1mg epi given • 20% intralipid started within 5-8 mins after LOC • Rec’d 500 ml lipid total • Soon after lipid started developed SB 35 • Atropine 0.5mg x 2 • Ext pacing started • HR 70 w/stable BP • To ICU on no pressors • 24* later hemiarthroplasty performed • Extubated end of case • DC to floor 3 days later • Completely neurologically intact Need to Know More??? Websites: 1. http://lipidrescue.org 2. http://www.lipidrescue.com References 1. http://lipidrescue.org 2. http://www.lipidrescue.com 3. Weinberg, GL (2012). Lipid Emulsion Infusion: Resuscitation for Local Anesthetic and Other Drug Overdose. Anesthesiology 2012; 117 (1), pp. 180-187. 4. Hiller, DB; Gregorio, GD; Ripper, R; Kelly, K; Massad, M; Edelman, L; Edelman, G; Feinstein, DL; Weinberg, GL. Epinephrine Impairs Lipid Resuscitation from Bupivacaine Overdose: A Threshold Effect. Anesthesiology 2009: 111 (3), pp.498-505.