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 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

 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 History of Lipid Rescue

Rat Experiment

Lipid Rescue Protocol

105 cc’s IV push 1050 cc/hr Calculations 70 Kg patient: 1.Bolus dose? 2.Infusion rate (cc/hr)? Notify pharmacy ASAP! “Rule of 15:” Bolus = ml/kg/min = 15 X wt(kg) = cc/hr

How it works “Partitioning”: Lipid Sink Lipid Pool Lipid Sponge

Location  Available at all satellite pharmacy windows: GOR 3 rd floor old trauma building  Hospital-wide date TBA  Currently in large omnicell just outside New TOR entrance  Once hospital wide, only in key omnicells, not every one.

Contents: 1.20% Intralipid (500ml) 2.Alaris pump tubing 3.Copy of protocol

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 Case Study

Websites: Need to Know More???

Weinberg, GL (2012). Lipid Emulsion Infusion: Resuscitation for Local Anesthetic and Other Drug Overdose. Anesthesiology 2012; 117 (1), pp 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 References