Local Anesthetic Toxicity

Chuck Magich, MS, CRNAStaff Nurse Anesthetist

R Adams Cowley, Shock Trauma CenterBaltimore, MDOctober 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

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

http://youtu.be/b70Li9r3pL8

http://youtu.be/B3au3aKU4oE

Lipid Rescue Protocol

105 cc’s IV push1050 cc/hr

Calculations70 Kg patient:1. Bolus dose?2. Infusion rate

(cc/hr)?

Notify pharmacy ASAP!

“Rule of 15:” Bolus = 1.5

0.25ml/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• 3rd 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.

What & Where?

Contents:1. 20% Intralipid

(500ml)2. Alaris pump tubing3. 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:

1. http://lipidrescue.org2. http://www.lipidrescue.c

om

Need to Know More???

LIPID RESCUE APP

1. http://lipidrescue.org2. http://www.lipidrescue.com3. 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.

References