Start with a free trial account for free content every month. Already a subscriber? Sign in.

Toxicology Sessions - LAST (Local Anesthetic Systemic Toxicity)

Jan Shoenberger, MD and Sean Nordt, MD PharmD FAAEM
00:00
13:05
Sign in or subscribe to listen

No me gusta!

The flash player was unable to start. If you have a flash blocker then try unblocking the flash content - it should be visible below.

Nurses Edition Commentary

Kathy Garvin, RN and Lisa Chavez, RN
00:00
02:23

No me gusta!

The flash player was unable to start. If you have a flash blocker then try unblocking the flash content - it should be visible below.

EMRAP 2019 02 February Written Summary 286 KB - PDF

To view chapter written summaries, you need to subscribe.

Sign up today for full access to all episodes.

John R. -

I found this formula for calculating the max dose of local anesthetic in adults. It does not address hepatic or renal metabolism issues.

"The formula is as follows: maximum allowable dose (mg/kg) x (weight in kg/10) x (1/concentration of local anesthetic) = mL lidocaine. Thus, if maximal dose is 7 mg/kg for lidocaine with epinephrine, using 1% lidocaine with epinephrine for a 60-kg patient: 7 x 6 x 1 = 42 mL lidocaine. Maximal doses for lidocaine without and with epinephrine are 3 mg/kg and 7 mg/kg, respectively."
A Simple Formula for Quick and Accurate Calculation of Maximum Allowable Volume of Local Anaesthetic Agents
Br J Dermatol 2014 Aug 12;[EPub Ahead of Print], K Walsh, R Arya.

Sean N. -

Hi John R.

Thank you for the comments and reference you included.

I do recommend that in any patient in which large doses of lidocaine or other local anesthetic are anticipated to be used is to calculate and draw up the maximum dose and volume BEFORE you start the procedure. This way you know before you start not to go over. Often it is only after large amounts of local anesthetic have already been given that the calculations are done or if patient is having systemic toxicity.

Aaron M. -

Great information on LAST. I always appreciate the tox/pharm segments on EM:RAP. One thing I've always wondered is this: when combining local anesthetics, e.g., a mixture of bupivacaine and lidocaine (both dosed below toxic mg/kg amounts), can these two agents' toxic doses be considered independent of each other? Or, would the combination have a synergy that would decrease the toxic threshold of either agent?

Sean N. -

Hi Aaron,

Thank you for the great question. If the two agents were mixed together e.g., 50:50 the safest assumption is to lower the potential toxicity by half i.e., rather than not to exceed 4 mg/Kg would decrease maximum dose to 2 mg/Kg for lidocaine without epinephrine and from 2 mg/Kg to 1 mg/Kg for bupivicaine without epinephrine as the total volume would be a mixture of both as 50:50. The mixture together would not necessarily be synergistic but would be additive as the pharmacologic mechanism of action is the same for both agents i.e., sodium channel blockers.

To join the conversation, you need to subscribe.

Sign up today for full access to all episodes and to join the conversation.

To download files, you need to subscribe.

Sign up today for full access to all episodes.
EM:RAP 2019 February Full episode audio for MD edition 243:18 min - 227 MB - M4AEM:RAP 2019 February German Edition Deutsche 94:05 min - 86 MB - MP3EM:RAP 2018 February Aussie Edition Australian 25:37 min - 35 MB - MP3EM:RAP 2019 February Canadian Edition Canadian 5:34 min - 8 MB - MP3EM:RAP 2019 February Spanish Edition Español 80:18 min - 110 MB - MP3EM:RAP 2019 February French Edition Français 0:24 min - 580 KB - MP3CVA Workflow 863 KB - PNG ImageEMRAP_2019_02_Feb_Board Review Answers_Vol.19_02 134 KB - PDFEMRAP_2019_02_Feb_Board Review Questions_Vol.19_02 346 KB - PDFEMRAP 2019 02 February Individual Summaries 670 KB - ZIPEMRAP 2019 02 February MP3 Individual Files 330 MB - ZIPEMRAP 2019 02 February Written Summary 286 KB - PDFEM:RAP 2019 February Spanish Written 817 KB - PDF

To earn CME for this chapter, you need to subscribe.

Sign up today for full access to all episodes and earn CME.

6 AMA PRA Category 1 Credits™ certified by CEME (EM:RAP)

  1. Complete Quiz
  2. Complete Evaluation
  3. Print Certificate