Local Anesthetic Systemic

Toxicity (LAST) in 2016

Patrick NARCHI, MD

Centre Clinical

16800 Soyaux

FRANCE

1- Is it so frequent ?

2 Surveys of French complications related to Peripheral Nerve Blocks

Auroy Y et al

/ 10.000 Cardiac

arrest

Seizures Nerve

injury

1997

n= 212781.4 7.5 1.9

2002

n= 439460.2 1.36 2.7

2-3 / 10.000 blocks

RAPM 2010

single shot 83 %

infusion 15 %

bolus during infusion 2 %

Administration

RAPM 2015

single shot 75%

infusion 12%

Field infiltration 10%

Intravenous ! 3%

Administration

2000- 2004: 3 deaths with IV bupivacaine

Blood toxicity of local anesthetics

in the postoperative period

1- exceptional with continuous infusion- low volume < 10 ml/h

- low concentrations: Ropi 0.2%

2- increase in alpha 1-glycoproteines

3- avoid boluses on surgical wards +++- nurses

- error in catheter identification …

2- Is it immediate ?

Timing of Convulsions after PNBlocks

Auroy Y, Narchi P 1997

• Within 3 min 69%

• after 5- 35 min 31%

RAPM 2010Timing of onset

Occurred > 5 min 25% 52%

RAPM 2015

2009 2015

Ultrasound 73 %

nerve simulation 40 %

Aspir + incremental 45%

Timing onset > 10 min

RAPM 2015

Anesthesiol 2014

Onset: 15 min after the injection

Intralipid: 30 min after 1st signs!

3- How it starts ?

RAPM 2010Symptoms

CNS & Cardiac

CNS

Cardiac

45%44%

11%

Symptoms

RAPM 2015

CNS + Cardiac

CNS

Cardiac45%

40%

15%

4- Which techniques are

the most questioned ?

RAPM 2010

• 1979- 2009 (30 years)

• 93 reported cases

Blocks

Epidural 33%

Axillary 17%

Interscalene 13%

RAPM 2015

– 2010 – 2014

– ASRA recommendations (2010)

– 67 reported cases

Blocks

Interscalene 23%

Field infiltration 22%

Epidural 16%

Penile block 12%

5- How to treat ?

How to treat ?

- CPR

- Benzodiazepines, thiopental

- Intubation … oxygen, …

- Avoid:

Propofol

High dose of epinephrine …

1- Lipid Emulsions

Lipid emulsion & cardiac bupivacaine

0

20

40

60

80

100

120

140

0 5 10 15 20

Time (minutes)

Fre

e C

on

ce

ntr

ati

on

(m

g/l)

Bupi Intralipid®

Ropi Intralipid®

Bupi Medialipide®

Ropi Medialipide®

Mazoit et al. Anesthesiology 2009Mazoit Anesthesiology 2009

Buffer Solution

Ropi medialipid

Ropi Intralipid

Bupi medialipid

Bupi Intralipid

• Human serum ++

Anesthesiol, Feb 2012

*

* *

A&A, April 2012

• isolated heart of rats

• Recovery « after » Asystole

• Efficacy criteria: RPP (Rate Pressure Product)

• 4 groups:• Intralipid

• Epinephrine

• Combination (Intralipid + epinephrine)

• Control

A&A, April 2012

Ventricular tachycardia: 0/12 (Lipid) 3/12 (Combination)

A&A, April 2012

• … the mean RPP and HR in the combination

group surpassed those of the lipid and epinephrine

groups during the 40-minute recovery period.

• Epinephrine

• reasonable in small doses.

• ASRA practice guidelines: boluses <1 μg/kg

Na Channel modulation

Peripheral

vasoconstriction

Cellular metabolism protection

« Sink effect »

Lipid Emulsion

Lipid Emulsions

• Cardiac toxicity % liposolubility

Bupi > Ropi > Levobupi> Lido

Weinberg GL 1998;88:1071-1075

http://www.youtube.com

(lipidrescue)

Intralipid

Bolus: 1.5 ml/kg … repeat once

Infusion 0.5 to 1 ml/kg/min

Do not exceed 10ml/kg

Not only Local anesthetics !

How to treat ?

- CPR

- Benzodiazepines, thiopental

- Intubation … oxygen, …

- Avoid:

Propofol

High dose of epinehrine …

- Lipid Emulsions

2- Prevention

Which local anesthetic ?

How much to inject ?

2- Prevention

Br J Anaesth 2010

ED99 : 5,7ml

1ml / nerve in axillary !

Lidocaine use in ultrasound-guided femoral

nerve block: what is the minimum effective

anaesthetic concentration ?

Taha, A. M, Br J Anaesth. 2013

• 62 patients Knee surgery

• Femoral block : 15ml lidocaineVariation of concentration « up-down sequential method »

15ml lidocaine 0,93% produce

a complete femoral block in 90% patients

Ropivacaine in ultrasound-guided femoral

nerve block: what is the minimal effective

anaesthetic concentration (EC90)?

Taha .2014 . Anaesthesia

45 patients knee surgery

USG Femoral nerve block : 15 ml ropivacaine

Up-down sequential method.

EC 90 : 0.167%

Ultrasound ?

2- Prevention

RAPM, Octobre 2012

• database: 12668 US-guided blocks (± nerve

stim)

• Time Period 2003- 2011

• Teaching hospital

• 12668 blocks

• Single shot (90%), catheters (10%)

• Combination US + Nerve stim 39%

RAPM, Octobre 2012

1 / 12668 patients !!

0,08/ 1000

LAST… new challenges

• « Non-anesthesia » providers

• Office or off-site

• Atypical symptoms !

• more « delayed onset »

• High risk patients:–Elderly–Muscle mass +++–Coronary patients