I gave this talk at the 2020 Winter Anesthesiology Meeting of the California Society of Anesthesiologists (#CSAHSWinter20). My objectives were to: 1. Discuss adjuvants for extending single-injection nerve block duration; 2. Provide an update on continuous peripheral nerve blocks; and 3. Address practical considerations and present a strategy for personalized postoperative pain medicine.

1. 2020 CSA Winter Anesthesia Conference
@EMARIANOMD
The Quest for Longer Block Duration:
Techniques and Evidence
Edward R. Mariano, M.D., M.A.S.
Professor of Anesthesiology, Perioperative & Pain Medicine
Stanford University School of Medicine
Chief, Anesthesiology and Perioperative Care
Veterans Affairs Palo Alto Health Care System

2. No financial disclosures.
2020 CSA Winter Anesthesia Conference

3. @EMARIANOMD #CSAHSWinter20
How Long Does Pain Last?
Lavand’homme, et al. CORR 2014;472:1409
TKA
Patients
Normal
Persistent Pain
Neuropathic Pain

4. @EMARIANOMD #CSAHSWinter20
How Do You See Pain Medicine?

5. @EMARIANOMD #CSAHSWinter20
Overview
 Adjuvants for extending single-injection nerve block
duration
 Update on continuous peripheral nerve blocks
 Practical considerations

6. @EMARIANOMD #CSAHSWinter20
Overview
 Adjuvants for extending single-injection nerve block
duration
 Update on continuous peripheral nerve blocks
 Practical considerations

7. @EMARIANOMD #CSAHSWinter20
“We Can Place a Catheter…
© Mike Mariano

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…But Single-Injection is Fine”
Heard at every anesthesiology residency
program everywhere!

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Epinephrine
 Vasoconstriction decreases vascular uptake
 May decrease plasma concentration and potential for
systemic toxicity
 Prolongs duration of lipophobic anesthetics (mepivacaine,
lidocaine) but not lipophilic long-acting anesthetics
– Ropivacaine already vasoconstrictive
Weber A, et al. A&A 2001;93:1327
<1
Day

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Clonidine
 Clinically relevant prolongation of brachial plexus
anesthesia at 0.5 mcg/kg + LA1
– May be more pronounced with lipophobic anesthetics
– 1 mcg/kg prolongs ropivacaine duration with slight increase in
sedation2
 Systematic review (27 studies)3
– Prolongs intermediate LA (mepivacaine) for select blocks
1. Singelyn FJ, et al. A&A 1996;83:1046 2. Casati A, et al. A&A 2000;91:388
3. McCartney C, et al. RAPM 2007;32:330
<1
Day

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Dexmedetomidine
 Mean 261 min more sensory block
 Mean 201 min more motor block (except
interscalene)
 Mean 3 min faster onset when >50 mcg
 Mean 289 min more analgesia (except
axillary), no difference at 24 hrs
Hussain N, et al. RAPM 2017;42:184
<1
Day

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Opioids
 Peripheral opioid receptors exist: relevant for
intraarticular injections
 No clear benefit for most opioids
– Results conflicting
– Opioid-induced side effects possible
 Buprenorphine of interest
– RCTs have shown longer duration of analgesia when added to
LA1,2
– Not FDA-approved for nerve blocks
1. Candido KD, et al. RAPM 2002;27:162
2. Candido KD, et al. Anesth 2010;113:1419
<1
Day

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Dexamethasone
• RCT of ISB: 0.5% bupiv, epi, and clonidine 75 mcg ± dex
8 mg1
– Sensory block (24 vs. 14 hr, p<0.001)
– Motor block (23 vs. 14 hr, p<0.001)
• RCT of axillary blocks: 1.5% lido ± dex 8 mg2
• RCT of SCB: 1.5% mepiv ± dex 8 mg3
• Mechanism? Optimal dose? Off-label USA
1. Vieira PA, et al. EJA 2009;27:285 2. Movafegh A,et al. A&A 2006;102:263
3. Parrington S,et al. RAPM 2010;35:422
IV works just as well as
perineural
Fredrickson et al. RAPM 2013; 38: 300
Desmet et al. BJA 2013;111:445
Rosenfeld et al. Anaesth 2016;4:380
~1
Day

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Dexamethasone
 May be different for distal brachial plexus
 8 mg Perineural > IV for axillary1
– Mean 4.6 hr more motor block
– Mean 4.0 hr more sensory block + analgesia
 5 mg Perineural > IV for infraclavicular2
– Mean 2.8 hr more motor block
– Mean 2.9 hr more sensory block
– Mean 3.5 hr more analgesia
1. Aliste J, et al. CJA 2017;64:29
2. Leurcharusmee P, et al. RAPM 2016;41:328
~1
Day

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Adjuvant Reliable Block
Duration >24 hrs
Epinephrine
Clonidine
Dexmedetomidine
Opioids except
buprenorphine
Buprenorphine
Dexamethasone
Based on actual studies; inspired by Dr. Patrick Wong, University of Ottawa

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4-Drug Combination
Buvanendran, et al. RAPM 2016;41:589
Clonidine alone
accounts for
prolongation

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Liposomal Bupivacaine
 Only FDA-approved in USA for
interscalene blocks for shoulder surgery
Viscusi ER. RAPM 2005;30:491
1-3
Days?
Not
Titratable

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Liposomal Bupivacaine

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Ilfeld BM. Anesth 2018;129:623

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Liposomal Bupivacaine for Block?
Ohri R, et al. RAPM 2012;37:607
Boogaerts JG, et al. CJA 1993;40:1201
 Is 96h of block always good?
96 hrs

21. @EMARIANOMD #CSAHSWinter20
Overview
 Adjuvants for extending single-injection nerve block
duration
 Update on continuous peripheral nerve blocks
 Practical considerations

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How Do You See Pain Medicine?

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How Do You See Pain Medicine?

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The “Gold Standard”

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Meta-analysis: CPNB vs. Opioids
Richman JM, et al. A&A 2006;102:248
Mean VAS
24h 48h
Infraclav 1.0 vs. 4.3 p<0.001 0.6 vs. 4.0 p<0.001
Interscal 1.4 vs. 3.6 p<0.001 0.5 vs. 2.3 p<0.001
Fem/LP 2.1 vs. 4.0 p<0.001 1.6 vs. 3.2 p<0.001
Sciatic 0.9 vs. 4.6 p<0.001 0.9 vs. 3.5 p<0.001

26. @EMARIANOMD #CSAHSWinter20
Overview
 Adjuvants for extending single-injection nerve block
duration
 Update on continuous peripheral nerve blocks
 Practical considerations

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Use Ultrasound
Ilfeld & Mariano. RAPM 2010;35:123

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Results
Popliteal
Mariano ER, et al. RAPM 2009;34:480
Mariano ER, et al. JUM 2009;28:1211
Mariano ER, et al. JUM 2009;28:1453
Mariano ER, et al. JUM 2010;29:329

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Mariano ER, et al. JUM 2015;34:1883
Lectures,
Scanning
Iterative
Practice,
Simulation
8 Hour Program

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Single-Orifice or
Multi-Orifice
Stimulating or
Non-Stimulating
Flexible Springwound
or Rigid Plastic
Through or Over the
Needle
Catheter Designs

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Leng & Mariano, et al. J Anesth 2015;29:308

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Catheter Type and Migration
Steffel & Mariano, et al. K J Anesth 2017;70:72
Cadaver-based study
CON: 4/15 (27%) dislocated vs. CTN 0/15 (p=0.043)

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Securing the Catheter
 Consider tunneling
 Use an anchoring device1
 Liquid adhesive
 Clear occlusive dressing
 Consider glue2
1. Borg & Mariano, et al. K J Anesth 2016;69:506
2. Klein SM, et al. Anesth 2003;98:590

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Summary
 We discussed:
– Adjuvants for extending single-injection nerve block duration
– Update on continuous peripheral nerve blocks
– Practical considerations