Interscalene Brachial Plexus Block with Liposomal Bupivacaine versus Standard Bupivacaine with Perineural Dexamethasone: A Noninferiority Trial

Summary by Zachary Headman DO, 12.19.22
https://pubs.asahq.org/anesthesiology/article/136/3/434/118269/Interscalene-Brachial-Plexus-Block-with-Liposomal


Take Home Messages:

  • Found that liposomal bupivacaine’s pain score over first 72 hours was not inferior to bupivacaine and dexamethasone as well as no differences in analgesia, motor and sensory resolutions, opioid consumption, readiness for PACU discharge, or adverse events.

  • Can use normal bupivacaine without the caveats that come with liposomal bupivacaine that include:

    • Diluting liposomal bupivacaine with another LA may disrupt the lipid carrier releasing a large amount of bupivacaine

    • Administration of any kind of local anesthetic is not recommended for 24 hours after giving liposomal bupivacaine

 

Summary:

Background: 

·       Interscalene nerve blocks are routinely performed to provide analgesia for shoulder surgeries. Additives such as dexamethasone or precedex have been used in regional anesthesia to extend block duration or improve depth of analgesia. 

·       This study compared liposomal bupivacaine vs standard bupivacaine with perineural dexamethasone.

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Study Design: Double blinded, prospective; noninferiority trial

Patient population: 112 patients undergoing ambulatory shoulder surgery were randomized into two groups. 

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Exclusion criteria:

·       Abnormal baseline sensory or motor exams

·       CRPS

·       History of reflex sympathetic dystrophy

 

Data points collected:

1.     Sensory and Motor exam prior to block

2.     Demographic Data 

3.     Sensory and Motor exam in recovery 

4.     Time to readiness for PACU discharge (used Post Anesthetic Discharge Scoring system)

5.     Total PACU time (from admission to discharge)

6.     Post op pain scores (for 3 days following initial procedure)

7.     Primary outcomes: Average numerical pain score at rest over 72h

8.     Secondary outcomes: opiate use, patient satisfaction in PACU, pain score ratings at each resting time point, pain scores with movement.

 

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Results

·       Average numerical pain score of liposomal bupivacaine was non-inferior to standard bupivacaine & perineural dexamethasone

·       Average numerical pain score for liposomal bupivacaine was statistically significantly lower for the post op 72hr period BUT not clinically significant 

·       No difference in opioid consumption between groups

·       No difference in sensory, motor, and analgesic blockade times between groups

·       No difference in PACU length of stay or discharge times between groups

Discussion: 

·       Hard to create true double blind as liposomal bupivacaine has milky appearance 

·       Skill level of practitioners differs which could effect amount of correctly placed medication (between C5&6 nerve roots)

·       Possible recall bias as post discharge info collected via telephone 

·       Liposomal bupivacaine provided similar analgesia to standard bupivacaine and perineural dexamethasone. 

·       Liposomal bupivacaine is significantly more expensive (about 300 dollars) when compared to Bupi-Dex mixture (about a dollar)