Lidocaine + Bupivacaine vs Bupivacaine Alone for Digital Nerve Blocks

09 Apr
April 9, 2015

Digital Nerve BlocksWhen I first learned digital nerve blocks in the late 1990’s I was taught to mix Lidocaine and Bupivacaine 50/50 to provide faster onset (Lidocaine) and a longer duration of action (Bupivacaine). My use of two agents for digital nerve blocks was recently questioned by one of my colleagues.

Any time additional medications are drawn up into a syringe there is opportunity for error, and there is additional time added to the procedure. A review of the (limited) literature will try to answer the following questions:

  1. Does the addition of Lidocaine to Bupivacaine decrease the time to onset of anesthesia?
  2. Does the addition of Lidocaine to Bupivacaine decrease the pain of injection?
  3. Does the use of Lidocaine with Epinephrine prolong the duration of digital block long enough to obviate the need for Bupivacaine?

What evidence is available for Digital Nerve Blocks?

The available evidence to answer these questions is scant at best. A 2014 review (24612831) evaluated 6 articles that evaluated the use of Lidocaine, Lidocaine with Epinephrine, Lidocaine with Bupivacaine, Bupivacaine, and Ropivacaine. As Ropivacaine is not a commonly used emergency department drug this review will focus on the articles that assessed the pharmacodynamics of Lidocaine and Bupivacaine only.

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Each study evaluated one or more of the following outcomes: Onset of anesthesia, duration of anesthesia, and pain of injection.

  1. Alhelali et al (19386869) compared 1% Lidocaine with epinephrine vs 0.5% Bupivacaine: 12 subjects, dorsal ‘ring’ approach, with bilateral middle finger blocks. Duration of analgesia was based on return of pain on pin prick.
  2. Thomson and Lalonde (16874214) compared 2% Lidocaine, 2% Lidocaine with Epinephrine, and Bupivacaine: 30 subjects, single volar injection, bilateral long fingers, and one small finger. Duration of anesthesia was based on return to normal sensation (this is typically longer than pin prick sensation.
  3. Valvalo and Leffler (8604868) compared 1% Lidocaine and 0.25% Bupivacaine vs 0.25% bupivacaine alone: 17 subjects, dorsal ‘ring’ approach, duration of anesthesia was based on return of pain on pin prick.
  4. Reichl and Quinton (3325593) compared 1% Lidocaine vs 0.5% bupivacaine: 24 (Lidocaine) and 29 (Bupivacaine) subjects, single volar injection. Duration of anesthesia was based on return of pain on pin prick.

Onset of Anesthesia

  • Three studies assessed onset of anesthesia.
  • Studies reported either mean, median, or both to describe onset of anesthesia. Ranges shown in parentheses.
StudyLidocaine with EpinephrineLidocaineLidocaine/BupivacaineBupivacaine
Alhelali et al. (19386869)Median 3.5 min
Range 3 - 8 min
Median 3.3 min
Range 3 - 8 min
Valvalo & Leffler (8604868)Mean 5 min
Median 4 min
Mean 5.35 min
Median 4 min
Reichl & Quinton (3325593)Mean 5.8 min
Range 5 - 8 min
Mean 11.2 min
Range 8 - 20 min

Pain of Injection

  • Two studies reported pain of injection.
StudyLidocaine with EpinephrineLidocaineLidocaine/BupivacaineBupivacaine
Alhelali et al (19386869)VAS 26mm
Range 4 - 52 mm
VAS 40.5 mm
Range 10 - 71 mm
Valvalo & Leffler (8604868)VAS 30mm
Mean 30mm
VAS 30 mm
Mean 30mm
  • VAS scores are medians unless stated otherwise.
  • There was a statistically and clinically significant (>13mm) difference in VAS pain scores when comparing Lidocaine with Epinephrine vs Bupivicaine containing injections.

Duration of Anesthesia

  • Three studies assessed duration of anesthesia.
StudyLidocaine with EpinephrineLidocaineLidocaine/BupivacaineBupivacaine
Alhelali et al (19386869)Median 5.4h
Range 3.8 - 7.7h
Median 11.7h
Range 4.1 - 15.2h
Thompson & Lalonde* (16874214)Mean 10.4h (95% CI 9.4 - 11.4)Mean 4.9h (95% CI 4.2 - 5.6)Mean 24.9h (95% CI 22.4 - 27.4)
Reichl & Quinton (3325593)Mean 1hMean 7.9h

*There was heterogeneity in the way this was measured with Thomson and Lalonde using return to normal sensation, and the others using pain on pinprick as an end point. Pain on pin prick is considered a more objective, and comparable finding for studies to use.

The use of Bupivacaine with or without Lidocaine clearly provides a longer duration of anesthesia. The addition of Epinephrine to Lidocaine appears to significantly prolong the duration of anesthesia.

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Conclusions

  • The addition of Lidocaine to bupivacaine DOES NOT decrease the time to onset of anesthesia, and DOES NOT decrease the pain of injection. It adds some risk of medication error, and adds time to the procedure.
  • Bupivicaine containing solutions, compared to Lidocaine with epinephrine INCREASE the pain of injection.
  • Lidocaine with epinephrine provides a long enough duration of anesthesia to allow the completion of most emergency department procedures. Bupivacaine can be considered when post procedural analgesia is desired.
  • In patient populations where pain of injection is a concern (pediatric, special needs adults) consider using Lidocaine with Epinephrine, rather than Bupavicaine.

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Others Thoughts:

Post Peer Reviewed By: Salim Rezaie, MD (Twitter: @srrezaie)

Bibliography

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Rob Bryant

Adjunct Assistant Clinical Professor of Emergency Medicine at Utah Emergency Physicians
REBEL EM Guest Contributor and Author
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12 replies
  1. Justin Hensley says:

    Would be nice if someone compared tendon sheath block pain vs classic “ring” block. Also, nobody tested bupivicaine with epi?

    Reply
    • Salim Rezaie says:

      Hey Justin,
      I just did a quick pubmed search and don’t see either of those scenarios covered. This wasn’t an exhaustive search, but not seeing it. I wonder if anyone else knows of any research?

      Salim

      Reply
      • Chris Turner says:

        Hi, I’m not usually one for personal anecdote but in the absence of any research out there I thought I’d add my tuppence worth. I’ve had a load of digital nerve blocks in my time (I am a grade A klutz who loves a bit of DIY). The dorsal (standard) approach blocks always stung a bit and one day I was offered the “benefit” of a single injection in (around?) the flexor sheath. Even now, years after I had it I am wincing remembering it. It was simply excruciating. Maybe somebody out there is up for doing the study? If they could get it past ethics they could compare L vs R on healthy volunteers using a VAS at various time intervals. They’re not doing it on me though….

        Thanks for a really good summary article, much appreciated.

        Chris

        Reply
  2. Rob Bryant says:

    The only direct pain comparison was with dorsal “ring approach’.
    Maybe the hand surgeons are not interested in pain of injection?!

    The Vinnycomb and Sahhar review included one other Bupivacaine vs Bupivacaine w epi study, 42 patients, no difference in duration of anesthesia or pain of injection (VAS 51 vs 53 (epi) for pain of injection, (single volar injection). VAS for pain with other bupivacaine containing solutions in dorsal approach were 30-40mm.(see table above). I did not include it in my review as I was looking to see if the addition of Lidocaine to bupivacaine helped in any way (it did not!).

    Reply
  3. Dennis says:

    It seems to me that the addition of lidocaine to bupivacaine to decrease the onset of action may have some limited benefit. I wouldn’t expect there to be decreased pain of injection without the addition of a buffer like sodium bicarbonate and or warming the mixture.

    Reply
    • Salim Rezaie says:

      Hello Dennis,
      TY for reading, I guess my rebuttal to your statement would be, why go through the additional steps of mixing anesthetics (i.e. lidocaine with bupivacaine), when this could cause errors and contamination, when a single agent would work just as well (i.e. lidocaine with epinephrine). TY for reading and a great question.

      Salim

      Reply
  4. Shyan Goh says:

    Some comments about your article:

    Since we are talking about using licenced manufactured products (ie using products straight without mixing and dilution with other products, for example, 1 or 2 % Lidocaine with epinephrine straight from the ampule) as opposed to unlicenced off-labelled manufacturing of products (eg mixing lidocaine with bupivacaine or lidocaine/bupivacaine with bicarbonate) I feel strongly that there should be some caveats highlighted to your readers:

    1. Commercially available 1 or 2 % Lidocaine with epinephrine rarely has concentration of epinephrine more concentrated than 1:100,000 in the solution where as there is some evidence of higher epinephrine concentration (1:20,000) causing tissue ischaemia necrosis (ref 1). Therefore it is important that doctors do not attempt to manufacture their own LA with epinephrine combination without due consideration of the actual concentration.

    Furthermore some referenced studies are primarily performed on healthy volunteers with/without tourniquet whereas the actual real world application, including the use of tourniquet when performing procedural work on fingers will complicate the applicability of the studies to emergency work. (ref 2)

    2. While the theoretical idea of combination of short acting with long acting local anaesthetics is attractive, the sole study quoted in this article actually comparing this suffers a fatal flaw:

    “We prepared lidocaine/ bupivacaine as a 1:1 solution by mixing 2.5 mL of 1% lidocaine with 2.5 mL of .25% bupivacaine in 5-mL syringes. We prepared bupivacaine by filling 5-mL syringes with 5 mL of .25% bupivacaine”

    Any discerning reader will realise that the authors are simply manufacturing the equivalent of 0.5% lidocaine/ 0.125% bupivacaine combination in the final 5 mL syringe, and this is to be compared with 0.25% bupivacaine. The authors call the combination 1:1 lidocaine/bupivacaine which reflects the basic mistake they have in assuming the respective concentration solution is unchanged, and their understanding of what 1:1 meant

    [1:1000 solution adrenaline = 1g adrenaline in 1000ml solution = 1000mg adrenaline per 1000ml solution = 1mg per ml]

    I do not know of anyone who uses the subtherepeuatic dose of 0.5% lidocaine for any work so there should be no surprise that the manufactured combination did not have faster anaesthetic effect. It is a pity that the authors also did not assess the duration of the anaesthesia from the combination vs straight bupivacaine.

    So my “morals of the story”:

    1. Stick to straight manufactured stuff if you did poorly in high school maths
    2. Oils aint oils when you actually read the articles critically; stop relying on others to do your thinking
    3. Not many healthy patients who does not need work on the fingers come to emergency department to get a digital block like what you see in studies. The real world is a lot complicated than that.

    Thank you for allowing to demyth your demyths.

    Reference

    1. Serafin, F. J. A precaution in the use of procaine epinephrine for regional anesthesia (Letter). J. Am. Med. Assoc. 91: 43, 1928.

    2. Lee j Crane S. Lidocaine with epinephrine for digital nerve blocks: a note of caution. Emerg Med J 2010;27:335 doi:10.1136/emj.2009.078410

    3. Valvano, M N, and S Leffler. 1996. Comparison of bupivacaine and lidocaine/bupivacaine for local anesthesia/digital nerve block. Annals of emergency medicine, no. 4.

    Reply
    • Salim Rezaie says:

      Hello Shyan,
      We always love post publication peer review on the site. Thats why we created it. I 100% agree with your final 3 take home messages. Thank you for reading and the time you spent on the rebuttal.

      Salim

      Reply
  5. Rob Bryant says:

    Shyan,
    Thank you for your feedback.
    I agree that we should limit our drug mixing, especially for those of us that are ‘mathematically challenged’.
    you are correct that the true concentration of Lido / bupiv. in the Valvano/Leffler study was 0.5% lido:0.125% Bupivacaine. Even with lower concentration lido and bupivacaine I think the results are still clinically useful in that the pain of injection was the same. The lack of difference in onset of action between 1% lido w epi and Bupivacaine (Alhelali) would suggest that even with a 1% Lido : 0.25% Bupivacaine mix the results probably would not differ.
    One of the listed studies did include injured / infected fingers (Reichl and Quinton). Interestingly they did note a difference in time of onset of anesthesia (5 min vs 11 min).
    This review has changed my practice, and I no longer add Lidocaine w or w out epinephrine to my bupivacaine. I also now use lidocaine with epinephrine preferentially over bupivacaine due to the (mild) decrease in pain on injection when performing digital nerve blocks for laceration repairs. For fracture management / dislocations where longer term pain control is desired, Bupivacaine is still reasonable.

    Thanks for your feedback.

    Rob

    Reply

Trackbacks & Pingbacks

  1. […] The use of epinephrine in digital nerve blocks has been shown to increase duration of action for the anesthetic, and to allow the avoidance of bupivacaine, thereby decreasing the pain of the injection. (REBEL flashback) […]

  2. […] we be mixing lidocaine and bupivacaine to get both rapid onset and long duration in digital nerve blocks? Great review by REBEL EM. […]

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