Triple-Blind Randomized Clinical Trial of Time Until Sensory Change Using 1.5% Mepivacaine With Epinephrine, 0.5% Bupivacaine, or an Equal Mixture of Both for Infraclavicular Block

Abstract

Mixing 1.5% mepivacaine (with epinephrine) with 0.5% bupivacaine speeds up PNB sensory (motor) onset compared with 0.5% bupivacaine alone.

Determination of the minimum effective volume of bupivacaine for ultrasound-guided infraclavicular brachial plexus block: a prospective, observer-blind, controlled study

“…Another study reported a median (range) time to onset of 6 (3–12) minutes for 40 mL of 0.5% bupivacaine. 18 However, these studies did not compare different volumes; thus, the evaluation of time to onset may have been less strict than in the present study. Indeed, the evaluation of sensory block in the latter study depended on the patients reporting a “different” (as opposed to the “same”) sensation during the touch test.…”

Equal mixture of 2% lidocaine with adrenaline and 0.5% bupivacaine 20 mL provided faster onset of complete conduction blockade during ultrasound-guided supraclavicular brachial plexus block than 20 mL of 0.5% bupivacaine alone: a randomized double-blinded clinical trial

“…Laur et al found that the number of patients feeling surgical incision (7 out of 31), block failure rate (6 out of 31) and GA conversion rate (4 out of 31) were significantly higher with bupivacaine even after 64 (50-84) minutes of the needle out to incision time. 3 In the present-day practice of US-guided precise injection techniques, where the MELAV for the US-guided supraclavicular BPB is below 20 mL, worries about the additive effect on toxicity caused by mixing of LA are also of no clinical relevance. 8 9 The limitation of our study is that we did not wait beyond 40 min to note the time for CCB in the bupivacaine group.…”

“…3 5 However, our finding of the duration of analgesia following LA mixture as significantly more than lidocaine and less than bupivacaine is well reported by many authors. [3][4][5] We represented 20 mL as low volume for USG-SCBPB. This is based on our experience that 5-6 mL more than the MELAV-99 will provide satisfactory duration of surgical anesthesia and analgesia for the most common bony surgical procedures of the elbow and forearm.…”

“…Mixing of two local anesthetics (LAs) to take advantage of the rapid onset of one agent and prolonged duration of action of another has been practiced since the 1960s. [1][2][3][4] However, the recent research yields conflicting findings about the clinical advantages of LA mixing. 40 mL equal mixture of Mepivacaine 1.5% (faster-onset, intermediateduration) with bupivacaine 0.5% (slower-onset, longer-duration) was shown to hasten the onset of conduction blockade in infraclavicular brachial plexus block (BPB); however, 30 mL of the same mixture was found to provide no benefit over bupivacaine in the onset of conduction blockade during interscalene BPB (ISB).…”

Periphere Regionalanästhesieverfahren – Standards im Wandel?!

“…Die Wirkdauer der Mischung war zwar länger als bei Anwendung von Mepivacain allein, aber auch deutlich kürzer als bei alleiniger Nutzung von Bupivacain. Folgestudien für weitere periphere RA-Verfahren zeigten ein ähnliches Muster keiner oder nur klinisch irrelevant beschleunigter Anschlagzeit und gleichzeitig verkürzter Wirkdauer von LA-Mischungen gegenüber langwirksamen Substanzen[25,26,27].PR A XISEMPFEHLUNGGerade bei Blockaden, bei denen eine besonders lange Wirkdauer gewünscht ist, sollte man keine Mischung von langwirksamen LA und LA mit kurzer Wirkdauer vornehmen. Vielmehr sollten lediglich Bupivacain oder Ropivacain in adäquater Dosis (und kombiniert mit einem Adjuvans wie intravenösem Dexamethason[28]) als Monosubstanzen verwendet werden.…”