0.25% Bupivacaine vs 0.5% Bupivacaine vs Mepivicaine/Bupivacaine: Comparisons of 3 local anesthetic regimens used in nerve blocks

Abstract

Background: Nerve blocks are a vital component of postoperative pain management. There are many local anesthetics (LA) that are utilized in providing nerve blocks. This study aims to gather information regarding the efficacy of 0.25% Bupivacaine vs 0.5% Bupivacaine vs Mepivacaine/Bupivacaine nerve blocks. Methods: Over a period of 4 months, patients who received a peripheral nerve block for postoperative pain were called within 48hrs of their surgery via telephone and asked standardized questions regarding their pain status. The data was then sorted according to what type of block was performed (Upper extremity[UE]{Supraclavicular, Interscalene, Intercostobrachial,}, Lower extremity[LE]{Femoral, Sciatic, Adductor Canal, Popliteal, Fascia Iliaca}, and other{TAP, PECs I & II, ESP, QL}) and the type of LA that was used (0.25% Bupivacaine, 0.5% Bupivacaine, Mepivacaine/Bupivacaine). Results: Overall, 35.54% of patients experienced pain in the Post Anesthesia Care Unit (PACU) with an average pain score of 6.5/10 (n=127). 47.54% of patients who received a block with 0.25% Bupivacaine experienced pain in the PACU with an average pain score of 6.8/10 (n=60). 32.14% of patients who received a block with 0.5% Bupivacaine experienced pain in the PACU with an average pain score of 5.8/10 (n=27). 0% of patients who received a block with Mepivacaine/Bupivacaine pain in the PACU experienced pain (n=10). The median pain return for 0.5% Bupivacaine, 0.25% Bupivacaine, and Mepivacaine/Bupivacaine were 23.5hrs, 9.5hrs, and 8.83hrs respectively (n=62). The median pain return for LE, UE, and Other blocks was 24.92hrs, 13.67hrs, and 11.87hrs respectively (n=74). The median motor function return for LE and UE blocks was 24.6hrs and 18.73hrs respectively (n=33). The median pain return for LE blocks which used 0.25% Bupivacaine and 0.5% Bupivacaine was 3hrs and 25.21hrs respectively (n=11). The median pain return for UE blocks that used 0.5% Bupivacaine and Mepivacaine/Bupivacaine was 19.83hrs and 8.83hrs respectively (n=13). The median pain return for Other blocks that used 0.25% Bupivacaine and 0.5% Bupivacaine was 9.5hrs and 23.5hrs respectively (n=33). The median motor function return for LE and UE blocks that used 0.5% Bupivacaine was 24.6hrs and 21.83hrs respectively (n=15). The median motor function return of UE blocks that used Mepivacaine/Bupivacaine was 15.96hrs (n=8). Conclusions: 0.5% Bupivacaine provided longer pain control in comparison to 0.25% Bupivacaine and Mepivacaine/Bupivacaine. (0.5% Bupivacaine is the superior local anesthetic for both upper and lower extremity nerve blocks). We conclude that as long as LA toxicity is not a problem, anesthesiologists should use 0.5% Bupivacaine for all nerve blocks to provide patients the maximum benefit from their regional anesthesia.