Comparison of axillary nerve block duration using mepivacaine in non-insulin diabetic or renal insufficiency patients: a controlled observational matched multicenter trial.

BACKGROUND: Although studies in diabetic patients demonstrated delayed recovery after long-acting local anesthetic, its effects with short-acting LA remains to be determined. Using mepivacaine, the authors evaluated the duration of axillary nerve blocks in diabetic (DP), renal failure (creatinine clearance <30 mL.min-1) (RP) and healthy patients (HP). METHODS: We prospectively included consecutive patients aged 18-80 years, with DP (N.=37), RP (N.=32) and HP (N.=48) scheduled for distal upper limb surgery. Before surgery, an axillary nerve block (20 mL mepivacaine 15 mg.mL-1) was performed with an ultrasound approach combined with nerve stimulation. Five mL was injected for each nerve: median, ulnar, radial, musculocutaneous nerves. The primary endpoint measured was the duration of sensory block. For statistical analysis, each HP patient was matched with RP and DP patient (1:1), with regards to age (range±5 years) and sex. RESULTS: Patient characteristics were similar between groups. Creatinine clearance was 14±8 mL.min-1 in RP group and HbA1c (%) was 7.5±1.5 in DP group. Mean duration of diabetic or renal insufficiency illness were respectively eight and 12 years. Onset time for sensory and motor blocks were similar between groups. Average time for sensory block duration was similar between DP vs. HP (235±52 vs. 230±54 min, P=0.71); and between RP vs. HP (234±51 vs. 229±57 min, P=0.65). CONCLUSIONS: The short-acting LA (mepivacaine) are associated with similar pharmacodynamic effects in diabetic and renal failure patients as compared with healthy patients.