Intrathecal 2-chloroprocaine for lower limb outpatient surgery: A prospective, randomized, double-blind, clinical evaluation

We evaluated the dose-response relationship of 2-chloroprocaine for lower limb outpatient procedure in 45 ASA physical status I-II outpatients undergoing elective lower limb surgery under spinal anesthesia, with 30 mg (group Chlor-30, n = 15), 40 mg (group Chlor-40, n = 15), or 50 mg (group Chlor-50, n = 15) of 1% preservative free 2-chloroprocaine. Onset time was similar in the three groups. General anesthesia was never required to complete surgery. Intraoperative analgesic supplementation as a result of insufficient duration of spinal block was required in 5 patients of group Chlor-30 (35%) and 2 patients of group Chlor-40 (13%) (P = 0.014), with a median (range) time for supplementation request of 40 (30-60) min. Spinal block resolution and recovery of ambulation were faster in group Chlor-30 (60 [41-98] min and 85 [45-123] min) than in groups Chlor-40 (85 [46-141] min and 180 [72-281] min) and Chlor-50 (97 [60-169] min and 185 [90-355] min) (P = 0.001 and P = 0.003, respectively), with no differences in home discharge time (182 [120-267] min in group Chlor-30, 198 [123-271] min in group Chlor-40, and 203 [102-394] min in group Chlor-50; P = 0.155). No transient neurologic symptoms were reported at 24-h and 7-day follow-up. We conclude that although 40 and 50 mg of 2-chloroprocaine provide adequate spinal anesthesia for outpatient procedures lasting 45-60 min, 30 mg produces a spinal block of insufficient duration.