Spinal 2-chloroprocaine: a comparison with procaine in volunteers

Recent studies using preservative-free 2-chloroprocaine (2-CP) for spinal anesthesia have shown it to be a reliable short-acting drug that provides similar anesthesia to lidocaine. In this randomized, double-blind, crossover study, we compared the characteristics of spinal 2-CP (30 mg) with those of procaine (80 mg) in eight volunteers to determine whether either drug produces spinal anesthetic characteristics ideal for outpatient surgery. By using sensation to pinprick, transcutaneous electrical stimulation, tolerance to thigh tourniquet, and motor blockade as surrogates for surgical efficacy, 2-CP compared similarly to procaine. Peak block height (T9 [range, T6 to T12] versus T6 [T4 to T8]; P = 0.0796), time to two-segment regression (51 +/- 17 min versus 53 +/- 10 min; P = 0.7434), tourniquet time tolerance (37 +/- 16 versus 49 min +/- 17 min; P = 0.1755), and time to return of motor strength (Bromage scale: 54 +/- 23 min versus 55 +/- 44 min, P = 0.9366; return of 90% quadriceps strength: 78 +/- 9 min versus 98 +/- 30 min; P = 0.0721) were all similar. Procaine did produce overall longer sensory blockade (P = 0.0011) and motor blockade at the gastrocnemius (P = 0.0004) and quadriceps (P = 0.0146) muscles. Times until the resolution of sensory blockade (103 +/- 12 min versus 151 +/- 26 min; P = 0.0003), ambulation (103 +/- 12 min versus 151 +/- 26 min; P = 0.0003), and micturition (103 +/- 12 min versus 156 +/- 23 min; P < 0.0001) were all prolonged after procaine. In conclusion, at the doses tested, spinal 2-CP (30 mg) may be a better choice for short outpatient procedures because it provides anesthesia with similar efficacy as procaine (80 mg) but with more rapid fulfillment of discharge criteria.