Randomized double-blind study of the clinical duration and efficacy of Nesacaine-MPF 2% and 3% in peribulbar anesthesia

Purpose: To compare 2 commercially available concentrations of Nesacaine(R) -MPF (2-chloroprocaine) to determine the time to onset of adequate motor bl ockade, the quality of surgical anesthesia, and the duration of motor block ade in the extraocular muscles after peribulbar anesthesia for cataract sur gery. Setting: Tampa Eye and Specialty Surgery Center, Tampa, Florida, USA. Methods: This double-blind, randomized, single-center study comprised 40 pa tients scheduled to receive peribulbar anesthesia before cataract surgery. Patients were given 5 mL of Nesacaine-MPF 2% or 3% before surgery. Beginnin g at the end of the injection, assessments of ocular and eyelid movement we re made every 2 minutes until adequate motor blockade wa achieved or 25 min utes elapsed. Ocular assessments were made immediately after completion of surgery, 60 minutes after the end of the initial injection, and at 15 minut e intervals thereafter until full recovery. Assessments of the quality of a nesthesia achieved by the patient during surgery were made by the surgeon. Results: The 3% solution provided significantly faster onset of surgical an esthesia than the 2% solution (mean 3.9 minutes +/- 2.2 [SD] versus 6.0 +/- 3.6 minutes) (P = .02) but also required more time for recovery from anest hesia (98.9 +/- 18.7 minutes versus 84.8 +/- 20.6 minutes) (P = .02). All p atients had adequate surgical anesthesia. Duration of occur motor function wa brief enough so that all patients could be sent home without an eye patc h. Both concentrations were safe for use in this procedure. Conclusion: Both Nesacaine-MPF 2% and 3% produced safe and effective peribu lbar anesthesia in all patients; however, the 3% solution provided better d uration of clinical anesthesia. J Cataract Refract Surg 1999; 25:1656-1661 (C) 1999 ASCRS and ESCRS.