ED90 of spinal 2-chloroprocaine 1% in ambulatory knee arthroscopy up to 45 min: a randomized biased-coin- up-and-down sequential allocation trial.

Background: A short acting spinal anesthetic facilitates smooth flow since quick recovery of motor function will facilitate unassisted ambulation. The aim of this study was to estimate the effective dose (ED90) of intrathecal 2-chloroprocaine 1% in outpatient knee arthroscopy.

Methods: Two cohorts were included in two different hospitals.