PT  - JOURNAL ARTICLE
AU  - Elsbeth J Wesselink
AU  - Seppe J Koopman
AU  - Rien van der Vegt
AU  - Peter M van de Ven
AU  - Jan P van der Aa
AU  - Carlijne Stapper
AU  - Friso Wesdorp
AU  - Laura de Kok
AU  - Yiyi Zhang
AU  - Eric J Franssen
AU  - Eleonora L Swart
AU  - Christa Boer
AU  - Marcel A de Leeuw
TI  - ED90 of spinal 2-chloroprocaine 1% in ambulatory knee arthroscopy up to 45 min: a randomized biased-coin- up-and-down sequential allocation trial
AID  - 10.1136/rapm-2021-103089
DP  - 2022 Jan 12
TA  - Regional Anesthesia & Pain Medicine
PG  - rapm-2021-103089
4099  - http://rapm.bmj.com/content/early/2022/01/12/rapm-2021-103089.short
4100  - http://rapm.bmj.com/content/early/2022/01/12/rapm-2021-103089.full
AB  - 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. In cohort I, a randomized biased-coin up-and-down design with 40 patients was used to find the ED90. Four dose-levels of plain 2-chloroprocaine 1% were used: 25, 30, 35 and 40 mg. The identified primary outcome, the ED90, was validated in 50 patients in cohort II with an open label design. Secondary outcomes included time to complete recovery from motor and sensory block with spinal injection as time zero, peak sensory block level, urine retention and time until hospital discharge.Results Forty patients were included in the final analysis in cohort I. The ED90 was estimated at 27.8 mg, successful spinal anesthesia was obtained in 38 patients (95%). Fifty patients were included in the final analysis in cohort II, 49 patients had successful anesthesia with a fixed round dose of 28 mg. In this Cohort, peak sensory block was T10/T11 (range: (L4–T4)). The median time to full recovery of the motor block was 60 min (45–60) and 90 min (75–105) for the sensory block. The mean time to hospital discharge was 2.9 hours (0.7).Conclusion The ED90 of 2-chloroprocaine 1% in knee arthroscopy was estimated to be 27.8 mg. In an external population, the ED90 resulted in successful anesthesia in 98% of the patients (95% CI 89% to 100%).Trial registration number Netherlands Trial Registry (NL6769).All data relevant to the study are included in the article or uploaded as supplementary information.