The Major Factor Of The Effects Of Epidural Anaesthesia Depend--The Total Dose Of The Local Anesthetic, Or The Concentration And Volume Of Local Anesthetic

Objective: Altering the concentration and volume of identical dose lidoca- ine,compared the anaesthetic effects of a constant dose of two different concentrations of epidural lidocaine for epidural anaesthesia,we can find the major factor of the effects of epidural anaesthesia depend.Methods:A total so 40 patients(20~70years old,undergoing arthroscope and great saphenous vein operations,ASAⅠ~Ⅱ)were punctured from lumbar 2~3 spinal inter space.they were randomly divided into two groups:1%lidocaine 30ml(n=20),or 2% liodcaine15ml(n=20).After epitural anaesthesia completed. The spread of the sensory block to pinprick and the dgree of motor block (modified Bromage scale) were measured at 15,30 and 40 min after injection.Results:No significant differences in the progression of analgesia and motor block were observed at any time between 1% and 2% lidocaine.The maximum cephalad spread was observed 30min after injection; the median was at T4 (range T3–T5) and at T4 (range T3–T6) for lidocaine 1%and 2%, respectively.Conclusions: The same doses but different volumes of lidocaine 1% and 2% produced comparable anaesthetic effects in patients. The effects of epidural anaesthe-sia depend primarily on the total dose of the local anaesthetic.