In this report

we studied anesthetic effects of various kinds

concentrations

adrenaline contents and mixtures of anesthetic solutions in epidural block. Method:We used double blind method.195 patients were divided randomly into 13 groups according to the various solutions used.Each group contained 15 patients.After putting a catheter into the epidural space correctely

we injected a bolus dose of 13 ml anesthetic solution via it at a speed of 1 ml/3 sec

then an anesthetist who was entirely ignorant of what solution had been injected observed the anesthetic effect

recorded the results of sensory and motor blokades. Results:①Comparing three different local anesthetic agents

we found that the fastest onset of action is xylocaine

then bupivacaine

and the last one is dicaine.The longest duration of action is bupivacaine

then dicaine and xylocaine.②Comparing vatious concentrations

we found that accompanying the lowering of the concentration

the anesthetized dermatomes will be decreased

onset of action delayed

the duration of action shortened

and the degree of blockade tends to be incomplete.③Comparing various adrenaline contents

we found that the anesthetic effects were significantly decreased in xylocaine and dicaine solutions without adrenaline But there was no significant differences between the solutions with 1:100

000 and 1:200

000 concentrations.In bu- pivacaine solution

we found that the duration of action in bupivacaine solution with 1:200

000 concentration of adrenaline was significantly longer than without adrenaline

and it was dis- similar to the results reported by past literatures④Mixture solutions:we found that they could not shorten the onset of action significantly. According to the facts described above

we use 2% xylocaine solution as the first dose in epidural block iu our bospital.If the duration of the operation is long

one hour later we reinject 0.75% bupivacaine or 0.4% dicaine solutions.The concentration of each solution stated above can not be exceeded

and should be significantly lowered in the cases of pain reliefs

high epidural blocks

old persons

children and critically ill patients.The concentration of adrenaline should not exceed 1:200

000

and it should be lowered or disused in the hypertensive patients.Mixture solutions have no remarkable advantages

they may not be adapted.