Prospective, up-down sequential allocation : first patient receives 50mg intrathecal chloroprocaine 1%.

An effective result will decrease the test dose of chloroprocaine with 2 mg for the next patient in this study.

An ineffective result will increase the test dose of chloroprocaine with 2 mg for the next patient in this study.

standard CSE procedure in outpatients for inguinal hernia. The first spinal dose of chloroprocaine 1% to start with is 50mg. This dose has been successfully used for spinal anesthesia in hernia repair outpatients to reach an adequate analgesia. 2,5 microgram of sufentanil will be added for prolongation of the analgesia. The testing interval is 2 mg.

Efficacy of the analgesia will be evaluated:

Successful : sensory block at or above T6 dermatome bilateral at the beginning of surgery without additional analgesia during surgery. Unsuccessful: sensory block under T6 dermatome bilateral and/or VAPS is more than 10 mm at the beginning of surgery what necessitates additional epidurals analgesia.

Patients who indicate an ineffective result will receive a rescue treatment by the administration of 5 ml chloroprocaine 3% epidural every 5 minutes with maximum of 30ml. When CSE fails, general anesthesia will be performed.

MLAD of chloroprocaine 1% with 2,5 mcg of sufentanil needed for the individual patient required for a sensory anesthesia at or above the T6 dermatome at the beginning of surgery with no additional epidural anesthesia required during surgery

highest sensible block

Time for regression of two segments