IRCT20120915010841N20 IRCT 2019-09-06 Hamedan University of Medical Sciences Comparison of 10 and 12 mg doses of intrathecal bupivacaine %0.5 on sensory block level and postdural puncture headache in patients under repeated spinal Comparison of 10 and 12 mg doses of intrathecal bupivacaine %0.5 on sensory block level and postdural puncture headache in patients under repeated spinal after failed spinal anesthesia in C/S. 2018-06-23 anticipated 40 Complete https://irct.ir/trial/40714 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Diagnostic, Randomization description: In this study , a randomized block design with four replications is used. we provide four paper sheets . We write two letters A and on two other sheets of letter B. We mix the papers together and put them in the drawer of the table.With each of the qualified patients, one of the papers is taken out randomly and will be assigned to one of the two Bupivacaine 10 and Bupivacaine 12 mg groups, depending on whether the drawn sheet is either A or B. After the random drawn out of four sheets, all the papers will be returned to the drawer and again the above procedure will continue for the next four patients until it reaches the sample volume, Blinding description: Participants knew the purpose of the study, but did not know which dose of bupivacaine would receive and the researcher did not know the dose. 2 Spinal anesthesia in cesarean section. Intervention 1: Intervention group: patients undergoing spinal anesthesia with 10 mg bupivacaine 0.5 %. Intervention 2: Intervention group: patients undergoing spinal anesthesia with 12 mg bupivacaine 0.5%. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is No more information.