comparison of adding neostigmine and fentanyl to bupivacaine in caudal analgesia in pediatric inguinal herniorrhaphy

Objective: the aim of the present trial was to compare efficacy and adverse effects of neostigmine against fentanyl when used as adjuvant to bupivacaine in caudal anesthesia. method: a total of 140 children, aged 16 year scheduled to elective herniorrhaphy, were enrolled. exclusion criteria were sacral area infection, history of allergic reactions to local anesthetics, bleeding tendency, neurological or spinal disease and lack of parent consent. patients were assigned, using permuted block randomization method, into four groups of 35. children in the first group received a caudal injection of 0.5 ml/kg bupivacaine 0.25% plus fentanyl 1µ/kg. the second group received 0.5 ml/kg bupivacaine 0.25% plus neostigmine 1µ/kg. patients in the third group received 0.5 ml/kg bupivacaine 0.25% plus combination of fentanyl 1µ/kg and neostigmine 1µ/kg, and those in the fourth group only received 0.5 ml/kg bupivacaine 0.25% concentration. to assess pain intensity, wong baker scale was used. time to first analgesic request and the dosage of analgesic agent was recorded. data were analyzed using spss 17.0.results:significant differences were observed among groups in terms of number of patients needing analgesic (p=0.01), time to first analgesic request (p=0.005) and analgesic dose. (p=0.05) the lowest number of requests for analgesia, lowest dose of pethidine and longest time to first analgesic request were in patients receiving combination of bupivacaine, neostigmine and fentanyl. conclusion: the present study shows that the combination of fentanyl and neostigmine, could prolong duration of analgesia, and decrease severity of pain when added to bupivacaine