title: Letter: Caudal block for post-operative pain relief in children.
mesh_terms: D000328:Adult; D000775:Anesthesia, Spinal; D002045:Bupivacaine; D002648:Child; D002944:Circumcision, Male; D004837:Epinephrine; D006801:Humans; D007649:Ketamine; D008297:Male; D010149:Postoperative Pain / Q000517:prevention & control*; D011343:Procaine
chemical_list: D011343:Procaine; D007649:Ketamine; D002045:Bupivacaine; D004837:Epinephrine