After approval of the Internal Review Board, the patients and families will be given the opportunity to participate in the proposed research study if inclusion criteria are met. The patient/family will sign the anesthesia consent form, as per protocol, by initialing the box at the bottom that states 'I do want, if indicated, regional anesthetic techniques employed for anesthetic maintenance and/or port operative pain relief for my child.' The primary anesthesia team (anesthesiologist/CNRA/resident) will be made aware that the need for a pressure transducer for the caudal epidural injection will be required and that a member of the research team will be documenting pressures during the procedure. Premedication with midazolam will be at the discretion of the attending anesthesiologist covering the case. Anesthesia induction may be performed with either intravenous medications or mask inhalation at the attending anesthesiologist's discretion; however no narcotics will be administered during induction, as is common when a caudal epidural is utilized for post-operative pain control. The airway will be secured using an oral endotracheal tube or laryngeal mask airway (LMA).