Pediatric urologic surgery is generally accompanied by use of a caudal or penile block for analgesia. A caudal block is performed by injecting local anesthetic in the low epidural space while a penile block is performed by injecting local anesthetic above the pubic symphysis. Local anesthetic in the epidural space is known to caudal vasodilation interiorly. It is unknown as to whether this vasodilation results in alteration in flow to the penile tissue and potentially changes tissue characteristics. The aim of this study is to measure blood ultrasound velocity in the dorsal penile artery and vein before and after a block.

Pediatric urologic surgery is generally accompanied by use of a caudal or penile block for analgesia. A caudal block is performed by injecting local anesthetic in the low epidural space while a penile block is performed by injecting local anesthetic above the pubic symphysis. Local anesthetic in the epidural space is known to caudal vasodilation interiorly. It is unknown as to whether this vasodilation results in alteration in flow to the penile tissue and potentially changes tissue characteristics. The aim of this study is to measure blood ultrasound velocity in the dorsal penile artery and vein before and after a block.

Inclusion Criteria:

• Children ages <7 years undergoing circumcision at TCH Penile or Caudal block to be performed at discretion of anesthesiology/Urology providers
• ASA classification1,2
• use of laryngeal mask airway

Exclusion Criteria:

• Previous cardiac surgery
• Antihypertensive medication
• requirement for intravenous anesthetic
• ASA classification non 1,2
• parental refusal of participation parental refusal of block
• patients requiring intubation

penile study only applicable to males

males undergoing circumcision using penile or caudal