Transversus Abdominis Plane Block in Children Undergoing Open Pyeloplasty Surgery

Primary open pyeloplasty is a common elective surgical procedure at The Hospital for Sick Children. All children are given fentanyl plus local anesthetic wound infiltration for intraoperative analgesia. A retrospective audit demonstrated that 63% of children required additional opioid treatment in the early recovery period following surgery. Concern exists regarding potential side effects of opioids including nausea or vomiting, respiratory depression, pruritus, over-sedation and delayed transition to oral intake. More importantly, children may under-report their pain or pain may not be recognized by medical staff leading to inadequate provision of analgesia. This suggests that the use of a regional technique, such as a TAP block, may benefit children undergoing open pyeloplasty.

The ultrasound guided TAP block introduces a local anaesthetic to the transversus abdominis plane which is one of three muscle layers in the abdominal wall. This results in a block of the nerves leading to the abdominal wall thereby reducing pain sensations.

Inclusion criteria

• American Society of Anesthesiologists (ASA) classification score 1-3
• age 1 month to 6 years inclusive

Exclusion criteria

• children undergoing an additional surgical procedure at an anatomical location not covered by a unilateral TAP block during the same anesthetic
• children in whom a TAP block is contraindicated, i.e. surgical scar or distorted anatomy at the site of injection
• postoperative admission to the intensive care unit
• children with a known allergy to bupivacaine
• children with a history of chronic abdominal pain requiring opioid analgesics
• children with known renal insufficiency
• children with known impaired hepatic function
• children with known impaired cardiac function
• children known hypersensitivity to sodium metabisulfite