Wound catheter infusion after abdominal surgery in baby's.

This study investigates the hypothesis that regional anesthesia provided by wound catheter infusion (WCI) with ropivacaine reduces pain postoperatively (as measured with COMFORT behavior scale and NRS Pain scores) and leads to a morphine-sparing effect of at least 30% after abdominal surgery in infants < 1 year of age.

Children will receive a woundcatheter at the end of the operation, which will be removed after 72 hours postoperatively.
One week after the operation the parents will be contacted to fill out a questionnaire.

At the end of abdominal surgery, following closure of the muscle layers and subcutaneous tissue, the surgeon will place a multi-hole wound catheter superficial to the muscle fascia under direct vision (On Q® Soaker Catheter, Halyard) and tunneled from a separate stab incision approximately 3 cm lateral to the wound.
Hereafter the skin is sutured. The catheter is fixated to the skin with a plaster (Steri Strip™ and Tegaderm™) and is connected to a syringe in a perfusor pump, which is filled with either ropivacaine 0.2% or saline (placebo). Before end of anesthesia, all children will receive a bolus dose via the wound catheter: ropivacaine 2 mg/kg (R group) or the same amount in ml/kg of saline (saline) in the control group. WCI is started postoperatively: ropivacaine 0.2 mg/kg/h (R group) or saline (control group) in the same amount.

At the end of surgery, the control group will receive a bolus dose of morphine 100 mcg/kg IV, because this is standard of care after major surgery in the Erasmus MC-Sophia (local pain protocol). Group R receives placebo (saline) in the same amount as IV bolus dose. All patients receive a first dose of paracetamol 20 mg/kg IV at the end of surgery. Paracetamol IV is continued on the PICU as standard analgesic, also according to local pain protocol.

Postoperatively, all children are admitted to the PICU. At the PICU, postoperative pain is assessed in all children using the COMFORT behavior scale and NRS pain. Based on these validated pain assessments, patients receive rescue morphine doses, when needed, according to an algorithm.

Children will be followed up for 72 hours postoperatively, after which the catheter will be removed.