Analgesia Nociception Index (ANI) has been proposed for the evaluation of the
nociception-antinociception balance in the perioperative period. In pediatric patients with
Moyamoay disease, where the management of analgesia may be rendered difficult by
pharmacological changes, we hypothesised that the monitoring of analgesia with ANI would
reduce intraoperative opioid consumption during EDAS surgery.