Ultrasound-guided ilioinguinal/iliohypogastric block did not reduce emergence delirium after ambulatory pediatric inguinal hernia repair: a prospective randomized double-blind study

Emergence delirium (ED) is a common postoperative complication of ambulatory pediatric surgery done under general anesthesia with sevoflurane. However, perioperative analgesic techniques have been shown to reduce sevoflurane-induced ED. The primary objective of this investigation was to examine whether an ultrasound-guided ilioinguinal/iliohypogastric (II/IH) nerve block for ambulatory pediatric inguinal hernia repair could reduce the incidence of sevoflurane-induced ED. The subjects of this prospective randomized double-blind study were 40 boys ranging in age from 1 to 6 years, who were scheduled to undergo ambulatory inguinal hernia repair. The patients were randomized to either receive or not to receive an ultrasound-guided II/IH nerve block (Group B and Group NB, respectively). General anesthesia was maintained with sevoflurane and nitrous oxide. The primary outcome assessed was ED, evaluated using the Pediatric Anesthesia Emergence Delirium (PAED) scale 30 min after emergence from general anesthesia. The secondary outcomes assessed were postoperative pain, evaluated using the Behavioral Observational Pain Scale (BOPS), and the amount of intra-operative sevoflurane given. The median PAED scale scores did not differ between Groups B and NB at 30 min (P = 0.41). BOPS scores also did not differ significantly between the groups, but the mean amount of intraoperative sevoflurane given was significantly lower in Group B than in Group NB (P < 0.01). Ultrasound-guided II/IH nerve block for ambulatory pediatric inguinal hernia repair did not reduce ED, but it did decrease the amount of intra-operative sevoflurane needed. Clinical Trial Registration: UMIN000008586.