Dexmedetomidine Sedation Versus General Anaesthesia for Inguinal Hernia Surgery in Infants (DEGA)

Dexmedetomidine Sedation Versus General Anaesthesia for Inguinal Hernia Surgery on Peri-operative Outcomes and Neurocognitive Development in Infants: A Randomized Controlled Trial

This is a prospective randomized controlled trial comparing dexmedetomidine sedation with caudal anaesthesia, and general sevoflurane anaesthesia with caudal anaesthesia for inguinal herniotomies in neonates and infants below 3 months of age. The investigators will compare the efficacy and adverse events associated with each of these techniques and neurodevelopmental outcomes of the infants in each group at 6 months and 2 years of age.

Several epidemiologic studies have suggested that children exposed to general anaesthesia (GA) in early childhood may be at increased risk of subsequent learning disabilities and behavioural problems. Animal studies have shown that exposure to GA agents during critical neuro-developmental windows induces neuronal apoptosis. All commonly used anaesthetic agents induce neurotoxicity with the exception of dexmedetomidine, a highly specific alpha-2 agonist which has been shown to be neuroprotective. GA is the current standard of care for inguinal hernia repair in infants at KKH. The investigators recently demonstrated that dexmedetomidine sedation with caudal block is a feasible alternative for inguinal hernia repair in infants below 3 months of age. This prospective randomized controlled trial will compare the early and long-term outcomes of infants following inguinal hernia surgery using dexmedetomidine sedation with caudal block versus GA with caudal block. This study aims: To compare the neurodevelopment at 6 months and 2years, of infants randomized to dexmedetomidine sedation with caudal block with those randomized to GA with caudal block for inguinal hernia surgery before 3 months of age. To compare the efficacy of dexmedetomidine sedation with caudal block versus GA with caudal block for inguinal hernia surgery, in terms of duration of anaesthesia, duration of surgery and surgeon's satisfaction with intraoperative conditions.

Intravenous dexmedetomidine sedation prior to single shot caudal anaesthesia and maintenance infusion of dexmedetomidine during bilateral inguinal hernia surgery.

General sevoflurane anaesthesia with endotracheal intubation and single shot caudal anaesthesia for inguinal hernia surgery. This is currently the standard anaesthetic technique for bilateral inguinal hernia surgery in neonates and infants in KKH.

Deferred imitation, test of declarative memory. Infants are assessed when first shown the "target" actions (DF1) and again on how well they reproduce the actions (DF2).

Inclusion Criteria: Infants below 3 months of age ( corrected age 54 weeks) presenting for elective inguinal hernia repair in KKH. Exclusion Criteria: History of prematurity younger than 28 weeks gestation, Requirement for CPAP greater than 6 cmH20 at time of surgery Significant cardiac pathology or cardiac conduction defects Unusually large hernia sacs Any contraindication for caudal anesthesia Surgeon refusal on account of anticipated prolonged or difficult surgery.

Jevtovic-Todorovic V, Hartman RE, Izumi Y, Benshoff ND, Dikranian K, Zorumski CF, Olney JW, Wozniak DF. Early exposure to common anesthetic agents causes widespread neurodegeneration in the developing rat brain and persistent learning deficits. J Neurosci. 2003 Feb 1;23(3):876-82. doi: 10.1523/JNEUROSCI.23-03-00876.2003.

Sanders RD, Sun P, Patel S, Li M, Maze M, Ma D. Dexmedetomidine provides cortical neuroprotection: impact on anaesthetic-induced neuroapoptosis in the rat developing brain. Acta Anaesthesiol Scand. 2010 Jul;54(6):710-6. doi: 10.1111/j.1399-6576.2009.02177.x. Epub 2009 Dec 9.

Mahmoud M, Mason KP. Dexmedetomidine: review, update, and future considerations of paediatric perioperative and periprocedural applications and limitations. Br J Anaesth. 2015 Aug;115(2):171-82. doi: 10.1093/bja/aev226.

Bong CL, Tan J, Lim S, Low Y, Sim SW, Rajadurai VS, Khoo PC, Allen J, Meaney M, Koh WP. Randomised controlled trial of dexmedetomidine sedation vs general anaesthesia for inguinal hernia surgery on perioperative outcomes in infants. Br J Anaesth. 2019 May;122(5):662-670. doi: 10.1016/j.bja.2018.12.027. Epub 2019 Mar 7.