Dexmedetomidine as adjunct to ilioinguinal/iliohypogastric nerve blocks for pediatric inguinal hernia repair: an exploratory randomized controlled trial

BackgroundAdult meta-analysis has identified dexmedetomidine as a potentially useful adjunct to prolong the duration of peripheral nerve blocks. However, no data exist regarding the adjuvant use of dexmedetomidine in the setting of pediatric peripheral nerve blocks. MethodsUsing a prospective, randomized, double-blind design, children (11/2-8years, ASA 1-2) scheduled for outpatient inguinal hernia repair were randomized to receive either an ultrasound-guided ilioinguinal/iliohypogastric nerve block (IINB) with plain ropivacaine 0.197% (Group LA; n=21) or ropivacaine 0.197% with adjunct dexmedetomidine 0.3gkg(-1) (Group LAD; n=22). The primary endpoint of the study was time to first postoperative administration of supplemental analgesia (FPASA) triggered by a pain score 4 (CHIPPS or NRS scale). Intention-to-treat (ITT) analysis was decided as the primary statistical analysis of the data. ResultsThe median time to FPASA was prolonged by 88% following the use of adjunct dexmedetomidine (4.0 and 7.6h in group LA and LAD, respectively) (P=0.0717). Patients in Group LA displayed a significantly higher number of patients with a CHIPPS score 4 in the PACU (7 vs 0; P=0.0029) as well as a higher incidence of PAED (4 vs 0; P=0.0485) when compared to patients in Group LAD. No adverse events were recorded in any of the study groups. ConclusionsThe use of dexmedetomidine as an adjunct to an IINB resulted in reduced incidences of CHIPPS pain scores 4 and PAED scores of 11 during early recovery following pediatric inguinal hernia repair. In addition, the use of adjunct dexmedetomidine was associated with a prolongation of the period to first supplemental analgesia demand. The results of the present exploratory study must be viewed as preliminary and need further validation by future larger sized studies and/or meta-analysis.