Role of Nebulised Dexmedetomidine, Midazolam or Ketamine as Premedication in Preschool Children Undergoing General Anaesthesia: A Prospective, Double-Blind, Randomised Study

Abstract

Background: Preschool-aged children are highly susceptible to peri-operative anxiety, which can impair induction of anaesthesia and provoke maladaptive behaviours post-operatively. Nebulisation offers a needle-free route that achieves high mucosal bio-availability while being well-tolerated. We compared nebulised dexmedetomidine, midazolam and ketamine as sedative premedicants in this population.

Methods: Ninety-six ASA I–II children (3–7 y) scheduled for elective surgery were randomised (1:1:1) to receive dexmedetomidine 2 µg kg⁻¹ (Group D), midazolam 0.2 mg kg⁻¹ (Group M) or ketamine 2 mg kg⁻¹ (Group K) in 3 mL saline via jet nebuliser 30 min before induction. Investigators, caregivers and data collectors were blinded. Primary outcome was quality of sedation at 30 min (five-point sedation scale, FPSS). Secondary outcomes included parental-separation anxiety (PSAS), mask-acceptance (MAS), haemodynamics, and emergence agitation (EAS). Data were analysed with two-way repeated-measures ANOVA or Kruskal-Wallis test as appropriate (α = 0.05).

Results: Group D showed deeper sedation than Groups M and K (median FPSS 4 vs 3 and 3; χ² = 8.56, p = 0.014). Parental separation was easiest with dexmedetomidine (mean rank 38.5 vs 43.8 and 56.9; p = 0.009) and mask acceptance was superior (mean rank 34.5 vs 51.7 and 53.5; p = 0.003). Emergence agitation was lowest with dexmedetomidine (median EAS 1 vs 2 and 2; p < 0.001). Haemodynamic variables remained within 15 % of baseline in all groups, although heart rate and mean arterial pressure were lower with dexmedetomidine intra-operatively (p < 0.05).

Conclusion: Nebulised dexmedetomidine 2 µg kg⁻¹ provides more satisfactory pre-operative sedation, smoother parental separation and mask induction, and less emergence agitation than equi-sedative doses of nebulised midazolam or ketamine in preschool children.