The preoperative period is a stressful event for the majority of individuals undergoing surgery. This is especially true in the paediatric patient due to a limited understanding of the nature of the illness and the need of surgery in young children. Paediatric anesthesiologists strive to minimize distress for children in the operating room (OR) environment and to provide a smooth induction of anaesthesia. Preoperative anxiety stimulates the sympathetic, parasympathetic, and endocrine systems, leading to an increase in heart rate (HR) and blood pressure (BP). There is a association between preoperative anxiety and an increased incidence of adverse postoperative clinical outcomes in paediatric patients. Postoperative behavioural changes related to stressful hospital experiences/induction of anaesthesia include general anxiety, enuresis, night-time crying, and temper tantrums. These changes are usually transient but may persist for up to one year. The incidence is greatest in pre-school children in whom it can be reduced by psychological preparation, premedication, and the support of parents.

Various pre-induction techniques in paediatric anaesthesia are primarily focused on relieving the preoperative anxiety of the child, but consideration of parental anxiety is also important. The use of pre-induction techniques is, in many respects, unique to paediatric anaesthesia, and therefore can be challenging for the anaesthetist who practices paediatric anaesthesia on an occasional basis. To alleviate preoperative anxiety and enable smooth parental separation, various drugs have been advocated suitable for use as sedative premedication. Midazolam, a GABA agonist, is the drug most frequently used for paediatric premedication. Fentanyl, an opioid analgesic whose effects are mediated via the m-opioid receptors. It is rapidly absorbed via the transmucosal route and for premedication, it is presented as a pleasant tasting lollipop. Ketamine is an N-methyl-d-aspartate (NMDA) receptor antagonist that produces a state of sedation, anaesthesia, immobility, analgesia, and amnesia. Dexmedetomidine, (DEX)  a-2 agonists have emerged as new alternative of premedication in paediatric anaesthesia. DEX has a differential specificity for the a1:a2 receptors of 1:1620, compared with 1 : 220 for clonidine, being considered a full and highly selective agonist of a-2-adrenergic receptors. Clinical investigations have demonstrated its sedative, analgesic and anxiolytic effects after intravenous administration to volunteers and post-surgical patients.

The present study will be designed to compare the efficacy of nebulized dexmedetomidine and nebulized ketamine for premedication in pediatric patients undergoing elective surgery under general anaesthesia.