the aim of this study is to study the pharmacokinetics and dynamics of nebulized dexmetedomidine in children undergoing major abdominal cancer surgery.

Inhalation of nebulized drug is an alternative route of administration that is relatively easy to set up, does not require venpuncture, but is associated with high bioavailability of the administered drug. Information on the pharmacokinetics of dexmedetomidine in the pediatric population is very limited, especially in children. To the best of investigators knowledge, there are no published reports on the pharmacokinetics of nebulized dexmedetomidine in children.

Inclusion Criteria:

• child aged 2-7 years
• ASA I or II
• scheduled for abdominal surgery
• with average weight, height, normal serum albumin

Exclusion Criteria:

• patients with allergy to the study drug
• patients with significant organ dysfunction
• patients with cardiac arrhythmia
• patients with congenital heart disease
• use of psychotropic medication and mental retardation.