Dexmedetomidine on Postoperative Cognitive Dysfunction and Serum Tau-217 Protein.

Effect of Dexmedetomidine on Serum Tau-217 Protein as a Biomarker for Post-operative Cognitive Dysfunction in Elderly Patients.

To assess the effect of Dexmedetomidine on serum Tau-217 protein and its relation to the incidence and severity of postoperative cognitive dysfunction in elderly patients undergoing major surgery under general anesthesia.

to assess the effect of dexmedetomidine on serum Tau-217 protein through measuring serum Tau-217 protein preoperative and postoperative period and comparing the 2 measurements , assessing the cognitive dysfunction in the elderly patients and comparing the correlation between the cognitive dysfunction with serum tau-217 level also assessing the neuroprotective effect of dexmedetomidine on postoperative cognitive dysfunction and its relation with serum Tau-217 level.

Inclusion Criteria:

• Patients aged > 65 years old, both genders, Basal Metabolic Index range 18.5 to less than 35 American Society of Anesthesiologists I - III with Glasgow Coma Scale 14-15 undergoing major surgery under general anesthesia.

Exclusion Criteria:

• Patients will be excluded if they refused the enrollment in our study, Glasgow Coma Scale<14 or if there is severe cardiac, liver or renal disease, patients have Alzehimer's Disease or any of the psychotic diseases, poorly educated patients and if there is any sensitivity to given drugs