Inclusion Criteria:  Aged more than 18 Gender: both. ASA grade I-II (American society of anesthiologists). Prepared to spine surgery under general anesthesia  Exclusion Criteria:  Ischemic heart patients Hypertensive patients Patients with atrial fibrillation or any previous history of attack of arrhythmias Patients on B.B ( beta-blockers) Chronic use of neuropsychiatric medications Renal Impairment Liver Dysfunction. Any complications during the procedure as massive hemorrhage Surgery for traumatic spinal cord