The most common procedure said to involve substantial bleeding is spine surgery. There is always a significant danger of bleeding and blood transfusion associated with these procedures, particularly complex and multilevel spine surgeries. Care of bleeding should be taken, as excessive blood loss can lead to impaired vision of surgical field, anemia, postoperative epidural hematoma and transfusion-related complications as transfusion reactions and transmission of infections.

For these reasons, improving surgical field is a must. Hemostasis procedures, including good positioning, controlled hypotension, local vasoconstrictors, epidural block, biological and chemical medications including desmopressin, aprotinin, tranexamic acid, epsilon, aminocaproic acid, dexmedetomidine, can all be used to decrease bleeding.

and In this study we compared the effect of tranexamic acid and dexmedetomidine on hemodynamics, blood loss, transfusion and the quality of the surgical field.

Sample size was 78 cases who underwent lumbar decompression and fixation surgery at 2 levels. They were divided into 3 equal groups (26 patients in each one) :

1. Control grup (group C): received loading IV infusion of 50 ml saline over 10 min before induction of anesthesia, then maintenance IV infusion of saline.

2. Tranexamic acid group (group T): received loading dose of tranexamic acid 10 mg/kg over 10 min before induction of

   anesthesia, then maintenance IV infusion of tranexamic acid 1mg/kg/h.

3. Dexmedetomidine group (group D): received loading dose of dexmedetomidine 1 μg/kg over 10 min before induction of anesthesia, then maintenance IV infusion of dexmedetomidine 0.3-0.7 μg/kg/h.

We compared the 3 groups regarding these characteristics : - Age, sex, body mass index and ASA classification

• Hemodynamics (mean arterial pressure & heart rate) and oxygen saturation.
• Amount of blood loss, blood transfusion, pre and post operative hemoglobin and hematocrit levels.
• Side effects, duration of surgery, emergence and discharge times.
• Score of intraoperative surgical field. The results revealed that dexmedetomidine achieved more hypotensive and bradycardiac effects than other study drugs, but tranexamic acid had the upper hand in decreasing the amount of blood loss and blood transfusion. Side effects were more in dexmedetomidine group than other groups, represented mainly as hypotension and bradycardia. Duration of surgery was shorter in tranexamic acid group than other groups. Emergence and discharge times were longer in dexmedetomidine group than other groups. There was no statistical significant difference between the 3 groups in surgical field score.

Inclusion Criteria:

• Patient consent. 2. Age: 21-60 years old. 3. Physical status: ASA І & II. 4. BMI: 18.5-30 kg/m2. 5. Type of operations : elective lumbar decompression and fixation surgeries at 2 levels. 6. Time of operation : less than 4 hours. 7. Type of anesthesia : general anesthesia.

Exclusion Criteria:

• 1. known history of allergy to study drugs. 2. Central nervous system disorder and metabolic diseases. 3. History or risk of thrombosis or active thromboembolic disease as deep vein thrombosis and pulmonary embolism. 4. Coagulopathies or taking drugs affecting coagulation ( INR>1.5 , PLatelets count less than 100.000 per microliter of blood ). 5. Patients on B- blockers.