Effect of Premedication with Clonidine vs. Atenolol in Providing Optimum Surgical Field in Spine Fusion Surgery Under General Anaesthesia

Abstract
Background: Spine surgeries are associated with significant blood loss, which vary from 10 to 30mL/kg and its volume depends on the number of spinal levels fused; body weight, surgery for tumors, and raised intra-abdominal pressure in the prone position. Blood loss can be an acute problem not only in major deformity surgery but also in less extensive fusion procedures. Controlled hypotension is among the most widely used techniques for reducing blood loss in various types of surgery including spine surgery.
Aim of Study: The aim of the work was to evaluate the effect of preoperative clonidine vs. Atenolol on providing optimum surgical field in patients undergoing spine fusion surgery, and to minimize intraoperative blood loss and lastly for assessment of intraoperative surgeon satisfaction.
Patients and Methods: This study was prospective double blinded randomized clinical trial, was conducted in Orthopedic Operative Rooms in Assiut University Hospitals on patients underwent spine fusion surgery. It was done from April 2016 till April 2017. Sixty patients (ASA I or II) were undergone elective spine fusion surgery were included in this study. Patients were randomly divided into three Groups I, II, III. Group 1 (control group), patients received oral placebo. Group II (Atenolol group), patients received oral Atenolol tablet 50mg, Group III (clonidine group), patients received oral clonidine tablet 100ug. These drugs were given to the patients 2hr before induction of anesthesia. The hemodynamic param-eters like Heart Rate (HR), Mean Arterial Blood Pressure (MAP), oxygen saturation (SPO2%) were checked intra and post operatively, intra-operative bleeding was measured, and the surgeon unaware of the group was asked to evaluate the quality of the operative field using the pre-defined Average Category Scale (ACS) at the end of surgical procedure.
Results: Both intra and post-operative Heart Rate (HR), Mean Arterial Blood Pressure (MAP) were more reduced in Group II than in Group III than in Group I. Intraoperative blood loss and need for blood transfusion were less in Group II than in Group III than in Group I. The field was much better in Group II than in Group III than in Group I.
Conclusion: This study concluded that both clonidine and atenolol were effective and safe, in terms of stable hemody-namic profile and reducing intraoperative bleeding; when given orally to patients as premedication in patients for spine surgeries under general anesthesia. However, out of the two drugs atenolol appeared to be better in terms of reduction of blood loss and providing good quality of surgical field when compared to clonidine.