Lidocaine Versus Esmolol for Optimizing Surgical Field Visibility

Intraoperative Lidocaine Versus Esmolol Infusion for Optimizing Surgical Field Visibility During Lumbar Discectomy

Intra-operative blood loss is an important attribution and predictor of the lumbar spine surgery and patient outcome. Stripping the muscle off bone makes more exposed bleeding spine surface is one of causes for blood loss during lumbar surgeries. The importance to decrease the bleeding is to improve the surgical field visibility which provides technical ease for surgeon and decreases the surgical time besides maintaining the hemodynamic stability. In past, there were many trials to minimize surgical blood loss by different drugs such as Na Nitroprusside, magnesium sulfate, volatile anesthetics and beta-adrenergic antagonist.

Sample size: Assuming mean and standard deviation of mean arterial pressure in lidocaine group versus esmolol group is 90±27.9 versus 73± 22.5 so the sample size will be 70 (35 in each group ) using Open Epi program with confidence level 95%, power of test 80% All patients will be hospitalized and visited a day before the surgery, full history with physical examination and routine investigation will be done, the nature and complications of the study will be explained in detail to the patient and informed written consent will be obtained from every participant. All patients will be kept nil orally 6 hours before the operation. All surgeries will be done by the same surgeon to decrease observer's bias. The surgeon and the outcome assessor (anesthesiologist collect the data) will be blinded to study drugs. Using computer generated randomization table, each group consists of 35 patients.

Group L (lidocaine group) (n=35): the Patient will receive IV bolus of 1.5mg/kg lidocaine 1% over ten minutes followed by continuous infusion of 1.5mg/kg/h and will be terminated 10 minutes before the end of surgery. Group E(esmolol group) (n=35): the Patient will receive IV bolus of esmolol 0.5 mg/kg over ten minutes followed by continuous infusion of 100-300 ug/kg/min and will be terminated 10 minutes before the end of surgery.

the Patient will receive IV bolus of 1.5mg/kg lidocaine 1% over ten minutes followed by continuous infusion of 1.5mg/kg/h

the Patient will receive IV bolus of esmolol 0.5 mg/kg over ten minutes followed by continuous infusion of 100-300 ug/kg/min

using the surgical field rating (SFR) scale of six points proposed by (Fromme et al 1986) : Grade 0: No bleeding - virtually bloodless field. Grade 1: Slight bleeding so no suctioning required. Grade 2: Slight bleeding so occasional suctioning required. Grade 3: Low bleeding- frequent suctioning required; bleeding threatens surgical field some seconds after suction is removed. Grade 4: Moderate bleeding- frequent suctioning required, bleeding threatens surgical field directly after suctioning. Grade 5: Sever bleeding so constant suctioning required; bleeding appears faster than can be removed by suction; surgical field severely threatened and surgery hardly possible.

Surgeon's satisfaction score Bad satisfaction. moderate satisfaction. Good satisfaction. excellent satisfaction

The number of patients need for blood transfusion: Acute blood loss more than 1,500 ml or 30% of blood volume is in need of blood transfusion

Blood loss= Hb (gdL/1) X V (mL)/Hbm (g/dL); Intraoperative blood volume loss (V)=blood in the suction container with adjustment for the used irrigating saline and the blood soaked by gauze pieces [4×4 soaked gauze piece =15 ml blood, completely soaked abdominal towel =150 ml blood].Hb= Hb concentration of suction container and Hbm=patient's mean hemoglobin concentration at the start

Inclusion Criteria: American society of anesthesiologist( ASA): I& II Physical status: Body Mass Index( BMI)=(25-35 kg/m2). Type of operations: lumbar discectomy. Written informed consent from the patient. Exclusion Criteria: Patient refusal. .Altered mental state . Patients on beta-blockers or with a known history of allergy to study drugs. Hepatic, renal, Cardiovascular and respiratory diseases. Diabetic patients. Patients receiving anticoagulants. Previous spine surgery