Comparison of scalp block vs local anaesthetic infiltration in preventing intraoperative hypertension in patients undergoing awake deep brain stimulation surgery

Placement of Deep brain stimulation electrodes is a stereotactically guided procedure for treatment of movement disorders (Parkinson disease, essential tremor, dystonias). Acute rise in blood pressure can precipitate intracranial hemorrhage especially during multiple passage of needles. Regional anaesthesia of scalp is essential for providing adequate intraoperative analgesia thus reducing intraoperative acute hypertension. Also, it reduces the doses of intraoperative analgesics and anti-hypertensives. It allows the surgeon for accurate placement of electrodes, improving the success rate of the surgery, which would have been difficult if done with sedation and general anaesthesia as verbal communication with the patient during the procedure is quite essential. Different modalities of regional anaesthesia of scalp commonly used are scalp block and local infiltration anaesthesia. This study is designed to compare the effects of local infiltration and scalp block in preventing intaoperative hypertension in deep brain stimulation surgeries. There has been a single study till date comparing these two modalities of anaesthesia in such surgeries. OBJECTIVES: PRIMARY OBJECTIVE: To compare the number of episodes of intraoperative hypertension in patients with local infiltration and with scalp block. SECONDARY OBJECTIVES: To compare requirement of analgesics, anti-hypertensives, sedatives, surgeon’s and neurologist’s satisfaction and perioperative complications in both groups. PLACE OF STUDY: This study will be conducted in the Department of Anaesthesia and Intensive Care, Nizam’s Institute of Medical Sciences from September 2021 to September 2022 (Single Institute). STUDY DESIGN: A Randomized comparative analysis will be conducted in 60 patients who are posted for Deep brain stimulation surgery, satisfying the inclusion and exclusion criteria. They will be divided randomly into two equal groups based on the modality of regional anaesthesia to be used and will be labelled as: Group L and Group S. Pre-operatively, Group L patients will receive 30 ml of local anaesthetic (15 ml of 0.5% Bupivacaine + 7 ml of 2% Lignocaine + 8 ml saline) in the sites of burr holes (i.e 2 sites-right and left, 15 ml in each site), by the surgeon. Group S patients will receive Scalp block with a total of 30 ml local anaesthetic (15 ml of 0.5% Bupivacaine + 7 ml of 2% Lignocaine + 8 ml saline) 15 ml on each side- right and left, by the anaesthesiologist. PARAMETERS TO BE RECORDED: All these parameters will be recorded intraoperatively for upto 4 hours after the beginning of surgery. 1. Vitals every 15 minutes for upto 4 hours from the beginning of surgery especially at: Infiltration, Incision, Burr hole, Dural coagulation, Dural cutting, Closure. 2. Number of hypertensive episodes. 3. Anti-hypertensive medications and their doses 4. Analgesics and their doses 5. Sedatives and their doses 6. Surgeon’s and neurologist’s satisfaction for electrode placement. INCLUSION CRITERIA: 1. ASA I,II,III 2. Age 18-70 yrs 3. Patients posted for Deep brain stimulation procedures. 4. Duration of DBS procedure lasting for 3-4 hours EXCLUSION CRITERIA: 1. Patients not willing to participate 2. Bleeding disorders or coagulopathies 3. Cardiac or respiratory compromise 4. Allergic to local anaesthetics 5. Local site infection. POST INCLUSION EXCLUSION CRITERIA: 1. Any intraoperative need for conversion to general controlled anaesthesia. 2. Any intraoperative complications observed (airway or respiratory compromise, seizures, cardiovascular compromise – needing either intubation or abandoning of procedure). STUDY HYPOTHESIS: Scalp block is superior over local anaesthetic infiltration in preventing intraoperative hypertension in patients undergoing awake deep brain stimulation surgery. Results will be published after the study.