Scalp Block: Hemodynamic Stability and Patient Comfort In Craniotomy Patients

Avoidance of hemodynamic fluctuations in the heart rate and or the blood pressure perioperatively, rapid postoperative recovery, and adequate postoperative pain relief are some of the important goals of neurosurgical anesthesia. Scalp block in association with general anesthesia is used to achieve these goals. Previous studies have been published related to the effect of scalp block on the perioperative outcomes on the craniotomy patients. The results reported so far are controversial and one cannot at this point define a positive effect for post-operative pain relief. This disparity in results may be the consequences of the size of the patient population. However scalp block is an accepted practice in the craniotomy patients. The investigators believe this is the first study which assesses the effectiveness of scalp block for asleep craniotomy with the largest sample size study so far conducted in the literature related to this topic. The aim of this study is to assess the effectiveness of scalp block for the perioperative comfort of the craniotomy patients undergoing resection for supratentorial tumors.

After the consent for the participation and enrollment in the study is done, patients will be randomized to two groups, a study group will receive a scalp block with a mixture of 2% lidocaine and 0.5% bupivacaine while the control group will receive the scalp block with saline. Intraoperatively, all patients will be preoxygenated, fentanyl (1-2mcg/kg) will be given and anesthesia will be induced with propofol (1-2mg/kg) and lidocaine (1-1.5mg/kg). Tracheal intubation will be facilitated by using either rocuronium (0.6 mg/kg) or succinylcholine (1-1.5mg/kg) intravenously. The lungs will be ventilated with a fresh gas flow of oxygen for 2 minutes before tracheal intubation with cuffed oral endotracheal tube. Anesthesia will be maintained with inhalational anesthetic Isoflurane, Sevoflurane or Desflurane (0.8-1 MAC) and fentanyl infusion (1-2mcg/kg) with the dose adjusted according to the patient's hemodynamics. Bilateral BIS or EEG to maintain an adequate level of depth of anesthesia will be used whenever feasible. After intubation, a scalp block will be performed. The randomization of the scalp block syringes will be provided by the pharmacy and neither the scalp block performer nor the attending will be aware of the syringe content. To standardize the block, a pain specialist is involved. Response to the pinning will be assessed using the hemodynamic parameters and rescue analgesics (fentanyl bolus 50 - 100 mcg) and/or propofol bolus 50 - 100 mg will be given as a bolus if significant response is noted. Significant response being a rise in the patient's heart rate and/or the blood pressure more than 20% from the patient's baseline heart rate and/or the blood pressure just before pinning. Similarly, response to the surgical incision will be noted and rescue analgesics will be given if needed. Intraoperative propofol requirement and opioid requirements will be recorded. The post-operative orders for pain control will be standardized for all the patients.