Pain relief for scalp pin application
The skull pin application in neurosurgical procedures were used to stabilize head position for surgery. They lead to intense noxious stimuli and increase in HR, MAP, plasma catecholamine and CBF even when the patients are under general anaesthesia. In patients with intracranial lesion due abnormal autoregulation are prone for raise in ICP with increase in MAP . These adverse effect can lead to acute cerebral edema and herniation of brain. Different techniques were employed to reduce this pin response-scalp block or pin site infiltration with local anaesthetic, opioids, shortacting β -blockers, deepening of anaesthesia with inhalation and α-2 agonist. Scalp block with local anaesthetics played major role in attenuating the hemodynamic effects as well as the sympathoadrenal response to skull pin insertion. Dexmedetomidine is selective alpha 2 agonist which has sedation, anaesthetic sparing and analgesic properties. It decreases thehemodynamic response in dose dependent fashion. It can be used as adjuvant for maintenance of anaesthesia in neurosurgical patients. In our study we compared Scalp block with Dexmedetomidine infusion in attenuation of pin response in neurosurgical patients.
Steps to reproduce
STUDY PROTOCOL After institutional Ethical Committee approval and informed consent ,60 ASA I-III patients were selected for the study based on the inclusion and exclusion criteria. Patient were randomized into two groups GROUPS Group S –Patients received scalp block with injection Bupivacaine 0.5% 30ml prior pin application Group D-Patients received intravenous dexmedetomidine 0.5mcg/kg i.v loading dose and 0.25mcg/kg/hr. In the operating room, standard monitors ECG, Noninvasive blood pressure, pulse oximetry and ETCO2 were placed in the patients. I.V access was secured. The baseline heart rate and blood pressure was recorded. General anaesthesia -Premedication with InjGlycopyrrolate 0.2mg i.v ,Inj Midazolam 1mg i.v and Inj Fentanyl 2mcg/kg i.vgiven.Induction with InjThiopentone 4-5mg/kg and muscle relaxant InjVecuronium 0.1mg/kg i.v given. After endotracheal intubation with appropriate size ETT bilateral air entry checked and anaesthesia was maintained with nitrous oxide and oxygen 50:50 ratio with 1MAC of sevoflurane and muscle relaxation with InjVecuronium 0.05mg/kg.Ventilation was maintained with tidal volume of 8-10ml/kg and frequency of 12-15/mt. Group D(Dexmedetomidine) patients were given bolus dose of dexmedetomidine 0.5mcg/kg as infusion over a period of 10mts,before induction of anaesthesia and continued as maintenance dose 0.25mcg/kg/hr from induction to 5mts after pinning. In Group S(Scalp block) patients, bilateral scalp block with 0.5% bupivacaine 30ml –(15ml on each side )was given. Skull pins were applied 5mts after scalp block.