Evaluation of the Hemodynamic Response of Intravenous Clonidine versus Ropivacaine Scalp Block to Insertion of Scalp Pins in Neurosurgical Patients.

Abstract

Background:The application of the skull-pin head-holder, used to stabilize the head during neurosurgical procedures, produces an intense nociceptive stimulus and results in abrupt increases in blood pressure and cerebral blood flow under general anesthesia. Different anesthetic and pharmacologic techniques, including local anesthetics, narcotics, antihypertensives, and deepening of anesthesia with inhalation anesthetics, have been used to blunt this deleterious effect with variable success.Aim:To compare the analgesic and hemodynamic effects of ropivacaine scalp block, and intravenous (IV) clonidine in attenuating the hemodynamic response to the scalp pin insertion in neurosurgical patients.Settings and Design:A comparative two group's clinical study of 64 patients undergoing elective craniotomy in Department of Anaesthesiology, Bangalore Medical College and Research Institute.Methodology:Sixty-four patients were allocated into any one of two groups of 32 patients each, by means of computer-generated randomization: (1) Group S: Patients receiving scalp block with injected ropivacaine 0.25% 30 ml. (2) Group C: Patients receiving 2 μg/kg IV clonidine.Statistical Methods:Descriptive and inferential statistical analysis has been carried out in the present study. Results on continuous measurements are presented on mean ± standard deviation (minimum–maximum) and results on categorical measurements are presented in number (%). Significance is assessed at 5% level of significance.Results:Increase in heart rate and blood pressure during pin insertion was attenuated by clonidine hydrochloride (P < 0.001). The number of patients who required more fentanyl and propofol to stabilize the hypertensive response were more in control group than clonidine group.Conclusion:IV clonidine maximally attenuated the hemodynamic response to application of head pins in a dose of 2 μg/kg compared to ropivacaine scalp block, thus maintaining intracranial pressure for neurosurgical anesthesia.