Efficacy of Dexmedetomidine Infusion on Propofol Requirement in Maintaining Depth of Anaesthesia in Elective Neurosurgical Procedures: A Randomised Controlled Study

Introduction: Dexmedetomidine, a selective alpha-2 adrenergic receptor agonist, is gaining momentum in neurosurgical anaesthesia for its sedative, analgesic, and sympatholytic effects. Propofol, although widely used, has its risks, like hypotension and respiratory depression at high doses. When these two drugs are given together during neurosurgical procedures, evaluating those changes may provide their potential as an anaesthetic adjunct while reducing risks associated with excessive propofol use when used alone. Aim: To evaluate the efficacy of Dexmedetomidine infusion in reducing intraoperative Propofol requirement and maintaining depth of anaesthesia during elective neurosurgical procedures. Materials and Methods: This was a randomised controlled study conducted at the Department of Anaesthesiology, Krishna Institute of Medical Sciences, Krishna Vishwa Vidyapeeth (Deemed to be University), Karad, Maharashtra, India, from February 2023 to October 2024. It comprised 50 the American Society of Anesthesiologists Physical Status (ASA-PS) I–II patients aged 18-60 years undergoing elective neurosurgery. Patients were randomised into two groups: Group P (standard anaesthesia with Propofol infusion) and Group PD (same regimen plus Dexmedetomidine infusion: 1 µg/kg bolus over 10 minutes followed by 0.5 µg/kg/hr). Propofol was titrated to maintain the Bispectral Index (BIS) between 40-60. Haemodynamic parameters, total Propofol consumption (mg/kg/hr), and intraoperative complications were recorded and analysed using Repeated-measures One way-Analysis of Variance (ANOVA) or Student’s t-test. Results: The two study groups were comparable in age (group P: 42.3±10.5 years; group PD: 41.8±9.8 years; p-value=0.82), Body Mass Index (BMI) (group P: 24.9±2.5 kg/m2; group PD: 25.1±2.4 kg/m2; p-value=0.85). Group PD showed significantly reduced intraoperative Propofol consumption compared to group P (3.00±0.8 mg/kg/hr vs. 4.50±1.0 mg/kg/hr, p-value <0.001). Haemodynamic parameters {Heart rate (HR), Mean Arterial Pressure (MAP)} remained more stable in the Dexmedetomidine group across all intraoperative time points. In the group PD, the incidence of hypotension was slightly lower than in group P {3(12%) vs. 6 (24%)}. Target BIS range (40- 60) was maintained in both the study groups. However, group PD consistently demonstrated lower BIS values (e.g., 52.0±3.8 vs. 55.2±4.5 at 5 min, p-value=0.02), with reduced variability (5.8±0.9% vs. 7.2±1.1%, p-value <0.001). Conclusion: Dexmedetomidine infusion significantly reduces the intraoperative Propofol requirement while maintaining adequate depth of anaesthesia and providing superior haemodynamic stability in elective neurosurgical procedures. Its use as an adjuvant can enhance anaesthetic efficiency and patient safety when carefully monitored.