Effect of dexmedetomidine on anaesthesia and analgesia requirement during bispectral index guided anaesthesia for neurosurgery-a randomised clinical trial

Background- Anaesthesia for neurosurgery aims to bestow good operating conditions and to ensure stable cerebral haemodynamics without sudden increase in the acute brain swelling or intracranial pressure. Recently developed monitors for depth of anaesthesia such as Bispectral Index (BIS, Aspect Medical System, Newton, NA, USA) and Spectral Entropy (GE healthcare, Helsinki, Finland) uses the dimensionless monotonic index for the measure of depth of anaesthesia. Dexmedetomidine, is the pharmacologically active of isomer of the medetomidine, and is a highly specific and selective α-2 adrenoceptor agonist. This drug provides haemodynamic stability intraoperatively when used as an adjuvant with standard general anaesthesia drugs. This is attributed to its central sympatholytic action. It has good analgesic and also anaesthetic sparing properties. Aim- To study the effect of dexmedetomidine on anaesthesia and analgesia requirement during Bispectral index Guided anaesthesia for neurosurgery. Methods- This was a Prospective, Randomised Clinical trial (Clinical trial registry of India number CTRI/2021/10/037597). After obtaining the Institutional Ethics Committee clearance and written informed consent from each patient, 60 adult patients of either sex of American Society of Anaesthesiologists (ASA) Grade I and II aged 20‑60 years undergoing neurosurgery under general anaesthesia were included in this study. Group D(n=30) received dexmedetomidine as an adjuvant anaesthetic agent in premedication. Group F(n=30) received anaesthetic agents as per standard general anaesthesia protocol. The following parameters were considered during the study like Haemodynamic changes in Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure(DBP) and Mean Arterial Pressure (MAP) from baseline, after induction and after application of dexemeditomidine at different time intervals in both the groups and also the Depth of anaesthesia using bispectral index monitoring, To calculate and compare the volume of inhalational agents used, Haemodynamic parameters Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure(DBP) and Mean Arterial Pressure (MAP) in post op period and adverse effects, if any. P value <0.05 was considered to be statistically significant.
Results and Conclusion- Haemodynamic changes in Heart Rate, Systolic Blood Pressure, Diastolic Blood Pressure and Mean Arterial Pressure in the patients who were administered dexemeditomidine (0.5ug/kg given over 10mins) were in more stable lower range intraoperatively. The volume of inhalational agents used after giving dexmedetomidine was significantly lower. Haemodynamic parameters Heart Rate, Systolic Blood Pressure, Diastolic Blood Pressure and Mean Arterial Pressure in post op period was also noted to be on stable lower range as compared to baseline in the group who received dexmedetomidine.