Efficacy of Magnesium Sulphate and Dexmedetomidine in Controlled Hypotension for Functional Endoscopic Sinus Surgery: A Randomised Clinical Study

Abstract

Introduction: The treatment of nasal sinus diseases with Functional Endoscopic Sinus Surgery (FESS) is a well-established and popular method. This procedure is performed under general anaesthesia or local anaesthesia. Intentional induction of hypotension has helped limit intraoperative blood loss. A bloodless surgical field improves visibility and lowers the possibility of damaging nearby structures, achieved by reducing the baseline Mean Arterial Pressure (MAP) by 30% or maintaining MAP at 60-70 mmHg. Aim: To compare the efficacy of dexmedetomidine and Magnesium Sulphate (MgSO4) in producing hypotensive anaesthesia during FESS. Materials and Methods: This randomised clinical study was conducted at BLDE Shri BM Patil Medical College and Research Centre, Vijayapura, Karnataka, India, from January 2021 to July 2022. In this study, 70 patients, aged 18 to 60 years of either sex, admitted for FESS surgeries under general anaesthesia with American Society of Anaesthesiologists (ASA) Grade 1 and 2 were randomly divided into two groups: 35 patients in the dexmedetomidine group and 35 patients in the MgSO4 group. Dexmedetomidine was given to group D as a loading dose of 1 μg/kg, followed by an infusion of 0.5 μg/kg/h, and MgSO4 was given to group M as a loading dosage of 40 mg/kg, followed by an infusion of 15 mg/kg/h. MAP was kept above 65 mmHg during induced hypotension. Parameters studied included Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), MAP. Data was analysed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) Statistics Software Version 23.0. A p-value <0.05 was considered statistically significant. Results: The demographic profiles regarding age, gender, ASA grade, and duration of surgery in both groups were comparable and showed no significant differences. At 30 minutes of surgery, MAP in group D was found to be statistically lower than that in group M with a p-value of 0.0001. Dexmedetomidine induced a significant reduction in HR, which was statistically validated with a p-value of 0.004 at 15 minutes. A statistically significant reduction in MAP was found in group D compared to group M at the time of intubation and later at 10 minutes (p-value=0.005) and 15 minutes (p-value=0.006). Conclusion: The target MAP of 60-70 mmHg or a 30% reduction from the baseline MAP was achieved significantly earlier in group D as compared with group M. Group D had lower infusion dosages, better surgical field visibility, and caused less bleeding. The dexmedetomidine group experienced extended sedation and postoperative recovery.

Keywords

• controlled blood pressure
• intraoperative bleed
• sinus surgery
• surgical field visibility