Normal Saline versus Balanced Salt Solution in Diabetic Patients Undergoing Elective Surgery with Spinal Anaesthesia: A Randomised Control Study

Introduction: Perioperative fluid management is of utmost importance in diabetic patients posted for surgery. Despite availability of a plethora of intravenous fluids, Normal Saline (NS) is still most commonly used in diabetic patients for perioprative fluid therapy. Aim: The present study was designed to compare NS with plasmalyte to study their effects on blood sugar, serum electrolytes, lactate levels and blood pH in diabetes mellitus patients undergoing elective surgery under subarachnoid block. Materials and Methods: The present double blinded randomised control study was carried out in the department of anaesthesiology and critical care at a Pt BDS PGIMS, Rohtak, Haryana, India, between November 2022 - April 2024. Seventy patients of age 30-85 years, with diabetes mellitus, American Society of Anaesthesiologists (ASA) class II scheduled for elective surgery under sub-arachnoid block were enrolled in a randomised controlled trial and randomly divided into two groups; Group A received NS and Group B received plasmalyte as intravenous fluid. Rest of the anaesthesia protocol was uniformly standardised in all the patients. Venous blood sample were drawn preoperatively, at one hour and six hours after the start of surgery for the measurement of blood sugar, serum sodium, potassium, chloride, serum lactate and pH. Recorded data was analysed with t-tests and Chi-square tests. Results: Mean age was 60.66±13.56 years in NS group and 64.80±12.52 years in plasmalyte group. Serum lactate levels were comparable in preoperative (mean value 1.34±6.57 mmol\L in NS group and 1.14±0.48 mmol/L in plasmalyte group; p-value 0.12) and postoperative period at six hours time point (mean value of lactate (mmol/L) in Group A (NS) was 1.33±0.61 mmol/L in NS group and 1.17±0.38 mmol/L in plasmalyte group; p-value 0.18), but lactate levels were significantly lower in plasmalyte group (1.05±0.32) than in NS group (1.29±0.56) in intraoperative period with p-value of 0.03. Serum electrolytes, blood pH and glucose levels were comparable at preoperative, intraoperative and postoperative in both groups. Conclusion: The present study results conclude that both plasmalyte and NS are comparable in maintaining blood sugar, serum electrolytes and blood pH perioperatively in patients with well optimised type II diabetes mellitus. However, plasmalyte is a promising alternative to 0.9% NS in terms of maintenance of lactate levels in diabetic patients.