Efficacy of Intravenous Fluid Plasmalyte and 6% Hetastarch in Preventing Spinal Anaesthesia Induced Hypotension in Patients undergoing Lower Abdominal Surgeries: A Randomised Clinical Study

Abstract

Introduction: Both crystalloids and colloid preloading is recommended for spinal anaesthesia. Preloading of intravenous fluids increases circulating volume and cardiac output; thus preventing spinal anaesthesia-induced hypotension. Crystalloids have a short intravascular half-life, poor plasma expanders and large volumes are thus required. Aim: To compare the efficacy of 5 mL/kg of 6% Hetastarch (colloid) to that of 15 mL/kg of Plasmalyte (crystalloid) solution to prevent hypotension during spinal anaesthesia in patients undergoing lower abdominal surgeries. Materials and Methods: This was a randomised clinical trial from June 2016 to April 2017 on a total 80 patients, belonging to American Society of Anaesthesiologist (ASA) Grade I and II scheduled for lower abdominal surgeries under spinal anaesthesia. They were divided into two groups- Group H and Group P. Patients in group H were preloaded with 5 mL/kg solution of 6% Hetastarch, whereas those in group P were preloaded with 15 mL/kg of Plasmalyte solution. After institution of spinal anaesthesia with 3.0 mL of hyperbaric Bupivacaine using 25G Quincke’s needle, Blood Pressure (BP) and other vital parameters were monitored intraoperatively every 3 minutes for first 30 minutes and then every 5 minutes till the end of surgery. Descriptive statistics, frequency (n) and percentages (%) were calculated and the variables between the groups were compared by Students t-test, Fischers exact test and Mann Whitney U-test. Results: Both the groups showed a fall in Mean Blood Pressure (MBP) immediately after the block. Group P showed more decline in MBP and Diastolic Blood Pressure (DBP) after the block and thedifference was statistically significant at 9, 12, 15, 18 and 21minute (p-value <0.05). A 30% patients in group P as comparison to 10% in Group H required ephedrine for the treatment of hypotension and found significant (p-value=0.025). Systolic Blood Pressure (SBP), pulse rate changes and nausea and vomiting among both groups was non-significant (p-value >0.05). Conclusion: Pre-loading with 5ml/kg of 6% Hetastarch is more effective than 15ml/kg of Plasmalyte in preventing hypotension in patients undergoing lower abdominal surgeries under spinal anaesthesia.