The Effects of 6% Hydroxyethyl Starch Compared with Normal Saline on Controlling Undesirable Hemodynamic Changes Following Spinal Anesthesia in Patients Undergoing Orthopedic Surgery: a Randomized Clinical Trial

Background: The aim of the current study was to compare the effects of normal saline solution and 6% hydroxyethyl starch (HES/HAES) solution on hemodynamic changes after spinal anesthesia in patients undergoing lower limb orthopedic surgery. Materials and Methods: This randomized clinical trial was performed on 50 patients undergoing surgery, aged 20-60, with physical status of ASA I, II. Before surgery, the hemodynamic status of each patient including systolic and diastolic blood pressure, heart rate, and central venous pressure was measured. Then, the patients were randomly divided into two groups and for the control group, 7 ml/kg 9% (or normal) saline and for the experimental group 6% hydroxyethyl starch were administered. Hemodynamic indices were re-measured after the completion of infusion, and then spinal anesthesia was performed. After anesthesia, hemodynamic indices were measured every 5 minutes for 1 hour and then every 10 minutes for 2 hours. The analysis of variance (ANOVA) for repeated measures was used to evaluate the significant changes in hemodynamic indices. Results: The mean and standard deviation of systolic and diastolic blood pressure, heart rate, and central venous pressure in the control group were 113.0 (7.3), 73.0 (6.0), 95.6 (5.7), and 5.8 (0.9), respectively, and in the intervention group were 104.8 (5.5), 66.1 (4.2), 95.8 (8.2), and 4.3 (0.9(. ANOVA for repeated measures showed that the incidence of decreasing changes in systolic and diastolic blood pressure, heart rate, and central venous pressure of the patients for whom hydroxyethyl starch was prescribed was significantly less than that of the patients for whom normal saline was prescribed. Conclusion: Hydroxyethyl starch has a more effective role in controlling hemodynamic changes before spinal anesthesia than normal saline.