Comparison of Sensory Block Levels with Crystalloid and Colloid Preloading in Spinal Anesthesia for Cesarean Delivery: A Randomized Controlled Study

Background: Spinal anesthesia is widely used for cesarean deliveries due to its effectiveness and safety. However, it often causes post-anesthesia hypotension, which poses risks to both the mother and baby. Fluid preloading is a common method to prevent hypotension, yet the ideal type and volume of fluid remain uncertain. This research investigates how crystalloid and colloid preloading influence sensory block levels and hemodynamic stability during spinal anesthesia for cesarean sections. Methods: Conducted as a randomized, double-blind, controlled trial at Imam Hossein Hospital in Tehran, Iran, from January to June 2022, this study involved 141 women undergoing elective cesarean sections under spinal anesthesia. Participants were randomly divided into three groups: normal saline, Ringer's lactate, or 6% hydroxyethyl starch (130/0.4). Sensory block levels were assessed every 5 minutes for the first 30 minutes and then at 60 and 90 minutes post-anesthesia. Continuous monitoring of hemodynamic parameters, such as systolic blood pressure and heart rate, was performed throughout the procedure. Results: The findings revealed that normal saline achieved the highest maximum sensory block level. Hydroxyethyl starch (HES) showed a slightly longer duration of the block and a reduced incidence of hypotension. Despite these trends, the observed differences among the groups were not statistically significant. Conclusion: This study demonstrates that the choice of preload fluid influences sensory block characteristics and hemodynamic stability during spinal anesthesia for cesarean sections. Additional research with larger sample sizes is necessary to refine fluid management strategies in this context.