Influence of the timing of administration of crystalloid on patients’ hypotension during spinal anesthesia for lower extremities: Preload versus co-load

Background: Spinal anesthesia is a commonly used neuraxial technique for lower limb surgeries. A frequent and significant complication associated with spinal anesthesia is hypotension. One preventive approach is the administration of intravenous fluids, but the optimal timing-whether before (preloading) or after (co-loading) the anesthetic-is still under investigation Aim: This study aimed to evaluate the effect of timing of crystalloid (Ringer's solution) administration on the incidence of hypotension following spinal anesthesia in patients undergoing lower extremity surgeries. Patients and Methods: A prospective, controlled study was conducted on 60 patients scheduled for lower limb surgeries under spinal anesthesia. Patients were randomly assigned to one of two groups: Group A (preload) received 15 mL/kg of Ringer's solution before intrathecal injection, while Group B (co-load) received the same volume immediately after spinal anesthesia. Hypotension was defined as a drop in systolic blood pressure greater than 20% from baseline. Ephedrine was used to manage hypotensive episodes. The incidence of hypotension, total ephedrine dose, and baseline hemodynamic parameters were recorded and analyzed. Results: The incidence of hypotension was significantly lower in the co-load group compared to the preload group (63.3% vs. 86.6%, p = 0.0014). Additionally, the total dose of ephedrine required was lower in the co-load group. Conclusion: Co-loading with Ringer's solution during spinal anesthesia appears to be more effective than preloading in preventing hypotension in lower extremity surgeries..