Comparative Analysis of Coload and Pre-Load in the Prevention of Spinal Anesthesia Induced Hypotension

Abstract

Background: Spinal anesthesia is widely used for elective lower abdominal and urologic procedures but is frequently complicated by hypotension due to sympathetic blockade, reduced venous return, and decreased cardiac output. Optimizing the timing of crystalloid administration may improve hemodynamic stability and reduce vasopressor exposure. Objective: To compare crystalloid preload versus crystalloid coload in preventing spinal anesthesia–induced hypotension and reducing vasopressor requirement in adults undergoing elective lower abdominal and urologic surgery. Methods: In this prospective comparative cross-sectional study, 44 ASA I–III patients (18–70 years) were allocated to receive Ringer’s lactate either as preload (10–15 mL/kg before intrathecal injection; n=22) or coload (same volume initiated at intrathecal injection; n=22). Hemodynamics were recorded at predefined intervals intraoperatively. Hypotension was defined as SBP decrease ≥20% from baseline or MAP <65 mmHg. Vasopressor use followed a standardized protocol, and total dose was expressed as ephedrine equivalents. Results: Hypotension occurred in 22.7% (5/22) of preload patients versus 50.0% (11/22) of coload patients (RR 0.45; 95% CI 0.19–0.99; p=0.049). Vasopressors were required in 27.3% (6/22) versus 54.5% (12/22), respectively (RR 0.50; 95% CI 0.23–0.99; p=0.048), and total ephedrine-equivalent dose was lower with preload (7.2±4.1 mg vs 11.8±6.5 mg; p=0.01). Minimum MAP was higher in the preload group (72.6±6.4 mmHg vs 66.1±7.9 mmHg; p=0.004). Conclusion: Crystalloid preload before spinal anesthesia reduced hypotension incidence, vasopressor requirement, and vasopressor dose while improving MAP stability compared with coload in elective lower abdominal and urologic surgery.