Fractionated versus Conventional Spinal Anesthesia for Prevention of Hypotension in Elderly Hip Fracture Surgery: A Randomized Controlled Study

BACKGROUND: Spinal anesthesia (SA), though preferred for lower limb orthopedic surgery, produces rapid sympathectomy following bolus intrathecal injection, which may precipitate significant hypotension in elderly patients. Fractionated dosing may improve hemodynamic stability. This study compared fractionated versus bolus SA on hypotension requiring vasopressor support. METHODS: This prospective, randomized, double-blind trial included 118 American Society of Anesthesiologists I-III participants aged ≥60 years undergoing femur fracture surgery under SA. Participants were randomized to receive either fractionated dosing (two-thirds initial dose followed by one-third after 60 s) or conventional bolus dosing of 0.5% hyperbaric bupivacaine with 60 μg intrathecal buprenorphine. Hemodynamics were recorded every 3 min for 30 min postinjection. The primary outcome was hemodynamic stability, prespecified as incidence of hypotension requiring vasopressors. Secondary outcomes included total vasopressor consumption, block characteristics, and adverse events. RESULTS: The incidence of hypotension requiring vasopressors was significantly lower in the fractionated group (19/59; 32.2%) compared with the bolus group (38/59; 64.4%) (P = 0.0005; relative risk: 0.50, 95% confidence interval: 0.33-0.76; number needed to treat 3.1). Total vasopressor requirement was also lower (5.68 ± 1.97 mg vs. 8.13 ± 4.35 mg; P = 0.0235). Sensory block duration was longer with fractionated dosing (224.9 ± 70.25 min vs. 199.25 ± 47.86 min; P = 0.0222), while block onset times, maximum sensory level, motor block duration, and adverse events were comparable between groups. CONCLUSIONS: Fractionated spinal dosing significantly reduces hypotension and vasopressor requirement in elderly femur fracture patients, while prolonging sensory block, without affecting motor recovery or safety profile. This simple technique may improve hemodynamic stability in this high-risk population.