Single shot spinal anesthesia with very low hyperbaric bupivacaine dose (3.75 mg) for hip fracture repair surgery in the elderly. A randomized, double blinded study

Purpose: Single shot spinal anesthesia is used worldwide for hip fracture repair surgery in the elderly. Arterial hypotension is a frequent adverse effect. We hypothesized that lowering local anesthetics dose could decrease the incidence of arterial hypotension, while maintaining quality of surgical anesthesia. Methods: In a randomized double blinded study, 66 patients over the age of 65 years, with hip fracture needing surgical repair, were assigned to B0.5 group 7.5 mg hyperbaric bupivacaine 5 mg/ml (control group), and B0.25 group 3.75 mg hyperbaric bupivacaine 2.5 mg/ml (study group). Sensory and motor block level, and hemodynamic parameters including blood presure, heart rate and vasopressor dose administration were registered, along with rescue anesthesia needs, the feasibility of surgery, its duration, and regression time of sensory anesthesia to T12. Results: After exclusions, 61 patients were included in the final analysis. Arterial hypotension incidence was lower in the B0.25 group (at the 5, 10, and 15 min determinations), and a lower amount of vasopressor drugs was needed (mean accumulated ephedrine dose 1.6 mg vs. 8.7 mg in the B0.5 group, p < 0.002). Sensory block regression time to T12 was shorter in the B0.25 group, mean 78.6 +/- 23.6 (95% CI 51.7-110.2) min vs. 125.5 +/- 37.9 (95% CI 101.7-169.4) min in the B0.5 group, p = 0.033. All but one patient in the B0.25 group were operated on under the anesthetic procedure first intended. No rescue anesthesia was needed. Conclusion: Lowering bupivacaine dose for single shot spinal anesthesia for hip fracture repair surgery in elderly patients was effective in decreasing the occurrence of arterial hypotension and vasopressor use, while intraoperative quality remained. (C) 2014 Sociedad Espanola de Anestesiologia, Reanimacion y Terapeutica del Dolor. Published by Elsevier Espana, S.L.U. All rights reserved.