Comparison of two doses of hypobaric bupivacaine in unilateral spinal anesthesia for hip fracture surgery: 5 mg versus 7.5 mg.

INTRODUCTION: Hip fracture is a frequent and severe disease. Its prognosis depends on the perioperative hemodynamic stability which can be preserved by the unilateral spinal anesthesia especially with low doses of local anesthetics. This study aims to compare the efficacy and hemodynamic stability of two doses of hypobaric bupivacaine (7.5 mg vs 5 mg) in unilateral spinal anesthesia.

METHODS: In this prospective, randomized, double-blind study, 108 patients scheduled for hip fracture surgery under unilateral spinal anesthesia were enrolled to receive either 5 mg (group 1) or 7.5 mg (group 2) of hypobaric bupivacaine. Spinal anesthesia was performed in lateral position. Patients' socio-demographic characteristics, hemodynamic profile, sensory and motor blocks parameters were recorded.

RESULTS: Both groups were comparable regarding to demographic data. Two cases of failure occurred in group 1 and one case in group 2 corresponding to a comparable efficiency rates (96.29% and 98.14% respectively; p = 0.5). A higher mean onset and lower mean regression times of sensory block were significantly noted in group 1 (7.79±3.76 min vs 5.75±2.35 min, p < 0.001 and 91.29±31.55 min vs 112.77±18.77 min, p <0.001 respectively). Incidence of bilateralization (29.62% vs 87.03%, p < 0.001), incidence of hypotensive episodes (59.25% vs 92.59%, p < 0.001) and vascular loading (1481.48±411.65 ml vs 2111.11±596.10 ml, p < 0.001) were significantly higher in group 2.

CONCLUSION: The dosage of 5mg of hypobaric bupivacaine in unilateral spinal anesthesia is as effective as the dosage of 7.5 mg with lower bilateralization incidence and better hemodynamic stability.