PROtocolized Care to Reduce HYpotension after Spinal Anesthesia (ProCRHYSA randomized trial): statistical plan

Background Spinal anesthesia is a regional anesthesia technique widely employed in clinical practice. The common side effects consist in a reduction of systemic vascular resistances, with systemic hypotension. To prevent this complication, blind administration of fluids is commonly used. This is accomplished on an empirical basis, carrying risk of possible volume overload. Vena cava ultrasound has been shown to be an effective method to assess fluid responsiveness in critical care patients, however this method has never been studied in a non critical population. Aim of this study is to assess the efficacy of vena cava ultrasound guided titrated volume repletion in preventing spinal anesthesia induced hypotension in an elective surgical population.