1. Department of Health Sciences, Section of Anesthesiology, University of Florence, 50121 Florence, Italy
2. Geriatric Intensive Care Unit, University of Florence, 50121 Florence, Italy
3. Department of Critical Care, Section of Anesthesiology and Critical Care Azienda USL Toscana Centro, Ospedale Santo Stefano, 59100 Prato, Italy
4. Unit of Internal Medicine and Cardiology, Department of Experimental and Clinical Medicine, University of Florence, 50121 Florence, Italy