1. Department of Anesthesiology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
2. Department Anesthesiology, Surgical-Trauma Intensive Care and Pain Clinic, Hospital Clínic Universitari, University of Valencia, 46010 Valencia, Spain
3. Department of Anaesthesiology, Critical Care and Pain Medicine, Policlinico Umberto I Teaching Hospital, Sapienza University of Rome, 00185 Rome, Italy