Continuous monitoring of patients will include electrocardiographic lead II, intraarterial pressure [and/or cardiac index (PICCO plus, Pulsion Medical Systems, Munich, Germany) - in concordance with clinical indications] and peripheral oxygen saturation (SpO2). Maintenance of anesthesia will be achieved with intravenous midazolam or propofol and/or fentanyl or remifentanyl. Neuromuscular blockade (cisatracurium) will be used in concordance with recent recommendations, and/or as part of the treatment prescribed by the attending physicians. The follow-up of the patients will last for 60 days or until hospital discharge (if it occurs earlier than day 60 after study enrollment).