type of surgery; type of anaesthesia (TIVA, balanced); type of analgesia (intravenous, epidural, perineural block); preoperative antibiotic prophylaxis; blood products transfusion; intraoperative fluid management (crystalloids Vs colloids, mL/Kg/h); type of ventilation (PCV/VCV); ventilation parameters (TV, Pins, PEEP, RR, FiO2); recruitment maneuvers (yes/no) (manuals, pressure controlled); intraoperative ventilatory problems ( (SpO2 < 90%, PaO2/FiO2 < 300, PaCO2 > 45 mmHg, increase of airways pressure over than 30 cmH2O, bronchospasm, needs of TV> 10 mL/Kg); hemorrhage or need of blood products transfusion; cardiovascular problems (hypotension, tachycardia, bradycardia, arrhythmia) and use of cardio/vasoactive drugs;