An operating room data sheet will be completed once for each patient recruited to include data describing patient factors (age, gender, American Society of Anesthesiologists grade, major co-morbid disease, etc), surgical factors (procedure category, grade and urgency of surgery, grade of surgeon, surgical checklist, etc), anaesthetic factors (anaesthetic technique, haemodynamic monitoring, airway, grade of anaesthetist, etc), post-operative care (post-operative recovery ward stay, post-operative invasive or non-invasive ventilation or inotrope within first 24 hours). A critical care data sheet will be completed once for each patient admitted to critical care at any time after surgery, to include data describing whether admission was planned or unplanned, organ support, SAPS III score and SOFA score etc). Patients will be followed until death or hospital discharge for the following outcomes: duration of critical care stay, critical care mortality, duration of hospital stay and in-hospital mortality.