Study procedures On the first day of admission, all the patients scheduled for cardiac surgery with an on-pump procedure will be asked for a consent for anonymous using of their information. Patients giving permission will be screened for participation in this study, and those fulfil the inclusion/exclusion criteria will be included for further research.~Blood ketone will be measured with StatStrip Glucose/Ketone Meters (Nova biomedical, United Kingdom) using sample leftover from blood gas analysis. No extra blood draw is needed. The levels of ketones will be measured at four time points:~Beginning of surgery;~The moment the cardio-pulmonary bypass machine takes over the circulation.~After the decoupling of the Cardio-pulmonary bypass machine~At the end of surgery.~Diagnosis of ketoacidosis is based on criteria mentioned. Epidemiology characteristics and perioperative variables will be extracted from electronic medical records.
Rationale:~During perioperative period, prolonged starvation, surgical stress, acute complications (e.g. infection) and medication changes all promote ketone generation, therefore increasing the risk of ketoacidosis. At present, there is no literature concerning the ketone production in patients undergoing cardiac surgery, regardless of the diabetes status.~Objectives:~The objectives of this study are to explore the change in blood ketone level during the perioperative period in patients with and without diabetes, to observe the incidence of perioperative ketoacidosis, and to investigate therapy and outcome of patients with perioperative ketoacidosis.