Cardiac surgery can vary from being routine elective surgery to time-critical emergency surgery. The term encompasses a broad range of procedures carried out on patients from neonates to nonagenarians. In the 63 years since the first open heart surgery was performed using cardiopulmonary bypass enormous advances have been made in the field such that an average person presenting for coronary bypass grafting in 2016 can expect a very low chance of peri-operative morbidity or mortality. When things go wrong however they can go badly wrong and at the worst possible moment (see Murphy’s Law). This talk focuses on describing common complications encountered in the postoperative period, with a focus on anticipation, prevention and planning for rapid recognition and successful management of potentially life threatening complications.