Background: Heparin decreases the risks of thrombotic phenomena in extracorporeal circulation. However, it must present a robust safety profile itself, especially for bleeding. Contamination of porcine heparin demands an alternative source and consequent assessment of safety. Objective: To evaluate the safety of unfractionated bovine heparin during on-pump cardiac surgery. Methods: Descriptive, retrospective study, evaluating medical records from all patients who had on-pump cardiac surgery over four years. We observed the occurrence of bleeding, thrombocytopenia, postoperative vasoplegia, activated clotting time values […]