Halothane is still unique in its ability to inhibit platelet aggregation and to increase bleeding time in vivo at clinical concentrations, although sevoflurane inhibits platelet aggregation induced by weak agonists. Propofol itself, but not its fat emulsion, inhibits platelet aggregation and suppresses calcium mobilization. Extradural anaesthesia has been shown to prevent hypercoagulability during the perioperative period. Aprotinin reduces both blood loss and the incidence of blood transfusion during major orthopaedic and cardiac surgery.