Figure 1. Cardiac surgery blood transfusion algorithm (updated from TACS)*.²¹ *To determine the need for RBC transfusion, consider patient status and haemoglobin. Transfuse red cells if Hb<70 g/L during CPB; <80 g/L post-CPB and <90 g/L in bleeding or unstable patients. †In general, the initial protamine dose should not exceed 400 mg, irrespective of the amount of heparin given. If an additional protamine dose does not shorten ACT, consider low fibrinogen levels or deficiency of enzymatic coagulation factors as a reason for the prolonged ACT and treat according to the algorithm. ‡BSS<2 (less than moderate)=no therapy; BSS 2–3 (moderate-severe)=institute stepwise treatment; assess bleeding after each product; BSS 4 (life-threatening)=administer therapy as necessary without waiting for laboratory results and combine therapies as appropriate. §POC INR should be performed >10–15 min after protamine or results may be inaccurate. ACT, activated clotting time; Blwk, bloodwork; BSS, bleeding severity scale; CBC, complete blood count; CPB, cardiopulmonary bypass; CT, clotting time; Hb, haemoglobin; IMP, investigational medicinal product; INR, international normalised ratio; POC, point of care.