Protamine/heparin ratio

Q: What ratio of protamine/heparin is optimal for reversal of anticoagulation during post cardio-pulmonary bypass (CPB) phase?


Answer:  2.6 mg protamine per 100 units of heparin

 It is very interesting that if the ratio exceeds above 2.6 mg protamine per 100 units of heparin, this excess protamine is associated with inhibited platelet function and factor V activation, prolonged activated whole blood clotting time (ACT), and excessive bleeding after CPB.

#surgical critical-care


References:

1. Shore-Lesserson L, Baker RA, Ferraris VA, et al. The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines-Anticoagulation During Cardiopulmonary Bypass. Ann Thorac Surg 2018; 105:650.

2. Boer C, Meesters MI, Veerhoek D, Vonk ABA. Anticoagulant and side-effects of protamine in cardiac surgery: a narrative review. Br J Anaesth 2018; 120:914. 

3. Mochizuki T, Olson PJ, Szlam F, et al. Protamine reversal of heparin affects platelet aggregation and activated clotting time after cardiopulmonary bypass. Anesth Analg 1998; 87:781. 

4. Ni Ainle F, Preston RJ, Jenkins PV, et al. Protamine sulfate down-regulates thrombin generation by inhibiting factor V activation. Blood 2009; 114:1658.