Protamine hypertension

When given rapidly, protamine causes hypotension due to a decrease in vascular resistance, possibly linked to the release of nitric oxide from endothelium. Flypotension can be minimised by slow administration over 10-15 minutes. Protamine does not affect myocardial contractility. In some patients, systemic hypotension occurs in conjunction with pulmonary hypertension and, in severe cases, right ventricular failure. The mechanism is activation of the complement pathways by the heparin-protamine complex leading to release of thromboxane A2, which mediates pulmonary vasoconstriction. Unlike in anaphylaxis, plasma histamine concentrations are not increased. When this syndrome develops protamine administration should be stopped, and some have recommended giving heparin in an attempt to reduce the size of the heparin-protamine complex. 

Too rapid of an administration of protamine can have serious side effects, including hypotension and anaphylaxis. Pulmonary hypertension, shortness of breath, flushing, and urticaria have all been associated with rapid administration. Patients with allergies to fish products may be allergic to protamine. 

Life-threatening pulmonary vasoconstriction occurred in a 62-year-old male chronic smoker with long-standing systemic hypertension and hypercholesterolemia within 10 minutes of an intravenous infusion of protamine 4 mg/kg after coronary artery bypass graft surgery the authors attributed this to the formation of large heparin-protamine complexes after rapid infusion of protamine [213"°"]. In another case acute pulmonary hypertension induced by protamine during elective coronary artery... 

Jerath A, Srinivas C, Vegas A, Brister S. The successful management of severe protamine-induced pulmonary hypertension using inhaled prostacyclin. Anesth Analg 2010 110(2) 365-9. 

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See also in sourсe #XX -- [ ]

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