[Anaphylaxis to protamine during cardiovascular surgery]

Protamine is a polypeptide with low molecular weights that is used widely to reverse heparin anticoagulation during cardiac surgery. Protamine, efficient and relatively sure, can produce multiple adverse reactions after intravenous administration, including pulmonary hypertension, or systemic hypotension leading at times to cardiovascular collapse and death. Physiopathologic mechanisms, underlying these reactions, are not clear. Immunologic and non-immunologic pathways are suggested. Some risk factors expose to protamine's adverse reactions. Preoperative identification of these factors should prompt specific preventive measures. The anesthesiologist and the cardiac surgeon must be vigilant when administrating protamine. Reheparinization and reinstitution of cardiopulmonary bypass should be considered in patients with refractory shock.