How is heparin resistance defined?

By William Aird

The need for high heparin doses to achieve a targeted level of anticoagulation. Some define it as the need for > 35,000 U heparin per day, or in the setting of cardiopulmonary bypass, the need for a dose of more than 500 U per kilogram of
body weight to achieve an activated clotting time of 400 to 480 seconds.

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