Protamine administration

" Heparin and protamine combine in proportion to weight.
One milligram of protamine neutralizes 1 mg (typically 100 U) of heparin.

Protamine administration:

 Always administer protamine slowly. The rate of administration is more important than the route of administration in preventing adverse hemodynamic effects.  One can either use a syringe or dilute the drug in a small volume of intravenous fluid and infuse by gravity  or calibrated pump. Because the syringe technique rather than hand-operated syringe administration, because this reduces the natural tendency to administer the protamine too quickly and it frees our hands for other important patient care activities (e.g., vasoactive drug titration, echocardiography examination) that coincide with protamine administration. The injected dose of protamine cannot neutralize heparin bound to plasma proteins or within endothelial cells. Release of heparin from these stored areas after initial protamine administration  may result in reappearance  of heparin anticoagulant effect  (heparin rebound). Small additional doses of protamine will provide neutralization when repeat testing (e.g., ACT initially normalizes to 110 s but 30 min later is 140 s) shows a heparin effect in a bleeding patient."