Relationship of protamine dosing with postoperative complications of carotid endarterectomy

Protamine sulfate (PS) neutralization of heparin (HEP) given during carotid endarterectomy (CEA) has been previously associated with an increased post operative stroke rate. Dosing regimens of PS have varied in previous studie s. The accuracy of PS dosing and its effect on postoperative complications was analyzed. The medical records of all patients undergoing elective CEAs from January 1993 to June 1996 in our institution were reviewed. A hematoma was defined as either an event requiring return to the operating room or w hen repeatedly identified in the medical record. The accuracy of dosing PS was determined utilizing a formula calculating the logarithmic exponential decay of HEP, which determined the residual HEP at the time of PS dosing. A n ideal PS dose was then calculated and compared to the dose given. Statist ical analyses was performed using a Fisher's exact test as well as the Stud ent's t-test. Four hundred-seven CEAs were performed in 365 patients. There were 10/407 (2.5%) postoperative strokes (STROKE) and 11/407 (2.7%) hemato mas, 3 of which required reoperation. Results indicate that (1) the adminis tration of PS significantly reduced the incidence of postoperative hematoma ; (2) there appears to be an association between the administration of PS a nd STROKE; (3) the inaccuracy in dosing PS appears to be based on a decisio n to dose PS to the total HEP given rather than the residual HEP on board a t the time of neutralization. The effect of PS overdosing is unclear, but i t may play a role in STROKE.