In patients post cardiac surgery do high doses of protamine cause increased bleeding?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether high doses of protamine causes increased bleeding in patients post cardiac surgery. Altogether 268 papers were found using the reported search, of which five presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these papers are tabulated. We conclude that high doses of protamine can cause increased bleeding and impaired platelet function but these effects have never been demonstrated below a ratio of 2.6:1 protamine to heparin.