1022: DEVELOPMENT OF STANDARDIZED PROTAMINE DOSING IN CARDIAC SURGERY PATIENTS DURING SUPPLY CHAIN ISSUES

Introduction: The importance of protamine in cardiac surgery cannot be overstated, however, there is not a standardized dosing approach at Michigan Medicine. Common practice at our institution is to administer 1mg of protamine for 100 units of heparin given. In April 2021, the Department of Pharmacy identified a critical shortage of protamine due to a nationwide supply issue. Pharmacy removed protamine from all areas including medication dispensing cabinets to conserve supply. Representatives from cardiac surgery, anesthesia, and pharmacy reviewed protamine use to determine optimal dosing in select cardiac surgery patients. Methods: This was a retrospective review that included cardiac surgery cases that received protamine between April 1, 2021and May 15, 2021. Patient demographics including weight and indication for cardiac surgery were recorded. Initial heparin dose, activated clotting time (ACT) and protamine doses were recorded. The primary outcome of the study was to determine protamine dosing based on the initial heparin dose and ACT. Results: 149 cardiac surgery cases were reviewed. Only 38% of cases received 1 dose of protamine. Of those cases 82% received an initial dose of 250mg of protamine. For patients that received only 1 dose of protamine, 89% had ACT< 140 and 11% had ACT > 140. Multiple protamine doses were identified in 65% of cases with ACT < 140 after first dose received compared to 35% of cases with ACT >140 after first dose. For cases that received multiple doses of protamine, 36% of those occurred without repeat ACT to guide supplemental dose. Our review also identified five patients that required take back to the OR for bleeding, all of which received more than 1 dose of protamine. Conclusions: Protamine dosing at Michigan Medicine for cardiac surgery patients is variable. Based on these results, a recommendation was made to standardize protamine dosing for cardiac surgery. If post-protamine ACT is less than 140, no additional protamine is needed after a single dose of 250mg. If post-protamine ACT is higher than 140 and /or overt bleeding is present, consider an additional dose of 50mg of protamine followed by subsequent dose/ACT monitoring. Standardized dosing allowed for conservation of this medication during a supply chain issue.