Investigation of heparin-related hypotensive adverse events during photopheresis: utility of a patient care database

BACKGROUND: Extracorporeal photopheresis (ECP) is a procedure in which leukocytes are harvested from a patient's whole blood, treated with a DNA binding dye and ultraviolet light to inactivate lymphocytes, and then returned into the patient's circulation. In January 2008, we observed moderately severe anaphylactoid reactions in eight of 16 patients undergoing ECP. CASE STUDY: Each affected individual exhibited hypotension of sudden onset, usually with tachycardia, during the return of heparin-anticoagulated blood at the end of the first cycle of collection of leukocytes. A systematic investigation of possible contributing factors revealed that all reactions were associated with administration of a single new lot of heparin. RESULTS: Changing to a different manufacturer of heparin eliminated the occurrence of further such hypotensive reactions during ECP. Although the symptoms were initially attributed to vasovagal reactions or dehydration, their temporal association with exposure to a new lot of heparin suggested a procedure-related phenomenon. Of particular note, was the finding that of the eight patients who had reactions at any time, six had initial exposures without reactions, suggesting a process of sensitization. CONCLUSION: This study demonstrated the value of a patient database listing lot numbers of all medications and components used in each routine ECP procedure for facilitating rapid determination of common patient exposures, making it easier to determine the cause of adverse events, in this case, a particular lot of heparin responsible for the hypotensive adverse events.