The Common Practice of Transfusing 1–2 Units of Fresh Frozen Plasma (FFP) to Patients with Mildly Prolonged Prothrombin Times (PT) Does Not Lead to Clinically Significant Changes in Their PT Values.

INTRODUCTION: Various guidelines define appropriateness of FFP administration based on prothrombin time (PT) greater than 1.5 times normal. However, FFP is often transfused to patients with PTs that are in the upper range of normal or mildly prolonged. There is a paucity of data on whether transfusion of FFP to such patients will change their PT.

METHODS: We retrospectively reviewed all FFP transfusions that were administered to patients with a PT below 17 seconds (normal reference range 11.3–13.6 seconds) at a tertiary care hospital in 2004. Patients were included in our analysis if their PT was measured prior to and within six hours of transfusion and if they received no more than two units of FFP. We identified 143 consecutive cases that met these criteria.

RESULTS: 66 patients received one unit and 77 patients received 2 units of FFP. The median decrease in PT after the infusion of one or two units of FFP was 0.4 seconds and 0.6 seconds respectively. The pretransfusion PTs in 6 patients ranged between 12.2–13 seconds (subgroup 1), in 17 patients 13–14 seconds (subgroup 2), in 46 patients 14–15 seconds (subgroup 3), in 37 patients 15–16 seconds (subgroup 4), and in 37 patients 16–17 seconds (subgroup 5). Patients in subgroups 1 and 2 were noted to have higher PT values after the administration of FFP (median prolongation of 0.6 and 0.1 seconds respectively). The PT shortened in subgroup 3 by 0.4 seconds (median) and in subgroups 4 and 5 by 0.9 seconds (median) when compared to the pretransfusion PT, which represent clinically insignificant corrections.

CONCLUSION: Transfusion of blood products is not without risks; given that PT values of less than 17 seconds do not significantly change following transfusion of one to two units of FFP, this clinical practice should be avoided.