Outcomes of massive transfusion recipients administered ABO-incompatible fresh frozen plasma.

Background: The provision of ABO-incompatible fresh frozen plasma (FFP) in massive transfusion (MT) has become accepted to conserve AB FFP stock. There is an evidence gap in non-trauma settings. We compare characteristics of patients who received ABO-compatible or ABO-incompatible FFP during an MT episode due to any cause of critical bleeding, and assess the impact of incompatible FFP transfusion on inhospital mortality.

Methods: Using the Australian and New Zealand Massive Transfusion Registry, data were extracted for patients aged ≥18 years who received an MT (defined as ≥5 red cell units in 4 h) between April 2011 and October 2018. Incompatible FFP was defined as transfusion of ≥1 unit of FFP with a bidirectional or minor ABO-mismatch in the first 24 h from MT initiation.

Results: A total of 7340 patients from 28 hospitals were included. Seventy-seven (1%) patients received incompatible FFP (26 trauma, 51 non-trauma). Those who had incompatible FFP received a median of seven units of FFP, compared to those who only received compatible FFP receiving five units, p = .005. A total of 226 units of incompatible FFP were provided overall. Incompatible FFP provision was not independently associated with inhospital mortality in MT (HR of 1.40 [95% CI 0.84-2.26, p = .2]). Variables independently associated with inhospital mortality included increased FFP volume in the first 24 h, age, Charlson Comorbidity Index score, and lower pre-transfusion fibrinogen and peri-transfusion pH values.

Conclusion: Transfusion of incompatible FFP in MT in our cohort was not independently associated with higher inhospital mortality, although the number of patients who received incompatible FFP was small.