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

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.

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.

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.

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.