Did critically bleeding RhD negative patients receive RhD matched RBCs

The Blood Stop and Go session included the following presentations:

1. Tor Audun Hervig: Pre-Hospital Use of Blood Products
2. Saif Ali: A large multicentre evaluation of massive hemorrhage protocol performance and compliance across adult and pediatric hospitals 
3. Laura Green: Massive transfusion - can we agree on a definition?
4. Sakara Hutspardol: Comparison of ROTEM and Conventional Coagulation Tests in Identifying Trauma-Induced Coagulopathy During Massive Hemorrhage Protocol
5. Helen Elizabeth Haysom: Did critically bleeding RhD negative patients receive RhD matched RBCs? Data from the Australian and New Zealand Massive Transfusion Registry

MODERATORS: Arwa Al-Riyami and Jouni Lauronen

After the presentation, there was a questions and answers session of about 5 minutes, which is also included in the recording.

Abstract

Did critically bleeding RhD negative patients receive RhD matched RBCs? Data from the Australian and New Zealand massive transfusion registry

H E Haysom¹, R Sparrow¹, M Tacey^2,3, C Wellard¹, K Badami⁴, Z McQuilten¹, E Wood^1
1Epidemiology and Preventive Medicine, Monash University, ²Northern Centre for Health, Education and Research, Northern Health, ³School of Population and Global Health, University of Melbourne, Melbourne, Australia, ⁴New Zealand Blood Service, Christchurch, New Zealand

Background: RhD negative (neg) is a low frequency phenotype and RhD neg RBC supply may be exhausted in critical bleeding requiring massive transfusion (MT). Limited data exist on the frequency and outcomes of RhD mismatched transfusions in the setting of critical bleeding in RhD neg patients, particularly females of childbearing potential (≤50 years). The Australian and New Zealand Massive Transfusion Registry (ANZ-MTR) captures hospital electronic data on patients who received MT (≥5 RBCs in any 4 h period) for any type of critical bleeding during their admission.

Aims: Using ANZ-MTR data, investigate the incidence and patterns in the use of RhD mismatched RBC transfusions in critically bleeding RhD neg patients.

Methods: All MT cases at participating ANZ-MTR hospitals during 2011 to 2018 were included. Variables collected included patient sex, age, ABO/RhD group, bleeding context, number and blood group of transfused RBCs and time of issue. Alloantibody data were from the New Zealand Blood Service. Data were analysed by statistical software (Stata). Significance was defined as p < 0.05.

Results: Of 9013 MT cases, 1207 (13.4%) were RhD neg patients (data from 28 hospitals). Of these, 939 (77.8%) received RhD neg RBCs only (matched); 268 (22.2%) received ≥1 RhD positive (pos) RBCs (mismatched) (23 hospitals).

The mismatched group, compared to the matched group, had higher incidence of: male recipients (76.5% vs. 61.6%, p < 0.001), out-of-hours MT onset (p = 0.05), MT for trauma bleeding (29.1% vs. 18%, p < 0.001), early MT within ≤2 h of hospital admission (32.8% vs. 22.4%, p < 0.001) and in-hospital mortality (26.1% vs. 20.4%, p = 0.047).

The total RBCs transfused during the MT admission episode was higher in the mismatched group than the matched group (14 [9, 22] vs. 10 [7, 14], p < 0.001). The mismatched group received median 6 [3, 11] RhD pos RBCs in total during their admission episode. Twenty RhD neg patients (18 male, 2 female) received exclusively RhD pos RBCs.

Mean (SD) age of all RhD neg patients was 61 (18) years with no difference between mismatched and matched groups. There were 323 patients (187 male, 136 female) (26.8%) aged ≤50 years, of whom 59 (56 males, 3 females) (18.3%) were in the mismatched group.

Of the 3 RhD mismatched younger females, mean (SD) age was 43 (5) years. One received 40 RBCs (18 RhD pos) for major trauma and died in hospital. Another received 15 RBCs (8 RhD pos) for terminal metastatic cancer bleeding; she survived the MT, but died within months. The third received 19 RBCs (3 RhD pos) for liver transplant surgery and survived.

Evaluable RBC alloantibody test results were available for 16/30 (53.3%) New Zealand RhD neg patients who received RhD pos RBCs. Of the 16 patients, 5 (31%) made a new anti-D antibody after the MT episode.

Summary/Conclusions: Of the total RhD neg patients requiring MT, 22.2% received a median of 6 RhD pos RBCs.

RhD neg females ≤50 years were almost always managed with RhD matched RBCs, suggesting close adherence to current transfusion policy (O RhD neg RBCs for patients with blood group unknown) for this specific patient demographic.

RhD neg patients who received RhD pos RBCs were more likely to have early commencement of MT within 2 h of hospital admission, receive more RBCs and to die in hospital, indicative of the emergency nature and severity of the critical bleeding. The high induction rate (31%) of new anti-D alloantibody in the small subset of evaluable cases is concerning and warrants further consideration.