Red Cell Transfusion Support for Hematology and Oncology Patients Is Both Substantial and Often Required Urgently. Results from the Bloodhound Study: A Comprehensive, Prospective Australian Study of Red Cell Use
Authors: Shortt Jake , Waters Neil , Comande Mary , Polizzotto Mark N , Moran Martine , Borosak Marija , Jolley Damien J , Wood Erica M 
Published: April 2020

Abstract
Although red cell (RC) transfusion is often essential for the management of malignant and benign hematology, few prospective data are available on RC use in this patient group.
In order to inform national emergency blood supply planning, we performed a longitudinal, prospective audit of RC use within the Australian state of Victoria (population 5.5 million) over a 9-month period (Jun ‘07–Feb ‘08). Our primary aims were to identify major clinical areas of RC utilisation and determine the urgency of RC use therein. Hemato-oncology (HO) patients were the largest overall user of RC in the state, prompting the detailed subgroup analysis reported in this abstract.
5132 RC units were randomly selected at point of production and distributed at a constant rate along with state-wide inventory (thus sampling 3.7% of the total population of RCs distributed during the study period). Details regarding the fate of each selected unit were actively followed by collation of associated case-report forms (CRFs). 5052 (98.4%) CRFs were returned; 4829 (95.6% CI±0.5%) of RCs were transfused. 1623 (33.6±1.3%) of these were administered to HO patients (median HO recipient age 68, range 1–100; 44% female). Clinical areas of use within the HO cohort included: malignant hematology/stem cell transplant, 34.8±2.3% of RCs; non-hematological oncology, 29.0±2.2%; benign hematology, 27.8±2.2% and hematinic deficiency, 8.4±1.4%.
Although few (1.5±0.1%) transfusions were required acutely (&lt;1 hr), the majority (53.6±2.4%) of HO recipients required RCs within 24hrs; only 3.1±0.9% of transfusions were considered deferrable for more than 1 week. Within individual clinical categories, urgency of RC supply was highest for the malignant disorders, with 59.7±4.1% of RCs for malignant hematology/SCT and 61.9±4.4% of RCs for non-hematological oncology required within 24hrs. The corresponding figures for benign hematology and hematinic deficiency were 36.4±4.4% and 24.4±9.5% respectively.
The ABO group of recipients did not differ from the background Australian population estimates, but there was a significant excess of Rh positivity in the benign hematology cohort, possibly due to segregation of Rh phenotype with transfusion-requiring hemoglobinopathies (89.4±2.9% Rh +ve in benign hematology vs 82.5±2.2% in Australian population; p&lt;0.001). Product modifications (including extended RC phenotyping, CMV screening, leucodepletion, irradiation) were more heavily utilised by HO patients than the wider transfused patient population.
These results demonstrate the continuing importance of RC support in HO patients, and underscore the predominantly high acuity of RC transfusion in this group. We suggest that using increasingly restrictive transfusion thresholds in the context of a major blood shortage would be unlikely to have a significant impact on RC demands by HO patients with established anemia. However, delaying the administration (or reducing the intensity) of myelosuppressive chemotherapy as part of a RC triaging strategy may result in major short-to-intermediate term gains in inventory for transfusion services. The identification of ongoing, largely avoidable, low acuity RC transfusion for hematinic deficiency within the cohort also provides an opportunity to improve clinical practice while conserving finite RC resources. Consideration of alternatives to transfusion, optimisation of hematinics and judicious use of erythropoietic stimulating agents remain an important and potentially under-utilised facet to HO patient care.