Endorsing single-unit transfusion combined with a restrictive haemoglobin transfusion threshold after knee arthroplasty

Problem The utility of single-unit transfusions in the presence of restrictive haemoglobin transfusion thresholds is unknown. Design A prospective, pre-post intervention study was undertaken to evaluate a new transfusion strategy designed to reduce the rate of allogeneic transfusion and promote single-unit transfusion. Setting Joint replacement centre within a public hospital. Participants Patients undergoing primary unilateral knee arthroplasty (baseline, n=93; postintervention, n=347). Objectives of the intervention Decrease the use of donor blood by (1) reducing the rate of donor transfusion and (2) endorsing the use of single-unit transfusion. Strategies for change A restrictive transfusion protocol was introduced, which included assessment of the need for transfusion based on haemoglobin value, and presence of signs, symptoms and comorbidity. Single or multiple units of blood were endorsed depending on the indication. Key measures for improvement Primary outcomes were transfusion rate; frequencies of attempted and successful single-unit transfusions. Secondary outcomes included 6-week haemoglobin and complications within 6 months postsurgery. Effects of change Transfusion rate significantly improved (41% (38/93) to 18% (64/347), chi(2) 21.3, p<0.001). The prescription of single units of blood (24% (9/38) to 33% (21/64), chi(2) 1, p=0.33) and successful single-unit transfusion (24% (9/38) vs 24% (15/64), chi(2) < 0.01, p=1.0) were unchanged as were most secondary outcomes. Lessons learnt Restrictive haemoglobin thresholds are a safe, potent frontline strategy for decreasing the rate of blood transfusion. Judicious endorsement of single units is a secondary strategy for reducing the consumption of donor blood when the transfusion haemoglobin trigger is strict.