Appropriateness and determinants of packed red blood cell transfusion in knee arthroplasty: a retrospective tertiary hospital study.

Inappropriate packed red blood cell (PRC) transfusion remains a concern in surgical patients, including those undergoing knee arthroplasty. This study aimed to evaluate the appropriateness of PRC transfusion and identify clinical and procedural factors associated with inappropriate transfusion practices. A retrospective cohort study was conducted in patients who underwent knee arthroplasty at a tertiary academic hospital. Transfusion episodes were assessed for appropriateness using predefined clinical criteria. Multivariable logistic regression was used to identify independent predictors of inappropriate transfusion. Of 2,983 patients who underwent knee arthroplasty between August 2015 and December 2018, 275 (9.22%) received PRC transfusion in 333 episodes. Among these, 77.5% were appropriate and 22.5% were inappropriate. Most transfusions occurred postoperatively, with a single-unit transfusion being the most common practice. Inappropriate transfusions were frequently administered to patients with hemoglobin ≥ 10 g/dL or hematocrit ≥ 30%, without documented clinical indications. The absence of clinical risk factors for ischemia and a preoperative hemoglobin level < 10 g/dL were independent predictors of inappropriate transfusion with an adjusted risk ratio 10.85 (95% CI, 5.43-21.70; p < 0.001) and 1.41 (95% CI, 1.01-1.96; p = 0.042), respectively. Although most PRC transfusions in knee arthroplasty patients were appropriate, a substantial proportion did not align with established clinical guidelines. The absence of clinical risk factors for ischemia was strongly associated with inappropriate transfusion. These findings underscore the need for enhanced adherence to evidence-based transfusion criteria and improved clinical documentation.