Platelet transfusions are commonly used in critically ill patients, but transfusion thresholds, count increments, and predictors of ineffectual transfusions remain unclear.
This retrospective study included consecutive adult nononcology patients who received platelet transfusions in ICUs at three Canadian academic hospitals between 2006 and 2015. Data were collected from a validated transfusion database. We determined independent predictors of ineffectual platelet transfusions, defined as transfusions that raised platelet counts by < 5 × 109/L. Reasons for transfusion were adjudicated in a subgroup of patients who underwent transfusion despite normal platelet counts.
We identified 7,320 ICU admissions (n = 7,073 patients) during which 15,879 platelet transfusions were administered. Most admissions (78.7%) were for cardiac surgery. Based on 5,700 analyzable transfusions, the median pretransfusion platelet count was 87 × 109/L (interquartile range [IQR], 57-130). The pretransfusion platelet count was ≥ 50 × 109/L and ≥ 150 × 109/L for 79.6% and 17.8% of transfusions, respectively. Reasons for transfusion despite a normal platelet count were active bleeding or surgery in patients receiving antiplatelet agents or anticoagulants. The median platelet count increment was 23 × 109/L (IQR, 7-44), and 21.8% of transfusions were ineffectual. ABO incompatibility, sepsis, liver disease, and red cell and cryoprecipitate transfusions were associated with a poor platelet count increment.
Platelet transfusions were commonly used in the ICU when platelet counts were ≥ 50 × 109/L. One platelet transfusion increased platelet count by 23 × 109/L. One in five transfusions was ineffectual, and ABO incompatibility was identified as a modifiable risk factor. These data can help direct efforts to reduce platelet overuse and improve transfusion quality.