Delayed cold-storage of room temperature platelets may extend shelflife from 5 to 14 days. We hypothesized the use of delayed cold-stored platelets in cardiac surgery would be associated with decreased postoperative platelet count increments but similar transfusion and clinical outcomes compared to room temperatuve stored platelets.


This is an observational cohort study of adults transfused with platelets intraoperatively during elective cardiac surgery between April 2020 and May 2021. Intraoperative platelets were either room temperature or delayed cold-stored based on blood bank availability rather than clinical features or provider preference. Differences in transfusion and clinical outcomes, including a primary outcome of allogenic transfusion exposure in the first 24 hours postoperatively, were compared between groups.


713 patient encounters were included: 529 (74%) room temperature, 184 (26%) delayed cold-stored platelets. Median (interquartile range) intraoperative platelet volumes were 1 (1, 2) units in both groups. Patients receiving delayed cold-stored platelets had higher odds of allogeneic transfusion in the first 24 hours postoperatively (81/184 (44%) vs. 169/529 (32%); adjusted odds ratio [aOR], 95% confidence interval [CI], 1.65 (1.13, 2.39); p=0.009), including both RBCs (65/184 (35%) vs. 135/529 (26%); aOR 1.54 (1.03, 2.29); p=0.035) and platelets (48/184 (26%) vs. 79/529 (15%); aOR 1.91 (1.22, 2.99); p=0.005). There was no difference in the number of units administered postoperatively amongst those transfused. Platelet counts were modestly lower in the delayed cold-stored platelet group (-9 x 109/L [95% CI: -16, -3]) through the first 3 days postoperatively. There were no significant differences in reoperation for bleeding, postoperative chest tube output, or clinical outcomes.


In adults undergoing cardiac surgery, delayed cold-stored platelets were associated with higher postoperative transfusion utilization and lower platelet counts compared to room temperature stored platelets without differences in clinical outcomes. The use of delayed cold-stored platelets in this setting may offer a viable alternative when facing critical platelet inventories but is not recommended as a primary transfusion approach.