CHIlled Platelet Study "CHIPS"

Inclusion Criteria:

• Viable neonates ≥ 3 kg at time of enrollment (as defined in Section 4.1) OR agegreater than 28 days and less than 85 years of age at time of consent; AND

• Planned complex cardiac surgery with planned use of cardiopulmonary bypass, with anexpectation of bleeding requiring platelet transfusion.

Exclusion Criteria:

• Expected order for washed or volume reduced platelets

• Patient with known anti-platelet antibodies

• Platelet transfusion refractoriness due to anti-HLA antibodies

• Known or suspected pregnancy

• Previously randomized in this study

• Conscious objection or unwillingness to receive blood products

• Known IgA deficiency

• Known congenital platelet disorder

• Known congenital bleeding disorder

• Planned post-operative extracorporeal membrane oxygenation (ECMO), ventricularassist device (VAD), and/or continuous renal replacement therapy (CRRT)/hemodialysis

• Patients intended to receive whole blood either intra-operative or post-operativefor bleeding

• Platelet transfusion (of any type) within 24 hours prior to the date of surgery

• Pre-operative thrombocytopenia, defined as platelet count <75x10(9)/L, based on themost recent labs completed within 72 hours prior to the date of surgery.