Massive Transfusion in Children-2: A Trial Examining Life Threatening Hemorrhage in Children

The MATIC-2 trial is a Bayesian, randomized, multicenter, adaptive platform phase III trial. The trial will include injured children with hemorrhagic shock anticipated to require massive blood transfusion, who will be randomized to receive either LTOWB or CT and Tranexamic Acid or placebo. The study investigators hypothesize that the use of LTOWB is non-inferior and/or superior for 24-hour mortality and that LTOWB does not increase the risk of adverse events or outcomes, such as thrombotic events, compared to CT. The investigators also hypothesize that the use of TXA is superior for 24-hour mortality and does not increase the risk of adverse events or outcomes, such as thrombotic events, compared to placebo. Objectives: The primary objectives are to: 1. Determine the effectiveness of LTOWB to reduce all-cause 24-hour mortality compared to CT in children with traumatic life-threatening hemorrhage. 2. Determine the effectiveness of TXA to reduce all-cause 24-hour mortality compared to placebo in children with traumatic life-threatening hemorrhage. Secondary objectives are to determine the effectiveness and safety of LTOWB and TXA to improve secondary and exploratory outcomes (or endpoints) in children with traumatic life-threatening hemorrhage. Safety objectives are to determine the effect of LTOWB and TXA on safety related outcomes/endpoints. The safety outcomes include: 1. Acute kidney injury 2. Acute respiratory distress syndrome 3. Arrhythmia 4. Abdominal compartment syndrome 5. Bleeding after hemostasis requiring intervention 6. Myocardial infarction 7. Pneumonia 8. Sepsis 9. Stroke 10. Seizure 11. Thrombotic events (arterial or venous) 12. Urinary Tract Infection 13. Alloimmunization in Rh negative female recipients of Rh+ LTOWB or RBC's 14. Organ failure (as determined by PELOD-2 score) Mechanistic Objectives are to: 1. Define trauma induced coagulopathy (TIC) according to measures of shock, hemostasis, and endothelial and immune function. 2. To determine if measures of shock, endothelial, immune, and hemostasis function upon admission (TIC endotype) predicts which hemostatic resuscitation therapies or combinations of therapies (LTOWB, CT, LTOWB + TXA, CT+TXA) for each study group improves outcomes without increasing the risk of adverse events. 3. To determine the mechanisms of how hemostatic resuscitation therapies or combinations of therapies (LTOWB, CT, LTOWB + TXA, CT+TXA) improve TIC endotypes and outcomes. Pharmacokinetic objectives are to evaluate the PK and PD properties of TXA in a population of children with life-threatening traumatic bleeding.