Thrombocytopenia is a common biological disorder in critically ill patients. The main supportive treatment is platelet transfusion with the aim of preventing and treating bleeding and securing invasive procedures. Current guidelines suggest that prophylactic platelet transfusion should probably be administered in non-bleeding critically ill patients at platelet count triggers of 10 to 20 G/L, albeit with very low certainty since extrapolated from studies carried out in stable patients with hematological malignancies. Indications for prophylactic platelet transfusion have not been properly addressed in adult ICU patients with regard to their particular risk of bleeding and prognosis. We propose the TRAMPOLINE study in order to address two different platelet count thresholds of 10 G/L (low threshold) or 20 G/L (high threshold) for the prevention of ICU-acquired bleeding in critically ill patients with severe thrombocytopenia.

Inclusion Criteria:

1. Age ≥ 18 y.o. AND

2. Hospitalisation in the ICU with at least one of the following life support during the current ICU stay (past or ongoing, regardless of indications)

   • circulatory support (inotropes/ vasopressors at any dose)
   • respiratory support (invasive mechanical ventilation, non-invasive ventilation, continuous positive airway pressure (CPAP), high-flow nasal oxygen, O2 supply ≥ 6 L/min)
   • renal replacement therapy for metabolic disturbances and/or acute and acute-on chronic kidney failure (if not previously under chronic hemodialysis) AND

3. Platelet count ≤ 20 G/L within the last 24h (first occurrence at any time during the ICU stay) AND

4. expected ICU stay for at least 48 hours from the time of enrollment AND

5. Signed consent by the patient or his/her relative, or under an emergency procedure (emergency enrollment notified in the medical file, with requirement for confirmation consent a posteriori)

Exclusion Criteria:

1. Major bleeding (WHO grade 3-4) or mild bleeding (WHO grade 2) within the present hospitalization
2. Major surgery within the recent 72 hours
3. Intracranial or retinal bleeding within the recent 7 days
4. Non- or contra-indication to prophylactic platelet transfusion (immune thrombocytopenia, thrombotic microangiopathy)
5. Indications for increased prophylactic platelet transfusion threshold > 20 G/L (conditions associated with increased risk of bleeding including, but not limited to extra-corporeal membrane oxygenation, therapeutic anticoagulant treatment, fibrinolysis…)
6. Known full refractory status to platelet transfusion (prophylactic transfusion not recommended)
7. Prophylactic platelet transfusion already applied at platelet count ≤ 20 G/L during the present ICU stay
8. Patient opposed to transfusion of blood products
9. Moribund patients (death expected within the next 24 hours)
10. Pregnancy/breastfeeding
11. Not covered by French Social Security (health insurance)
12. Patient under safeguarding of justice