Platelets are used in critical to either prevent or treat bleeding. The problem is that despite all the research and studies we still don't know that much on the best way to clinically use platelets... and they are tricky indeed:
- Platelets must be stored at room temperature
- Because of the risk of bacterial growth the shelf life of platelet units is only 5 days
- Maintaining a constant pool of platelets for clinical work is extremely difficult and resource-intensive
- Transfusion related risks are notable (e.g. febrile reaction 1/14, allergic reactions 1/50, bacterial sepsis 1/75'000)
When it comes to their usage intensivists often have a different approach than haematologists and guidelines mostly vary from hospital to hospital, from country to country. However, instead of searching all the literature yourself you might consider reading the article by Kaufman RM et al. published just this month in the Annals of Internal Medicine.
A panel of 21 specialists, covering almost all areas of medicine involved in handling platelets, performed a systematic review by looking up publications from 1900 to 2013. From 1024 identified studies, 17 RCTs and 53 observational studies were included in the review. The result of their work are guidelines on the use of platelets including their grade of recommendation. Short:
- Platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypo proliferative thrombocytopenia < 10 x 109 cells/L (Grade: strong recommendation; moderate-quality evidence)
- Platelets should be transfused prophylactically for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L (Grade: weak recommendation; low-quality evidence)
- Prophylactic platelet transfusion is recommended for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L (Grade: weak recommendation; very low-quality evidence)
- Prophylactic platelet transfusion is recommended for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L (Grade: weak recommendation; very low-quality evidence)
- Routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass (CPB) is NOT recommended. Platelet transfusion for patients having CPB who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction is NOT recommended (Grade: weak recommendation; very low-quality evidence)
- Recommendations for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous) cannot be made (Grade: uncertain recommendation; very low-quality evidence)
It is remarkable to see that after a century of intense research we are left with some moderate-quality evidence and lots of low quality evidence and therefore weak recommendations. I guess guidelines will continue to vary from doctor to doctor, hospital to hospital... country to country.
Kaufman RM et al. Ann Intern Med, Nov 11, 2014: Open access article