In the United States, patients who are critically ill receive approximately 20% of platelet and fresh frozen plasma (FFP) transfusions, exceeding 2 million units of each annually. While most transfusions occur in the setting of bleeding, many transfusions are given to reverse coagulopathy or correct thrombocytopenia in an attempt to decrease perceived procedural complications. A recent guideline from the journal CHEST® addresses platelet transfusion goals in patients who are bleeding and nonbleeding and answers questions about transfusion strategies for common bedside procedures in the setting of coagulopathy and thrombocytopenia. The guideline does not address patients admitted with trauma and patients who are neurocritical.
Why conserve?
Platelets and FFP are scarce resources. Although potentially lifesaving when administered in the correct setting, they are associated with adverse events. Platelets, in particular, carry more immunologic than nonimmunologic adverse events, some of which may not be immediately apparent.
Key recommendations
Stable nonbleeding critically ill patients with thrombocytopenia
In patients with a low risk of bleeding, observational studies showed no difference in mortality or length of stay in patients who were thrombocytopenic and transfused with platelets compared with those who were not. Adverse events were low in both groups, suggesting that it is safe to transfuse if platelet levels fall below 10 x 109/L.
Classifying patients as high or low risk of bleeding is challenging, as there is no universally accepted tool. The International Medical Prevention Registry on Venous Thromboembolism tool is an example of a tool that may help clinicians make this determination. However, it should not replace clinical judgement.
Patients at high risk should be transfused if the platelet counts fall below 30 to 50 x 109/L. These include those with coexisting thrombocytopenia and derangement in their coagulation profile and anatomical or structural abnormalities (eg, a critical airway or treatment with angiogenic medications).
Patients with thrombocytopenia and serious active bleeding
There are surprisingly few studies that address the threshold of platelet transfusion in the general critically ill population and significant heterogeneity in what intensivists consider severe bleeding. The panel agreed that a World Health Organization grade of 3 or 4 bleeding is considered severe and suggests transfusion if levels are below 50 x 109/L. This includes patients who require RBC transfusion, have moderate or severe hemodynamic instability, or have central nervous system bleeding. It is important to note that this threshold is largely based on clinical convention; given the catastrophic possibility of harm, the panel chose not to deviate from the current standard of practice.
Vascular procedures
Limited evidence suggests that routine prophylactic transfusions of platelets or FFP before placement of central venous catheters may be unnecessary, as studies have shown no difference in mortality or rates of hemodynamically significant bleeding. It is important to highlight that patients may still need to be transfused with platelets based on their individual risk to prevent spontaneous bleeding. Studies did not address patients with an International Normalized Ratio (INR) greater than 3.
Additional considerations include catheter size and insertion site, use of ultrasound guidance, operator experience, and coexistence of coagulopathy and thrombocytopenia.
Bedside thoracic or abdominal procedures
Similarly, thoracentesis and paracentesis are considered low-risk procedures for bleeding. Evidence suggests that preprocedural platelet or FFP transfusion does not provide benefit in preventing major bleeding.
Lumbar puncture
There is considerable variation among professional societies regarding recommended thresholds for lumbar puncture. Considering that a spinal hematoma is a rare complication that represents a devastating harm, clinicians should aim to transfuse blood products to target a platelet count above 40 to 50 x 109/L and an INR range of 1.5 to 2.
Bronchoscopy or gastrointestinal endoscopy
For patients undergoing bronchoscopy in the ICU without biopsy, there is no difference in mortality or increased procedural bleeding. Hence, prophylactic transfusion of platelets and FFP is not recommended.
In patients with portal hypertension undergoing gastrointestinal (GI) endoscopy to treat variceal bleeding, FFP and platelet transfusion are associated with increased mortality and rebleeding. However, the patients included in the studies were older and had worse liver and kidney disease. GI endoscopy is considered a low-risk procedure, and it is unlikely that endoscopy alone without biopsy would increase bleeding. Therefore, the focus should be on determining the individual attributable risk for complications based on clinical characteristics rather than the risk of the endoscopic procedure, as it is unlikely that transfusion will improve its safety.
The economic cost
The cost of blood product transfusion varies both globally and across the United States based on the transfusion setting, institutional size, region, and payor. The cost of an apheresis, leukoreduced platelet unit in the United States is approximately $1,400 and $269 for one unit of FF. Major determinants of cost are blood bank acquisition and handling of the blood product, laboratory testing, and administrative and nursing costs. This does not account for patient-specific factors that can increase those costs, such as alloimmunization.
Challenges of implementation
Changing decades of clinical practice and overcoming the fear of poor outcomes and procedural complications are difficult, particularly in the face of limited evidence. However, they are not impossible. Patient blood management strategies have successfully decreased RBC transfusion through physician education, real-time decision support tools integrated into electronic medical systems, and institutional initiatives aimed to minimize and optimize transfusion parameters.
Call to action
Adopting a more conservative approach, as outlined in this guideline, could potentially save up to half a million units of platelets and FFP annually. This would optimize utilization of scarce resources, reduce health care costs, and minimize unnecessary patient exposure to the risks associated with transfusions that offer no clear additional benefit. With both safety and sustainability in mind, we encourage clinicians to embrace these recommendations and urge institutions to develop local policies that support implementation and monitoring of transfusion practices.