HOW I DO – Blood Transfusion 5 – Leukoreduction, FFP, Cryoprecipitate

HOW I DO – Transfusion of Blood Products PART – 5

(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)

Question: In last part, we covered some important points related to RBC transfusion. 1. For most patients with chronic anemia, don’t transfuse more than 1-2 units. Such as those with iron or B12 deficiency. If there is an easily treatable cause like iron def or B12 def, most patients should not be transfused at all. Gradual rise in Hb by treatment is safer. 2. Ensure RIGHT Blood for RIGHT patient. Most of the incompatible transfusions are due to wrong identification at the bedside. 3. Blood warming is not required in routine practice. 4. Two units of red cells can easily be given on same day to most patients. 5. Each unit of red cell can be transfused in 1-2 hours. No need to prolong. In fact, over 4 hours increases risk of infection. 6. Do not give red cells using same line as other fluids or medicines. Central line or other multiple lumen catheters can have other fluids or medicines going from additional lumen.

We have covered platelet and red cell transfusions. What about other blood products?

Answer: Let us talk about other less common blood products i.e. FFP – Fresh Frozen Plasma, Cryoprecipitate. But before we go on, a few words on red cell preparations. Many of you may have heard of leukoreduced red cells. They are routinely used for thalassemia major. To reduce risk of transfusion reactions (febrile nonhemolytic type), and formation of antibodies to red cells (alloimmunization) mainly. Alloimmunization reduces red cell life span – a critical issue in patients who need chronic transfusions. Many thalassemia patients develop antibodies leading to transfusions required every 7-14 days, instead of every 28 days.

Leukocytes in blood unit have no additional value during transfusion of red cells. But are one of the reasons for transfusion reactions especially fever. In addition, leukocytes contain CMV virus. Hence removing leukocytes reduces risk of CMV transmission as well. This is important for those with immunocompromised state. Complete removal of leukocytes is not feasible, but 3-4 log reduction means 99.9 percent removal. This is achieved by using either a bedside filter, as frequently used in thalassemia major patients. Or by leukoreduction done at the time of preparation of blood components (pre storage). Later is preferred, and is now standard practice for many modern blood banks. In the western world, this has been the practice for decades. Such high level of reduction makes febrile reactions rare. We have seen this in our practice as well, as our blood bank does leukoreduction for all units. Pre storage leukoreduction is more efficient and reliable, compared to bed side using filer attached to blood transfusion set. If your patient has history of febrile reactions with blood products, you should specifically request blood bank for leukoreduced red cells.

Irradiated blood products are not used in routine practice. Only in hematology practice for patients with significant immune suppression, especially post BMT/Stem Cell Transplant. In developed countries, it is frequently used for all patients with blood cancers. But this recommendations and implementation in practice is variable.

Washed red cells are for removing all plasma from red cell unit. This is used where patient is IgA deficient. Or recurrent severe rash after transfusions, thought to be related to allergy to plasma proteins.

Que: Thank you. Now what are the important points related to FFP, Cryoprecipitate?

Ans: Usual dose for FFP is 2-4 units (10-15 ml per kg). Each unit is about 200-250 ml. FFP is generally given as 1 unit per hour. Two to four units for an average adult will bring up the coagulation factor levels to about 50% of baseline. This is sufficient for correction of coagulopathy in most cases. However, different factors have different half life. For the most common clinical conditions, this means that FFP have to be repeated every 6-8 hours. I have seen many patients given 2 units FFP and then no repeat dosing. And then we are called for recurrent bleeding. In severe cases of coagulopathy, where there is not only deficiency (as in liver disease) but also extensive consumption (as in DIC for example), more FFP and more frequent usage is necessary. This can be managed by monitoring of various coagulation parameters, most commonly PT, aPTT, Fibrinogen.

FFP is also used to manage rare factor deficiency patients e.g. factor 5, 11.

Where Fibrinogen is the main need, or additional important need, cryoprecipitate are used. They contain mainly fibrinogen, but also some von Willebrand factor, and small amount of factor 8, factor 13. These are mainly used in DIC (in addition to FFP), vWF deficiency, hemophilia A (where factor 8 concentrate is not available, or not affordable), fibrinolysis (due to thrombolytic agents, snake bite, etc). For hemophilia A however, cryoprecipitate is far inferior to factor concentrate in terms of efficacy, and should rarely be used. Fibrinogen concentrates are now available, including in India. And we have used these, but cost is significantly higher compared to cryoprecipitate. Volume of each unit is about 50 ml, and hence can be given rapidly. Standard dose is about 1 unit per 10 kg body weight. i.e. common adult dose is 6-10 units. Lower number of units is frequently used in practice by non hematology experts. This should be discouraged as anything lower than 6 units is unlikely to be adequate in adult. This suboptimal dosing can put patients at a significant risk from bleeding.

October 13th, 2024. Dr Chirag A. Shah; M.D. Oncology/Hematology (USA), 9998084001. Diplomate American Board of Oncology and Hematology. Ahmedabad. drchiragashah@gmail.com   www.shyamhemoncclinic.com