A physician in San Francisco asks if other institutions allow for transfusion of platelets through rapid flow blood and fluid warming devices (which can achieve flow rates as fast as 1000 mL/minute) provided the system is QC'ed, has sufficient safety features, accommodates standard blood and solution bags, and does not exceed 300 mmHg pressure. Her institution allows transfusion of red cells, plasma and platelets through rapid flow warmers, but some of their anesthesiologists fear putting platelets through the line, but cannot provide scientific evidence for their concerns.

Editor's NOTE: The information at:

• Guidance for FDA Reviewers: Premarket Notification Submissions for Blood and Plasma Warmers

and the prior e-Network Forum discussions

• Experience with Blood Warmers
• Methods for Warming Blood Products

may be germane to this discussion.

ADDENDA Aug. 21, 2005

1. The same San Francisco physician who initiated the discussion adds that while in her experience many anesthesiologists are willing to put platelets through a "regular" fluid warmer where the infusion rates are in the 30-100mL/ minute rate, most of the anesthesiologists that she knows do NOT put the platelets through the "hot line" rapid infuser because:

1. the line pressures are high
2. when the rapid infuser is in use, the need for red cells and FFP is emergent
3. there is almost always another line through which the platelets can be transfused. In fact, some anesthesiologist are advising against transfusing platelets through any type of fluid warmer.

ADDENDA Aug. 24, 2005

2. A Transfusion Service QA Specialist reports that the following reference may be of interest to the discussion: AABB Guidelines for the Use of Blood Warming Devices (© 2002). She comments that the AABB publication lists the following as one of the few "absolute contraindications" to use of a blood warming device: "Administration of Platelets, Cryoprecipitate, or Granulocyte suspensions (Warming may render these products less effective.)" Additional references are cited in this publication.

ADDENDA June 20, 2008

3. A Quality Improvement and Blood Bank Supervisor at a Department of Pathology and Laboratory Medicine in a heartland state would appreciate clarification of the use of blood warmers and administration of fresh frozen plasma. Her institution thaws plasma in an FDA approved device that does not exceed the 37C requirement. Their trauma service uses a Sims Level I rapid infuser that consists of a disposable countercurrent heat exchanger through which water warmed to about 41.5°C in is circulated by a pump. (This does NOT imply that the blood product is warmed above 37C). This countercurrent warming device is combined with automated pneumatic pressure infusers. Her institution also uses HOTLINE fluid warmers that can deliver normal body temperature fluids to patients at routine flow rates using a triple lumen tubing that maintains a layer of 42ºC circulating solution around the patient line, eliminating patient line cool down. The Level I infuser instrument contraindicates use for administration of cryoprecipitate, platelets and granulocytes. The manufacturer has provided 510K clearance information for its use in warming blood. They have also sent accompanying abstracts which have studied the effects of temperature on red cell integrity/hemolysis. The inquiring colleague has not received any information regarding damage to coagulation factors when FFP is warmed above 37 degrees. Their blood administration policy states that blood components other than packed red cells, including FFP, should not be given through their institution's blood warmers. Their trauma service is asking for guidance on the use of blood warmers that use countercurrent warming systems in which the warming solution exceeds 37 C for administration of fresh frozen plasma, since the manufacturer of the blood warmer states that this is not contraindicated. The inquiring colleague posted a question similar to the aforementioned to the AABB Standards Technical Department and they cited AABB Standard 3.8 which states: "Warming devices shall be equipped with a temperature sensing device and a warning system to detect malfunctions and prevent hemolysis or other damage." They went on to state: "In terms of using your blood warmer for FFP, not contraindicated is not the same as approved for use. "Other damage" might include deterioration of clotting factors or adverse effects on plasma proteins. If FFP is to be infused using these devices the equipment should be qualified, the procedure validated and that it demonstrated that damage does not occur."

Before going to a lot of work designing and executing and interpreting a study to determine if the warmers inflict "other damage," the inquiring colleague would like to pose this question to the blood bank community via the e-Network Forum. Have studies been done to qualify these blood warmers/temperatures as safe and efficacious for administration of FFP/FP24?

ADDENDA July 1, 2008

4. A transfusion medicine physician in Maryland reports that his trauma center's policy is that platelets are transfused separately from RBCs and plasma, and not through a massive transfusion blood warming device. They do not routinely use a warmer with platelets, but do NOT have a specific policy forbidding it. Plasma would routinely be warmed in the trauma center for a patient at risk for hypothermia and would be administered through a massive transfusion blood warming device.

Please submit comments to the e-Network Forum.

Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator