Reducing the size of platelet concentrate pools as a means of coping with product shortages and rising costs

A colleague in Michigan reports that historically the physicians at his hospital have ordered a 6-unit random donor pool for adult patients needing platelet transfusions. Because of limited random donor platelet availability and blood component costs, this hospital is now considering asking its physicians to routinely ordering a 5-unit pool instead of the traditional 6-unit pool, especially for oncology and hematology patients. The inquiring colleague would like to hear from institutions that have successfully cut down their platelet usage by reducing the number of platelet units in a standard pool.

The following responses were received.

ADDENDA July 22, 2003

1. Dr. Ronald E. Domen, Medical Director of the Blood Bank and Transfusion Medicine Service at Penn State University College of Medicine (attribution used with permission) reports that at his institution, they had formerly used a 7-unit pool but they were successful a few years ago in reducing it to a 6-unit pool by showing that, on average, a 6-unit pool contained at least 3 x 10¹¹ platelets. During periods of shortage, they will not uncommonly reduce the pool size to 5 or 4 units in order to accommodate all of their patients. He refers colleagues to a paper by Hoeltge GA et al. entitled "An optimized strategy for choosing the number of platelet concentrates to pool" in Arch Pathol Lab Med 1999;123928-930.
   
   
2. A transfusion medicine physician from New York reports that his hospital's standard platelet pool is 5 units for everyone except small children and those over 7 feet tall. In shortage situations they have frequently gone down to pools of 4 and on rare occasions even to 3 units.
   
   Their reasoning has been as follows. Perhaps 95% of platelet transfusions are prophylactic and of questionable value and safety to the patient, and in their opinion, no one has demonstrated the benefits of prophylactic platelet transfusion in a randomized trial. The main predictor of future bleeding in thrombocytopenic patients is previous or current bleeding, not the platelet count. Thus they feel confident in giving smaller pools to patients receiving prophylactic transfusions (e.g., those who aren't bleeding, nor covered with petechiae or purpura). He adds that the platelet units they are now transfusing typically contain more platelets than those previously manufactured. A pool of five in their experience will typically raise the platelet count by 20-40,000/µl or so in a stable patient (if ABO identical). A pool of three by perhaps 10-25,000 /µl. In really sick patients, the increments may be half this, but are also usually clinically quite satisfactory at keeping the count above 10,000/µl. These are more than adequate increments, in his opinion, for non-bleeding patients. He further adds that there is evidence that some of the newly proposed risks of platelet transfusion (multi-organ dysfunction, leukemic recurrence) may be dose-related.
   
   Given the absence of proof of benefit for prophylactic transfusion they have become therapeutic minimalists, if not yet nihilists, about platelet transfusions to non-bleeding patients. For actively bleeding patients with moderate to severe thrombocytopenia (less than perhaps 30-50,000) a trial of one dose of higher numbers of platelets may be reasonable. But his empirical rule of thumb in almost all instances is that if one or two boluses of 5 units of platelets doesn't have any noticeable effect on the bleeding problem, the bleeding problem is not likely treatable by platelet transfusions.

ADDENDA July 23, 2003

3. A colleague with many years of experience in blood banking asks the obvious question (verbatim) "Has anyone looked at selecting this number based on individual patient criteria such as weight, (i.e., blood volume), and pretransfusion platelet count? I would think that a 90 lb recipient and a 290 lb recipient could never be best served by the same-sized platelet pool, regardless of the number selected."

ADDENDA July 24, 2003

4. A California transfusion medicine physician occasionally interacts with clinicians who submit orders for more platelet concentrates than the usual dose, and he has graciously shared a representative progress note from his "collection". His consultation notes addressing larger than usual platelet requests are typically structured into two paragraphs, with paragraph #1 being customized to the specific situation, and paragraph #2 as a standardized text that is pasted into the electronic medical record where appropriate. The second paragraph specifically addresses the topic of reducing the number of platelet concentrates in a standard sized pool.
   • Paragraph #1 (verbatim) "I thank Dr. XXX for discussing Mr. YYY's recent course, and agree with his plan to maintain platelets > 50,000/µl in the immediate post-operative period. This morning's platelet count of 43,000/µl prompted a transfusion request, for which a pool of 5 platelet concentrates was issued. I anticipate that this will provide a satisfactory platelet increment. Accordingly, Dr. XXX and I agreed to adjust the original transfusion request of 10 platelet concentrates (2 pools of 5) to the single pool of 5 that was issued."
   • Paragraph #2 (verbatim) "Historically, many medical centers used a pool of 8 to 10 platelet concentrates as a standard adult dose. Improved platelet yields from whole blood donations, along with better storage and pooling techniques, allow an adult dose with fewer donor exposures, typically 4 to 6 platelet concentrates per pool. Based on quality control measurements from our blood supplier, which I review monthly, our transfusion committee has determined that a pool of 5 platelet concentrates constitutes a standard adult platelet dose. In most instances, a platelet order should consist of one adult dose, followed by clinical evaluation and laboratory platelet count before additional transfusion requests are made. Blood bank physicians are available 24x7 to discuss cases of particular concern to our providers. Thank you for allowing me to participate in the care of Mr. YYY."
     
     
5. A transfusion medicine physician and highly regarded colleague at an academic medical center in New Haven Connecticut reports that several years ago they reduced the size of their platelet pools to 4 units for in-house patients, while outpatients receive 5-unit pools. In times of extreme shortages, they issue 2-3-unit pools to in-house patients to stretch the inventory. The physicians at that hospital have not double-ordered to compensate. They have had a substantial reduction in platelet usage (and costs) over the past few years compared to when their pool size was 6-8 units. Total platelet usage has dropped while the number of pools used has not. According to the New Haven colleague, "They give fewer platelets per pool - not less pools. 'Not less tea, less tea flavor' so to speak". Outcomes are reportedly positive (bleeding stops) and they have not had any problems that they are aware of. House staff are now used to this change. They work closely with residents/attendings when patients continue to bleed, providing more product pools when requested. This occurs infrequently. It does happen (<1/week) , and when it does they just give more platelets. They rolled this strategy out after a hospital-wide physician-nurse education/notification program. They have no immediate plans to drop to an even lower platelet pool size.

ADDENDA July 25, 2003

6. A colleague in Minnesota would like to add to the dialogue regarding reducing the size of platelet concentrate pools. At his institution they transfuse 1 platelet concentrate per 10 kg of body weight, and since 1999 their maximum dose has been 5 concentrates per pool. (Rare exceptions for increased platelet dose are made for patients with very large body weights.) Quality control reports from their blood supplier indicate that 5 leukoreduced platelet concentrates yields approximately the same number of platelets as 1 apheresis platelet.
   
   This institution handles a dual inventory of both platelet concentrates and apheresis platelets, but currently transfuses approximately 5,000-6,000 platelet pools per year. Of course, some of these pools are given to pediatric patients who receive less than 5 platelets per pool.
   
   Even after taking this into consideration, the reporting colleague claims a conservative estimate reveals a cost savings of around $300,000 per year since switching from an adult pool size of six to a pool size of five.

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