Wednesday, February 29, 2012

The sound of silence (Musings on blood safety regulations)

This month's blog is a short snapper. I've meant to try this for awhile, since some say that blogs should be relatively short, i.e., 250-500 words. Mine are typically much longer and it no doubt takes dedicated readers to read them. 

The blog's title derives from an old Simon and Garfunkel classic.

The blog is a personal synopsis (with musings) of this paper, available as free fulltext from the Jan. issue of Transfusion:
Why the paper appealed: 

1. It gets at the craziness that characterizes so many of the 'rules' governing transfusion medicine;

2. Away back when, circa 1974, having just been promoted to clinical instructor at the Winnipeg Red Cross Blood Transfusion Service* (now CBS), I went to a multi-day workshop sponsored by Ortho in Don Mills, Ontario, just outside Toronto. 
*Winnipeg BTS was a combined transfusion service (serving all of Winnipeg and environs, stretching into NW Ontario) and blood centre, still the only one in Canada.
One of the required workshop tasks was for each attendee to research a topic and present it to the group. The topic I chose was the 'storage lesion.' 

Pretty sexy, eh? I knew nothing about it, so thought may as well learn something. Who'd have 'thunk' ATP and 2,3 DPG would still be current 35+ years later?

As background, AABB and the U.S. FDA require RBCs to be stored between 1 and 6°C for up to 35 or 42 days depending on the anticoagulant-preservative solution. However, RBCs can be transported in containers that keep the temperature between 1 and 10°C. 

The U.S. FDA recently clarified storage vs transport: RBCs issued in coolers to an OR are in storage and not transport, hence must be kept at 1 and 6°C.

Other countries have similar distinctions for storage vs transport. The origin of the different temperatures ranges for RBC storage and transport is unknown.

Imagine this scenario:

1. Unused RBC units are returned from the OR to the transfusion service at 8°C and are discarded since they exceed the 1 to 6°C storage range.

2. RBC units from the blood supplier arrive at the transfusion service at 8°C and are placed into inventory since they adhere to the 1 to 10°C for transport.

Say what? Difference makes little sense. As the authors write [paraphrased]:
(1) Differing temperature ranges likely do not increase patient safety and should be reconsidered, since improved utilization and cost control of all hospital services is essential. Increased wastage of an already scarce resource can lead to low blood inventories, putting patients at risk.
(2) The change from OR fridges to coolers was to reduce incompatible blood transfusions associated with using shared refrigerators for several ORs where blood for patients of different ABO groups were stored. But the cost of improved safety has been increased blood wastage to comply with temperature regulations that lack scientific verification.
The authors' conclusion (paraphrased):
Data show there may be no detriment to increasing the storage temperature range to 1 to 10°C for a few hours, such as while RBCs are in a cooler in the OR. But data are incomplete and may not apply to storage with current materials. Research on differences in metabolite formation, biochemical changes, and microbial growth between RBCs stored at 1 to 6°C and 1 to 10°C would help demonstrate the most appropriate storage temperature range. 
Kudos to the authors for tackling this issue. In a way it's sad that the authors use cost constraint as a major motivator for re-thinking the regulations. No doubt money 'makes the world go around.' But why weren't such rules challenged a long time ago on science alone?

Wouldn't it be great if more iffy, nutball regulations (those lacking scientific evidence) were challenged?

Perhaps the 'powers that be' could develop a mechanism for trench workers in various countries to suggest which regulations may not be warranted? Then research could be done that clarifies the issue.

Suitable challenges would involve regulations that 
  • Seem arbitrary (unrelated to safety) 
  • Are inconsistent with other regulations
  • Cause increased work / money without apparent justification
  • Sound of silence (Simon & Garfunkel) The song title fits behavior in the TM community about iffy rules and regulations. But mainly it's included because I love the tune, lyrics and artists.
As always, the views are mine alone. Comments are most welcome BUT, due to excessive spam, please e-mail me personally or use the address in the newsletter notice. 


  1. Anonymous9:02 AM

    On a personal level (not scientific at all, I am quite prepared to take the implied risk of using salad dressing that is past its best-before date. And yogurt (sheesh, it is already fermented, or whatever). Clearly, this affects only me (and whoever might have to put up with my up-chucking when my experiment didn't work out - hasn't happened yet), which is quite different from providing products to patients/clients. Anyhow, I myself have passed my best-before date, so what the hey.

    Thanks for this interesting topic!

  2. Thanks, anonymous. Interesting analogy about food. Like blood products, food is subject to many safety regulations. The difference between 'best before' and 'use by' dates may be misunderstood by consumers and varies from country to country.

    'Best before' generally means the date that food can be expected to retain its optimum properties (best quality), assuming it is stored properly according to package directions. 'Best before' is associated with frozen and canned foods, eggs, cereal, yogurt, and more.

    As you say, food past its 'best before' date doesn't mean we need to discard it but the quality may not be ideal. It's legal to sell such food.

    We consume it at our own risk, but the risk is usually not life-threatening (no guarantees) but more a question of tolerating a yuk! factor directly correlated to increasing age.

    In contrast, food past its 'use by' date presents a safety risk, even if it looks and smells okay, and is illegal to sell. It's associated with short-term perishables such as deli meat, fish and milk.

    'Best before' and 'use by' may have parallels in the recently resurrected controversy about potential risks associated with transfusing older blood.

    For example, for most patients 'fresh blood' (RBC less than a week old) may turn out to be equivalent to 'best before', i.e., using older blood may have risks that are minor in the grand scheme of things, as opposed to being a life-threatening version of 'use by'.

    Time and research will tell. Risk management and cost-benefit analyses are everything these days.