Monday, 3 October 2016

Saving Blood; Strategies to Shatter Resistance

The evidence is clear: avoiding unnecessary transfusions saves lives and generates savings with clinical criteria. Nature echoes this aphorism in an article that collects research insisting that regarding blood transfusions less is more. This issue of blood is very awkward and contradictory. Not surprisingly, for modern nations, having a system of voluntary donation is a matter of pride. Many people believe it and when there is a disaster, the first reaction of many people is lining up to give blood. And it should be noted that the evidence favours the popular intuition: transfusions work better for the injured with major bleeding and for more complex patients, but can also be harmful for patients with smaller problems.

Transfusion = transplant?

The transfused red blood cells have two problems: the first is that in the storage process they lose flexibility, which can make them less effective in transporting oxygen, and the second is that they are actually foreign cells containing antigens (beyond ABO and Rh) that arouse immunological reactions of varying intensities. On these physio-pathological issues, there is still not enough research, but many believe that the origin of the transfusion problems is in these two points.

Why do we now doubt transfusions (and not before)?

Transfusions have a place in the popular imagination and during the war (both the civil Spanish war and later the world war), when it was possible to industrialize the transfusion process, the climate was not favourable to clinical trials. This is understandable, but the question is, how come until 1999 (more than half a century after the end of the World War II) the first clinical trial to question the effectiveness of transfusions fails to materialise? And the answer, far from being scientific, comes from the world of clinical work, because transfused patients suffer acute problems of uncertain evolution or underlying conditions (such as cancer) with poor prognosis and therefore, if in the process complications appear or death occurs, it’s almost impossible to know to what extent the introduction of foreign red blood cells has contributed to the unfortunate outcome.

The head thinks one thing and the heart does another

It is well known that nowadays most prescribers are aware of the evidence and know that you have to be restrictive when recommending transfusions, but the clinical reality explained in the Nature article is another, if you oversee two examples: a) a 2011 British  audit conducted on over 9,000 transfusions found that half of them were potentially avoidable, b) in two ICU of Johns Hopkins Hospital, although the vast majority of doctors assured that they were aware of the transfusion lintel, a review of medical records revealed that between 84% and 92% of transfused patients have had haemoglobin levels higher than those admitted by the doctors themselves.

Stanford Hospital’s strategy to save blood

At Stanford, when a doctor prescribes a transfusion, the system automatically checks the patient’s haemoglobin levels and if these are above the transfusion threshold, the system displays a message that kindly reminds the doctor of what the guide says on the subject and asks him to justify his decision. As seen in the chart, it has been observed that this action has prevented 24% of transfusions, assumed as unnecessary, with a direct impact on savings of $1.6 million, plus a significant reduction in bed occupancy and a decrease in the transfused patients’ mortality rate from 5.5% to 3.3%.

Patient Blood Management (PBM): a comprehensive strategy to for appropriate transfusions

The PBM projects (see in this blog: "Saving Blood: more quality, less mortality and morbidity, lower costs") develop strategies that go beyond Stanford, as these not only cover the transfusion threshold but also apply guidelines to optimize the volume of red cells before certain scheduled surgeries, in addition to ensuring techniques to reduce bleeding during operations. PBM is considered today a "Triple Aim," project because it increases the patients’ survival rate, improves clinical outcomes and reduces costs.

Jordi Varela

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