Blood, still saving lives but … there are risks

Transcript

Professor Aryeh Shander, Chief of the Department of Anesthesiology, Englewood Hospital, New Jersey, USA: Transfusions are so engrained in clinical practice that, in many clinical situations, a significant number are given to alleviate physicians' discomfort rather than care for the patient's needs.

Professor Hans Gombotz, Chief of the Department of Anesthesiology and Intensive Care, General Hospital Linz, Austria: Transfusion practice is based on behaviour rather than evidence.

Professor James Isbister, Consultant in Haematology and Transfusion Medicine, Sydney Medical School: We really must change transfusion medicine practice. There is no other alternative. And there is a sense of urgency. This change will be from a product focus to a patient focus, and this is what we're referring to as 'patient blood management'.

What is the evidence telling us?

In 2006, Tinmouth and colleagues analysed the association between red blood cell transfusions and increased mortality and morbidity in the critically ill. They wrote: We have witnessed a dramatic paradigm shift, whereby red blood cell transfusions once regarded as one of the great advances in modern medicine, are now considered harmful in some clinical situations. In 42 of the 45 studies that Marik and Koren reviewed in 2008, they found the risk of red cell transfusion outweighed the benefits. The risk was neutral in 2 studies, and the benefits outweighed the risks in only a subgroup of one study. They concluded: Our analysis suggests that in adults, intensive care unit trauma and surgical patients, red blood cell transfusions are associated with increased morbidity and mortality, and therefore, current transfusion practices may require reevaluation in 2009. The first international consensus conference on transfusion outcomes considered the benefits of transfusions across a total of 495 studies. The findings indicated that in 59% of clinical scenarios, transfusions were not beneficial at all. In 29% of the cases, it was uncertain whether these transfusions were beneficial. It was only in 12% of this populations that transfusions were deemed to be helpful.

Why are transfusions causing harm?

Blood is a complex biological fluid. A great deal of work has been done to understand the multiple biochemical and biomechanical changes that take place once it is removed from its host and stored. However, the possible clinical implications of transfusing this stored biological product are only beginning to be better understood. Dr Andreas Maier Hellman and colleagues from the Helios clinic, Erfurt, Germany, used a cytoscan to film the sublingual micro-circulation pre- and post-transfusion in a patient with severe gastrointestinal bleeding. The patient's haemoglobin fell to 2.8 grams per deciliter. This video shows the microcirculation after initial resuscitation within a cellular body, and expanded what red blood cells are left as circulating through all the multicell and single-cell capillaries. The next video shows the same micro-circulation after the transfusion of 3 units of stored allogeneic red blood cells. Clearly, here there is reduced flow, single cell capillaries are swollen, there was uneven distribution of the red cells, blockage in sludging and many areas where there are no red blood cells in contact with the tissues. This work starts to provide insights into the possible mechanisms underlying the limited evidence for transfusion efficacy.

What can clinicians do?

Aryeh Shander: As clinicians, we have learned 3 key lessons. First, even the most profound anaemia can be sustainably and quickly corrected without utilising allogeneic blood products. Second, perioperative blood loss, even in complex procedures, can be significantly reduced. And third, post-operative treatment of asymptomatic anaemia should be applied universally to sufficiently restore the patient's endogenous red cell volume.

We have no choice but to act now

It really is a sobering thought when one considers that allogeneic blood transfusion has a potential for a wider range of adverse clinical outcomes than probably any other medical intervention.

Professor Donat Spahn, Chairman of the Department of Anaesthesiology, University Hospital Zurich, Switzerland: After considering all available evidence on transfusion and outcomes, we are left with the conclusion that transfusion is a major multiplier of morbidity and mortality. Maintaining the status quo, as we've seen in transmission practice today, would just not be accepted or tolerated in any other field of medicine in the context of current safety and quality standards.

Learn more about patient blood management.