It’s now over four centuries since the English physician William Harvey carried out what has now been recognized as the first effective study covering the circulation and transfusion of blood. The actual science of blood transfusion itself, as we would understand it, only dates back to the start of the twentieth century with the discovery of distinct blood types.
The search for blood substitutes
This is an ongoing search, as there currently are no actual substitutes for human blood. However, extensive research is being carried out in this area. The aim is to discover a liquid which would be able to work, at least for a short period of time, to transport oxygen and replace blood.
It is the case that products are currently being tested which can undertake some of the work accomplished by red blood cells. This might involve carrying oxygen to tissue, but these products are not currently capable of replicating the other key functions of our blood.
The use of volume expanders
The use of volume expanders is a treatment which can be used when the body goes into a type of shock due to the loss of a volume of fluids. As either a volume restoration treatment or as a preventative, solutions are given which can expand the fluid volume and this allows blood to continue to circulate to vital organs. Such solutions use a vein to introduce them directly into the patient’s bloodstream.
While they do then both boost the volume of fluids and aid with blood circulation, they neither carry oxygen nor raise the actual blood cell numbers.
The process of blood salvage
When undergoing surgery, patients can require blood transfusions either during (intra) or after (post) their operation. This is to replace blood lost during the procedure. In some circumstances, this lost blood can be saved through the use of a special machine. After collection, this ‘salvaged’ blood can then be given back to the patient.
Obviously, one key advantage of such actions, called autologous transfusions, is that it reduces any requirements to source transfusions from other blood donors. However, the process cannot be used in all circumstances. For example, some studies have located remaining tumour cells in such blood when it has been salvaged during cancer surgery.
The use of hematopoietic growth factors
These hormone-like substances occur naturally in the human body; they cause our bone marrow to create more blood cells. Man-made versions of these substances have now become available and can be of help to people who have been identified as having a low blood cell count. Such growth factor products can be used to boost white or red blood cells and platelet counts.
While it’s obvious that these growth factors can help transfusion-needing patients, they are not a solution in every circumstance. There is a range of identified drawbacks which can limit their use.
The first of these concerns the time taken for growth factors to raise a patient’s blood count. The period needed for such growth can cover many days or even weeks. But, often, such as when an individual is heavy bleeding, then the blood cell levels need to be raised much more quickly than these hormones are capable of delivering.
It’s also possible that growth factors might cause quicker growth of certain cancer cells. Such possibilities might include breast, cervical, head and lung cancers as well as multiple myeloma and lymphocytic leukemia. This means that growth factors may well not be used when the treatment being undertaken is expected to cure the identified cancer. It is also a further possibility that patients who are suffering from severe bone marrow disease simply do not have sufficient blood-producing cells present in their bone marrow to effectively respond to the growth factors.
A final limitation in the use of Hematopoietic Growth Factors is the fact that such treatments usually are much more expensive than standard blood transfusions. This means that such treatments are likely to be used only for as short a time as is possible.
As you will have recognized, finding alternatives to blood transfusions is clearly a work-in-progress. The information we’ve provided assesses the current situation; we hope it has clearly highlighted what possibilities are being considered and provides a useful guide to this subject.