Alternatives to blood transfusions
Because transfusions carry risks and because the blood supply is limited, doctors try not to transfuse if they can avoid it. In some cases, options other than blood product transfusions may be available.
When a patient has lost a lot of body fluids but does not need blood, shock may be treated or prevented by giving solutions to keep the circulation going. The most common solutions are normal saline (sterile water with a precise amount of salt) and lactated Ringer’s solution (saline plus other chemicals). Other such solutions (called volume expanders) include albumin, hydroxyethyl starch (HES), dextrans, and purified protein fractions. All of these increase fluid volume, but do not change the number of blood cells.
The body naturally makes hormone-like substances called hematopoietic growth factors that cause the bone marrow to make more blood cells. Scientists have learned how to make some of these growth factors in the lab to help people with low blood cell counts. Growth factors can be used to boost red blood cell, white blood cell, or platelet counts.
Growth factors may help patients who would otherwise need transfusions. But they have some drawbacks that may limit their use in some cases:
- Unlike transfusions, growth factors often take many days or weeks to raise blood counts, so they may not be useful in people who need their blood cell levels raised quickly, such as those who are actively bleeding.
- People who have severe bone marrow disease may not respond to the growth factors because they do not have enough blood-producing cells in their bone marrow.
- Some growth factors might cause certain types of cancer cells (such as lymphocytic leukemia, multiple myeloma, head and neck cancer, breast cancer, cervical cancer, and some kinds of lung cancer cells) to grow more quickly.
- Growth factors generally cost a lot more than transfusions.
Because of these drawbacks, certain growth factors are not used in people whose treatment is expected to cure their cancer. And when they are used, they are given for as short a time as possible.
Intra-operative or post-operative blood salvage
Patients getting surgery sometimes need transfusions to replace blood lost during or after the operation. In some cases this lost blood can be “salvaged” or saved by collecting it with a special machine and giving it back into the patient.
Giving a person back his or her own (autologous) blood cuts down on the need for transfusions from other donors. But some studies have found tumor cells in blood salvaged during cancer operations, so this is not something that can be done for all patients. (Another type of autologous transfusion is described in the “Donating blood” section.)
So far, there is no real substitute for human blood. But researchers are working to develop a liquid that can carry oxygen and replace blood, at least for a short time, in certain situations.
Products that are being tested include hemoglobin-based oxygen carriers and perfluorochemical compounds. They can do some of the work of red blood cells, such as carrying oxygen to tissues, but cannot replace the many functions that human blood does. Of the oxygen-carrying compounds that are being tested in US clinical trials, none has been approved by the FDA as of 2011.
Most blood substitutes are experimental and are rarely used. They may be used as short-term measures in patients whose religious beliefs do not allow them to have blood product transfusions. They may also help patients with rare blood types and those whose immune systems would destroy donated blood. The substitutes may be used until matching donated blood can be found, which in some cases might take several days.
Last Medical Review: 09/27/2011
Last Revised: 09/27/2011