New Methods for Saving Blood

By John Langone

Ever since it became clear that AIDS and other infections could be transmitted through blood transfusions, the public has regarded receiving blood as risky. Even though blood is now screened more thoroughly than ever, scientists too are concerned about the vulnerability of the nation's blood supply, and this has led to a search for ways to circumvent the donor system. One approach is synthetic hemoglobin, the oxygen-carrying component of red blood cells; another is a drug to increase the production of red cells. A third is increasingly being used in elective surgery: autologous transfusion, in which patients are given blood that they had donated and banked for themselves.

But a hemoglobin substitute is still some years away, and synthetic red- cell expanders are only in the test stages. There are also drawbacks to laying in a private stock of blood for a transfusion that may never be necessary. Three pints are typically requested for surgery, and drawing, processing and storing them can be expensive -- about $200 a pint per year. The donor must also pay the cost of transporting the blood to where it is needed -- an especially difficult task if the patient is involved in an automobile accident miles from his blood bank.

To overcome such drawbacks, doctors at Northwestern Memorial Hospital in Chicago have developed a technique that promises to get safe blood quickly to a patient. It is a form of autologous transfusion but with an important difference. Most hospitals try to reclaim part of the blood lost by a patient during surgery. When faced with gaping wounds that ooze large quantities of blood into body cavities -- as in open-heart or orthopedic surgery -- surgeons can reclaim half of it with suction devices, cleanse it in purifying machines and send it back into the patient. The rest is lost because it either spills out or is soaked up by the gauze sponges used to keep the operating field dry.

What makes the Northwestern technique special is that virtually all the blood lost in an operation is salvaged. It is wrung out by hand from the saturated sponges directly into a bowl of saline solution. The solution is filtered and then passed into a centrifuge, where the red blood cells are separated. Within 15 minutes the reclaimed blood is back in circulation. Says Northwestern anesthesiologist Ann Ronai: "We're trying to salvage as much blood as possible during the operation, because it's better than somebody else's." The savings can be enormous: when the sponge method is combined with conventional suction, 90% of lost blood can be returned.

Still, it is often impossible to retrieve a patient's blood, particularly in trauma cases in which the victim of a shooting or highway accident has lost an enormous amount at the scene. Since blood is not always readily available in these circumstances, researchers are seeking a synthetic hemoglobin for emergency use.

Scientists at a number of centers are also trying to develop ways to increase the body's own production of red blood cells. Doctors at Michael Reese Hospital in Chicago are testing a technique that seems to fill the bill. They use a genetically engineered copy of a compound called erythropoietin, a hormone made in the kidneys that controls red-cell production.

In early animal studies, Dr. Steven Gould of Michael Reese injected man- made EPO into baboons and then collected their blood. The result: when animals were given EPO prior to surgery that involved major blood loss, they made new red cells immediately after the operation; those that did not receive the drug did not begin replacing their red cells for four days. Says Gould: "If a patient is anemic following surgery, it's possible that EPO can stimulate recovery enough so that we can decrease or avoid homologous transfusions." In fact, in clinical tests the drug has already freed anemic kidney-dialysis patients from the need for transfusions.

Other blood-saving approaches are aimed at improving surgical techniques that make transfusions necessary. Since scalpels draw a good deal of blood, some surgeons are turning to the laser knife, which cuts cleanly with a fine beam of energy. But a laser requires considerable training: it must be held away from the targeted tissue while the surgeon aims the beam, checks its power and concentrates on cutting -- all at the same time.

A new user-friendly "contact laser" may change all that. Developed by Dr. Stephen Joffe of the University of Cincinnati Medical Center, it has a fiber tip that is placed directly against tissue, allowing the surgeon to work as closely as with a scalpel. A British study showed that the laser reduced blood loss by 80% during mastectomies; another, by Joffe, found that when the laser was beamed through an endoscope (a flexible tube inserted into the body), it stopped bleeding from ulcers 90% of the time. Says Joffe: "This laser can convert a major operation into a minor one simply by lessening the bleeding."

With reporting by Barbara Dolan/Chicago