DEFERRAL OF PATIENTS FOR AUTOLOGOUS BLOOD DONATION

Recently, an article in the New England Journal of Medicine (1) reported that the cost of autologous donation was exceedingly high when measured against the actual risk of contracting a transfusion transmitted disease. The article measured the benefits of autologous donation only in terms of cost and did not consider the enormous psychological comfort that autologous donation provides. Generally patients are highly motivated to donate their own blood. The Medical staff at Yale New Haven Hospital is aware of and supportive of the autologous program. The Blood Bank Transfusion Unit on CB 363 presently collects approximately 1600 autologous units per year. Unfortunately, not every patient can donate and not every visit to donate results in a donation. Ensuring the safety of the patient both as a donor and as a future recipient is of utmost importance, to the staff in the transfusion clinic and Blood Bank. A variety of circumstances can compromise that safety, resulting in deferral from donation.

Donor Deferral
Deferral will usually fall into two broad categories, donor safety and transfusion or recipient safety. Patients are deferred because they might not tolerate the donation itself, in effect the acute blood loss may put the patient at risk because of the loss of either volume or red cell mass. Common examples are patients with cardiomyopathy or anemic patients. The second major cause for deferral is that the donation may result in an unsafe unit of blood. The most common example of this is the patient who may be intermittently bacteremic from a chronic infection such as osteomyelitis. Transfusing bacteremic blood could have catastrophic consequences.

Donor Standards
We follow the donor standard guidelines that have been established by the American Association of Blood Banks. These standards include a minimum body weight for the donor, vital sign limits for temperature, pulse and blood pressure, and minimum hemoglobin or hematocrit values. In addition, the "Standards" do not permit collection from anyone who is being treated for bacteremia or has a bacterial infection which may be associated with bacteremia. Finally, the donation should occur no closer than 72 hours prior to surgery.

The donor's body weight is important because it correlates to the donor's total blood volume. The approved and licensed blood collecting bags are manufactured to contain and store a standard range of blood volumes. More or less blood would result in an alteration of the ratio of added anticoagulants and nutrient solutions which could have an adverse effect on the stored blood. Collecting a standard unit which is 450mL (+/- 10%) and approximately 9.2% of a normal weight (70Kg) person, from a smaller individual could result in excessive blood loss which could produce signs and symptoms of anemia or more likely hypovolemia. The most serious risks would be acute hypotension and low oxygen-carrying capacity resulting in possible organ ischemia. Therefore, the lowest acceptable weight is 110 lbs.

The pulse must be between 50 and 100 beats per minute and the blood pressure must measure no more than 100 diastolic and 180 systolic. These are a relatively direct evaluation of cardiovascular stability, which is obviously necessary for a donor to sustain an acute blood loss. In addition, abnormalities in pulse and blood pressure may be associated with and reflect underlying diseases which may have an impact on the ability to donate. It is the responsibility of the Blood Bank physician to evaluate the patient's ability to donate under these circumstances. The Blood Bank director or his physician staff have both the responsibility and the legal authority to make the final decision regarding the acceptability of a donor who wishes to donate autologous blood. This responsibility cannot be transferred to the patient's referring physician.

The temperature must be < 99.5 F. This is an important measure of the possibility of ongoing (intercurrent) infection. While we all recognize that autologous donation is aimed at avoiding viral infection, it is often overlooked that the blood must also be free of any bacteria. One frequently encountered problem is "one stop shopping" for presurgical work-up. Patients are sent for a variety of preadmission tests that often include invasive procedures such as biopsies and then are sent to donate blood. Since there is a fresh open wound, we cannot reasonably rule out the possibility of a transient bacteremia. Bacterially contaminated units even when stored in a refrigerator may become grossly infected. This is especially true of the cryophilic or cold loving bacteria such as Yersinia enterocolitica. While very common ailments, such as urinary tract infections and upper respiratory tract infections are the most frequent reasons for bacteremic deferral other situations such as the presence of indwelling catheters, orthopedic appliances, abscesses and being on antibiotic therapy for almost any reason also fall into this category. The medical staff of the Blood Bank assesses the entire clinical picture before turning anyone away. Fortunately there is usually enough time to allow the condition to resolve so that donation can be safely performed at a another visit.

The patient must have a hematocrit sufficient to sustain an acute blood loss without causing an iatrogenic anemia that might eventually require transfusion support. Obviously there is little sense in taking blood out only to have to put it back in. The minimum acceptable hematocrit is 33%. In an adult, each unit of blood donated will probably result in a 3 point drop in hematocrit. In essence, autologous donation is discouraged if the predicted hematocrit is going to be much below 30% at the time of surgery.

While every effort is made to accommodate both the patient's wish and the referring physician's request that the patient donate autologous blood, some individuals cannot for the reasons discussed above. One practical solution is using blood expressly donated for the patient by people selected by the patient. Frequently this will be members of the patient's family but is not limited to them alone. This is called directed donation. There are some drawbacks however. Directed donor blood undergoes the same testing that volunteer blood does and is not known to be any safer than volunteer donor blood. The incidence of hepatitis is actually somewhat greater in directed donor blood and the incidence of HIV is about the same as compared to volunteer donor blood. The reason for this finding is that directed donors are more likely to be first time donors. The volunteer donor pool consists of a great many repeat donors who have already been multiply tested for TTD markers. Anyone who tests positive for a TTD marker such as hepatitis is permanently deferred. Beyond this, the donor's blood type must be serologically compatible for ABO and Rh for the unit to be useable. Another consideration is that directed donations are not collected at Yale due to FDA licensing restrictions. Directed donation can be arranged with the Connecticut Red Cross in Farmington. Directed donor blood is generally not covered under most insurance plans.

You can arrange an autologous donation at Yale New Haven Hospital by making an appointment with the Transfusion Service at 785-4707. Please call Dr. Steven Mechanic, the Assistant Director or Dr. Edward Snyder, the Director of the Blood Bank at 785-2441 if you have any medical questions. You may also call Judy Cohen, R.N. at 785-4707 for scheduling questions.

References

1. Etchason, M. et al. Cost Effectiveness of preoperative blood donation. NEJM, 1995; 332:719.

Steven Mechanic, M.D