Evaluation of a decision aid for patients considering autologous blood donation before open-heart surgery

Background: Patients undergoing open-heart surgery frequently require one o r more blood transfusions. Because of the risks of receiving blood from vol unteer donors, some patients choose to donate their own blood before surger y. This reduces their risk of exposure to volunteer-donated blood, but it i ncreases their chance of receiving any transfusion, either of self-donated or volunteer-donated blood. Also, preoperative hemoglobin levels tend to be lower in patients who donate their own blood, and surgeons may be more lik ely to give transfusions to patients with self-donated blood. To help patie nts decide whether to donate their blood before surgery, we designed a deci sion aid comprising a booklet and audiotape and assessed its effectiveness. Methods: The 59 study subjects were a sample of consecutive patients referr ed to the Ottawa Heart Institute between Oct. 1, 1998, and Jan. 5, 1999, fo r future coronary artery bypass grafting, valve surgery or combined surgery . All were eligible to donate blood. Initial questionnaires were administer ed in the clinic by a physician or study nurse, and follow-up questionnaire s were completed at home and mailed in after use of the decision aid. Outco me measures included patients' knowledge, values (importance ratings), pref erences for transfusion methods, decisional conflict (the amount of uncerta inty about the course of action to take), risk perception and acceptability of the decision aid. Results: Mean knowledge scores on a 15-item test increased from 67% correct responses before the decision aid to 85% correct responses after use of th e aid (p < 0.001); the effect was similar when the patients were divided in to subgroups according to education level. The number of patients favouring donating their own blood increased from 41 (69%) before to 45 (76%) after use of the aid. Nine (64%) of 14 initially uncertain patients preferred aut ologous donation after use of the aid. The overall mean score for decisiona l conflict was unchanged, at 1.7, which indicated a low level of uncertaint y. Risk perception improved, from 0%-14% correct responses on an 8-item tes t before the aid to 18%-60% correct responses after use of the aid. The dec ision aid was acceptable to the majority of patients, and 95% indicated tha t they would recommend it to others. Interpretation: The decision aid improved knowledge and risk perceptions of blood donation and transfusion, and it helped uncertain patients to make c hoices.