Is the deferred-donor notification process effective?
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Biomedical subjects
Publications and source records attributed to E P Scott.
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In spite of growing awareness of the potential risks associated with transfusion, the number of platelet units transfused in the United States continues to increase each year. There is a growing interest in ensuring that all transfusions are administered for appropriate reasons. Prospective review of requests for transfusions has been used to accomplish this goal. Although successful in reducing the number of inappropriate transfusions, this review method requires great time commitments by blood bank personnel and physicians. A knowledge-based system (ESPRE) that aids hospital blood bank personnel in the review of requests for platelet transfusions has been developed. The system automatically obtains most of the required patient data via a direct link to the hospital's main laboratory computers. The system generates a printed report that includes a list of patient-specific data, a list of the conditions for which a transfusion would be appropriate for the particular patient (given the clinical condition), and the conclusions drawn by the system. During a preliminary clinical evaluation of ESPRE, 73 randomly selected platelet transfusion requests were evaluated for approval by laboratory personnel and ESPRE. Overall, ESPRE would have approved 71 of the requests and laboratory staff would have approved 72. Forty-four percent of the requests would have been approved for the same reasons given by the staff. There were only three disagreements on final approval between ESPRE and blood bank personnel. This computerized expert system is a promising approach to the prospective review of all platelet transfusions.
The expert system for platelet request evaluation (ESPRE) is being developed to support independent learning and decision making regarding the use of platelet transfusions while physicians are actively engaged in clinical practice. The knowledge of transfusion medicine incorporated in ESPRE has been largely gathered from blood bank physicians responsible for determining the appropriateness of blood product administration. Knowledge acquisition methods have included structured and unstructured interviews with protocol analysis using real and fabricated transfusion cases and critiques of an expert system prototype's conclusions. For knowledge representation, ESPRE uses frames with embedded production rules to provide processing efficiency and facilitate knowledge base development. ESPRE automatically acquires key laboratory findings from a laboratory information system. Systems such as ESPRE require careful evaluation and, if proven effective and accurate, present to laboratorians a new tool for delivering high-quality and individually adapted health care.
ESPRE is a knowledge-based system which aids in the review of requests for platelet transfusions in the hospital blood bank. It is a microcomputer-based decision support system written in LISP and utilizes a hybrid frame and rule architecture. By automatically obtaining most of the required patient data directly from the hospital's main laboratory computers via a direct link, very little keyboard entry is required. Assessment of time trends computed from the data constitutes an important aspect of this system. To aid the blood bank personnel in deciding on the appropriateness of the requested transfusion, the system provides an explanatory report which includes a list of patient-specific data, a list of the conditions for which a transfusion would be appropriate for the particular patient (given the clinical condition), and the conclusions drawn by the system. In an early clinical evaluation of ESPRE, out of a random sample of 75 platelet transfusion requests, there were only three disagreements between ESPRE and blood bank personnel.
Because many potential bone marrow transplant patients lack HLA-matched siblings, there is growing interest in carrying out transplantations using matched, unrelated volunteer donors. We developed a local registry of 2147 informed donors who consented to be listed in the Bone Marrow Donor Registry. This registry was used to carry out 420 donor searches for 351 patients. The initial computer search involved matching for HLA-A and HLA-B locus antigens only because most donors had not been typed for HLA-DR antigens. Depending on the degree of HLA-A and HLA-B antigen mismatching allowed, suitably matched (HLA-DR-identical, mixed lymphocyte culture nonreactive) donors were located for 6% to 16% of patients. This resulted in 13 bone marrow transplants. This study shows that a small, local bone marrow donor registry can locate donors for a few patients; however, a large network involving an expanded number of donors will be necessary to allow an extensive evaluation of unrelated bone marrow transplantation.
Nicotine base was used in a conditioned taste aversion (CTA) paradigm to avert male Sprague-Dawley rats to saccharin solution (0.1%, w/v). Experiments investigated different dose routes of nicotine administration and duration of action as determinants in nicotine-induced CTA. In Experiment 1 nicotine was injected intraperitoneally (IP) at doses of 0.5, 1.0, or 3.0 mg/kg 30 min after drinking saccharin solution. Using a two-bottle choice test, no CTA was observed, although all nicotine animals showed obvious symptoms of malaise including seizures in the highest dose group. Experiment 2 showed dose-related CTA when nicotine (10.0, 30.0, or 50.0 mg/kg) was cutaneously applied 30 min following saccharin drinking. Experiment 2B showed that the aversions were due to associative rather than nonassociative factors such as sensitization or enhanced neophobia. In Experiment 3, the following group treatments were begun 30 min after saccharin drinking to distribute identical total nicotine doses over an extended period of time: One IP injection of 2.0 mg/kg nicotine (in a saline vehicle) and four injections of saline solution, three injections of 0.67 mg/kg nicotine and two injections of saline, five injections of 0.40 mg/kg nicotine, or five injections of saline. All injections were spaced 30 min apart. Compared with saline-injected controls, CTA occurred in the rats receiving either three or five injections of nicotine but the group receiving one injection did not differ from the control group. There was no difference in CTA between the groups receiving three or five injections.
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A transfusion reaction in a 76-year-old man was followed by severe but transient thrombocytopenia after infusion of whole blood. A high-titer platelet-specific antibody (anti-PLA) was demonstrated in the plasma of the implicated unit and in the serum of the blood donor. In addition, three previous recipients of blood from the implicated donor had posttransfusion episodes of unexplained thrombocytopenia. These cases represent the first reported clinical examples of posttransfusion thrombocytopenia caused by passively transfused platelet-specific alloantibodies.
Two hundred forty-three patients received 22,717 U of platelets in our hospital during a three-month period. Those with hematologic diseases accounted for 43% of the patients but used 86% of the platelets. Sixty-eight percent of the transfusions were given to prevent bleeding and 32% were given to treat active bleeding. Ninety-two percent of therapeutic transfusions but only 22% of prophylactic transfusions met guidelines established by the Transfusion Therapeutics Committee of the University of Minnesota Hospital and Clinics, Minneapolis. However, 78% of prophylactic platelet transfusions that did not meet the guidelines involved patients with at least one clinical factor that their physicians believed placed them at an increased risk of bleeding. Following this analysis, the guidelines were modified and applied prospectively to requests for platelets. This resulted in a 14% decrease in the number of platelet units used during the following year. We conclude that published recommendations for platelet transfusions do not reflect the complex nature of many patients' conditions and that the use of guidelines developed by the medical staff can alter the use of platelet transfusions.