Massive extracorporeal blood clotting during discontinuous flow leukapheresis

Current status of plasmapheresis in toxicology

Although the elimination of specific toxins by the removal of all plasma constituents is a crude approach, further refinements of the technique should permit safer and more selective detoxification in the future. Currently the mainstay of treatment of intoxicated patients remains careful, aggressive, supportive care. Plasmapheresis should be considered as yet an unproven, hazardous form of therapy for the treatment of intoxication. Its main role should be confined to a research setting in which investigators attempt to develop more advanced and potentially useful apheresis techniques. Membrane plasmapheresis with subsequent on-line treatment of the plasma by sorbent may remove specific plasma solutes. The plasma may be perfused back to the patient without the need to use replacement fluids, thus avoiding many of the side effects of conventional exchange. Bile acids have been removed by circulating plasma over charcoal-coated glass beads, and several toxic substances were shown to be absorbed by perfusion over amberlite resin columns. Another productive area for future research includes the use of plasma exchange therapy for the treatment of acute endogenous intoxications. Recent examples include the treatment of severe preeclampsia, extensive rhabdomyolysis, and life-threatening bleeding in a hemophiliac with inhibitors to clotting factors. Although plasmapheresis in the management of intoxications is still an experimental technique, it may open the door to the treatment of previously intractable syndromes, both medical and toxicologic.

Therapeutic apheresis. Applications and future directions

The past 10-15 years have been witness to major technological achievements in the field of therapeutic apheresis. Concurrently, a large number of diseases, primarily with an immunological basis, have been treated with apheresis. In this paper, we review the various applications of therapeutic apheresis, adverse reactions associated with the mode of therapy, and future research directions. Several representative diseases are also discussed in detail.

Panel IX: Complications related to equipment and technique

Automated cytapheresis, when performed by experienced operators using modern equipment, is remarkably free of adverse effects. A declining pattern of equipment failure and related problems has been recorded in the 220,000 procedures performed by the American Red Cross in the past 5 years. Other cytapheresis centers report similar findings. Current CBCS are safe and reliable, and defects in plastic disposables, while irritating, result in little danger to the donor. Operator vigilance and careful attention to the details of the procedure can eliminate the majority of serious potential complications that have been encountered to date.

Adverse reactions to whole blood donation and plasmapheresis

Whole blood donation is recognized to be extremely safe, yet there have been reports of serious problems stemming from whole blood donation, and so-called "donor reactions" are regularly seen. While the physiologic causes of the common donor reactions are not completely understood, some effects of whole blood donation (such as transient iron deficiency) are understood but probably not significant. In order to avoid accepting any volunteer donor who might be at risk of a serious reaction, we may have been overly cautious in exclusion of potential donors. The pheresis donor is subjected to potential depletion of the protein or cellular elements being removed, problems caused by the device used for automated pheresis, or problems related to the infusion of potentially toxic substances. Documented benefit to the patient must balance these additional risks.

Leukapheresis and granulocyte transfusion

Granulocyte transfusion is becoming widely used in the treatment of infections in granulocytopenic patients. Several techniques are available for granulocyte collection. Some involve centrifugation of the whole blood and one removes granulocytes from whole blood by reversible adhesion to nylon fibers. The risks to the donor from leukapheresis do not appear to be greater than from whole blood donation. Granulocytes collected by centrifuge techniques function normally in vitro and have normal intravascular recovery and disappearance following transfusion. Granulocytes collected by filtration leukapheresis function almost normally in vitro but have a reduced intravascular recovery and abnormal kinetics as they leave the circulation. The role of leukocyte typing and compatibility testing for granulocyte transfusion is controversial. When the recipient has circulating antibody against donor leukocytes, transfused leukocytes do not circulate or migrate to sites of infection but are sequestered in the liver and spleen. Clinical studies have not defined whether patients benefit equally well clinically from transfusion of compatible or incompatible granulocytes. Initial reports of clinical trials of granulocyte transfusion were promising. However, similar patients who did not receive granulocytes were not studied. Most subsequent controlled trials showed a clear benefit from granulocyte transfusion while others did not. Differences in antibiotic therapy, chemotherapy, use of laminar flow rooms, and grouping of patients make it difficult to compare these clinical trials. Some, but not all, infected granulocytopenic patients benefit from transfusion. Granulocyte transfusions improve survival of granulocytopenic patients with gram negative sepsis and prolonged bone marrow aplasia. Studies are now attempting to identify other patients who should receive granulocytes, the optimum dose and schedule of transfusions, the optimum time to begin transfusion, and the value, if any, of prophylactic transfusions.