Platelet transfusion therapy

Autologous blood sequestration using a double venous reservoir bypass circuit and polymerized hemoglobin prime

Cardiac surgery often necessitates transfusion of homologous blood. Hemoglobin based oxygen carrying solutions (HBOCs) transport oxygen, suggesting use in cardiopulmonary bypass. HBOC was used in a novel oxygenator double-reservoir circuit that permits acute sequestration of a portion of the autologous blood volume during bypass. Two groups of seven mongrel dogs each were studied in an experimental bypass model using global myocardial ischemia and cardioplegia protection: HBOC group, initial venous return drained to a separate reservoir and hypothermic bypass was conducted with HBOC containing perfusate in a second bypass reservoir; Control group, crystalloid prime in a conventional circuit. Hemodynamics and metabolic and hematologic parameters were measured before and 60 min after aortic clamp removal and reinfusion of sequestered autologous blood. Blood gases, base excess, hematocrit, total hemoglobin, and platelet counts were measured. In the HBOC group, metabolic acidosis did not occur, and ventricular function was preserved. Net conservation of platelets was noted at study conclusion: control 33+/-13 x 10(3) per mm3 versus HBOC 48+/-13 x 10(3), p < 0.05. HBOC based priming in a double venous reservoir system permits bypass at very low hematocrit, with preservation of cardiac function. Net conservation of the platelet mass occurs, a portion of which is not exposed to the deleterious effects of hypothermia and cardiopulmonary bypass.

The role of blood component therapy in the management of canine and feline patients with cancer

Blood component therapy may be required for a variety of pathologic reasons in the cancer patient. The tumor itself not only affects various cell lines, but treatment with chemotherapeutic agents can induce cytopenias. In addition, chronic and acute hemorrhage can be caused by tumor erosion and rupture or by paraneoplastic coagulopathies. Component replacement will depend on the underlying hematologic deficiencies and should be performed in conjunction with treating the cause of the deficiency.

Anesthesia considerations for pediatric cancer

The multidisciplinary approach to the care of children with cancer demands an understanding of all aspects of its treatment. Recognition of potential anatomic and physiologic derangements which may result from specific types of malignancy allows optimal preoperative preparation. Understanding the anesthetic implications of cancer chemotherapy, irradiation and surgery, and the medical complications which result, is essential. The anesthesiologist is involved in critical perioperative issues during surgical resection in the operating room, but just as importantly plays a crucial role in a variety of procedures performed in remote locations. An awareness of special problems related to cancer and its treatment allows optimal anesthesia care while dealing with such issues as radical surgery, organ system failure, acute and chronic pain, and terminal illness.

Efficacy of platelet transfusions in immune thrombocytopenia

Records of 11 patients with immune thrombocytopenia (idiopathic and quinidine-induced) were evaluated retrospectively for response to platelet transfusion. Good post-transfusion platelet count increments occurred on one or more occasions in seven of the 11 patients, with 13 of 31 platelet transfusions (42 percent) resulting in immediate post-transfusion increments of 20,000/mm3 or more. Next-day platelet counts remained elevated in association with five of these 13 transfusions. This study demonstrates that, contrary to common opinion, platelet transfusions can raise the platelet count in many patients with immune thrombocytopenia, and therefore may be beneficial in actively bleeding or high-risk patients with this disorder.

Platelet collection using the IBM 2997 cell separator

Platelets were collected using the dual-channel module on the IBM 2997 Blood Fraction Separator. We carried out 320 procedures to harvest platelets for therapeutic purposes and yielded 5.1 +/- 1.5 X 10(11) platelets (mean +/- SD). Infusion into previously unsensitized recipients with hypomegakaryocytic thrombocytopenia achieved increments at 1 hr of 19 +/- 7.3 X 10(9)/liter/m2 (mean +/- SD) and at 24 hr of 15 +/- 6.3 X 10(9)/liter/m2. The only consistent donor reaction was mild hypocalcaemia, easily corrected by calcium gluconate infusion. Changes in donor packed-cell volume and white cell count were not statistically altered (p greater than 0.05) but donor platelet counts fell from 216 +/- 43.1 X 10(9)/liter to 162.5 +2- 41.7 X 10(9)/liter (mean +/- SD) (p less than 0.01). Additional plateletphereses were carried out in seven normal volunteers, using the same technique, in order that the function of the harvested platelets could be studied. Following radiochromium labelling and reinfusion into the same donors, normal in vivo recoveries were obtained at 10 min (59.4 +/- 3.4%; mean +/- SD) and platelet mean life span was also normal (218 +/- 12 hr; mean +/- SD). Furthermore, in vitro platelet factor III availability and aggregation patterns of the harvested platelets did not differ from control values and their ultrastructural appearance was normal.

Autoimmune thrombocytopenic purpura: current concepts and recommended practices

Autoimmune thrombocytopenic purpura is the most common autoimmune disorder encountered in the pregnant patient. It is potentially fatal for the mother and fetus yet treatable and potentially curable. Analysis of current perinatal literature reveals not only a great deal of interest and activity in the study of this syndrome and its special problems during pregnancy but also significant controversy. The disease can be acute or chronic and vary in time of onset and severity of manifestations. If not forewarned with an awareness of this disorder's pathogenesis and potential fetal effects particularly in the pregnant woman who has undergone splenectomy, the obstetrician cannot respond appropriately. The usefulness of platelet antibody determinations to facilitate obstetric management decisions is discussed. The importance of cooperative care among the obstetrician, hematologist, and neonatologist is emphasized. Recommendations for management of autoimmune thrombocytopenic purpura in pregnancy are derived from a review of current concepts of the disorder's pathogenesis, pathophysiology, criteria for diagnosis, and modes of therapy as well as special maternal/fetal considerations of antepartum, intrapartum, and postpartum care.

Causes of death in patients with non-Hodgkin's lymphoma

The causes of death and postmortem findings in patients treated for non-Hodgkin's lymphoma at a single institution over a 13-year period were reviewed. Postmortem examination (70% of the entire sample) revealed evidence of lymphoma in 67 of 80 patients. The most frequent extranodal sites of involvement were the respiratory tract, bone marrow, liver, kidney, and gastrointestinal tract in that order. The most common cause of death was infection (33% of cases). Predisposing factors for infection included the underlying disease, (i.e., lymphomatous infiltration of organ systems) and granulocytopenia secondary to combination chemotherapy. Other causes of death included hemorrhage and respiratory failure secondary to lymphomatous infiltration of the lung. Despite advances in therapy and supportive care of patients with non-Hodgkin's lymphoma, many patients still die of this disease or of sequelae related to its treatment.

Oncology Grand Rounds. Platelet transfusion--clinical applications in the oncology setting

The increased availability of platelets for transfusion has been a major factor in the improved prognosis noted in patients with acute nonlymphocytic leukemia. This review summarizes our current understanding of the proper use of platelet transfusion for patients with leukemia and cancer, with a particular emphasis on the management of alloimmunized patients. The need for careful and close collaboration between the blood bank and the referring clinicians is emphasized. Cryopreservation of autologous platelets, which can be of considerable assistance in the management of alloimmunized patients, and a summary of the large number of questions that still require further investigation are presented.