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Biomedical subjects

R G Strauss

Publications and source records attributed to R G Strauss.

At least 55 records · Page 3Linked to original sources
PubMed1996

Mechanisms of adverse effects during hemapheresis.

For over 20 years blood components have been collected from normal donors by automated hemapheresis. Cell separators have become increasingly sophisticated, and relatively pure component "concentrates" can be obtained quite safely. Cytapheresis donors are monitored carefully, and serious reactions are very rare. In contrast, therapeutic apheresis procedures may be technically demanding and frequently are performed on very sick patients. Large volumes of blood are rapidly removed from the patient, anticoagulated, and separated into components by the automated cell separator. The blood component containing the pathogenetic factor (e.g., plasma containing an antibody) is retained outside of the body, and the remaining components (e.g., red cells, white cells, and platelets) plus the replacement fluid are reinfused. Complications can occur in normal cytapheresis donors because of the technical challenges of the procedure (e.g., extracorporeal circuit to be filled, use of citrate anticoagulant, need for large bore intravascular access, and rapid blood flow rates). All of these factors apply also to therapeutic patients plus the additional requirement for replacement fluids, and the clinical features of the underlying illness for which each patient is being treated. Fortunately, even with therapeutic patients, most complications are of modest severity and are easily managed with only temporary slowing or interruption of the hemapheresis procedure.

Blood Component Removal↗
PubMed1996

Changing patterns of red blood cell transfusion in very low birth weight infants.

OBJECTIVE: Anemia develops in increasing numbers of critically ill very low birth weight (VLBW) infants who survive the neonatal period, and they receive multiple red blood cell (RBC) transfusions. Despite their need for prolonged medical treatment, we hypothesized that VLBW infants presently receive fewer RBC transfusions as a result of the growing awareness of transfusion risks and improvement of neonatal care. METHODS: RBC transfusion practices and clinical outcomes in infants with birth weights of 1.5 kg or less were analyzed retrospectively in three selected years: 1982, before awareness of the human immunodeficiency virus; 1989, before surfactant availability; and 1993, before erythropoietin approval. RESULTS: Progressive declines in RBC transfusions, donor exposures, and transfusion volumes occurred concurrently with decreases in morbidity and mortality rates. Transfusions per infant (mean +/- SD) declined from 7.0 +/- 7.4 in 1982 to 5.0 +/- 5.8 in 1989 to 2.3 +/- 2.7 in 1993 (p < 0.001). This decline was associated with a decrease in pretransfusion hematocrit (33.6% +/- 2.8% in 1982, 34.2% +/- 3.7% in 1989, and 29.8% +/- 5.1% in 1993; p < 0.001). The distribution of RBC transfusions given by week of life among study years did not change; 70% of RBC transfusions were given within the first 4 weeks, when infants are sickest. Although the percentage of VLBW infants weighing more than 1 kg at birth and never receiving any RBC transfusions increased with time (17% in 1982, 33% in 1989, and 64% in 1993), more than 95% of infants weighing 1 kg or less in all years received transfusions. CONCLUSIONS: Overall administration of neonatal transfusions has decreased markedly, most likely because of multiple factors. Because most RBC transfusions are given to infants weighing 1 kg or less in the first weeks of life, therapeutic strategies should focus on this group of VLBW infants during this critical period. The temporal changes observed in transfusion patterns emphasize the importance of including concurrent controls in future studies evaluating transfusion interventions.

Erythrocyte Transfusion↗
PubMed1996

AS-1 red cells for neonatal transfusions: a randomized trial assessing donor exposure and safety.

BACKGROUND: Despite recent optimism about the use of erythropoietin therapy to treat the anemia of prematurity, very-low-birth-weight infants who are severely ill receive multiple red cell (RBC) transfusions. Many physicians transfuse relatively fresh RBCs to newborn infants, exposing them to multiple donors and possibly increasing their risk of acquiring transfusion-transmitted infections. STUDY DESIGN AND METHODS: A randomized, single-blind clinical trial was conducted to determine, as the primary endpoint, whether RBCs collected from one dedicated donor and stored for < or = 42 days in AS-1 storage media could safely supply all small-volume RBC transfusions (15 mL/kg/dose) needed by very-low-birth-weight infants (0.6-1.3 kg) during the first 84 days of life. Secondary endpoints were the assessment of the possible adverse clinical and biochemical effects of transfusing AS-1 RBCs stored for < or = 42 days. Control infants received identical nursery care, except they received fresh RBCs stored < or = 7 days in CPDA-1. RESULTS: Infants transfused with AS-1 RBCs were exposed to a mean of 1.6 donors,-compared with an exposure to 3.7 donors for infants given CPDA-1 RBCs (p < 0.05). Neither clinical transfusion reactions nor the results of multiple laboratory tests were significantly different in infants who received slow transfusions (15 mL/kg) of AS-1 RBCs stored for < or = 42 days and in infants who received the same volume of CPDA-1 RBCs stored < or = 7 days. CONCLUSION: AS-1 RBCs, usually from only one dedicated donor, can safely supply all RBCs needed by most very-low-birth-weight infants-a practice that decreases donor exposure and likely increases transfusion safety.

Adenine↗
PubMed1996

Bacterial contamination rates following processing of bone marrow and peripheral blood progenitor cell preparations.

BACKGROUND: The performance of cultures to assess possible bacterial contamination of bone marrow and peripheral blood progenitor cell preparations is required by the standards of the American Association of Blood Banks. STUDY DESIGN AND METHODS: Consecutive (n = 893) bone marrow and peripheral blood progenitor cell preparations were cultured for assessment of possible contamination by microorganisms. RESULTS: Consecutive bone marrow and peripheral blood progenitor cell preparations (n = 893) were cultured; the overall positive rate detected was 2.5 percent (22/893). The isolates predominantly were skin contaminants (gram-positive cocci) and so-called water-borne organisms (gram-negative rods). The 6.0-percent rate of positivity in 317 bone marrow preparations was higher than the 0.5-percent rate in 576 peripheral blood progenitor cell preparations (p < 10(-6)). Culture-positive preparations were transfused to 16 patients at this institution; however, none of these transfusions led to documented sepsis with the contaminating organism. CONCLUSION: The culture method described here complies with the standards of the American Association of Blood Banks. Contamination can be detected in both bone marrow and peripheral blood progenitor cell preparations. When contaminated preparations are transfused, there are few complications that can be attributed to the contamination.

Blood↗
PubMed1996

Cadaver skin allografts and transmission of human cytomegalovirus to burn patients.

BACKGROUND: The potential role of cadaver skin as a vehicle for CMV transmission to burn patients has never been clearly defined. We sought to determine if a cytomegalovirus (CMV)-positive cadaver allograft transmits CMV infections to CMV-seronegative burn patients. STUDY DESIGN: All patients in this study were CMV seronegative on admission. They received CMV-seronegative blood products, and cadaver allografts for temporary wound closure and management without regard to the donor's CMV serum status (positive or negative). RESULTS: Of 493 patients admitted from 1989 to 1993, 22 were CMV seronegative on admission and required cadaver allografts for their burn wounds. Five (22.7 percent) of 22 patients seroconverted during hospitalization: one of five had CMV pneumonia develop, two had CMV viruria develop, and three had persistent fever, abnormal liver enzymes, and diarrhea not ascribable to bacterial or other viral agents. CONCLUSIONS: Cytomegalovirus infections result from using CMV-seropositive cadaver allografts on seronegative burn patients.

Adolescent↗
PubMed1995

Clinical perspectives of granulocyte transfusions: efficacy to date.

The literature pertaining to the use of granulocyte transfusions as treatment for progressive bacterial, yeast, and fungal infections in severely neutropenic patients is reviewed. Efficacy in treating bacterial infections that are unresponsive to antimicrobial therapy is well established--especially if bone marrow failure does not recover rapidly and neutropenia is persistent. The role of therapeutic granulocyte transfusions for yeast and fungal infections has potential merit, but current data are incomplete and findings are inconsistent. The possibility of greater success has been raised by use of recombinant granulocyte colony stimulating factor to greatly increase the yield of neutrophils collected from normal donors.

Bacterial Infections↗
PubMed1995

Clinical perspectives of platelet transfusions: defining the optimal dose.

To halt bleeding in patients with severe thrombocytopenia due to bone marrow failure, it is desirable to achieve a post-transfusion blood platelet count of 40 x 10(9)/L by platelet transfusions. Based on calculations of corrected count increments, each 1 x 10(11) platelets transfused will increase the blood platelet count approximately 10 x 10(9)/L per each square meter of patient body surface area. Thus, the post-transfusion blood platelet count will be approximately 20 x 10(9)/L following transfusion of 3 x 10(11) platelets to a 5 foot, 8 inch patient weighing 170 pounds (2.0 m2), who is bleeding because of a pre-transfusion platelet count of 5 x 10(9)/L. The post-transfusion platelet count likely will be even lower in sick patients (sepsis, amphotericin B plus antibiotic therapy, splenomegaly, graft-vs.-host disease, etc.) or if platelets are lost from the unit by leukofiltration before transfusion. Although a dose of 3 x 10(11) platelets is acceptable, in a regulatory sense for product quality, it is inadequate to control bleeding in most thrombocytopenic adult patients. Adjusting dose for body size, bleeding patients with pre-transfusion blood platelet of < 10 x 10(9)/L and weighing > 120 pounds should receive approximately 6 x 10(11) platelets, those weighing 30 to 120 pounds should receive 3 x 10(11) platelets, and infants weighing < 30 pounds (15 kg) should receive 5-10 ml/kg of platelet concentrate.

Bone Marrow Diseases↗
PubMed1995

Efficacy and safety of plateletpheresis by donors with low-normal platelet counts.

Our practice is to defer donors with blood platelet (PLT) counts of < 180 x 10(9)/L because PLT yields are low, when compared to PLT units collected from donors with higher counts. In an attempt to minimize deferral, we determined whether 33 donors, who repeatedly demonstrated low-normal PLT counts (150-180 x 10(9)/L) on multiple occasions during the prestudy period. might safely donate satisfactory apheresis PLT units simply by extending the apheresis collection time by 20 min (men) and 40 min (women). Repeat plateletpheresis procedures were scheduled at > or = 28-day intervals. The mean PLT yield (N = 92) was 5.8 x 10(11) with 97% of units containing > or = 4.0 x 10(11) PLTs. Although donors entered the study only after they had repeatedly exhibited predonation PLT counts of < 180 x 10(9)/L, PLT counts were not always below this level at the time of study collections. However, analyzing only donations with true predonation PLT counts of < 180 x 10(9)/L (N = 35), the mean PLT yield was excellent-5.4 x 10(11) with 97% of units containing > or = 4.0 x 10(11) PLTs. The average fall in donor blood PLT counts (pre-vs. postdonation) was 36%, with only ten of 99 postdonation counts being < 100 x 10(9)/L; the lowest was 69 x 10(9)/L. Thus, extending the apheresis collection time permitted donors who in the past were routinely deferred because of low PLT counts to safely donate satisfactory PLT units.

Blood Donors↗
PubMed1995

A method to collect, store and issue multiple aliquots of packed red blood cells for neonatal transfusions.

Premature neonates require multiple red blood cell (RBC) transfusions. Single-donor programs have been proposed as a means to limit donor exposures, but methods must be developed to collect, store long-term and issue multiple aliquots of RBCs from a single donor. We evaluated a method by which RBCs could be collected, leukocyte depleted, repeatedly centrifuged for issuance as multiple small aliquots of high-hematocrit cells and then resuspended for continued storage throughout 42 days. The quality of RBCs handled by the method were compared to cells stored in standard fashion. Leakage of intracellular potassium, hemoglobin and lactic dehydrogenase into the extracellular fluid from RBCs processed by either method was comparable-indicating maintenance of RBC integrity. Multiple cultures, taken throughout the period of storage, were sterile to document that extensive handling did not introduce contamination. This new method appears promising as a means to provide RBCs for neonates.

Blood Donors↗
PubMed1995

Red blood cell transfusion practices in the neonate.

Premature infants, particularly those with a birthweight of less than 1.0 kilograms and respiratory disease, frequently require red blood cell (RBC) transfusions. The major mechanisms causing the anemia of prematurity are phlebotomy blood losses and a diminished ability to mount an effective erythropoietin response to the falling RBC mass. Although the indications for RBC transfusions have not been defined by controlled clinical trials, usual transfusion practices are discussed. In addition, the potential role for recombinant erythropoietin in the treatment of anemia of prematurity is analyzed critically. Finally, an overall approach to managing the anemia of prematurity is provided.

Anemia, Neonatal↗
PubMed1994

Recombinant human erythropoietin vs transfusions in the treatment of anemia of prematurity. A cost-benefit analysis.

OBJECTIVE: To evaluate the costs relative to the benefits of using recombinant human erythropoietin (rHuEPO) therapy as an alternative to red blood cell (RBC) transfusions in infants with anemia of prematurity. DESIGN: A cost-benefit analysis of rHuEPO therapy was performed based on its use in very-low-birth-weight premature infants. SETTING AND PATIENTS: Data were drawn from published studies or were provided by the University of Iowa Hospitals and Clinics, Iowa City. MAIN OUTCOME MEASURES: Costs and benefits were analyzed as a comparison of incurred costs to averted costs. Incurred and averted costs of rHuEPO therapy and RBC transfusions included direct product costs and estimates of costs of adverse events. The analysis was viewed in terms of net savings. Sensitivity analysis was performed. RESULTS: The base case analysis yielded a net loss of $299.48 per infant. A 54% reduction in the direct product costs of rHuEPO therapy yielded a break-even point. No other variations in the sensitivity analysis resulted in a net savings. CONCLUSION: Using assumptions based on the current state of clinical research, it appears that routine use of rHuEPO with supplemental RBC transfusions would not generate any cost savings as an alternative to RBC transfusions alone. As further evidence is compiled on the efficacy of rHuEPO therapy in very-low-birth-weight premature infants, the true costs may be better established.

Anemia, Neonatal↗
PubMed1994

Effects on donors of repeated leukocyte losses during plateletpheresis.

All blood components collected by automated cytapheresis contain donor leukocytes. The possibility that repeated cytapheresis donation might lead to clinically important leukocyte losses and immunodeficiency has been a long-standing concern. Although convincing data do not exist to substantiate this concern, it is common practice to limit the number of annual cytapheresis donations per donor and to monitor donors for developing lymphocytopenia. Clinically significant immunodeficiency is unlikely to occur unless donors lose > 1 x 10(11) lymphocytes within a few weeks period of time or unless donor lymphocyte counts fall persistently to < 0.5 x 10(9)/L. Each plateletpheresis procedure, when performed using modern cell separators that are designed to produce a relatively "pure" platelet concentrate, leads to the loss of 1.0 x 10(6) to 5.0 x 10(7) leukocytes. Thus, automated plateletpheresis as performed in 1994 is extremely unlikely to cause clinically significant lymphocyte depletion and consequent immunodeficiency.

Blood Donors↗
PubMed1994

Preoperative autologous donation: surgery clinic staff knowledge/attitudes. Preoperative Autologous Blood Donation Study Group.

Preoperative autologous blood donation (PABD) is both under- and overused. Although the decision to order PABD lies with the surgeon, it is quite likely that other surgery clinic personnel influence patient acceptance and enrollment into PABD programs. Accordingly, we measured knowledge, attitudes, and the referral practice of clinic personnel pertaining to PABD. We administered a questionnaire to 102 nurses and 33 clerks working in surgery clinics at three university medical centers--one center in an area with a high incidence of AIDS and two centers in areas of low incidence of AIDS. Knowledge of PABD was poor when assessed by six questions. Only 6% each of nurses and clerks answered all questions correctly; 55% of nurses and 54% clerks missed three or more of the six questions. Surprisingly, no differences (P > .05) in knowledge deficits were noted when personnel from high and low AIDS areas were compared--indicating an overall need for education about PABD. In general, attitudes about PABD were positive, as most respondents (63%) gave favorable answers. Clinic personnel from the high AIDS area had even more favorable attitudes (P = .02). Because of these favorable attitudes, it seems likely that educational programs dealing with PABD would be readily accepted by clinic personnel. Greater knowledge should enhance the effectiveness of clinic staff in identifying, counseling, and referring eligible patients for this service.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Treatment of severe cardiac allograft rejection with extracorporeal photochemotherapy.

Two patients were treated with photopheresis for marked cardiac allograft rejection with hemodynamic compromise that had become unresponsive to standard therapy. Multiple episodes of rejection had occurred, and initial response to standard therapy was favorable. However, progressive deterioration was documented by serial endomyocardial biopsies, fever, congestive heart failure, and abnormal cardiac catheterization findings. In the absence of retransplantation, death seemed imminent. Photopheresis was begun. Both patients received oral 8-methoxypsoralen and > or = 5 x 10(9) mononuclear cells were collected, treated with ultraviolet light A for 1.5 hours, and were reinfused. One procedure was performed weekly x4 and then monthly x5. Responses were striking with rapid loss of fever, improvement in exercise tolerance, normalization of cardiac hemodynamics, and improvement in endomyocardial biopsies. Although our experience with these two patients is anecdotal, photopheresis merits further study as treatment for severe cardiac allograft rejection.

Adult↗
PubMed1994

Physician recommendation as the key factor in patients' decisions to participate in preoperative autologous blood donation programs: Preoperative Autologous Blood Donation Study Group.

To determine whether the physician or patient had initiated the discussion regarding preoperative autologous blood donation (PABD) and to assess the relative importance of the physician's recommendation in patients' decision to donate, responses were obtained from 254 of 409 patients (62%) who had donated preoperatively during the 3 study months. Nearly all (96%) strongly agreed they would donate again for themselves and nearly all (94%) strongly agreed they would recommend PABD to others. Patients initiated the discussion about PABD 23% of the time, while 71% indicated strong surgeon input. The remaining respondents said their surgeon had "mentioned it, but said it was up to me." The importance of avoiding transfusion reactions was rated significantly greater among those whose surgeons had initiated the discussion, as was the relative weight of the surgeon's recommendation. The desire to alleviate the blood shortage was rated much less important among patients who had initiated the discussion themselves.

Attitude to Health↗