Thrombocytopenia in allogeneic peripheral blood stem cell collections.
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Bone Marrow↗
Biomedical subjects
M E Brecher
Publications and source records attributed to M E Brecher.
North American Multicenter Study on flow cytometric enumeration of CD34+ hematopoietic stem cells.
Transplant centers often rely on CD34+ cell quantitation by flow cytometry to ensure adequacy of hematopoietic progenitor cell collection. Because of variation in interpretation, a lack of interlaboratory proficiency studies, and no generally accepted methodology, comparison of CD34 data from site to site is difficult. Twenty-one samples from marrow and peripheral blood stem cell collections were shipped to 10 participating North American laboratories for analysis. Duplicate samples were included to assess reproducibility. Participants were surveyed for methodology. Three centers had previously attempted to standardize their methodology among themselves. The variability observed in the CD34 values ranged from a max/min. reported value per sample of 2.9 to 749 (median 76). Exclusion of two outlying sites reduced the variability of results to 1.2 to 27 (median 3.1). Variation among the three standardized sites ranged from 1.2 to 4.4 (median 1.6). Overall reproducibility (excluding the outlying sites B and G) ranged from a minimum of 0-16.5 (percent mean difference) for site C to a maximum of 4.1-133 for site H. Strategies for gating were found to largely influence results. We observed an alarming variation among the CD34 cell counts reported from different laboratories. Standardization substantially reduced observed variation. The need for standardized methodology, reporting, quality control, and proficiency testing is underscored by these findings.
Antigens, CD34↗
Apheresis. New opportunities.
Recent advances in apheresis have emerged in a variety of clinical settings. Improvements in granulocyte and peripheral blood stem cell collection and mobilization, the changing role of intravenous gamma globulin, the importance of patient assessment and selection of replacement fluids, and the progress in both affinity apheresis and photopheresis are presented. These current trends, their limitation, and their promise in treating a diversity of diseases inspire the future of this technology.
Antigens, CD34↗
A paradigm for consensus. The University Hospital Consortium guidelines for the use of albumin, nonprotein colloid, and crystalloid solutions.
OBJECTIVE: To develop contemporary, comprehensive guidelines for the appropriate and efficient use of albumin, nonprotein colloid, and crystalloid solutions. DESIGN: A systematic, literature-based, consensus exercise employing a modified Delphi method. PARTICIPANTS: Thirty-one medical and allied health professionals from 26 University Hospital Consortium (Oak Brook, Ill) member institutions were initially chosen to participate. Participants were selected on the basis of their recognized research in the use of albumin, nonprotein colloid, and crystalloid solutions, and/or experience in the review of appropriateness of such use. A total of 24 participants completed the exercise. MAIN OUTCOME MEASURES: Group responses were statistically analyzed in an iterative consensus development process. Five separate questionnaire rounds were designed to establish criteria for the appropriate use of albumin, nonprotein colloid, and crystalloid solutions. RESULTS: Consensus guidelines were developed outlining the appropriate use of these products for 12 clinical indications, including hemorrhagic shock, nonhemorrhagic (maldistributive) shock, hepatic resection, thermal injury, cerebral ischemia, nutritional intervention, cardiac surgery, hyperbilirubinemia of the newborn, cirrhosis and paracentesis, nephrotic syndrome, organ transplantation, and plasmapheresis. CONCLUSIONS: The Delphi method, a systematic, literature-based consensus process, was shown to be useful in the development of complex clinical practice guidelines for the use of albumin, nonprotein colloid, and crystalloid solutions. It is anticipated that the guidelines will assist health care providers to develop local institutional policies and procedures for the appropriate and efficient use of albumin and albumin alternatives. Institutions reviewing and updating existing local guidelines may use the University Hospital Consortium guidelines as a model for comparison.
Academic Medical Centers↗
Acute normovolemic hemodilution is a cost-effective alternative to preoperative autologous blood donation by patients undergoing radical retropubic prostatectomy.
BACKGROUND: Preoperative autologous blood donation is accepted as a standard of care for radical prostatectomy. Acute normovolemic hemodilution (ANH) is an alternative method for obtaining autologous blood. The cost and benefits of these two autologous blood-collection techniques are compared. STUDY DESIGN AND METHODS: Thirty consecutive patients scheduled for radical prostatectomy underwent ANH to a target hematocrit level of 28 percent. Blood was transfused in the perioperative period to maintain the hematocrit level > 25 percent. Hematocrit levels, transfusion outcomes and costs, and postoperative outcomes for these patients (hemodilution group) were compared with a matched patient cohort who preoperatively donated 3 units of blood for autologous use in prostatectomy surgery (nonhemodilution group, n = 30). RESULTS: Thirty patients underwent ANH to a hematocrit level of 28.7 +/- 1.7 percent, and 1740 +/- 346 mL (3.5 +/- 0.7 units) of blood were collected. Three (10%) of the patients in each cohort had allogeneic blood exposure. Transfusion costs were 73 percent higher for the nonhemodilution group patients than for the hemodilution group patients ($330 +/- $100 vs. $191 +/- $55, p < 0.001). No differences were found in postoperative outcomes. CONCLUSION: An integrated blood conservation program utilizing hemodilution and a defined transfusion trigger can decrease the requirement for preoperative donation of blood for autologous use in radical prostatectomy. Point-of-care autologous blood procurement is more cost-effective than preadmission donation of autologous blood units.
Aged↗
Preoperative autologous blood donation: benefit or detriment? A mathematical analysis.
BACKGROUND: Advocates of preoperative autologous blood donation (PABD) often fail to consider the needs of individual patients and the effects of donation on hematocrit. Mathematical modeling is used here to analyze PABD. STUDY DESIGN AND METHODS: A model of PABD was constructed to simulate the transfusion of red cells once a predetermined minimum hematocrit was reached. Preoperatively deposited units not needed to maintain a hematocrit at this level were not transfused. Final hematocrits were compared to the hematocrit that would be expected if the patient had not donated blood for his or her own operative use. RESULTS: For many patients, particularly those with normal initial hematocrits, large estimated blood losses must occur before the minimum hematocrit is reached. It is also known that patients donating multiple units typically cannot maintain their baseline hematocrit. In such cases, for blood losses of any volume, the final hematocrit was lower if units were collected preoperatively and transfusion did not occur. Preoperatively donating patients are more likely to be transfused earlier and more frequently than nondonating patients. Derived figures, based on individual patient values, help predict which patients will benefit most from PABD. CONCLUSION: PABD may actually lead to decreased postoperative hematocritis (with enhanced risk of ischemia) and otherwise unnecessary transfusions.
Blood Donors↗
Mathematical analysis of isovolemic hemodilution.
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Blood Volume↗
Correction of bone marrow nucleated cell counts for the presence of fat particles.
Although the use of bone marrow transplantation has increased greatly in recent years, the quality control procedures used in bone marrow processing laboratories remain less than ideal. Accurate marrow total nucleated cell (TNC) counts are essential for effective monitoring of bone marrow collection and processing. Aspirated marrow is variably contaminated by fat particles, resulting in overestimation of marrow TNC by automated analyzers. A recently-marketed hematological analyzer (Cobas-Helios; Roche Diagnostic Systems, Branchburg, NJ) offers the potential to correct marrow TNC counts for fat particles using available software. The authors investigated the accuracy of corrected TNC counts on 21 marrow samples, using a visual chamber count as the reference method. The correction methods studied were software correction, using the Cobas-Helios differential system, and replacement of the sample plasma with saline. Uncorrected automated marrow TNC counts (mean, 28.4 x 10(9)/L) were significantly higher than the visual reference counts (mean, 23.1 x 10(9)/L). Neither the mean corrected automated count (24.3 x 10(9)/L) nor the mean saline replaced count (24.6 x 10(9)/L) differed significantly from the mean visual reference count. For both the corrected automated and saline replaced counts, 20 of the 21 data points (95%) fell within a 95% confidence interval computed for the reference method. The authors conclude that both the corrected automated method, using the Cobas-Helios, and the saline replacement method are acceptable alternatives to the visual chamber count.
Adult↗
Transfusion-transmitted bacterial infection.
Transfusion-transmitted bacterial infection is a persistent but often underemphasized problem facing transfusion medicine today. The present status of bacterial contamination of red cells, platelet products and plasma, frequency of contamination, and types of organisms implicated is reviewed. Current methods of prevention and detection are discussed, as well as typical clinical presentations and therapy.
Anti-Bacterial Agents↗
Atypical reactions associated with use of angiotensin-converting enzyme inhibitors and apheresis.
BACKGROUND: Anaphylactic or atypical reactions, characterized by flushing, hypotension, dyspnea, and bradycardia, have been reported in patients undergoing hemodialysis, low-density lipoprotein apheresis, IgG affinity column apheresis, therapeutic plasma exchange, and desensitization immunotherapy while receiving angiotensin-converting enzyme (ACE) inhibitor therapy. STUDY DESIGN AND METHODS: Records were reviewed of 299 consecutive patients undergoing therapeutic plasma exchange with colloid replacement at the University of North Carolina Hospitals from September 1981 through December 1993. Charts were selected for further analysis if atypical reactions (flushing or hypotension defined as a mean decrease in blood pressure of 20 torr or greater) occurred during apheresis or if there was concurrent administration of an ACE inhibitor. RESULTS: Fourteen (4.7%) of 299 patients were receiving ACE inhibitor therapy at the time of apheresis; all 14 experienced an atypical reaction. In contrast, 20 (7%) of 285 patients not receiving ACE inhibitors developed atypical reactions (p < 0.001). The 14 ACE inhibitor patients accounted for 41 percent (14/34) of all patients having atypical reactions during apheresis. CONCLUSION: Patients receiving ACE inhibitor therapy who are undergoing therapeutic plasma exchange with albumin replacement solutions are at high risk (100%) for atypical reactions. It is recommended that ACE inhibitors be withheld for at least 24 hours before that procedure.
Anaphylaxis↗
Mathematical and computer modeling of acute normovolemic hemodilution.
BACKGROUND: Advocates of acute normovolemic hemodilution (ANH) frequently neglect to consider the decreasing hematocrit of the patient during both hemodilution and the subsequent operative procedure and the need to begin transfusion at some minimal hematocrit. STUDY DESIGN AND METHODS: For more accurate prediction of the efficacy of ANH, equations were derived and a computer model developed that allowed accounting for the decreasing hematocrit due to blood loss in an isovolemic patient and calculating the red cell volume on a minute-by-minute basis; the model also began the transfusion of ANH blood on a mL-for-mL basis when the minimal hematocrit was reached and transfused any remaining blood following completion of the case. The red cell volume saved by performing ANH for a given estimated blood volume (EBV) was expressed as either the fraction of the red cell volume of a routinely banked unit of blood (red cells stored in additive solution: volume 350 mL, hematocrit 0.65) or the number of units saved. RESULTS: The number of units saved in a typical example--EBV, 5000 mL; pre-ANH hematocrit, 0.40; minimal hematocrit at which transfusion was begun, 0.25 over a range of estimated blood losses (500-2500 mL); and 1 to 5 ANH units drawn--never exceeded 0.6. Even with extensive hemodilution, as in a child (EBV, 1500 mL; pre-ANH hematocrit, 0.40; minimal hematocrit at which transfusion was begun, 0.15; 5 units drawn; and estimated blood losses, 2500, 1500, and 1000 mL) with a postdilution hematocrit of 0.16, the savings would have been only 0.29, 0.44, and 0.49 units, respectively. CONCLUSION: Because of the decreasing hematocrit in a bleeding isovolemic patient and the need to begin transfusion at some minimal hematocrit, the theoretic savings in red cell volume attributable to ANH is less than had previously been appreciated, and additional ANH does not necessarily result in additional patient benefit.
Blood Transfusion↗
Platelet bacterial contamination and the use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe.
BACKGROUND: Currently, the maximum outdate for platelets is 5 days, because of the increasing chance of bacterial growth over time. Various methods for rapid detection of bacterial contamination of blood components have been described, with mixed results and no general acceptance. A recently described, molecular biologic approach for the detection of bacterial contamination involves a chemiluminescence-linked universal DNA bacterial probe to a highly conserved bacterial region of ribosomal RNA (rRNA). STUDY DESIGN AND METHODS: A multicenter trial of a chemiluminescence-linked universal bacterial rRNA probe for the detection of bacterial contamination in platelet concentrates is described. At each of five sites, platelet concentrates (no older than 1 day from date of phlebotomy) were inoculated in triplicate with isolates of four bacterial species (Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus epidermidis, and Staphylococcus aureus) to a final concentration of 10 to 50 colony-forming units (CFUs) per mL and in triplicate to a final concentration of 1000 CFUs per mL. At one site, an additional 6 platelet concentrates were inoculated with sterile saline to serve as controls. Inoculated units were then subjected periodically to quantitative cultures and probe analyses. A total of 126 platelet concentrates were studied over a period of 7 days (120 inoculated with bacteria and 6 with sterile saline). RESULTS: This assay was, in some cases, able to detect S. aureus bacterial contamination in the range of 100 to 1000 CFUs per mL; the majority of samples (B. cereus, P. aeruginosa, S. aureus, and S. epidermidis) with contamination exceeding 10(4) CFUs per mL; and all samples with contamination of 2.1 x 10(5) CFUs per mL or greater. Increasing the sample size from the recommended 0.4 mL to 1.0 mL resulted in an unacceptable loss of specificity (83.3%). CONCLUSION: The routine use of this assay would be expected to result in a decreased risk of septic platelet transfusion reactions and could lead to a lengthening of the current 5 day storage period for platelets. Further, the pooling of random-donor platelet concentrates before storage instead of immediately before transfusion may be possible if this rRNA probe is employed to detect bacteria in the pool.
Bacillus cereus↗
Blood volume determination as a function of hematocrit and mass in three preservative solutions and saline.
Accurate blood volume determination is useful both clinically and in research. In many instances, however, direct measurement of blood volume is impractical due to the risk of bacterial contamination. For this reason, mass is often used to estimate volume. The relationship between mass and volume (density) varies with different suspension solutions and hematocrits. In this paper, equations are derived to calculate volume as a function of hematocrit and mass for pooled red cells suspended in four solutions: CPD plasma (whole blood), additive solutions 1 and 3 (AS-1 and AS-3), and saline. To validate this approach, the actual versus predicted blood volumes in 10 individual blood samples suspended in either AS-1 or saline are compared. The equations predict the volume of blood to within 0.5% and 1.0% in samples with low/normal and high hematocrits (15% to 85%, respectively). Use of these equations allow for accurate and rapid conversion of mass to volume for these blood products.
Blood Preservation↗
Effects of 3-5 log10 pre-storage leucocyte depletion on red cell storage and metabolism.
A new, in-line high-efficiency 3-5 log10 leucodepletion filter system (Leukotrap RC system) was used to investigate the effect of pre-storage white cell removal on the quality of AS-3 red cell concentrates stored for 42 d at 4 degrees C. Median residual white cell content was 4 x 10(5) when filtration was performed at 22 degrees C within 8 h of phlebotomy (n = 20) and 3.2 x 10(4) when filtration was performed at 4 degrees C 12-24 h after phlebotomy (n = 24). None exceeded 1 x 10(6) WBC per red cell product. Filtration was rapid (median 28 min), and red cell loss averaged (mean +/- 1 SD) 6.4 +/- 0.7%. In a paired study design, post-transfusion recoveries of 42 d stored red cells in the filtered units averaged 84 +/- 6% v 82 +/- 8% for unfiltered units (P < 0.05) and post-storage haemolysis. ATP, osmotic fragility, K+ and pH were significantly (P < 0.05) better in the filtered units. Reduced glycolytic activity was also observed in the filtered units, and there was a correlation between osmotic fragility, glucose consumption, and lactate produced in standard units that was not present in leucodepleted units. In conclusion, this study suggests that leucodepletion of AS-3 red cell concentrates prior to storage results in better maintenance of the integrity of the red cell membrane with reduced glycolytic activity. There was a modest improvement in post-infusion viability sufficient to offset the filtration-induced loss and to result in an equivalent red cell product.
Adenosine Triphosphate↗
Microwave elution of red cell antibodies.
Using a commercial microwave oven (750 W, 2,450 MHz), we compared the use of microwave energy to the commonly used method of acid-glycine elution (Elu-Kit II, Gamma Biologicals, Houston, Tex., USA) to elute antibodies from direct antiglobulin test positive red blood cells (RBC). Using a 33% suspension of RBCs in cold saline (1-6 degrees C) in a polypropylene test tube, the microwave technique was comparable for eluting Rh (except anti-c and anti-e) and Kell and superior for eluting Duffy, Kidd antibodies while acid-glycine was superior in eluting S and s antibodies. Consistent results were obtained using the microwave technique when the RBC suspension reached temperature of 57-64 degrees C. Heat or the rate of temperature rise appears to play an important role in the microwave elution process although other not yet identified microwave properties may also be a factor. Microwaves are a quick (8 s) alternative to well-established methods of elution and have shown to give consistent results in our study. Commercially available microwave ovens vary substantially in power, making it necessary to perform an initial calibration of the microwave in order to determine a location within the microwave cavity where exposure to microwaves will consistently achieve temperatures of 57-64 degrees C in all cell suspensions.
Acids↗
Relationship of hemoglobin level and duration of hospitalization after total hip arthroplasty: implications for the transfusion target.
We analyzed the relationship of hemoglobin level and duration of hospitalization of patients who underwent primary cemented total hip arthroplasty for degenerative joint disease at our institution. Retrospectively, we reviewed the medical records of 332 patients treated during a 16-month period (May 6, 1989, to Aug. 20, 1990). The following variables were analyzed: number of postoperative days to dismissal from the hospital, level of hemoglobin preoperatively and at dismissal, decrease in hemoglobin level from preoperatively to time of dismissal, patient age, surgeon, and blood products transfused. No correlation was found between level of hemoglobin at dismissal, preoperative hemoglobin level, or decrease in hemoglobin concentration from preoperatively to time of dismissal and number of days to dismissal from the hospital. Advanced age was associated with a longer hospital stay. A slight but statistically significant difference was noted in duration of hospitalization among patients operated on by different surgeons. Patients who received both autologous and homologous blood required more transfusion (3.8 units) and had a longer hospital stay (10.7 days) than did patients who received autologous blood only (2.4 units and 9.5 days) or homologous blood only (2.6 units and 10.2 days). We conclude that variation in hemoglobin levels among patients in our study was unrelated to duration of hospitalization. This finding suggests that transfusion of autologous or homologous blood to achieve a higher hemoglobin level (higher transfusion target) solely for shortening hospital stay is unwarranted.
Age Factors↗
The use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe and blood gas analysis for the rapid detection of bacterial contamination in white cell-reduced and nonreduced platelets.
Because of the rising incidence of bacterial growth and septic platelet transfusions in aging units, platelet storage is currently limited in the United States to 5 days. This approved shelf life of platelets might be altered if methods were devised to rapidly detect infected units and/or to decrease the incidence of bacterially contaminated platelets. An investigation was conducted on the effect of a prototype blood collection system with an in-line filter for the production of white cell-reduced platelet-rich plasma on the growth of bacteria in platelets prepared from whole blood that had been inoculated with Staphylococcus epidermidis. Additional studies were conducted with a chemiluminescence-linked ribosomal RNA (rRNA) gene probe and with blood gas analysis to identify possible methods for the rapid detection of bacterial contamination. All units were followed for 9 days of storage. The filtration of the platelet-rich plasma resulted in an approximate 2 log10 reduction in white cells with an average loss of 6.7 percent of platelets. Filtration did not appear to alter bacterial growth. In all platelet units that supported growth, pO2 dropped to negligible values and pCO2 rose relative to culture-negative units. The changes were most sensitive and specific beyond 5 days of storage. The universal bacterial rRNA probe assay was able to detect S. epidermidis in concentrations as low as 1 x 10(3) colony-forming units per mL in some cases and reliably detected all units contaminated at a concentration of 1 x 10(4) colony-forming units per mL.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Gas Analysis↗
Microwave dissociation of antigen-antibody complexes: a new elution technique to permit phenotyping of antibody-coated red cells.
To evaluate the effectiveness of microwave irradiation in dissociating IgG from red cells (RBCs), the use of chloroquine diphosphate (CDP) was compared to that of microwaves. Fifteen paired samples of RBCs from 15 patients with positive direct antiglobulin tests (DATs) were treated with both CDP and microwave radiation. Total microwave exposure times ranged from 20 to 100 seconds. Posttreatment DATs were performed, and the reaction grades of the posttreatment DATs were compared. RBC phenotyping was also performed on repeatedly microwaved RBCs to demonstrate possible effects on RBC antigen expression. Microwaves successfully reduced the reaction grade of the DAT in 14 of 15 samples; CDP reduced the reaction grade in 12 of 15 samples. In samples with a DAT of 2+ or greater (n = 13), the microwave method yielded a greater reduction in DAT strength in six cases (results in the other 7 cases were identical with both methods) (p = 0.01). Five of eight cases with a DAT of 3+ showed a greater reduction in the DAT with microwave treatment than with CDP treatment; results in the remaining three cases were identical (p = 0.03). RBC antigenicity remained unchanged after exposure to microwave radiation (A, B, C, c, D, E, e, Fya, Fyb, Jka, Jkb, K, k, S, and s). Microwave treatment required less than 10 minutes per sample, while CDP treatment required 30 to 120 minutes per sample (mean, 88 min). The microwave technique of antigen-antibody dissociation from RBCs provides a rapid and accurate method of facilitating the phenotyping of RBCs coated with warm autoantibodies and is superior to other methods, which destroy RBC antigens.(ABSTRACT TRUNCATED AT 250 WORDS)
Antigen-Antibody Complex↗