Mark E. Brecher

Dose of Prophylactic Platelet Transfusions and Prevention of Hemorrhage

BACKGROUND We conducted a trial of prophylactic platelet transfusions to evaluate the effect of platelet dose on bleeding in patients with hypoproliferative thrombocytopenia. METHODS We randomly assigned hospitalized patients undergoing hematopoietic stem-cell transplantation or chemotherapy for hematologic cancers or solid tumors to receive prophylactic platelet transfusions at a low dose, a medium dose, or a high dose (1.1x10(11), 2.2x10(11), or 4.4x10(11) platelets per square meter of body-surface area, respectively), when morning platelet counts were 10,000 per cubic millimeter or lower. Clinical signs of bleeding were assessed daily. The primary end point was bleeding of grade 2 or higher (as defined on the basis of World Health Organization criteria). RESULTS In the 1272 patients who received at least one platelet transfusion, the primary end point was observed in 71%, 69%, and 70% of the patients in the low-dose group, the medium-dose group, and the high-dose group, respectively (differences were not significant). The incidences of higher grades of bleeding, and other adverse events, were similar among the three groups. The median number of platelets transfused was significantly lower in the low-dose group (9.25x10(11)) than in the medium-dose group (11.25x10(11)) or the high-dose group (19.63x10(11)) (P=0.002 for low vs. medium, P<0.001 for high vs. low and high vs. medium), but the median number of platelet transfusions given was significantly higher in the low-dose group (five, vs. three in the medium-dose and three in the high-dose group; P<0.001 for low vs. medium and low vs. high). Bleeding occurred on 25% of the study days on which morning platelet counts were 5000 per cubic millimeter or lower, as compared with 17% of study days on which platelet counts were 6000 to 80,000 per cubic millimeter (P<0.001). CONCLUSIONS Low doses of platelets administered as a prophylactic transfusion led to a decreased number of platelets transfused per patient but an increased number of transfusions given. At doses between 1.1x10(11) and 4.4x10(11) platelets per square meter, the number of platelets in the prophylactic transfusion had no effect on the incidence of bleeding. (ClinicalTrials.gov number, NCT00128713.)

Bacterial Contamination of Blood Components

SUMMARY Blood for transfusion is a potential source of infection by a variety of known and unknown transmissible agents. Over the last 20 years, astounding reductions in the risk of viral infection via allogeneic blood have been achieved. As a result of this success, bacterial contamination of blood products has emerged as the greatest residual source of transfusion-transmitted disease. This paper summarizes the current status of detection, prevention, and elimination of bacteria in blood products for transfusion.

Transfusion medicine: looking to the future

The evolution of transfusion medicine into a clinically oriented discipline emphasising patient care has been accompanied by challenges that need to be faced as specialists look to the future. Emerging issues that affect blood safety and blood supply, such as pathogen inactivation and more stringent donor screening questions, bring new pressures on the availability of an affordable blood supply. Imminent alternatives for management of anaemia, such as oxygen carriers, hold great promise but, if available, will require close oversight. With current estimates of HIV or hepatitis C viral (HCV) transmission approaching one in 2000000 units transfused, keeping to a minimum bacterial contamination of platelet products (one in 2000) and errors in transfusion, with its estimated one in 800000 mortality rate, assume great urgency. Finally, serious difficulties in blood safety and availability for poor, developing countries require innovative strategies and commitment of resources.

A standardized method for calculating blood loss

BACKGROUND: The estimation of blood loss for a surgical procedure is both poorly reproducible and typically underestimated. Therefore, comparison of surgical transfusion outcomes such as blood loss and amount of blood transfused from one institution to another, or from one surgeon to another, is difficult. Recently, mathematical modeling has contributed to our understanding of transfusion strategies. STUDY DESIGN AND METHODS: A mathematical model of blood loss for a surgical hospitalization was developed on the basis of recently described mathematical principles for blood loss and hemodilution. The model was designed so that the calculation of blood loss would be based on easily measured factors such as the patients blood volume, the number and type of red cell units transfused, the initial hematocrit, the discharge hematocrit, the transfusion trigger, the volume of intraoperatively salvaged blood transfused, and the amount of hemodilution performed. The calculated blood loss was then compared with the intraoperative blood loss actually estimated by the anesthesiologist in 250 consecutive patients who underwent radical retropubic prostatectomy. RESULTS: The mathematical equations were placed in a computer model to allow rapid calculation of a particular patients blood loss. Figures were derived from the computer modelling to facilitate rapid manual calculation of the blood loss. There was a significant relation (p < 0.001) between the calculated blood loss for the hospitalization and the estimated intraoperative blood loss. However, the calculated blood loss was on average 2.1 times the intraoperative blood loss estimated by the anesthesiologist. CONCLUSION: The use of such mathematical modeling to rapidly estimate a patients blood loss has the potential to allow ready, objective comparisons between sites and even surgeons. It also allows for a more judicial and informed decision as to what (if any) blood should be available or what blood‐conservation techniques should be employed for a specific patient.

Evaluation of an automated culture systemfor detecting bacterial contamination of platelets: an analysis with 15 contaminating organisms

BACKGROUND: Approximately 1 in 2000 platelet components are bacterially contaminated. The time to detection of 15 seeded organisms in platelets recovered from an automated culture system was studied.

a Prospective Randomized Comparison of Three Blood Conservation Strategies for Radical Prostatectomy

BACKGROUND Preoperative autologous blood donation is a standard of care for elective surgical procedures requiring transfusion. The authors evaluated the efficacy of alternative blood-conservation strategies including preoperative recombinant human erythropoietin (rHuEPO) therapy and acute normovolemic hemodilution (ANH) in radical retropubic prostatectomy patients. METHODS Seventy-nine patients were prospectively randomized to preoperative autologous donation (3 U autologous blood); rHuEPO plus ANH (preoperative subcutaneous administration of 600 U/kg rHuEPO at 21 and 14 days before surgery and 300 U/kg on day of surgery followed by ANH in the operating room); or ANH (blinded, placebo injections per the rHuEPO regimen listed previously). Transfusion outcomes, perioperative hematocrit levels, postoperative outcomes, and blood-conservation costs were compared among the three groups. RESULTS Baseline hematocrit levels were similar in all groups (43%+/-2%). On the day of surgery hematocrit decreased to 34% +/-4% in the preoperative autologous donation group (P < 0.001), increased to 47%+/-2% in the rHuEPO plus ANH group (P < 0.001), and remained unchanged at 43%+/-2% in the ANH group. Allogeneic blood exposure was similar in all groups. The rHuEPO plus ANH group had significantly higher hematocrit levels compared with the other groups throughout the hospitalization (P < 0.001). Average transfusion costs were significantly lower for ANH (

Growth of bacteria in inoculated platelets: implications for bacteria detection and the extension of platelet storage

194+/-

United States thrombotic thrombocytopenic purpura apheresis study group (US TTP ASG): Multicenter survey and retrospective analysis of current efficacy of therapeutic plasma exchange

192) compared with preoperative autologous donation (

Protecting the Blood Supply From Emerging Pathogens: The Role of Pathogen Inactivation

690+/-

Acute normovolemic hemodilution is a cost-effective alternative to preoperative autologous blood donation by patients undergoing radical retropubic prostatectomy

128; P < 0.001) or rHuEPO plus ANH (