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Transfusion Bulletin

Update

Author(s): (Various Authors)

Vol. 12, No. 2 (2004-08 - 2004-08)

Performance of time-series methods in forecasting the demand for red blood cell transfusion

* A. Pereira
Transfusion, 2004, 44: 239-746

Planning the future blood collection efforts must be based on adequate forecasts of transfusion demand. In this study, univariate time-series methods were investigated for their performance in forecasting the monthly demand for RBCs at one tertiarycare, university hospital. Three time-series methods were investigated: autoregressive integrated moving average (ARIMA), the Holt-Winters family of exponential smoothing models, and one neural - network - based method. The time series consisted of the monthly demand for RBCs from January 1988 to December 2002 and was divided into two segments: the older one was used to fit or train the models, and the younger to test for the accuracy of predictions. Performance was compared across forecasting methods by calculating goodness-of-fit statistics, the percentage of months in which forecast-based supply would have met the RBC demand (coverage rate), and the outdate rate. The RBC transfusion series was best fitted by a seasonal ARIMA (0,1,1) (0,1,1)12 model. Over 1-year time horizons, forecasts generated by ARIMA or exponential smoothing laid within the ± 10 percent interval of the real RBC demand in 79 percent of months (62% in the case of neural networks). The coverage rate for the three methods was 89, 91, and 86 percent, respectively. Over-2-year time horizons, exponential smoothing largely outperformed the other methods. Predictions by exponential smoothing laid within the ±10 percent interval of real values in 75 percent of the 24 forecasted months, and the coverage rate was 87 percent. Over 1-year time horizons, predictions of RBC demand generated by ARIMA or exponential smoothing are accurate enough to be of help in the planning of blood collection efforts. For longer time horizons, exponential smoothing outperforms the other forecasting methods.


HB Content-based Transfusion Policy successfully reduces number of RBC units Transfused

Arslan, S. Toprak, M. Arat and Y. Kayalak
Transfusion, 2004 : 44 : 485-488

RBC transfusions should be based on Hb content of the products instead of units. As high as a 50-percent difference in Hb content can be encountered between two units. In this study, 500 mL of whole blood (WB)-generated RBCs according to their total Hb content was used to decrease the number of units ordered by using a new software called Hemosoft. Fifty-one consecutive patients were enrolled for the study. The median age and male-to-female ratio were 38 (range, 16-69) and 28:23, respectively. Patients‘ diagnoses were 38 acute leukemia, 11 lymphoma, and 2 multiple myeloma. When placing orders for RBCs, clinicians were asked to sent the information about patient`s actual body weight (ABW) and their actual and target Hb. The total blood volume of the recipient was calculated, and the aim was to find the best RBCs from the inventory to decrease two-unit orders to one unit, or four units to two or one unit, all done using Hemosoft. Posttransfusion Hb was checked 2 hours after transfusion. ABW and the median pretransfusion Hb level were 64 kg (range, 40-100) and 7.3 g per dL (5.5-9.8), respectively. A total of 104 RBC units were ordered for 51 patients. In 49 (96.1%), the order was for two units and in 2 (3.9%) was for three units. Hemosoft successfully found a suitable match in 62.7 percent (32/51) of the orders. Actual number of RBCs transfused was two units (41.25) and one unit (58.8%), respectively. In total, 72 units were transfused with a reduction of 30 percent (72/104) from the original order. The median target Hb level was 9.3 g per dL (range, 7.0-11.3) and overall success rate to achieve it was 96.6 percent (range, 73.8-124.2). There was no impact of inventory size, but the ABW of the recipient was found significant to have a successful match unit (58.8 ± 11.0 kg vs. 75.0 ±8.4 kg, respectively; p = 0.0001.) We clearly demonstrated that the number of RBC transfusions could be minimized by the rational use of the Hb content of the units. Although the total numbers of patients who shall benefit from this approach seems to be limited, it allows us to use high-Hb-content units rationally by using anin-house blood-banking software.


Transfusion-Transmitted Bacterial Infection: Risks, Sources and Interventions

S. J. Wagner
Vox Sanguinis (2004) 86, 157-163

Records of the transmission of bacterial infections by transfusion date back to the beginning of organized blood banking. Despite tremendous strides in preventing viral infection through careful donor screening and viral testing, there has been little improvement in reducing the risk of bacterial sepsis since the introduction of closed collection systems. Based on the French Haemovigilance study, the British Serious Hazards of Transmission (SHOT) study and fatality reports to the United States Food and Drug Administration, the risk of clinically apparent sepsis exceeds the risk of HIV, HBV and HCV transmission. Sources of contamination include the skin, blood, disposables and the environment. Potential interventions to reduce transfusion-associated bacterial sepsis include improvements to donor arm preparation, diversion of the first aliquot of whole blood, introduction of bacterial testing and/or implementation of pathogen reduction methods.


Enhancing the Evidence Base for HIV/AIDS control in India

Lalit Dandona
Nati MED J India 2004; 17:160-6

An optimum evidence base is necessary for the effective control of HIV/AIDS in India, as the lack of an adequate evicence base on critical issues leads to controversy and hurdles. To assess the trends in the HIV/AIDS evicence base for India, a PubMed literature search for publications from India in 2002 and 2003 on HIV/AIDS was done, and absracts from India in one major international HIV/ AIDS conference in 2002, and presentations at one major HIV/AIDS conference in India in 2003 were reviewed. The PubMed search revealed 145 papers with abstracts on HIV/AIDS from India during this period, which was 1.4% of the worldwide HIV/ AIDS publications. Of these 145 publications, 124 (85.5%) were based on original research and, of these, 27.4% were in the basic sciences, 62.9% in the clinical sciences, and 9.7% in the public health sciences; 53.2% of the original research papers were published in journals with impact factors ranging from 0 to 1. Many vital issues for HIV control, such as validation of the methods used to assess HIV burden in the population, large-scale impact assessment of HIV prevention programmes, post-effectiveness of HIV interventions, and critical evidence-to-policy issues, were not covered. Of the 8824 abstracts accepted for presentation at the XIV International AIDS Conference 2002 at Barcelona, 8% were from India-a fair representation given that India has about 10% of the world` HIV burden. However, the utility of this information is severely limited with the majority of it not getting translated into detailed papers in the peer-reviewed literature for widespread scrutiny and use. The views expressed by many experts at the Fourth International Conference on AIDS India 2003 at Chennai were impressive, but the presentation and discussion on original research data from India were sparse. From these various sources, it is estimated that the available evidence base for HIV/AIDS control in India is suboptimal. Using certain assumptions, it is estimated that to provide an adequate evidence base for the control of HIV/ AIDS in India, quality original HIV/AIDS research in India would have to double in the basic and clinical sciences, and increase by more than 5 times for the public health sciences. Enhancing this evidence base to an optimum level would require optimizing its demand, systematically planning its supply locally in India and creating an environment suitable for its development. To effectively control HIV/AIDS in India, strategic planning is needed to develop an evidence base that covers all critical areas where information is needed. Formation of a Society for HIV/AIDS Research in India by involving all the major stakeholders could help build up momentum towards establishing a comprehensive, relevant, dynamic and long term evidence base that provides rigorous and timely information needed for HIV/AIDS control.


Current Performance of Patient Sample Collection in the UK

M.F. Murphy, B.E. Stearn and W.H. Dzik
Transfusion Medicine, 2004, 14 113-121

Collection of the patient sample for pre-transfusion testing begins a complex chain of events in the transfusion process. Hospitals in England and North Wales were surveyed to compare local policies against recommendations of the British Committee for Standards in Haematology (BCSH). Hospitals also measured the frequency of rejected and miscollected samples designated as wrong blood in tube (WBIT). 185 of 360 (51.4%) hospitals returned questionnaires and 182 of 185 (98%) hospitals reported that a policy for sample collection existed. Apart from frequent omission of the gender of the patient there was 96% compliance with all mandatory identifies of the BCSH guidelines. Practice allowing additions or changes to labeling on sample tubes and request forms varied. 3.2% of samples submitted were rejected for various reqsons the most frequent being incomplete or missing information (49.5% of the total rejected samples). The corrected mean frequency for WBIT in the 27 hospitals with one or more observed WBIT was 1 in 1501 samples and the median corrected frequency for WBIT was 1 in 1303 samples. This study has identified great variation in the policy and practice for sample collection for pre-transfusion testing. Regular tracking of the rates of sample rejection and WBIT could be used to identities poor performance in individual hospitals requiring investigation and action.


Platelet Function Testing to Assess Effectiveness of Platelet Transfusion Therapy

Mohamed E. Salarna, Sundara Raman, Mary Jo Drew,
Majdi Abdel-reheem, Muhammad N. Mahmood.
Transfusion and Apheresis Science (30)2004, 93-100

Post transfusion corrected count increments (CCI) following administration of platelets is the standard method for assessing effectiveness of platelet transfusion therapy. However improvement in platelet count following transfusion may not necessarily indicate improvement in platelet function or restoration of primary haemostatic capacity. To address this possibility, we investigated the effectiveness of platelet transfuse on based on results of the platelet function Analyzer (PFA-100) and post-transfusion CCI. Platelet transfusion requests with different indications received at the blood bank were evaluated for inclusion in the investigation. Pre-transfusion, the following laboratory tests were performed:

  1. PFA-100 assays (blood collected in 3.2% buffered sodium citrate) performed with CEPI and CADP test cartridges:
  2. complete blood count (in EDTA) and platelet count.
  3. routine coagulation profile including PT. PTT., fibrinogen and D-Dimer.

Only patients with normal coagulation profile were included. The same set of tests were performed on a new blood sample collected 10-60 min post transfusion. Chart review and clinical evaluation for response to platelet therapy were performed on each occasion of transfusion.

Thirty one patients; 5 of whom were transfused on more than one occasion were evaluated 35 transfusion incidents were included, post transfusion outcomes were divided in to two groups. Those that resulted in shortening (>40 s) or normalization of the closure time(Group A) and those that had no change or greater prolongation of the closer time (Group B) when compared to the pre transfusion value. 17 and 18 transfusion episodes were categorized as Group A and Group B respectively. In Group A with improved PFA testing. Nine patients had bleeding as indication for transfusion and six of these had on concomitant improvement in their clinical picture as confirmed by control of hemorrhage. In contrast in group B with no improvement in PFA testing. Seven patients had bleeding as indication for transfusion and none showed occasion of hemorrhagic symptoms. These findings were statistically significant (p=0.0114). Similar evaluation using the post transfusion CCI showed no correction to bleeding symptoms in these patients (p=0.500). In this evaluation platelet function testing using the PFA. 100 provided a better indication of transfusion outcome than did the post transfusion CCI. Using this approach, PFA. 100 may be art an effective aid for assessing effectiveness of platelets functions.

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