Current uses of transfusion administration sets: a cause for concern?

There is potential for inappropriate use of transfusion administration sets when used in combination with modern infusion pumps with consequences for patient safety. The aims of our study were to (i) establish if the design and testing of transfusion sets specified in International Standard ISO 1135-4 are adequate for their current applications, (ii) identify if infusion pumps currently supplied in the UK for blood component administration are suitable for this purpose and (iii) determine the additional control measures needed to be applied by manufacturers and users to ensure patient safety. Keyword literature search was carried out to review and correlate important transfusion parameters with resultant adverse effects. Units for occlusion pressure, flow rate and haemolysis were standardised for ease of comparison. A sample of transfusion set instructions for use was reviewed. Principal suppliers of infusion pumps to the UK market were surveyed to identify those sold for blood transfusion, their recommended operating parameters and compatible transfusion sets. Previous work showed clinically unacceptable haemolysis at pressures above 40 kPa. Modern infusion pumps operate under negative pressures of up to 210 kPa. ISO 1135-4 design and test requirements do not match this performance and in particular omit testing under negative pressure. Transfusion sets surveyed did not indicate flow or pressure restrictions or specify the blood components with which they had been validated. ISO 1135-4 requires updating and has been initiated. Meanwhile, recommendations are made for transfusion set manufacturers concerning pressure limitations and restrictions on blood component type and for users concerning purchase, configuration and validation of infusion pumps and disposables.

When and why is blood crossmatched? A prospective survey of transfusion laboratory practice in two regions in the north of England.

BACKGROUND AND OBJECTIVES: This study was undertaken to provide data relating to the timing of laboratory crossmatch procedures, and the source of requests for out of hours crossmatch, to support interpretation of error reports originating in the transfusion laboratory, received by the Serious Hazards of Transfusion haemovigilance scheme. MATERIALS AND METHODS: Data on the timing, origin and urgency of all crossmatch requests were collected in 34 hospitals in northern England over a 7-day period in 2008. Additional data on clinical urgency were collected on crossmatches that were performed out of hours. RESULTS: Data were obtained on 2423 crossmatches, including 610 (25.2%) performed outside core hours. 30.3% of out of hours crossmatch requests were for transfusions that were set up outside 4 h of completion of the crossmatch. CONCLUSION: 2008 Serious Hazards of Transfusion data showed that 29/39 (74%) of laboratory errors resulting in 'wrong blood' occurred out of hours whilst our audit shows that only 25% of crossmatch requests are made in that time period, suggesting that crossmatching performed outside core hours carries increased risks. The reason for increased risk of error needs further research, but 25 laboratories had only one member of staff working out of hours, often combining blood transfusion, haematology and coagulation work. A total of 25% of out of hours requests were not clinically urgent. Hospitals should develop policies to define indications for out of hours transfusion testing, empower laboratory staff to challenge inappropriate requests and ensure that staffing and expertise is appropriate for the workload at all times.

Massive transfusion--evaluation of current clinical practice and outcome in two large teaching hospital trusts in Northern England.

BACKGROUND AND OBJECTIVES: Although numerous guidelines exist for the management of massive blood loss, there have been few data confirming whether these guidelines are observed in practice or whether compliance results in improved outcome. We have performed a retrospective audit of cases of massive transfusion in two major teaching hospital trusts in Northern England to investigate the use of blood components and patient outcome. MATERIALS AND METHODS: The massive transfusion population was electronically derived from a list of all blood component transfusions in 2006. Data from the intensive care and patient administration databases established hospital outcome. Factors independently predictive of survival were identified by logistic regression. Data are presented as medians and interquartile ranges. Odds ratios (OR) are given with 95% confidence intervals. RESULTS: Two hundred and four patients had a massive transfusion. Although only 1.3% of all transfused patients, the massive transfusion group used 10% of the total blood products. Their mortality rate was 34%. Factors independently predictive of survival were: a ratio of fresh frozen plasma: red blood cells > 1.1, OR 7.22 (1.95-26.68), and elective surgery, OR 4.56 (1.88-11.05). Factors independently predictive of death were: age (per year), OR 0.97 (0.95-0.99), liver disease, OR 0.25 (0.09-0.70), male gender, OR 0.41 (0.19-0.89), vascular surgery, OR 0.34 (0.12-0.96) and number of adult packs of platelets transfused, OR 0.69 (0.57-0.83). CONCLUSION: Massive transfusion occurs rarely but has a high mortality and requires a disproportionate amount of blood products. An increased ratio of fresh frozen plasma to red blood cells was associated with improved outcome.

American fresh frozen plasma for neonates and children.

From the spring of 2004 the United Kingdom Blood Services have been importing fresh frozen plasma from United States donors for all neonates and children born after 1 January 1996. The decision to mandate the use of American plasma in this age group was taken by the Department of Health in 2002 as part of its precautionary approach to the risk of transfusion transmitted variant Creutzfeldt-Jakob disease. In this article we explain the background to this decision and explore some of the implications it raises for clinical practice.

A modified Kleihauer technique for the quantification of foetomaternal haemorrhage.

The Kleihauer technique, based on acid elution of maternal red cells, is the mostly widely used technique in the UK to screen for, and estimate the volume of, foetomaternal haemorrhage (FMH) and for determining the need for additional doses of anti-D immunoglobulin to prevent maternal alloimmunization. However, technicians often report difficulties in identifying and accurately counting maternal red cells in the blood film, leading to imprecision in the calculated FMH. In this report, we describe a simple modification of the standard Kleihauer technique, based on performing acid elution of only half of the film. Compared to the standard method, the modified technique showed improved accuracy and reduced interobserver variability across a range of simulated FMH volumes. There was a high degree of correlation between the new technique and FMH estimated by flow cytometry (r2 = 0.916, P < 0.001). Technicians found the new technique easy to incorporate into routine practice in a busy teaching hospital laboratory and were impressed by the relative ease of counting maternal ghost cells. The modified technique has been used routinely in our laboratory for 3 years, during which time our performance in the UK National External Quality Assurance Scheme for FMH has been uniformly satisfactory.

MRI of perineural extramedullary granulocytic sarcoma.

Granulocytic sarcoma is an extramedullary solid tumour consisting of myelogenous leukaemic blast cells, usually seen in acute myeloid leukaemia and less commonly in patients with chronic myeloid leukaemia or myeloproliferative disorders. Blast cells have a predilection for periosteal and perineural regions and rarely precede evidence of systemic disease. We present two patients, aleukaemic on peripheral blood counts, both at presentation and during subsequent treatment. We present the MRI features of this rare but important condition.

Chronic disseminated intravascular coagulopathy cured by abdominal aortic aneurysm repair.

Disseminated intravascular coagulopathy (DIC) may rarely be caused by a previously asymptomatic abdominal aortic aneurysm (AAA). The authors describe a recent case where repair of the AAA provided a complete cure for the patient's bleeding tendency. The multidisciplinary management of this patient is presented, and the evidence for the rare causal role of AAA in DIC is discussed. Coagulation disorders in aneurysm patients are probably under-reported, and warrant careful perioperative assessment.

Haemochromatosis: a time for guidelines?

Hereditary haemochromatosis is an autosomal recessive metabolic abnormality which causes excessive absorption of dietary iron. Iron accumulation leads to potentially fatal damage to organs such as the heart, liver and pancreas. Normal life expectancy can be restored simply by therapeutic venesection. Discovery of the gene, HFE, has rekindled interest in pathogenesis, management and screening strategies.

Lymphocyte subset analysis and glycosylphosphatidylinositol phenotype in patients with paroxysmal nocturnal hemoglobinuria.

Using multicolor flow-cytometry we have examined 19 patients with paroxysmal nocturnal hemoglobinuria (PNH) (18 with active disease and 1 spontaneous remitter) to determine absolute numbers of lymphocyte subsets and the proportion of glycosylphosphatidylinositol (GPI)-deficient clones amongst these subpopulations. Lymphocyte subsets were abnormal in all patients; the most frequent findings were low absolute numbers of natural killer (NK) cells (median, 0.08 x 10(9)/L; normal range, 0.2 to 0.4 x 10(9)/L) and low absolute numbers of B cells (median, 0.05 x 10(9)/L; normal range, 0.06 to 0.65 x 10(9)/L). GPI-deficient B, T, and NK cells were identified in 88%, 84%, and 89% of patients, respectively. The proportion of GPI-deficient cells within individual lymphoid lineages was highly variable, though in most patients the percentage of GPI-deficient NK cells was considerably higher than B or T cells. These observations can be explained when mechanisms of normal lymphopoiesis are considered. Despite these quantitative and qualitative abnormalities, no patients suffered an excessive number or severity of infections. The detection of PNH clones amongst all lymphocyte lineages may provide important information regarding the natural history of the disease and additional insights into kinetics of adult lymphopoiesis.

Five-year follow-up of a prospective randomised multi-centre trial of weekly chemotherapy (CAPOMEt) versus cyclical chemotherapy (CHOP-Mtx) in the treatment of aggressive non-Hodgkin's lymphoma. Central Lymphoma Group.

BACKGROUND: Weekly alternating regimen known as CAPOMEt is compared to standard cyclical chemotherapy (CHOP-Mtx) in aggressive non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Three hundred and eighty-one patients with aggressive NHL were randomised to receive either cyclophosphamide, doxorubicin, vincristine, prednisone and methotrexate (CHOP-Mtx) on a cyclical basis or a weekly regimen incorporating the same drugs with the addition of etoposide (CAPOMEt). RESULTS: After pathological review, 281 patients were deemed eligible. At the census date of 31 March 1994, 158 patients were alive with a median follow up of 5.9 years (minimum 3.0 years). Analysis of all patients and eligible patients showed no significant treatment differences in the rates of complete remission (CR), failure free survival (FFS) or overall survival (OS) between the two arms. The actuarial median OS was 24 months for CAPOMEt compared with 31 months for CHOP-Mtx, with five-year actuarial survival rates of 37% and 43%, respectively. Myelosuppression was significantly more severe with CHOP-Mtx and neurotoxicity was much more common with CAPOMEt. CONCLUSION: Weekly CAPOMEt is equally effective as standard cyclical CHOP-Mtx treatment in aggressive NHL.

Circulating primitive stem cells in paroxysmal nocturnal hemoglobinuria (PNH) are predominantly normal in phenotype but granulocyte colony-stimulating factor treatment mobilizes mainly PNH stem cells.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia resulting from a somatic mutation in a hemopoietic stem cell. In most cases of hemolytic PNH, the majority of the marrow cells are derived from the PNH clone. Recent evidence has indicated, however, that the majority of the most primitive peripheral blood stem cells (PBSCs) in PNH appear to be of normal phenotype. This has led to tentative suggestions that normal PBSCs could be collected and used for autologous transplantation. We have investigated this possibility in four PNH patients by treating them with granulocyte colony-stimulating factor (G-CSF) in an attempt to mobilize normal progenitors. The expression of glycosylphosphatidylinositol (GPI)-linked proteins was analyzed by flow cytometry on mature neutrophils, late stem cells (CD34+/CD38+), and primitive stem cells (CD34+/CD38-). The phenotyping and stem cell quantitation was performed in steady-state blood and post-G-CSF administration. The most primitive PBSCs (CD34+/CD38-) were almost all normal before G-CSF treatment, even when the patients' neutrophils were mainly PNH. However, after G-CSF, the cells that were mobilized into the peripheral blood were of a similar phenotype to the mature neutrophils, ie, mainly PNH. It is possible that PNH-stem cells are preferentially destroyed by complement in the peripheral blood leaving only normal cells in the circulation. After G-CSF, the PNH cells in the marrow are released into the blood. Our findings suggest that it would be difficult to collect sufficient numbers of normal stem cells for autologous transplantation.

Reticulocyte indices in patients with end stage renal disease on hemodialysis.

The diagnosis of iron deficiency anaemia in haemodialysis patients is difficult. Two states of deficiency occur, storage (absolute) and functional iron deficiency. Conventional measures, lack precision in assessing both storage and functional iron deficiency. This study investigated the accuracy of reticulocyte indices in comparison to the conventional haematological measures in the identification of haemodialysis patients with iron deficiency. A cross-sectional study of 72 haemodialysis patients was performed. Mean haemoglobin was 9.6 +/- 0.16 g/dl. Mean haemoglobin content of reticulocytes (CHr) was normally distributed and correlated with MCV, MCH and red cell ferritin. Mean haemoglobin concentration of reticulocytes (CHCMr) correlated with MCH. CHr and CHCMr had positive predictive values of 0.61 and 0.54 respectively. A low CHr or CHCMr identified 5 and 4 and 17 and 21 further patients with iron deficiency with normal serum ferritin or transferrin saturation respectively. Reticulocyte measures provide a direct measure of adequacy of haemoglobin synthesis in haemodialysis patients. In this study their usefulness was somewhat limited, but requires further investigation.

Novel Haematological Parameters in Patients Receiving Recombinant Human Erythropoietin and Undergoing Haemodialysis.

Recombinant Human Erythropoietin (EPO) replacement therapy effectively treats the chronic anaemic associated with end stage renal disease. However due to an increase in demand, a functional iron deficiency state may arise which is characterised by an inability to supply iron and subsequent EPO resistance. Indicators of iron status are potentially misleading in this situation. Red cell ferritin (RCFer) and reticulocyte indices may be more reliable measures of functional iron deficiency. We investigated, prospectively, the value of RCFer and reticulocyte indices to detect functional iron deficiency in 11 patients, 10 male and 1 female, mean age 51 years (ranges 20-74) commencing subcutaneous EPO therapy. All patients had received oral ferrous sulphate 600 mg, total dose, daily for 6 weeks prior to starting EPO. Study subjects had a mean aluminium of 1.1 mmol/L (28.9 µg/L) and parathyroid hormone (PTH) 109pg/L. Serum folate, vitamin B12 deficiencies and bleeding diathesis were excluded. Dialysis adequacy was maintained with a mean Kt/V (a measure of the amount of plasma cleared of urea divided by the urea distribution volume V) of 1.0 and urea reduction ratio of 64%. Haemoglobin rose from a mean value of 8.0-9.9g/dl (p < 0.01). There was an associated significant fall in both serum ferritin (SF) (205.5-62.88 µg/1, p< 0.01) and RCFer (19.96-10.8 ag/red cell, p < 0.001). After 96 days of EPO therapy, 18% of patients had a demonstrably reduced RCFer (< 7 ag/red cell) whilst none had a reduced SF (< 15 µg/L) and 75% had a transferrin saturation (TS) < 20%. Mean SF levels remained consistently above 50µg/L. There was no significant change in TS verifying its poor sensitivity as a marker of functional iron deficiency. Mean haemoglobin content of reticulocytes (CHr) and mean haemoglobin concentration of reticulocytes (CHCMr) fell (p < 0.001, p < 0.01 respectively) to levels suggesting iron deficiency at 3 months. These results suggest that RCFer and CHr may help detect the onset of functional iron deficiency in patients commencing EPO therapy despite oral iron. EPO therapy leads to a significant depletion of both erythroid and storage iron.

Evaluation of RBC ferritin and reticulocyte measurements in monitoring response to intravenous iron therapy.

Intravenous (IV) iron therapy can reduce erythropoietin (EPO) requirements in dialysis patients. Monitoring this response accurately is difficult. Estimation of red blood cell ferritin (RBCFer) and reticulocyte indices may give additional valuable information about iron availability to the erythroblasts (erythron). We evaluated the use of RBCFer, mean hemoglobin content of reticulocytes (CHr), and mean hemoglobin concentration of reticulocytes (CHCMr) in a prospective, nonblinded study of 22 hemodialysis patients (16 men and six women with a mean age of 62 years [range, 24 to 80 years]). All patients had an initial serum ferritin of < or = 60 microg/L. Patients with features known to produce EPO resistance and underlying bleeding/hematologic disorders were excluded. Patients were established on subcutaneous EPO and given IV iron therapy. The mean hemoglobin level remained constant throughout the study (P = 0.087). Serum ferritin and RBCFer increased significantly (P < 0.001 and 0.015, respectively) while a reduction in transferrin saturation became significant at the end of the study (P = 0.0047). A sharp increase in reticulocytes occurred in the first 14 days after commencement of IV iron, and there was an initial decrease in the percentage of hypochromic RBCs. An early decline in RBCFer was apparent. CHr increased with IV iron, indicative of increased iron supply to the developing erythron. Measurement of RBCFer and CHr provide evidence of increased iron supply for erythropoiesis during IV iron therapy. These measures help identify patients with functional iron deficiency and allow more accurate monitoring of response to IV iron therapy.

Detection and quantitation of the CBFbeta/MYH11 transcripts associated with the inv(16) in presentation and follow-up samples from patients with AML.

We have developed a competitor-based RT-PCR technique which will detect and quantitate the CBFbeta/MYH11 transcripts associated with inv(16)(q22;p13) and have used it to study presentation and follow-up samples of acute myeloid leukaemia (AML). The levels of the leukaemia-specific transcripts are expressed as a ratio to a ubiquitously expressed mRNA species (Abl) which controls for RNA degradation. This technique has been applied to 75 consecutive patients presenting with either de novo AML or tMDS; 6/75 patients analysed were positive for the inv(16), all were confirmed by conventional cytogenetics. The inv(16) has a strong association with M4Eo, but we found only 2/6-positive patients to have this diagnosis (two patients with M2, one patient M1 and one patient had MDS). At presentation the levels of CBFbeta/MYH11 transcripts were 0.1-10/Abl transcript (mean 3.3/Abl transcript). Seventeen follow-up samples were available on 5/6 of these patients, and on two further patients in whom stored material was available. Following the first cycle of chemotherapy the level of transcripts was at least 10(-2) lower (0.1-10 x 10(-2)/abl transcript) than their presentation sample. Subsequent samples on these patients when in remission gave transcript levels in the range (1.0 x 10(-4) - 2 x 10(-3)/abl transcript), and three long-term follow-up samples were negative. We have developed a quantitative test which opens the possibility of predicting relapse by detecting changes in the numbers of leukaemia-specific transcripts.

Red cell ferritin, a marker of iron deficiency in hemodialysis patients.

Estimation of red cell ferritin (RCFer) may give a good indication of iron supply to the erythron and it may therefore be clinically useful for the detection of functional iron deficiency. In a cross-sectional study of hemodialysis patients on erythropoietin (EPO) therapy and regular oral iron we have compared the RCFer levels with conventional indicators of iron status. The patients studied, 19 female, 48 male, mean age 62 +/- 3.6 years (range 20-83 years) were characterized by the following mean parameters: aluminum 1.24 +/- 0.12 mumol/L, PTH 115.7 +/- 39 pg/mL, vitamin B12 626 +/- 71.2 ng/L, serum folate 18.8 +/- 2.2 micrograms/L, and hemoglobin 9.8 +/- 0.3 g/dL (range 7.3-12.4). The median serum ferritin (SF), RCFer, total iron binding capacity (TIBC), transferrin saturation (TS), and serum iron were 68 micrograms/L, 14.1 ag ferritin/red cell, 57 mumol/L, 20% and 11.5 mumol/L, respectively. Eleven patients had a reduced RCFer (< 7 ag ferritin/red cell), 5 had a SF of < 15 micrograms/L and 22 a TS of < 16%. The occurrence of functional iron deficiency was suggested by the presence of 10 subjects with reduced RCFer despite normal SF levels (15-240 micrograms/L). Four patients with reduced SF showed acceptable levels of RCFer, suggesting that some patients may maintain an adequate iron supply despite diminished iron stores. Despite oral iron therapy, a significant number of patients (63%) on regular hemodialysis remain relatively iron deficient with a serum ferritin of less than 100 micrograms/L. It has previously been proposed that oral iron provides adequate supplementation during increased demand caused by EPO stimulation. The present study has demonstrated overt iron deficiency in five subjects and suggests functional iron deficiency in a further seven (22% of total patients). We therefore conclude that oral iron therapy cannot maximize the response to EPO.