Improving safety in blood transfusion using failure mode and effect analysis.

BACKGROUND: One of the medical areas where errors can have more serious consequences is the process of blood transfusion. We used failure mode and effect analysis (FMEA) for evaluating potential failures and improving transfusion safety in a medium-size urban hospital with a highly complex transfusion service. STUDY DESIGN AND METHODS: Each failure mode was evaluated using the likelihood of occurrence, severity of the effect, and probability of detection. The obtained results allowed each failure to be prioritized and decisions to be made in an organized manner to determine solutions. We define measures and indicators that allow the comparison of their results in a longer time period than most of the previous studies. RESULTS: The most important failures were those regarding 1) transmitting information about the transfusion request, 2) patient identification, 3) sample identification, 4) cross-matching ordered tests, 5) transfusing blood components, 6) completing and sending the transfusion control document, and 7) reporting of transfusion reactions. The application of the FMEA methodology allowed implementation of safety measures and monitoring of the measures using indicators, including the mandatory records of the hemovigilance system. There was a 56% improvement in the risk prioritization numbers in the second stage of the FMEA. CONCLUSION: FMEA allows for identification of factors that reduce safety in this hospital, analysis of the causes and consequences of these errors, design of corrective measures, and establishment of indicators to monitor their application. The FMEA methodology can help other institutions to identify their own specific vulnerabilities.

[Congenital xerocytosis]. / Xerocitosis congénita.

Hereditary xerocytosis is a genetic disease inherited as an autosomal dominant trait and is a rare cause of hemolytic anemia. It is caused by abnormal erythrocyte membrane permeability: monovalent cation pump activity is increased and the Na/K pump cannot compensate for the K lost. As a consequence, xerocytes dehydrate, becoming rigid and sensitive to metabolic stress and oxidation. Morbility depends on the severity of the hemolytic anemia. Periodic episodes of jaundice are common during mild infections; most patients remain asymptomatic but experience mild-to-moderate hemolytic anemia, which is generally well compensated. The diagnostic clues are a markedly increased flow through the Na/K pump with a decrease in total intracellular cation content and subsequent red cell dehydration. Treatment is based on monitoring for eventual complications and careful observation during infections, which may worsen the anemia. Splenectomy is not useful and for some authors may even be contraindicated. The prognosis is generally very good. We report the case of a patient with episodes of hemolytic anemia during intercurrent infections and positive diagnostic tests for hereditary xerocytosis.

Xerocitosis congénita / Hereditary xerocytosis

La xerocitosis hereditaria es un trastorno genético de herencia autosómica dominante y constituye una causa muy poco frecuente de anemia hemolítica. Se produce por una alteración en la permeabilidad de la membrana eritrocitaria: la actividad de la bomba de cationes monovalentes está aumentada y la bomba sodio-potasio no puede compensar las pérdidas de potasio. Como consecuencia se produce la deshidratación del hematíe, haciéndolo rígido y sensible al estrés metabólico y a los oxidantes. La morbilidad de este cuadro depende del grado de anemia hemolítica que provoque. Con frecuencia existen episodios periódicos de ictericia coincidiendo con infecciones banales, la mayoría de pacientes permanecen asintomáticos con un grado entre leve y moderado de anemia hemolítica, generalmente bien compensada. El marcado incremento del flujo sodio-potasio a través de la membrana del hematíe con descenso en el contenido catiónico total intracelular y la deshidratación del hematíe son las claves diagnósticas. El tratamiento de esta enfermedad se basa en la monitorización de posibles complicaciones y en una observación cuidadosa ante infecciones que pueden dar lugar a exacerbaciones de la anemia. La esplenectomía no es útil, para algunos autores incluso podría estar contraindicada. El pronóstico es, por lo general, bueno. Presentamos el caso de un paciente con episodios de anemia hemolítica coincidiendo con infecciones intercurrentes, con las pruebas diagnósticas de xerocitosis hereditaria (AU)

High incidence of the CD8/9 (+G) beta 0-thalassemia mutation in Spain.

BACKGROUND AND OBJECTIVE: In Spain, as in other Mediterranean regions the most common beta-thalassemia mutations are due to point mutations in gene regions that are critical for production of mRNA, such as [IVS-I-nt1 (G-->A), IVS-I-nt6 (T-->C), IVS-I-nt110 (G-->A)] which interrupt normal RNA processing or nonsense mutations [CD39 (C-->T)] which interrupt the translation of mRNA. The frameshift mutation CD8/9 (+G) is a very common allele in Asian Indians but is rare in the Mediterranean regions in which isolated alleles with this mutation have been found in Israel, Greece, Portugal and Turkey. DESIGN AND METHODS: We performed a molecular analysis of 175 chromosomes corresponding to 233 beta-thalassemia patients (221 heterozygous, 10 homozygous and 2 compound heterozygous) who belong to 169 Spanish families. The study of beta-thalassemia was made by PCR-ARMS, the alpha genes by Southern blot, the phenotype of Hb Lepore by enzymatic amplification and the presence of -158 gamma G C-->T mutation by PCR and digestion with the restriction enzyme XmnL. RESULTS: Twenty of these 233 patients showed the beta-thalassemia mutation CD8/9 (+G) (17 were heterozygous, 2 homozygous and in one patient the mutation was associated with a structural variant Hb Lepore Boston). INTERPRETATION AND CONCLUSIONS: These data reveal the heterogeneity of beta-thalassemia in Spain and the relatively high frequency (8.6%) of the frameshift mutation CD8/9 (+G). It is surprising that homozygotes for beta zero-thalassemia due to this mutation with very high Hb F values (around 90%) present a phenotype of intermediate thalassemia.

[Identification of 5 variants of the hemoglobin beta chain using DNA analysis (amplification, sequencing and restriction enzymes)]. / Identificación de 5 variantes de Hb de cadena beta mediante análisis del ADN (amplificación, secuenciación y enzimas de restricción).

PURPOSE: To confirm the conventional techniques for studying structural haemoglobinopathies and to show off the simplicity and efficacy of new methods based on the study of DNA. PATIENTS AND METHODS: Peripheral blood samples of 17 patients with 5 haemoglobin variants detected by conventional and shown off by means of sequencing according to Sanger's method, plus PCR-RFLP, were studied. RESULTS: Five structural haemoglobin variants were found, which distributed as follows: 7 cases of Hb Complutense (beta 127 Gln-->Glu), 1 Hb D-Punjab (beta 121 Glu-->Gln), 3 Hb Hofu (beta 126 Val-->Glu), 3 Hb J-Baltimore (beta 16 Gly-->Asp) and 3 Hb San Diego (beta 109 Val-->Met). CONCLUSIONS: These results allow us to stress the simplicity and usefulness of DNA analysis (sequencing , amplification and enzymatic digestion) to identify haemoglobin variants as opposed to laborious analysis of the primary structure by means of HPLC peptide separation.

[PCR study of bcl-2 rearrangement in autologous transplantation of peripheral stem cells in follicular non-Hodgkin's lymphoma]. / Estudio por PCR del reordenamiento bcl-2 en el trasplante autólogo de células progenitoras de sangre periférica en el linfoma no hodgkiniano folicular.

OBJECTIVE: To value the usefulness of the bcl-2 rearrangement analysis by PCR in the study of the minimal residual disease in patients with follicular non-Hodgkin's B cell lymphoma (NHL) submitted to peripheral blood stem-cell transplantation (PSCT). PATIENTS AND METHOD: The study was done on 12 patients diagnosed with low grade B-cell NHL, who were entered in a program of myeloablative chemotherapy followed by rescue with progenitor cells obtained from peripheral blood. At the time of peripheral stem-cells (PSC) harvesting, 8 patients did not present medullar infiltration and four of them presented medullar infiltration according to conventional histological criteria. The study was done on DNA from samples taken from bone marrow and cells taken in the apheresis. The DNA samples were studied by PCR to determine the existence of the bcl-2 rearrangement. RESULTS: At the time of apheresis, 8 patients did not present medullar infiltration according to conventional histological criteria but 7 of them presented bcl-2/JH rearrangement. Most patients studied (10 out of 12) showed bcl-2/JH rearrangement (minimal residual disease) in apheresis products. However, in 2 of these 10 patients, such rearrangement was negative in the bone marrow samples obtained 3-6 and 12 months after transplantation. CONCLUSION: In some patients with follicular NHL submitted to PSCT, the bcl-2/JH rearrangement had negativized after transplantation, this implies that the tumoral cells present in apheresis products lost their clonogenic capacity and were not able to subsist in vivo and that the myeloablative polychemotherapy schedules are able to eradicate the t(14; 18) translocation bearing cells or, at least, to decrease their number in bone marrow to levels below those of PCR detection.

[Value of analyzing reticulocyte subpopulations in polycythemia]. / Valor del análisis de las subpoblaciones reticulocitarias en el estudio de las poliglobulias.

OBJECTIVE: The evaluation of the RNA content in reticulocytes by means of flow cytometry allows us to differentiate three reticulocyte populations by their degree of maturity: LFR, MFR and HFR. We have studied the value of those reticulocyte subpopulations for the differential diagnosis in polycythemia. PATIENTS AND METHODS: We have studied 25 polycythemia patients, 12 of these were diagnosed of polycythemia vera (PV) and 13 of secondary polycythemia (PS). Reticulocytes and their different reticulocyte populations were automatically analyzed by flow cytometry using the Sysmex R-2000 analyzer (TOA Corp. Japan). We calculated the reticulocyte maturity index (RMI) which is the percentage of the equation (MFR + HFR) x 100/LFR (9). We have also studied hemogram parameters (Hct, Hb, VCM, HCM, RDW, leukocytes and platelets), iron metabolism (serum iron, ferritin, transferrin and transferrin saturation index), and erythropoietin levels. The findings were statistically analyzed using the Pearson correlation test and the comparison tests of averages of independent samples (Student's t). RESULTS: Patients with PV present high RMI and MFR + HFR (medium and high fluorescence reticulocytes) as compared with secondary polycythemia . We did not find any correlation between RMI and other analytical parameters (erythropoietin, ferritin, serum iron, transferrin), except for the transferrin saturation index (TSI), with a correlation factor r: 0.5486 for p < 0.05. CONCLUSION: This higher proportion of younger reticulocytes in PV might be explained because they are a parameter that would reflect the expansion of erythropoietic bone progenitor cells, which would be more increased in PV than in PS. However, another possible explanation would consist in the existence of associated ferropenia in PVs, which lead to an increase in cytoplasmic levels of transferrin receptor mRNA.