Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
1.
Transfus Med Hemother ; 47(2): 119-128, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32355471

RESUMO

BACKGROUND: Roughly one quarter of short-term temporary deferrals (STTD) of blood donors are low-hemoglobin deferrals (LHD), i.e. STTD due to a hemoglobin (Hb) value falling below a cutoff of 125 g/L for female and 135 g/L for male donors. Since voluntarily donating blood is a prosocial activity, donors may perceive deferral as social exclusion, which can cause social pain, decrease self-esteem, and lead to antisocial behavior. However, little is known about the causal impacts of LHD on donor return. STUDY DESIGN AND METHODS: We conducted a quasi-experiment with 80,060 donors invited to blood drives in the canton of Zurich, Switzerland, between 2009 and 2014. Within a narrow window of Hb values around the predetermined cutoff, the rate of LHD jumps discontinuously. This discontinuous jump allows us to quantify the causal effects of LHD on donor return, as it is uncorrelated with other unobserved factors that may also affect donor return. RESULTS: We found different behavioral reactions to LHD for female and male donors. Female donors do not react to the first LHD. However, after any repeated LHD, they are 13.53 percentage points (p <0.001) less likely to make at least 1 donation attempt within the next 18 months and make 0.389 fewer donation attempts (p <0.001). Male donors react to the first LHD. They are 5.32 percentage points (p = 0.139) less likely to make at least 1 donation attempt over the next 18 months and make 0.227 (p = 0.018) fewer donation attempts. After any repeated LHD, male donors are 13.30 percentage points (p = 0.004) less likely to make at least 1 donation attempt and make 0.152 (p = 0.308) fewer donation attempts. CONCLUSION: LHD have detrimental impacts on donor return, especially if they occur repeatedly - suggesting that avoiding false LHD and helping donors to better cope with them helps to maintain the pool of prospective donors.

2.
J Appl Clin Med Phys ; 18(6): 258-267, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28944980

RESUMO

PURPOSE: To report our early experiences with failure mode and effects analysis (FMEA) in a community practice setting. METHODS: The FMEA facilitator received extensive training at the AAPM Summer School. Early efforts focused on department education and emphasized the need for process evaluation in the context of high profile radiation therapy accidents. A multidisciplinary team was assembled with representation from each of the major department disciplines. Stereotactic radiosurgery (SRS) was identified as the most appropriate treatment technique for the first FMEA evaluation, as it is largely self-contained and has the potential to produce high impact failure modes. Process mapping was completed using breakout sessions, and then compiled into a simple electronic format. Weekly sessions were used to complete the FMEA evaluation. Risk priority number (RPN) values > 100 or severity scores of 9 or 10 were considered high risk. The overall time commitment was also tracked. RESULTS: The final SRS process map contained 15 major process steps and 183 subprocess steps. Splitting the process map into individual assignments was a successful strategy for our group. The process map was designed to contain enough detail such that another radiation oncology team would be able to perform our procedures. Continuous facilitator involvement helped maintain consistent scoring during FMEA. Practice changes were made responding to the highest RPN scores, and new resulting RPN scores were below our high-risk threshold. The estimated person-hour equivalent for project completion was 258 hr. CONCLUSIONS: This report provides important details on the initial steps we took to complete our first FMEA, providing guidance for community practices seeking to incorporate this process into their quality assurance (QA) program. Determining the feasibility of implementing complex QA processes into different practice settings will take on increasing significance as the field of radiation oncology transitions into the new TG-100 QA paradigm.


Assuntos
Análise do Modo e do Efeito de Falhas na Assistência à Saúde , Neoplasias/cirurgia , Radiocirurgia/estatística & dados numéricos , Planejamento da Radioterapia Assistida por Computador/métodos , Humanos , Radiocirurgia/métodos , Dosagem Radioterapêutica , Gestão de Riscos
3.
Br J Haematol ; 174(4): 624-36, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27072601

RESUMO

Results of genotyping with true high-throughput capability for MNSs antigens are underrepresented, probably because of technical issues, due to the high level of nucleotide sequence homology of the paralogous genes GYPA, GYPB and GYPE. Eight MNSs-specific single nucleotide polymorphisms (SNP) were detected using matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry (MALDI-TOF MS) in 5800 serologically M/N and S/s pre-typed Swiss blood donors and 50 individuals of known or presumptive black African ethnicity. Comparison of serotype with genotype delivered concordance rates of 99·70% and 99·90% and accuracy of genotyping alone of 99·88% and 99·95%, for M/N and S/s, respectively. The area under the curve of peak signals was measured in intron 1 of the two highly homologous genes GYPB and GYPE and allowed for gene copy number variation estimates in all individuals investigated. Elevated GYPB:GYPE ratios accumulated in several carriers of two newly observed GYP*401 variants, termed type G and H, both encoding for the low incidence antigen St(a). In black Africans, reduced GYPB gene contents were proven in pre-typed S-s-U- phenotypes and could be reproduced in unknown specimens. Quantitative gene copy number estimates represented a highly attractive supplement to conventional genotyping, solely based on MNSs SNPs.


Assuntos
Antígenos de Grupos Sanguíneos/genética , Dosagem de Genes , Genótipo , Sistema do Grupo Sanguíneo MNSs/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Alelos , População Negra , Etnicidade , Glicoforinas/genética , Humanos , Polimorfismo de Nucleotídeo Único
4.
Transfusion ; 55(11): 2645-52, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26174157

RESUMO

BACKGROUND: Little is known about the long-term effects of interventions aimed at increasing turnout among voluntary blood donors. STUDY DESIGN AND METHODS: We use a retrospective natural experiment with all 40,653 donors who were repeatedly invited to blood drives in Zurich, Switzerland, between 2010 and 2013. The intervention is a quasi-randomized phone call informing donors of a current shortage of their blood type. The panel structure of the data allows identification of different types of donors reacting to the phone call. RESULTS: Our analysis reveals two types. Type 1 donors make up 27.1% of the population. They are highly motivated and exhibit a baseline donation rate of 59.4% (p < 0.001). The phone call raises their probability to donate by 9.9% at the upcoming blood drive (p < 0.001). However, the phone call reduces their donation rate by 2.3% (p = 0.003) at each future blood drive. In contrast, the 72.9% of Type 2 donors exhibit a low baseline donation rate of 5.8% (p < 0.001). The phone call raises their probability to donate by 5.8% at the upcoming blood drive (p < 0.001). Moreover, the phone call leads to habit formation in Type 2 donors and increases their donation rate by 2.1% at the next blood drive (p = 0.03). CONCLUSION: Behavioral interventions are effective at increasing donation rates in the short run. However, they can crowd out the intrinsic motivation of the most motivated donors. Thus, blood donation services should avoid interventions for highly motivated donors and target them at irregular donors. Our results also sound a warning on using other interventions.


Assuntos
Doadores de Sangue/psicologia , Telefone , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Motivação , Estudos Retrospectivos , Inquéritos e Questionários , Suíça
5.
Med Phys ; 38(2): 857-71, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21452723

RESUMO

Task Group 154 (TG154) of the American Association of Physicists in Medicine (AAPM) was created to produce a guidance document for clinical medical physicists describing recommended quality assurance (QA) procedures for ultrasound (U.S.)-guided external beam radiotherapy localization. This report describes the relevant literature, state of the art, and briefly summarizes U.S. imaging physics. Simulation, treatment planning and treatment delivery considerations are presented in order to improve consistency and accuracy. User training is emphasized in the report and recommendations regarding peer review are included. A set of thorough, yet practical, QA procedures, frequencies, and tolerances are recommended. These encompass recommendations to ensure both spatial accuracy and image quality.


Assuntos
Física , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Radioterapia/normas , Relatório de Pesquisa , Sociedades Científicas , Humanos , Imageamento Tridimensional , Lasers , Masculino , Posicionamento do Paciente , Imagens de Fantasmas , Física/educação , Controle de Qualidade , Tomografia Computadorizada por Raios X , Ultrassonografia , Estados Unidos
6.
Spine J ; 10(2): 153-8, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20142072

RESUMO

BACKGROUND CONTEXT: During the last decade, vertebral augmentation techniques with cement (kyphoplasty and vertebroplasty) have revealed that 75% to 100% of individuals with osteoporotic vertebral compression fractures have good to moderate pain relief postoperatively, as well as adequate restoration of the vertebral body height. The volume of cement injected into a vertebra varied in different reports. To our knowledge, there are no studies that report on the physiological distribution of thoracic and lumbar vertebrae body volumes. PURPOSE: The purpose of this study was to quantitatively evaluate thoracic and lumbar vertebral body volumes. STUDY DESIGN/SETTING: Forty computed tomography (CT) scans of the thoracic and lumbar spines were used to measure a volume of each vertebral body. METHODS: Forty CT scans with standard 2.5-mm bone window cuts of the thoracic and lumbar vertebrae (20 men and 20 women) were analyzed to measure the volumetric capacity of vertebral bodies using a BrainLAB Software (iPlan RT image 4.0) program. The software was tested for validity and reliability in two pilot studies. Mean and standard deviations for each vertebral body volume were calculated and recorded. The vertebral body working distance and the so-called "safe zone" were also measured to determine a size of a balloon to be used in kyphoplasty. RESULTS: Vertebral body volume increased gradually from T1 to L4 with the exception of L5, which measured to be smaller than L4. The mean thoracic vertebrae volume was 15.0 cm(3) (ranged in the absolute values from 5.2 to 39.5 cm(3)), and the mean lumbar vertebrae volume was 35 cm(3) (ranged in the absolute values from 19.7 to 61.5 cm(3)). Men had larger volume vertebral bodies only in the lumbar spine compared with women. The average vertebral body working distances from T1 to T4 was 23.4+/-2.7 mm, from T5 to T9 was 30.3+/-3.6 mm, and from T10 to L5 was 35.5+/-3.9 mm. CONCLUSIONS: Knowing the physiological variability of vertebral body volumes may help prevent complications as a result of underaugmentation or overaugmentation with excessive amount of cement during kyphoplasty or vertebroplasty in osteoporotic compression fractures. We recommend using 10 mm balloons from T1 to T4, 15 mm balloons from T5 to T9, and 20 mm balloons from T10 to L5 for kyphoplasty.


Assuntos
Vértebras Lombares/anatomia & histologia , Vértebras Torácicas/anatomia & histologia , Adolescente , Adulto , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Radiografia , Valores de Referência , Fatores Sexuais , Vértebras Torácicas/diagnóstico por imagem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA