NIAIC - Medical Device and Equipment Alerts 2010

Medical Device and Equipment Alerts MDEA Updates - 2010

NIAIC - Medical Device and Equipment Alerts 2011

Medical Device and Equipment Alerts MDEA Updates - 2011

NIAIC - Medical Device and Equipment Alerts 2009

Medical Device and Equipment Alerts MDEA Updates - 2009

Colite à Clostridium difficile: nouvelles recommandations de prise en charge [Clostridium difficile infections: update on new European recommendations].

Clostridium difficile infections: update on new European recommandations While metronidazole and vancomycin have been the only drug options to date for the treatment of C. difficile infection, new therapeutic approaches with promising results have recently emerged for the treatment of the first episode and relapses. Fidaxomicin is a new macrocyclic antibiotic more active against C. difficile and with a narrow spectrum allowing preservation of the intestinal microbiota. While having the same efficacy as vancomycin for the treatment of the first episode, this agent is associated with a lower rate of relapse. The highest relapse-free cure rate is achieved through fecal microbiota transplantation, which should be considered for patients with multiple relapses.

Bone mineral density (BMD), micro-architecture estimation (TBS) and vertebral fracture assessment (VFA) extracted from a single DXA device in combination with clinical risk factors improve significantly the identification of women at high risk of fracture

Introduction: Osteoporosis (OP) is a systemic skeletal disease characterized by a low bone mineral density (BMD) and a micro-architectural (MA) deterioration. Clinical risk factors (CRF) are often used as a MA approximation. MA is yet evaluable in daily practice by the Trabecular Bone Score (TBS) measure. TBS is a novel grey-level texture measurement reflecting bone micro-architecture based on the use of experimental variograms of 2D projection images. TBS is very simple to obtain, by reanalyzing a lumbar DXA-scan. TBS has proven to have diagnosis and prognosis value, partially independent of CRF and BMD. The aim of the OsteoLaus cohort is to combine in daily practice the CRF and the information given by DXA (BMD, TBS and vertebral fracture assessment (VFA)) to better identify women at high fracture risk. Method: The OsteoLaus cohort (1400 women 50 to 80 years living in Lausanne, Switzerland) started in 2010. This study is derived from the cohort COLAUS who started in Lausanne in 2003. The main goals of COLAUS is to obtain information on the epidemiology and genetic determinants of cardiovascular risk in 6700 men and women. CRF for OP, bone ultrasound of the heel, lumbar spine and hip BMD, VFA by DXA and MA evaluation by TBS are recorded in OsteoLaus. Preliminary results are reported. Results: We included 631 women: mean age 67.4±6.7 y, BMI 26.1±4.6, mean lumbar spine BMD 0.943±0.168 (T-score -1.4 SD), TBS 1.271±0.103. As expected, correlation between BMD and site matched TBS is low (r2=0.16). Prevalence of VFx grade 2/3, major OP Fx and all OP Fx is 8.4%, 17.0% and 26.0% respectively. Age- and BMI-adjusted ORs (per SD decrease) are 1.8 (1.2- 2.5), 1.6 (1.2-2.1), 1.3 (1.1-1.6) for BMD for the different categories of fractures and 2.0 (1.4-3.0), 1.9 (1.4-2.5), 1.4 (1.1-1.7) for TBS respectively. Only 32 to 37% of women with OP Fx have a BMD < -2.5 SD or a TBS < 1.200. If we combine a BMD < -2.5 SD or a TBS < 1.200, 54 to 60% of women with an osteoporotic Fx are identified. Conclusion: As in the already published studies, these preliminary results confirm the partial independence between BMD and TBS. More importantly, a combination of TBS subsequent to BMD increases significantly the identification of women with prevalent OP Fx which would have been miss-classified by BMD alone. For the first time we are able to have complementary information about fracture (VFA), density (BMD), micro- and macro architecture (TBS & HAS) from a simple, low ionizing radiation and cheap device: DXA. Such complementary information is very useful for the patient in the daily practice and moreover will likely have an impact on cost effectiveness analysis.

Penalties for Patient Charge Evasion (PDF 153 KB)

Penalties for Patient Charge Evasion

Les malformations utérines: diagnostic, pronostic et prise en charge en 2008 [Congenital uterine anomalies: diagnosis, prognosis and management in 2008].

The müllerian anomalies or congenital uterine anomalies are relatively frequent if we keep in mind that 3-4% of our female patients present with a müllerian anomaly, although many among them are asymptomatic. It is important to evoke this diagnosis for all patients with a history of recurrent miscarriage, late abortion and premature delivery, for the adolescent consulting for primary amenorrhea, dysmenorrhea or dyspareunia as well as for the woman consulting for infertility. We will review pathogenesis, diagnostic methods, standard classification with a description of the different types of congenital uterine anomalies and the recommended management.

Design of Novel Frequency Generation Circuit with Application to Ultra-Wideband Distributed Oscillators

Given the urgence of a new paradigm in wireless digital trasmission which should allow for higher bit rate, lower latency and tigher delay constaints, it has been proposed to investigate the fundamental building blocks that at the circuital/device level, will boost the change towards a more efficient network architecture, with high capacity, higher bandwidth and a more satisfactory end user experience. At the core of each transciever, there are inherently analog devices capable of providing the carrier signal, the oscillators. It is strongly believed that many limitations in today's communication protocols, could be relieved by permitting high carrier frequency radio transmission, and having some degree of reconfigurability. This led us to studying distributed oscillator architectures which work in the microwave range and possess wideband tuning capability. As microvave oscillators are essentially nonlinear devices, a full nonlinear analyis, synthesis, and optimization had to be considered for their implementation. Consequently, all the most used nonlinear numerical techniques in commercial EDA software had been reviewed. An application of all the aforementioned techniques has been shown, considering a systems of three coupled oscillator ("triple push" oscillator) in which the stability of the various oscillating modes has been studied. Provided that a certain phase distribution is maintained among the oscillating elements, this topology permits a rise in the output power of the third harmonic; nevertheless due to circuit simmetry, "unwanted" oscillating modes coexist with the intenteded one. Starting with the necessary background on distributed amplification and distributed oscillator theory, the design of a four stage reverse mode distributed voltage controlled oscillator (DVCO) using lumped elments has been presented. All the design steps have been reported and for the first time a method for an optimized design with reduced variations in the output power has been presented. Ongoing work is devoted to model a wideband DVCO and to implement a frequency divider.

Field trials of an improved cost-effective device for detecting peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae) in rural Argentina

An improved device for detecting peridomestic Triatoma infestans consisting of one-liter recycled Tetra Brik milk boxes with a central structure was tested using a matched-pair study design in two rural areas in Argentina. In Olta (La Rioja), the boxes were installed beneath the thatched roofs and on the vertical wooden posts of each peridomestic structure. After a 5-month exposure, at least one of the recovered boxes detected 88% of the 24 T. infestans-positive sites, and 86% of the 7 negative sites by timed manual collections at baseline. In Amamá (Santiago del Estero), the boxes were paired with the best performing prototype tested before (shelter unit). After 3 months, some evidence of infestation was detected in 89% (boxes) and 79% (shelters) of 18-19 sites positive by timed collections, whereas 19% and 16% of 32 negative sites were positive, respectively. Neither device differed significantly in the qualitative or quantitative collection of every sign of infestation. The installation site did not modify significantly the boxes' sampling efficiency in both study areas. As the total cost of each box was half as expensive as each shelter unit, the boxes are thus the most cost-effective and easy-to-use tool for detecting peridomestic T. infestans currently available.

Numerical simulation of left ventricular assist device implantations: comparing the ascending and the descending aorta cannulations.

In this work we present numerical simulations of continuous flow left ventricle assist device implantation with the aim of comparing difference in flow rates and pressure patterns depending on the location of the anastomosis and the rotational speed of the device. Despite the fact that the descending aorta anastomosis approach is less invasive, since it does not require a sternotomy and a cardiopulmonary bypass, its benefits are still controversial. Moreover, the device rotational speed should be correctly chosen to avoid anomalous flow rates and pressure distribution in specific location of the cardiovascular tree. With the aim of assessing the differences between these two approaches and device rotational speed in terms of flow rate and pressure waveforms, we set up numerical simulations of network of one-dimensional models where we account for the presence of an outflow cannula anastomosed to different locations of the aorta. Then, we use the resulting network to compare the results of the two different cannulations for several stages of heart failure and different rotational speed of the device. The inflow boundary data for the heart and the cannulas are obtained from a lumped parameters model of the entire circulatory system with an assist device, which is validated with clinical data. The results show that ascending and descending aorta cannulations lead to similar waveforms and mean flow rate in all the considered cases. Moreover, regardless of the anastomosis region, the rotational speed of the device has an important impact on wave profiles; this effect is more pronounced at high RPM.

Pathogenèse, dépistage et prise en charge de l'anévrysme de l'aorte abdominale

RESUME L'anévrysme de l'aorte abdominale est une dilatation permanente et localisée de l'aorte abdominale d'un diamètre transverse supérieur à 30 mm. Il s'agit d'une maladie dégénérative et inflammatoire fréquente de l'aorte, présente chez environ 5% des hommes de 65 à 74 ans de la population générale, et chez 10% des hommes hospitalisés pour une revascularisation coronarienne chirurgicale. En effet, bien que la pathogenèse de l'anévrysme de l'aorte abdominale diffère de celle du processus d'athérosclérose, les deux maladies partagent de nombreux facteurs de risque, en particulier l'âge, l'hypertension artérielle et le tabagisme. L'anévrysme de l'aorte abdominale est une maladie silencieuse, et dans 20% des cas, sa première manifestation clinique est la rupture aiguë avec choc hémorragique. La mortalité totale d'une telle complication dépasse 90% et sa mortalité strictement opératoire est d'environ 50%. Ces chiffres contrastent étonnamment avec une mortalité inférieure à 5% en cas de cure chirurgicale élective de l'anévrysme, justifiant un programme de dépistage systématique de cette maladie par ultrasonographie abdominale. Plusieurs études ont actuellement prouvé l'efficience de tels programmes, tant du point de vue de leur impact sur la mortalité que de leur rapport coût-efficacité. La question d'un dépistage systématique de la population générale ou de celui de souspopulations sélectionnées en fonction de leurs facteurs de risque reste toutefois débattue. La prise en charge de l'anévrysme de l'aorte abdominale est en principe conservatrice pour les anévrysmes de faibles diamètres, la mortalité d'une telle approche étant comparable à celle d'une attitude d'emblée chirurgicale. L'indication opératoire est par contre posée pour les anévrysmes d'un diamètre supérieur à 55 mm en raison du risque inacceptable de rupture, la valeur du diamètre transverse de l'aorte représentant le facteur prédictif de rupture le plus fréquemment utilisé en pratique quotidienne. La cure chirurgicale ouverte est le traitement de référence de l'anévrysme de l'aorte abdominale, mais la cure minimale invasive par endoprothèse, disponible depuis le début des années 1990, représente une alternative attrayante. Le choix de l'approche thérapeutique dépend fortement des caractéristiques anatomiques de l'aorte, ainsi que des comorbidités et de la préférence du patient.

Analyse de la prise en charge médicale et de l'impact économique des patients ayant présentés des coûts extrêmes dans un hôpital universitaire [Analysis of the medical management and the economic impact of patients who have represented extreme costs at a university hospital]

Les coûts de traitement de certains patients s'avèrent extrêmement élevés, et peuvent faire soupçonner une prise en charge médicale inadéquate. Comme I'évolution du remboursement des prestations hospitalières passe à des forfaits par pathologie, il est essentiel de vérifier ce point, d'essayer de déterminer si ce type de patients peut être identifié à leur admission, et de s'assurer que leur devenir soit acceptable. Pour les années 1995 et 1997. les coûts de traitement dépassant de 6 déviations standard le coût moyen de la catégorie diagnostique APDRG ont été identifiés, et les dossiers des 50 patients dont les coûts variables étaient les plus élevés ont été analysés. Le nombre total de patients dont I'hospitalisation a entraîné des coûts extrêmes a passé de 391 en 1995 à 328 patients en 1997 (-16%). En ce qui concerne les 50 patients ayant entraîné les prises en charge les plus chères de manière absolue, les longs séjours dans de multiples services sont fréquents, mais 90% des patients sont sortis de l'hôpital en vie, et près de la moitié directement à domicile. Ils présentaient une variabilité importante de diagnostics et d'interventions, mais pas d'évidence de prise en charge inadéquate. En conclusion, les patients qualifiés de cas extrêmes sur un plan économique, ne le sont pas sur un plan strictement médical, et leur devenir est bon. Face à la pression qu'exercera le passage à un mode de financement par pathologie, les hôpitaux doivent mettre au point un système de revue interne de I'adéquation des prestations fournies basées sur des caractéristiques cliniques, s'ils veulent garantir des soins de qualité. et identifier les éventuelles prestations sous-optimales qu'ils pourraient être amenés à délivrer. [Auteurs] Treatment costs for some patients are extremely high and might let think that medical care could have been inadequate. As hospital financing systems move towards reimbursement by diagnostic groups, it is essential to assess whether inadequate care is provided, to try to identify these patients upon admission, and make sure that their outcome is good. For the years 1995 and 1997, treatment costs exceeding by 6 standard deviations the average cost of their APDRG category were identified, and the charts of the 50 patients with the highest variable costs were analyzed. The total number of patients with such extreme costs diminished from 391 in 1995 to 328 in 1997 (-16%). For the 50 most expensive patients, long stays in several services were frequent, but 90% of these patients left the hospital alive, and about half directly to their home. They presented an important variation in diagnoses and operations, but no evidence for inadequate care. Thus, patients qualified as extreme from an economic perspective cannot be qualified as such from a medical perspective, and their outcome is good. To face the pressure linked with the change in financing system, hospitals must develop an internal review system for assessing the adequacy of care, based on clinical characteristics, if they want to guarantee good quality of care and identify potentially inadequate practice.