Análisis y diseño de antenas dipolo y parche para aplicaciones implantadas en el cuerpo humano

En els darrers anys, els sistemes de telemetria per a aplicacions mèdiques han crescut significativament en el diagnòstic i en la monitorització de, per exemple, la glucosa, la pressió de la sang, la temperatura, el ritme cardíac... Els dispositius implantats amplien les aplicacions en medicina i incorpora una millora de qualitat de vida per a l’usuari. Per aquest motiu, en aquest projecte s’estudien dues de les antenes més comuns, com son l’antena dipol i el patch, aquesta última és especialment utilitzada en aplicacions implantades. En l’anàlisi d’aquestes antenes s’han parametritzat característiques relacionades amb l’entorn de l’aplicació, així com també de la pròpia antena, explicant el comportament que, a diferencia amb l’espai lliure, les antenes presenten a canvis d’aquests paràmetres. Al mateix temps, s’ha implementat una configuració per a la mesura d’antenes implantades basat en el model del cos humà d’una capa. Comparant amb els resultats de les simulacions realitzades mitjançant el software FEKO, s’ha obtingut gran correspondència en la mesura empírica d’adaptació i de guany de les antenes microstrip. Gràcies a l’anàlisi paramètric, aquest projecte també presenta diversos dissenys de les antenes optimitzant el guany realitzable amb l’objectiu d’aconseguir la millor comunicació possible amb el dispositiu extern o estació base.

Medicine and Science in a New Medical-surgical Context: The Royal College of Surgery of Barcelona (1760–1843)

Taking the Royal College of Barcelona (1760 -1843) as a case study this paper shows the development of modern surgery in Spain initiated by Bourbon Monarchy founding new kinds of institutions through their academic activities of spreading scientific knowledge. Antoni Gimbernat was the most famousinternationally recognised Spanish surgeon. He was trained as a surgeon at the Royal College of Surgery in Cadiz and was later appointed as professor of theAnatomy in the College of Barcelona. He then became Royal Surgeon of King Carlos IV and with that esteemed position in Madrid he worked resiliently to improve the quality of the Royal colleges in Spain. Learning human bodystructure by performing hands-on dissections in the anatomical theatre has become a fundamental element of modern medical education. Gimbernat favoured the study of natural sciences, the new chemistry of Lavoisier and experimental physics in the academic programs of surgery. According to the study of a very relevant set of documents preserved in the library, the so-called “juntas literarias”, among the main subjects debated in the clinical sessions was the concept of human beings and diseases in relation to the development of the new experimental sciences. These documents showed that chemistry andexperimental physics were considered crucial tools to understand the unexplained processes that occurred in the diseased and healthy human bodyand in a medico-surgical context. It is important to stress that through these manuscripts we can examine the role and the reception of the new sciences applied to healing arts.

Medical futility at the end of life: the perspectives of intensive care and palliative care clinicians.

Objectives Medical futility at the end of life is a growing challenge to medicine. The goals of the authors were to elucidate how clinicians define futility, when they perceive life-sustaining treatment (LST) to be futile, how they communicate this situation and why LST is sometimes continued despite being recognised as futile. Methods The authors reviewed ethics case consultation protocols and conducted semi-structured interviews with 18 physicians and 11 nurses from adult intensive and palliative care units at a tertiary hospital in Germany. The transcripts were subjected to qualitative content analysis. Results Futility was identified in the majority of case consultations. Interviewees associated futility with the failure to achieve goals of care that offer a benefit to the patient's quality of life and are proportionate to the risks, harms and costs. Prototypic examples mentioned are situations of irreversible dependence on LST, advanced metastatic malignancies and extensive brain injury. Participants agreed that futility should be assessed by physicians after consultation with the care team. Intensivists favoured an indirect and stepwise disclosure of the prognosis. Palliative care clinicians focused on a candid and empathetic information strategy. The reasons for continuing futile LST are primarily emotional, such as guilt, grief, fear of legal consequences and concerns about the family's reaction. Other obstacles are organisational routines, insufficient legal and palliative knowledge and treatment requests by patients or families. Conclusion Managing futility could be improved by communication training, knowledge transfer, organisational improvements and emotional and ethical support systems. The authors propose an algorithm for end-of-life decision making focusing on goals of treatment.

Summarization of specialized discourse: the case of medical articles in Spanish

In this article, we present the current state of our work on a linguistically-motivated model for automatic summarization of medical articles in Spanish. The model takes into account the results of an empirical study which reveals that, on the one hand, domain-specific summarization criteria can often be derived from the summaries of domain specialists, and, on the other hand, adequate summarization strategies must be multidimensional, i.e., cover various types of linguistic clues. We take into account the textual, lexical, discursive, syntactic and communicative dimensions. This is novel in the field of summarization. The experiments carried out so far indicate that our model is suitable to provide high quality summarizations.

Use of mobile devices to answer online surveys: implications for research.

BACKGROUND: There is a growing use of mobile devices to access the Internet. We examined whether participants who used a mobile device to access a brief online survey were quicker to respond to the survey but also, less likely to complete it than participants using a traditional web browser. FINDINGS: Using data from a recently completed online intervention trial, we found that participants using mobile devices were quicker to access the survey but less likely to complete it compared to participants using a traditional web browser. More concerning, mobile device users were also less likely to respond to a request to complete a six week follow-up survey compared to those using traditional web browsers. CONCLUSIONS: With roughly a third of participants using mobile devices to answer an online survey in this study, the impact of mobile device usage on survey completion rates is a concern. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01521078.

Bloodstream infections related to totally implantable venous access port: What is the situation in our hospital?

Port-a-Cath© (PAC) are totally implantable devices that offer an easy and long term access to venous circulation. They have been extensively used for intravenous therapy administration and are particularly well suited for chemotherapy in oncologic patients. Previous comparative studies have shown that these devices have the lowest catheter-related bloodstream infection rates among all intravascular access systems. However, bloodstream infection (BSI) still remains a major issue of port use and epidemiology data for PAC-associated BSI (PABSI) rates differ strongly depending on studies. Also, current literature about PABSI risk factors is scarce and sometimes controversial. Such heterogeneity may depend on type of studied population and local factors. Therefore, the aim of this study was to describe local epidemiology and risk factors for PABSI in adult patients in our tertiary- care university hospital. We conducted a retrospective cohort study in order to describe local epidemiology. We also performed a nested case-control study to identify local risk factors of PABSI. We analyzed medical files of adult patients who had a PAC implanted between January 1st, 2008 and December 31st, 2009 and looked for PABSI occurrence before May 1st, 2011 to define cases. Thirty nine PABSI occurred in this population with an attack rate of 5.8%. We estimated an incidence rate of 0.08/1000 PAC-days using the case-control study. PABSI causative agents were mainly Gram positive cocci (62%). We identified three predictive factors of PABSI by multivariate statistical analysis: neutropenia on outcome date (Odds Ratio [OR]: 4.05; 95% confidence interval [CI]:1.05- 15.66; p=0.042), diabetes (OR: 11.53; 95% CI: 1.07-124.70; p=0.044) and having another infection than PABSI on outcome date (OR: 6.35; 95% CI: 1.50-26.86; p=0.012). Patients suffering from acute or renal failure (OR: 4.26; 95% CI: 0.94-19.21; p=0.059) or wearing another invasive device (OR: 2.99; 95%CI:0.96-9.31; p=0.059) did not have a statistically increased risk for developing a PABSI according to classical threshold (p<0.05) but nevertheless remained close to significance. Our study demonstrated that local epidemiology and microbiology of PABSI in our institution was similar to previous reports. A larger prospective study is required to confirm our results or to test preventive measures.

Monitoring of posture allocations and activities by a shoe-based wearable sensor.

Monitoring of posture allocations and activities enables accurate estimation of energy expenditure and may aid in obesity prevention and treatment. At present, accurate devices rely on multiple sensors distributed on the body and thus may be too obtrusive for everyday use. This paper presents a novel wearable sensor, which is capable of very accurate recognition of common postures and activities. The patterns of heel acceleration and plantar pressure uniquely characterize postures and typical activities while requiring minimal preprocessing and no feature extraction. The shoe sensor was tested in nine adults performing sitting and standing postures and while walking, running, stair ascent/descent and cycling. Support vector machines (SVMs) were used for classification. A fourfold validation of a six-class subject-independent group model showed 95.2% average accuracy of posture/activity classification on full sensor set and over 98% on optimized sensor set. Using a combination of acceleration/pressure also enabled a pronounced reduction of the sampling frequency (25 to 1 Hz) without significant loss of accuracy (98% versus 93%). Subjects had shoe sizes (US) M9.5-11 and W7-9 and body mass index from 18.1 to 39.4 kg/m2 and thus suggesting that the device can be used by individuals with varying anthropometric characteristics.

Social and medical vulnerability factors of emergency department frequent users in a universal health insurance system.

OBJECTIVES: The objectives were to identify the social and medical factors associated with emergency department (ED) frequent use and to determine if frequent users were more likely to have a combination of these factors in a universal health insurance system. METHODS: This was a retrospective chart review case-control study comparing randomized samples of frequent users and nonfrequent users at the Lausanne University Hospital, Switzerland. The authors defined frequent users as patients with four or more ED visits within the previous 12 months. Adult patients who visited the ED between April 2008 and March 2009 (study period) were included, and patients leaving the ED without medical discharge were excluded. For each patient, the first ED electronic record within the study period was considered for data extraction. Along with basic demographics, variables of interest included social (employment or housing status) and medical (ED primary diagnosis) characteristics. Significant social and medical factors were used to construct a logistic regression model, to determine factors associated with frequent ED use. In addition, comparison of the combination of social and medical factors was examined. RESULTS: A total of 359 of 1,591 frequent and 360 of 34,263 nonfrequent users were selected. Frequent users accounted for less than a 20th of all ED patients (4.4%), but for 12.1% of all visits (5,813 of 48,117), with a maximum of 73 ED visits. No difference in terms of age or sex occurred, but more frequent users had a nationality other than Swiss or European (n = 117 [32.6%] vs. n = 83 [23.1%], p = 0.003). Adjusted multivariate analysis showed that social and specific medical vulnerability factors most increased the risk of frequent ED use: being under guardianship (adjusted odds ratio [OR] = 15.8; 95% confidence interval [CI] = 1.7 to 147.3), living closer to the ED (adjusted OR = 4.6; 95% CI = 2.8 to 7.6), being uninsured (adjusted OR = 2.5; 95% CI = 1.1 to 5.8), being unemployed or dependent on government welfare (adjusted OR = 2.1; 95% CI = 1.3 to 3.4), the number of psychiatric hospitalizations (adjusted OR = 4.6; 95% CI = 1.5 to 14.1), and the use of five or more clinical departments over 12 months (adjusted OR = 4.5; 95% CI = 2.5 to 8.1). Having two of four social factors increased the odds of frequent ED use (adjusted = OR 5.4; 95% CI = 2.9 to 9.9), and similar results were found for medical factors (adjusted OR = 7.9; 95% CI = 4.6 to 13.4). A combination of social and medical factors was markedly associated with ED frequent use, as frequent users were 10 times more likely to have three of them (on a total of eight factors; 95% CI = 5.1 to 19.6). CONCLUSIONS: Frequent users accounted for a moderate proportion of visits at the Lausanne ED. Social and medical vulnerability factors were associated with frequent ED use. In addition, frequent users were more likely to have both social and medical vulnerabilities than were other patients. Case management strategies might address the vulnerability factors of frequent users to prevent inequities in health care and related costs.

Teaching motivational interviewing to medical students : a pre-post test pilot study

Objective: To test the efficacy of teaching motivational interviewing (MI) to medical students. Methods: Thirteen 4th year medical students volunteered to participate. Seven days before and 7 days after an 8-hour interactive training MI workshop, each student performed a videorecorded interview with two standardized patients: a 60 year old alcohol dependent woman and a 50 year old cigarette smoking man. Students' counseling skills were coded by two blinded clinicians using the Motivational Interviewing Treatment Integrity 3.0 (MITI). Inter-rater reliability was calculated for all interviews and a test-retest was completed in a sub-sample of 10 consecutive interviews three days apart. Difference between MITI scores before and after training were calculated and tested using non-parametric tests. Effect size was approximated by calculating the probability that posttest scores are greater than pretest scores (P*=P(Pre<Post)+1/2P(Pre=Post)), P*>1/2 indicating greater scores in posttest, P*=1/2 no effect, and P*<1/2 smaller scores in posttest. Results: Median differences between MITI scores before and after MI training indicated a general progression in MI skills: MI spirit global score (median difference=1.5, Inter quartile range=1.5, p<0.001, P*=0.90); Empathy global score (med diff=1, IQR=0.5, p<0.001, P*=0.85); Percentage of MI adherent skills (med diff=36.6, IQR=50.5, p<0.001, P*=0.85); Percentage of open questions (med diff=18.6, IQR=21.6, p<0.001, P*=0.96); reflections/ questions ratio (med diff=0.2, IQR=0.4, p<0.001, P*=0.81). Only Direction global score and the percentage of complex reflections were not significantly improved (med diff=0, IQR=1, p=0.53, P*=0.44, and med diff=4.3, IQR=24.8, p=0.48, P*=0.62, respectively). Inter-rater reliability indicated weighted kappa ranged between 0.14 for Direction to 0.51 for Collaboration and ICC ranged between 0.28 for Simple reflection to 0.95 for Closed question. Test-retests indicated weighted kappa ranged between 0.27 for Direction to 0.80 for Empathy and ICC ranged between 0.87 for Complex reflection to 0.98 for Closed question. Conclusion: This pilot study indicated that an 8-hour training in MI for voluntary 4th year medical students resulted in significant improvement of MI skills. Larger sample of unselected medical students should be studied to generalize the benefit of MI training to medical students. Interrater reliability and test-retests suggested that coders' training should be intensified.

Medical and legal professionals' attitudes towards confidentiality and disclosure of clinical information in forensic settings: a survey using case vignettes.

OBJECTIVE: When potentially dangerous patients reveal criminal fantasies to their therapists, the latter must decide whether this information has to be transmitted to a third person in order to protect potential victims. We were interested in how medical and legal professionals handle such situations in the context of prison medicine and forensic evaluations. We aimed to explore the motives behind their actions and to compare these professional groups. METHOD: A mail survey was conducted among medical and legal professionals using five fictitious case vignettes. For each vignette, participants were asked to answer questions exploring what the professional should do in the situation and to explain their justification for the chosen response. RESULTS: A total of 147 questionnaires were analysed. Agreement between participants varied from one scenario to another. Overall, legal professionals tended to disclose information to a third party more easily than medical professionals, the latter tending to privilege confidentiality and patient autonomy over security. Perception of potential danger in a given situation was not consistently associated with actions. CONCLUSION: Professionals' opinions and attitudes regarding the confidentiality of potentially dangerous patients differ widely and appear to be subjectively determined. Shared discussions about clinical situations could enhance knowledge and competencies and reduce differences between professional groups.

Guidleines for Removal of Traffic Control Devices in Rural Areas, October 2005

It is commonly regarded that the overuse of traffic control devices desensitizes drivers and leads to disrespect, especially for low-volume secondary roads with limited enforcement. The maintenance of traffic signs is also a tort liability concern, exacerbated by unnecessary signs. The Federal Highway Administration’s (FHWA) Manual on Uniform Traffic Control Devices (MUTCD) and the Institute of Transportation Engineer’s (ITE) Traffic Control Devices Handbook provide guidance for the implementation of STOP signs based on expected compliance with right-of-way rules, provision of through traffic flow, context (proximity to other controlled intersections), speed, sight distance, and crash history. The approach(es) to stop is left to engineering judgment and is usually dependent on traffic volume or functional class/continuity of system. Although presently being considered by the National Committee on Traffic Control Devices, traffic volume itself is not given as a criterion for implementation in the MUTCD. STOP signs have been installed at many locations for various reasons which no longer (or perhaps never) met engineering needs. If in fact the presence of STOP signs does not increase safety, removal should be considered. To date, however, no guidance exists for the removal of STOP signs at two-way stop-controlled intersections. The scope of this research is ultra-low-volume (< 150 daily entering vehicles) unpaved intersections in rural agricultural areas of Iowa, where each of the 99 counties may have as many as 300 or more STOP sign pairs. Overall safety performance is examined as a function of a county excessive use factor, developed specifically for this study and based on various volume ranges and terrain as a proxy for sight distance. Four conclusions are supported: (1) there is no statistical difference in the safety performance of ultra-low-volume stop-controlled and uncontrolled intersections for all drivers or for younger and older drivers (although interestingly, older drivers are underrepresented at both types of intersections); (2) compliance with stop control (as indicated by crash performance) does not appear to be affected by the use or excessive use of STOP signs, even when adjusted for volume and a sight distance proxy; (3) crash performance does not appear to be improved by the liberal use of stop control; (4) safety performance of uncontrolled intersections appears to decline relative to stop-controlled intersections above about 150 daily entering vehicles. Subject to adequate sight distance, traffic professionals may wish to consider removal of control below this threshold. The report concludes with a section on methods and legal considerations for safe removal of stop control.

Late migration of percutaneous bio-absorbable devices--a word of caution.

BACKGROUND: Closures of atrial septal defects or a patent foramen ovale (PFO) are increasingly performed percutaneously. The experience of late migration of a new bio-absorbable device is presented here, followed by conceptual discussion. METHODS: Six months post PFO closure with a BioSTAR® device a patient presented with chest pain. Echocardiography showed a hyperechogenic structure perforating the aortic wall. RESULTS: Surgical exploration showed a perforation of the ascending aorta by one metallic, non absorbable arm. This is the second case of late (>6 months) dislocation of the residual framework of the occluder. CONCLUSIONS: The overall incidence of perforation of cardiac structures due to secondary dislocation is low. However this complication exists and should kept in mind in symptomatic patients with new onset of chest pain, after percutaneous procedures. The concept of biodegradation, with residual, non absorbable metal braiding, should be reviewed, analyzing in particular long term results and incidence of secondary dislocation.

Que faire d'un stagiaire dans votre consultation [Tips for hosting a medical student in a PC consultation].

Hosting a medical student in one's primary care consultation challenges the practitioner to be a clinical teacher as well as providing high-quality patient care. A few tips can make this double task easier. Before the consultation it is possible to define the student's learning objectives and to plan the consultation. During the consultation itself some teaching models exist (One minute preceptor, SNAPP) that facilitate the teaching by maximising the teaching moments for each student-patient encounter. And finally after the consultation a time of reflection where both student and clinical teacher can think about what went well and what could be done better.

Predictive factors of adrenal insufficiency in patients admitted to acute medical wards: a case control study.

BACKGROUND: Adrenal insufficiency is a rare and potentially lethal disease if untreated. Several clinical signs and biological markers are associated with glucocorticoid failure but the importance of these factors for diagnosing adrenal insufficiency is not known. In this study, we aimed to assess the prevalence of and the factors associated with adrenal insufficiency among patients admitted to an acute internal medicine ward. METHODS: Retrospective, case-control study including all patients with high-dose (250 μg) ACTH-stimulation tests for suspected adrenal insufficiency performed between 2008 and 2010 in an acute internal medicine ward (n = 281). Cortisol values <550 nmol/l upon ACTH-stimulation test were considered diagnostic for adrenal insufficiency. Area under the ROC curve (AROC), sensitivity, specificity, negative and positive predictive values for adrenal insufficiency were assessed for thirteen symptoms, signs and biological variables. RESULTS: 32 patients (11.4%) presented adrenal insufficiency; the others served as controls. Among all clinical and biological parameters studied, history of glucocorticoid withdrawal was the only independent factor significantly associated with patients with adrenal insufficiency (Odds Ratio: 6.71, 95% CI: 3.08 -14.62). Using a logistic regression, a model with four significant and independent variable was obtained, regrouping history of glucocorticoid withdrawal (OR 7.38, 95% CI [3.18 ; 17.11], p-value <0.001), nausea (OR 3.37, 95% CI [1.03 ; 11.00], p-value 0.044), eosinophilia (OR 17.6, 95% CI [1.02; 302.3], p-value 0.048) and hyperkalemia (OR 2.41, 95% CI [0.87; 6.69], p-value 0.092). The AROC (95% CI) was 0.75 (0.70; 0.80) for this model, with 6.3 (0.8 - 20.8) for sensitivity and 99.2 (97.1 - 99.9) for specificity. CONCLUSIONS: 11.4% of patients with suspected adrenal insufficient admitted to acute medical ward actually do present with adrenal insufficiency, defined by an abnormal response to high-dose (250 μg) ACTH-stimulation test. A history of glucocorticoid withdrawal was the strongest factor predicting the potential adrenal failure. The combination of a history of glucocorticoid withdrawal, nausea, eosinophilia and hyperkaliemia might be of interest to suspect adrenal insufficiency.