Estudio de cohortes para evaluar la prevalencia de QT prolongado y arritmias en pacientes críticos durante la primera fase de la pandemia por COVID-19 / Cohort study to assess the prevalence of prolonged QT and arrhythmias in critically ill patients during the early phase of the COVID-19 pandemic

Antecedentes y objetivo: Los pacientes con infección por SARS-CoV-2 pueden presentar afectación cardiovascular, incluyendo miocarditis, arritmias y prolongación del intervalo QT. Nuestro objetivo fue evaluar el impacto de la COVID-19 y su tratamiento en la repolarización ventricular y el desarrollo de arritmias en pacientes críticos. Material y métodos: Estudio de cohortes retrospectivo de pacientes críticos con infección confirmada por SARS-CoV-2 durante un periodo de 3meses. Se registraron los datos clínicos relevantes y el tratamiento específico administrado para la COVID-19. Se consideró QTc prolongado cuando medía ≥460ms en mujeres y ≥450ms en hombres. Se registró la incidencia y el tipo de arritmias durante el mismo periodo. Resultados: Se evaluaron 77 pacientes con una edad media de 62±13años: 20 mujeres y 57 hombres. El 60% de los pacientes eran hipertensos, el 52% presentaban un IMC>30 y el 70% desarrollaron fracaso renal agudo durante el ingreso. El 56% de los pacientes presentaron prolongación del QTc. El 44% presentaron algún tipo de arritmia durante su estancia en la UCI, siendo en el 21% arritmias auriculares. La mortalidad global fue del 53%, sin diferencias entre los pacientes con o sin QTc prolongado. Conclusiones: En nuestra serie, una elevada proporción de pacientes críticos con COVID-19 han presentado QTc prolongado y arritmias. Los factores implicados se han relacionado con la elevación de biomarcadores cardiacos, la propia afectación miocárdica del virus y la medicación concomitante recibida en la UCI.(AU)

Introduction and objective: Patients with SARS-CoV-2 infection may present cardiovascular involvement including myocarditis, arrhythmias and QT interval prolongation. Our objective was to evaluate the impact of COVID-19 and its treatment on ventricular repolarization and development of arrhythmias in critically ill patients. Material and methods: Retrospective cohort study of critically ill COVID-19 patients during a 3-month period in whom at least one ECG was available. Relevant clinical data and specific treatment administered for COVID-19 were recorded. Prolonged QTc was considered prolonged when it measured ≥460ms in women and ≥450ms in men. The incidence and type of arrhythmias during the same period were recorded. Results: A total of 77 patients with a mean age of 62±13years, 20 women and 57 men, were evaluated. Sixty percent of the patients were hypertensive, 52% had a BMI>30, and 70% developed acute renal failure during admission. Some 56% of the patients presented QTc prolongation. Forty-four percent presented some type of arrhythmia during their stay in the ICU, 21% of which were atrial arrhythmias. Overall mortality was 53%, with no differences between patients with or without prolonged QTc. Conclusions: In our series, a high proportion of critical patients with COVID-19 presented prolonged QTc and arrhythmias. The factors involved have been related to the elevation of cardiac biomarkers, the myocardial involvement of the virus and concomitant medication received in the ICU.(AU)

Cohort study to assess the prevalence of prolonged QT and arrhythmias in critically ill patients during the early phase of the COVID-19 pandemic.

INTRODUCTION: Patients with SARS-CoV-2 infection may present cardiovascular involvement including myocarditis, arrhythmias and QT interval prolongation. Our objective was to evaluate the impact of COVID-19 and its treatment on ventricular repolarization and development of arrhythmias in critically ill patients. METHODS: Retrospective cohort study of critically ill COVID-19 patients during a 3-month period in whom at least one ECG was available. Relevant clinical data and specific treatment administered for COVID-19 were recorded. Prolonged QTc was considered prolonged when it measured ≥ 460 ms in women and ≥450 ms in men. The incidence and type of arrhythmias during the same period were recorded. RESULTS: A total of 77 patients with a mean age of 62 ±â€¯13 years, 20 women and 57 men, were evaluated. Sixty percent of the patients were hypertensive, 52% had a BMI > 30, and 70% developed acute renal failure during admission. Some 56% of the patients presented QTc prolongation. Forty-four percent presented some type of arrhythmia during their stay in the ICU, 21% of which were atrial arrhythmias. Overall mortality was 53%, with no differences between patients with or without prolonged QTc. CONCLUSIONS: In our series, a high proportion of critical patients with COVID-19 presented prolonged QTc and arrhythmias. The factors involved have been related to the elevation of cardiac biomarkers, the myocardial involvement of the virus and concomitant medication received in the ICU.

Surgical Apgar score as a complication predictor in gastrointestinal oncologic surgery.

INTRODUCTION AND AIMS: Surgical resection of gastrointestinal (GI) cancer is the cornerstone of curative treatment but entails considerable morbidity. The surgical Apgar score (SAS) is a practical and objective instrument that provides immediate feedback. The aim of the present study was to evaluate the performance of the SAS for predicting complications at 30 days in patients with primary GI cancer that underwent curative surgery. MATERIALS AND METHODS: A prospective observational study was conducted that included 50 patients classified into a low SAS (≤ 4) group or a high SAS (≥ 5) group. Complications were defined as any event classified as a Clavien-Dindo grade II to V event. Bivariate and multivariate analyses were performed through the Cox regression and a p<0.05 was considered significant. RESULTS: Overall postoperative morbidity was 50.0%, with no mortality. Eighty-six percent of cases were catalogued as having an ASA≥3. Eighty-eight percent had a high SAS, of whom 45.5% presented with a complication, whereas 12.0% had a low SAS and a complication rate of 83.3%. In the multivariate analysis, the BMI (OR: 3.351, 95% CI: 1.218-9.217, P=.019), SAS (OR: 0.266, 95% CI: 0.077-0.922, P=.037), surgery duration (OR: 3.170, 95% CI: 1.092-9.198, P=.034), and ephedrine use (OR: 0.356, 95% CI: 0.144-0.880, P=.025) were significantly associated with the development of adverse outcomes. CONCLUSIONS: SAS was shown to be an independent predictive factor of postoperative morbidity at 30 days in the surgical management of GI cancer and appears to offer a reliable sub-stratification in a high-risk population with an ASA≥3.

Design and verification of the shielding around the new Neutron Standards Laboratory (LPN) at CIEMAT.

The construction of the new Neutron Standards Laboratory at CIEMAT (Laboratorio de Patrones Neutrónicos) has been finalised and is ready to provide service. The facility is an ∼8 m×8 m×8 m irradiation vault, following the International Organization for Standardization 8529 recommendations. It relies on several neutron sources: a 5-GBq (5.8× 10(8) s(-1)) (252)Cf source and two (241)Am-Be neutron sources (185 and 11.1 GBq). The irradiation point is located 4 m over the ground level and in the geometrical centre of the room. Each neutron source can be moved remotely from its storage position inside a water pool to the irradiation point. Prior to this, an important task to design the neutron shielding and to choose the most appropriate materials has been developed by the Radiological Security Unit and the Ionizing Radiations Metrology Laboratory. MCNPX was chosen to simulate the irradiation facility. With this information the walls were built with a thickness of 125 cm. Special attention was put on the weak points (main door, air conditioning system, etc.) so that the ambient dose outside the facility was below the regulatory limits. Finally, the Radiation Protection Unit carried out a set of measurements in specific points around the installation with an LB6411 neutron monitor and a Reuter-Stokes high-pressure ion chamber to verify experimentally the results of the simulation.

[Prevention of venous thromboembolic disease in the critical patient: an assessment of clinical practice in the Community of Madrid]. / Profilaxis de la enfermedad tromboembólica venosa en el paciente crítico: aproximación a la práctica clínica en la Comunidad de Madrid.

OBJECTIVE: To analyze measures referred to venous thromboembolic prophylaxis in critically ill patients. DESIGN: An epidemiological, cross-sectional (prevalence cut), multicenter study was performed using an electronic survey. Comparison of results with quality indexes of the Spanish Society of Intensive Care Medicine, the American College of Chest Physician guidelines and international studies. SETTING: Intensive Care Units (ICUs) in the Community of Madrid (Spain). PATIENTS: All patients admitted to the ICU on the day of the survey. VARIABLES OF INTEREST: General aspects of venous thromboembolic prophylaxis and protocols used (risk stratification and ultrasound screening). A descriptive analysis was performed, continuous data being expressed as the mean or median, and categorical data as percentages. RESULTS: A total of 234 patients in 18 ICUs were included. Eighteen percent (42/234) received no prophylaxis, and 55% had no contraindication to pharmacological prophylaxis. Of the 192 patients receiving prophylaxis, 84% received pharmacological prophylaxis, 14% mechanical prophylaxis and 2% combined prophylaxis. Low molecular weight heparin was the only pharmacological prophylaxis used, with a majority use of enoxaparin (17 of 18 ICUs). In patients with mechanical prophylaxis (31/192), antiembolic stockings were the most commonly used option (58%). Pharmacological prophylaxis contraindications were reported in 20% of the patients (46/234), the most frequent cause being thrombocytopenia (28% of the cases). Fifty percent of the ICUs used no specific venous thromboembolic prophylaxis protocol. CONCLUSIONS: Pharmacological prophylaxis with low molecular weight heparin was the most frequently used venous thromboembolic prophylactic measure. In patients with contraindications to pharmacological prophylaxis, mechanical measures were little used. The use of combined prophylaxis was anecdotal. Many of our ICUs lack specific prophylaxis protocols.

[Extracorporeal lung support in patients with severe respiratory failure secondary to the 2010-2011 winter seasonal outbreak of influenza A (H1N1) in Spain]. / Uso de oxigenador de membrana extracorpóreo en pacientes con insuficiencia respiratoria aguda grave refractaria en la epidemia de gripe estacional 2010-2011 por influenza A (H1N1) en España.

OBJECTIVE: To describe the use of extracorporeal membrane oxygenation (ECMO) in refractory respiratory failure. DESIGN: A prospective, observational, multi-center study was carried out. SETTING: Intensive Care Units (ICU) in 148 Spanish hospitals. PATIENTS: Subjects admitted during epidemic weeks 50-52 of 2010 and weeks 1-4 of 2011, receiving respiratory support with ECMO. MAIN VARIABLES OF INTEREST: Clinical and blood gas features, complications and survival of patients with ECMO. RESULTS: Out of 300 ICU admitted patients, 239 (79.6%) were mechanically ventilated. ECMO was available in only 5 ICUs. Nine patients were treated with ECMO (3% of the total and 3.2% of the ventilated patients). In 77.7% of the cases some hypoxemia rescue technique was previously used. ECMO was initiated when ARDS proved refractory to standard treatment. ECMO therapy was started a median of 4.5 days after the onset of mechanical ventilation. The median duration of ECMO was 6 days. Veno-venous (VV) ECMO was the most frequent cannulation mode (88.9%). Four patients had complications associated with ECMO therapy. The median ICU and hospital stay was 17 and 29 days, respectively. In five patients (55.5%), ECMO assistance was satisfactory suspended. The ICU and hospital survival rate was 44.4%. CONCLUSIONS: The use of ECMO in refractory respiratory failure in patients with influenza A (H1N1) is rare in Spain. The hospital survival achieved with its use allows it to be regarded as a possible rescue technique in these patients.

Gripe A pandémica en una unidad de cuidados intensivos: experiencia en España y Latinoamérica (Grupo Español de Trabajo de Gripe A Grave/Sociedad Española de Medicina Intensiva, Crítica y Unidades Coronarias) / Pandemic Influenza A in the ICU: Experience in Spain and Latin America GETGAG/SEMICYUC/(Spanish Work Group on Severe Pandemic Influenza A/SEMICYUC)

Introducción: La pandemia de gripe A (H1N1)v es la primera pandemia en la que las unidades de cuidados intensivos (UCI) desempeñan un papel fundamental. Su evolución ha sido muy rápida desde los primeros casos diagnosticados en México y la afectación posterior de países del cono sur hasta su llegada a Europa durante la época estival. Objetivo: Comparar las características clínicas y de evolución de los pacientes críticos ingresados hasta el 31 de julio de 2009 en España con algunas series de Latinoamérica. Material y método: Se consideraron 6 series de pacientes ingresados en la UCI. Se realizaron comparaciones de las características clínicas, complicaciones y evolución entre las series. Resultados: Los datos evidencian una población joven (35-45 años) con predominio de ingresos por neumonía viral con grave insuficiencia respiratoria y una elevada necesidad de ventilación mecánica (60-100%). Si bien algunas determinadas poblaciones, como los obesos, las embarazadas y los pacientes con enfermedad pulmonar crónica, parecen estar expuestas a un riesgo más elevado, la ausencia de comorbilidades alcanza un porcentaje considerable en casi todas las series (40-50%). La mortalidad superior en Latinoamérica osciló entre el 25 y el 50%, y demostró el particular potencial patogénico del nuevo virus. El uso del tratamiento antiviral es tardío (entre 3 y 6 días) y poco generalizado, con mayor retraso en Latinoamérica respecto de España. Conclusiones: Estos datos indican que una estrategia de tratamiento más intensivo con un acceso más precoz y fácil al antiviral podría reducir el número de pacientes que requieren UCI y su mortalidad (AU)

Introduction: Pandemic Influenza A (H1N1)v infection is the first pandemic in which intensive care units (ICU) play a fundamental role. It has spread very rapidly since the first cases were diagnosed in Mexico with the subsequent spread of the virus throughout the Southern Cone and Europe during the summer season. Objective: This study has aimed to compare the clinical presentation and outcome among the critical patients admitted to the ICU until July 31, 2009 in Spain with some series from Latin America. Material and method: Six series of critically ill patients admitted to the ICU were considered. Clinical characteristics, complications and outcome were compared between series. Results: Young patients (35-45 years) with viral pneumonia as a predominant ICU admission cause with severe respiratory failure and a high need of mechanical ventilation (60-100%) were affected. Obesity, pregnancy and chronic lung disease were risk factors associated with a worse outcome, however there was a high number of patients without comorbidities (40-50%). Mortality rate was between 25-50% and higher in the Latin America series, demonstrating the specific potential pathogenesis of the new virus. The use of antiviral treatment was delayed (between 3 and 6 days) and not generalized, with greater delay in Latin America in regards to Spain. Conclusions: These data suggest that a more aggressive treatment strategy, with earlier and easier access to the antiviral treatment might reduce the number of ICU admissions and mortality (AU)

Multivariate near-infrared reflection spectroscopy strategies for ensuring correct labeling at feed bagging in the animal feed industry.

A key concern in animal feed factories is guaranteeing the correct labeling of compound feeds. Therefore, due to incorrect labeling, there is an urgent need for new control methods on the claims that can be made. In this study, this question has been tackled with different multivariate classification algorithms based on the near-infrared spectral fingerprint obtained from a given compound feed analyzed in its original physical market presentation form (i.e., cubes, coarse meals, pellets). The objective of this paper is the evaluation of different methods for establishing a separation among 24 feed types. Two linear methods, soft independent modeling of class analogy (SIMCA) and partial least squares (PLS) with two approaches to classification (PLSD and PLS-LDA); and one nonlinear method, support vector machines (SVM), were studied. The database used had the following structure: a first division was made between granules and meals; within these two groups, there was a second division according to three animal species to which the feed was marketed (bovine, ovine, and porcine); within each species there was a third division according to the age or physiological status of the animal (i.e., lactating dairy cattle, starters, etc.). Given the database structure, all the methods were evaluated following two strategies: (1) development of a model composed of the nine classification models corresponding to the structure of the data; and (2) development of a unique model that discriminates among the 24 classes of different feeds. With both strategies the lowest percentage of misclassified samples was achieved with the SVM method (3.96% with strategy 1 and 2.31% with strategy 2). Among the linear methods evaluated, SIMCA yielded the best results, with a percentage of 8.47% misclassified samples with strategy 1 and 4.05% misclassified samples with strategy 2. The results in this study show the ability of near-infrared spectroscopy to make acceptable classifications of feed types based only on spectral information, with differences in performance depending on the multivariate algorithm used.

[Pandemic influenza A in the ICU: experience in Spain and Latin America. GETGAG/SEMICYUC/(Spanish Working Group on Severe Pandemic Influenza A/SEMICYUC)]. / Gripe A pandémica en una unidad de cuidados intensivos: experiencia en España y Latinoamérica (Grupo Español de Trabajo de Gripe A Grave/Sociedad Española de Medicina Intensiva, Crítica y Unidades Coronarias).

INTRODUCTION: Pandemic Influenza A (H1N1)v infection is the first pandemic in which intensive care units (ICU) play a fundamental role. It has spread very rapidly since the first cases were diagnosed in Mexico with the subsequent spread of the virus throughout the Southern Cone and Europe during the summer season. OBJECTIVE: This study has aimed to compare the clinical presentation and outcome among the critical patients admitted to the ICU until July 31, 2009 in Spain with some series from Latin America. MATERIAL AND METHOD: Six series of critically ill patients admitted to the ICU were considered. Clinical characteristics, complications and outcome were compared between series. RESULTS: Young patients (35-45 years) with viral pneumonia as a predominant ICU admission cause with severe respiratory failure and a high need of mechanical ventilation (60-100%) were affected. Obesity, pregnancy and chronic lung disease were risk factors associated with a worse outcome, however there was a high number of patients without comorbidities (40-50%). Mortality rate was between 25-50% and higher in the Latin America series, demonstrating the specific potential pathogenesis of the new virus. The use of antiviral treatment was delayed (between 3 and 6 days) and not generalized, with greater delay in Latin America in regards to Spain. CONCLUSIONS: These data suggest that a more aggressive treatment strategy, with earlier and easier access to the antiviral treatment might reduce the number of ICU admissions and mortality.

Advanced nonlinear approaches for predicting the ingredient composition in compound feedingstuffs by near-infrared reflection spectroscopy.

For quantitative applications, the most common usage of near-infrared reflection spectroscopy (NIRS) technology, calibration involves establishing a mathematical relationship between spectral data and data provided by the reference. This model may be fairly complex, since the near-infrared spectrum is highly variable and contains physical/chemical information for the sample that may be redundant, and multivariate calibration is usually required. When the relationship to be modeled is nonlinear, classical regression methods are inadequate, and more complex strategies and algorithms must be sought in order to model this nonlinearity. The development of NIRS calibrations to predict the ingredient composition, i.e., the inclusion percentage of each ingredient, in compound feeds is a complex task, due to the nature of the parameters to be predicted and to the heterogeneous nature of the matrices/formulas in which each ingredient participates. The present paper evaluates the use of least squares support vector machines (LSSVM) and two local calibration methods, CARNAC and locally biased regression, for developing NIRS models to predict two of the most representative ingredients in compound feed formulations, wheat and sunflower meal, using a large spectral library of 7523 commercial compound feed samples. For both ingredients, the best results were obtained using CARNAC, with standard errors of prediction (SEP) of 1.7% and 0.60% for wheat and sunflower meal, respectively, and even better results when the algorithm was allowed to refuse to predict 10% of the unknowns. Meanwhile, LSSVM performed less well on wheat (SEP 2.6%) but comparably on sunflower meal (SEP 0.60%), giving results very similar to those reported previously for artificial neural networks. Locally biased regression was the least successful of the three methods, with SEPs of 3.3% for wheat and 0.72% for sunflower meal. All the nonlinear methods improved on the standard approach using partial least squares (PLS), which gave SEPs of 5.3% for wheat and 0.81% for sunflower meal.

Non-linear regression methods in NIRS quantitative analysis.

Due to its speed and precision, near-infrared reflectance spectroscopy (NIRS) has become a widely used analytical technique in many industries. It offers, moreover, a number of other advantages which make it ideal for meeting current demands in terms of control and traceability: low cost per sample analysed; little or no need for sample preparation; ability to analyse a wide range of products and parameters; a high degree of reproducibility and repeatability. NIRS can be built into in-line processes, and - since no reagents are required - produces no waste. However, the major drawback to the use of NIRS for its most traditional application (the generation of prediction equations) is that it is a secondary method, and as such needs to be calibrated using a conventional reference method. For quantitative applications, calibration involves ascertaining the optimum mathematical relationship between spectral data and data provided by the reference method. The model may be fairly complex, since the NIRS spectrum is highly variable and contains physical/chemical information for the sample which may be redundant. As a result, multivariate calibration is required, based on a set of absorption values from several wavelengths. Since the relationship to be modelled is often non-linear, classical regression methods are unsuitable, and more complex strategies and algorithms must be sought in order to model this non-linearity. This overview addresses the most widely used non-linear algorithms in the management of NIRS data.

Use of artificial neural networks in near-infrared reflectance spectroscopy calibrations for predicting the inclusion percentages of wheat and sunflower meal in compound feedingstuffs.

The use of near-infrared reflectance spectroscopy (NIRS) calibrations to predict the ingredient composition in compound feeds (i.e., inclusion percentage of each ingredient) is a complex task, regarding both the nature of the parameters to be predicted, since they are not well-defined chemical entities, and the heterogeneousness of the matrices/formulas in which each ingredient participates. The present paper evaluates the use of nonlinear regression methods, such as artificial neural networks (ANN), for developing NIRS calibrations to predict these parameters. Two of the most representative ingredients in the Spanish compound feed formulations (wheat and sunflower meal) were selected for evaluating ANN possibilities, using a large spectral library comprising a total of 7523 commercial compound feed samples; 7423 were used as training set and 100 as validation set. Three general models of networks were studied: multilayer perceptron with back-propagation training (BP), multilayer perceptron with Levenberg-Maquartd training (LM), and radial basis function nets (RBF); moreover, in accordance with a factorial design, more complex architectures were evaluated gradually, changing the number of hidden layers and hidden neurons, for the determination of the optimal network topology. For both ingredients, the best results were obtained using ANN with BP training, showing prediction error values (SEP) of 2.72% and 0.66% for wheat and sunflower meal, respectively. These SEP values showed a significant improvement (19%-49% for sunflower meal and wheat, respectively) in comparison with those obtained using calibrations developed with linear methods.

Optimization of discriminant partial least squares regression models for the detection of animal by-product meals in compound feedingstuffs by near-infrared spectroscopy.

This paper evaluates two multivariate strategies for classifying near-infrared (NIR) spectroscopic data for the detection of animal by-product meals (henceforth generically termed AbP) as an ingredient in compound feedingstuffs. Classification models were developed to discriminate between the presence and absence of animal-origin meals in compound feeds using two forms of discriminant partial least squares (PLS) regression: the algorithms PLS1 and PLS2. The training set comprised 433 commercial feeds, of which 148 contained AbP and the other 285 were stated to be AbP-free. Since the initial set contained unequal numbers of each class, the effect of this imbalance was analyzed by applying the same algorithms to a training set containing equal numbers of AbP-free and AbP-containing samples. The best classification model (97.42% of samples correctly classified), obtained with PLS2, that showed less sensitivity to the use of class-unbalanced sets, was externally validated using a set of 18 samples (10 AbP-containing and 8 AbP-free); all samples were correctly classified, except for one AbP-free sample that was classified as containing AbP (false positive). The results suggest that the application of PLS discriminant analysis to NIR spectroscopic data enables detection of AbP, a feed ingredient banned since the bovine spongiform encephalopathy (BSE) crisis; this confirms the value of NIRS qualitative analysis for product authentication purposes.

Experiencia asistencial en el 11-M / Caring for the victims of M-11

No disponible

Implementation of LOCAL algorithm with near-infrared spectroscopy for compliance assurance in compound feedingstuffs.

Seven thousand four hundred and twenty-three compound feed samples were used to develop near-infrared (NIR) calibrations for predicting the percentage of each ingredient used in the manufacture of a given compound feedingstuff. Spectra were collected at 2 nm increments using a FOSS NIRSystems 5000 monochromator. The reference data used for each ingredient percentage were those declared in the formula for each feedingstuff. Two chemometric tools for developing NIRS prediction models were compared: the so-called GLOBAL MPLS (modified partial least squares), traditionally used in developing NIRS applications, and the more recently developed calibration strategy known as LOCAL. The LOCAL procedure is designed to select, from a large database, samples with spectra resembling the sample being analyzed. Selected samples are used as calibration sets to develop specific MPLS equations for predicting each unknown sample. For all predicted ingredients, LOCAL calibrations resulted in a significant improvement in both standard error of prediction (SEP) and bias values compared with GLOBAL calibrations. Determination coefficient values (r(2)) also improved using the LOCAL strategy, exceeding 0.90 for most ingredients. Use of the LOCAL algorithm for calibration thus proved valuable in minimizing the errors in NIRS calibration equations for predicting a parameter as complex as the percentage of each ingredient in compound feedingstuffs.

Characterizing T-cell receptor gamma-variable gene in Aotus nancymaae owl monkey peripheral blood.

Gammadelta T lymphocytes have a heterodimeric complex formed by the association of gamma and delta chains as receptor. Proliferation of this lymphocyte population has been observed, when infection by several pathogens such as Mycobacterium tuberculosis and Plasmodium spp. occurs. The New World Monkey Aotus nancymaae has become a very good experimental model for the immunological and physiopathological study of these infectious agents. The A. nancymaae gamma-variable region was characterized from peripheral blood samples by using cDNA and genomic DNA polymerase chain reaction amplification, DNA sequencing, and dot-blot hybridization techniques. Seventeen different T-cell receptor gamma-variable (TCRGV) sequences were obtained. These sequences were distributed among TCRGV subsets 1, 2, or 3, according to human subset classification. Although no subset 4 amplification was obtained, this subset was detected by dot-blot hybridization. The presence of these 4 subsets resembles the behavior displayed by 'gammadelta-low species' (humans and mice), where high diversity among these lymphocytes can be observed. Homologies greater than 70% were found with respect to humans. Sequence convergence between human and A. nancymaae subsets 1 and 3 highlights Aotus as a promising model for studying these lymphocyte functions.

[Prognosis of patients admitted to the coronary or intensive care unita after an out of hospital episode of sudden death]. / Pronóstico de los pacientes ingresados en la unidad coronaria o de cuidados intensivos tras un episodio de muerte súbita extrahospitalaria.

INTRODUCTION AND OBJECTIVE: Out of hospital sudden death constitutes a major sanitary problem. Early diagnosis and treatment are considered as the most important factors related with short term prognosis. However, there is little information about the outcome of patients admitted to the hospital after a successful recovery from an episode of sudden death outside the hospital. The objective of this study was to analyze the prognosis of patients who initially recovered after an episode of out-of-hospital cardiac arrest and who were admitted to the coronary or intensive care unit. PATIENTS AND METHODS: The clinical characteristics and outcome of 110 consecutive patients admitted to the coronary and intensive care units after an episode of extrahospital sudden death, who initially recovered with success, were retrospectively studied. RESULTS: A total of 33 (30%) patients were discharged alive and without severe neurological damage, 67 (61%) patients died before discharge from hospital and 77 (70%) died or presented severe and permanent neurological damage. The latter group versus those who survived was older (63.6 +/- 13.5 vs 55.2 +/- 12.6 years old; p < 0.006) and had a longer delay in the beginning of cardiopulmonary resuscitation (8.3 vs 2.8 min.; p < 0.01). Mortality or severe neurological damage rate was higher in the group of those who had asystolia than in those with ventricular fibrillation in the first ECG (84% vs 55%), in those who arrived to the hospital unconscious (73.7% vs 15.4%) and in those who arrived in functional class IV (81% vs 16.6%). CONCLUSIONS: Up to 30% of the patients admitted after an episode of extrahospital cardiac arrest were discharged alive and without severe neurological damage. Advanced age, functional class IV and the delay of cardiopulmonary resuscitation are related to a unfavorable outcome.

Pressure-controlled ventilation versus controlled mechanical ventilation with decelerating inspiratory flow.

OBJECTIVE: To ascertain whether pressure-controlled ventilation offers any advantage with respect to conventional controlled mechanical ventilation with decelerating flow. DESIGN: Prospective, comparative study. SETTING: Intensive care unit. PATIENTS: Eleven consecutive critically ill adult patients. MEASUREMENTS AND MAIN RESULTS: Study of respiratory mechanics and arterial blood gases after 30 mins of pressure-controlled ventilation. Repetition of the same measurements after 30 mins of controlled mechanical ventilation with decelerating flow waveform, with equal tidal volumes, using a commercially available mechanical ventilator. Student's t-test for paired comparisons. A lesser maximum inspiratory flow rate was required for pressure-controlled ventilation (55.7 +/- 16 L/sec) than for controlled mechanical ventilation (72 +/- 2 L/sec) (p < .001). Nevertheless, the peak pressures measured in the orotracheal tubes of the patients were higher in pressure-controlled ventilation (20.4 +/- 3.5 cm H2O) than in controlled mechanical ventilation (18.4 +/- 4.8 cm H2O) (p < .05). This model measured pressure in the inspiratory line, providing erroneous information regarding the behavior of pressures in the airway. The peak pressure measured by the ventilator was significantly higher in controlled mechanical ventilation than in pressure-controlled ventilation and was, in addition, reached at initiation of inspiration in ten of 11 patients with controlled mechanical ventilation, while peak pressure measured in the orotracheal tube was invariably reached at the end of the inspiration, both in pressure-controlled ventilation and controlled mechanical ventilation. The rest of the parameters analyzed, including end-inspiratory pressure, mean pressure, intrinsic positive end-expiratory pressure, and arterial blood gases, showed no differences. The difference between quasi-static compliances almost reached statistical significance (72 +/- 25.4 mL/cm H2O in pressure-controlled ventilation vs. 68.8 +/- 24.3 mL/cm H2O in controlled mechanical ventilation; p = .052). CONCLUSIONS: Our study failed to demonstrate any important difference between pressure-controlled ventilation and controlled mechanical ventilation with decelerating inspiratory flow waveform. The differences in the airway pressures detected by the ventilator are spurious and are due to the place (inspiratory line) where these pressures were measured. The difference between the peak pressure measured in the orotracheal tube has statistical, but not clinical, value and is lower in controlled mechanical ventilation. Based on the limited number of variables we studied and unless the tendency indicated in the quasi-static compliance is demonstrated in the future, we do not believe that pressure-controlled ventilation contributes any uniqueness to the theory or practice of mechanical ventilation.

Interaction between intrinsic positive end-expiratory pressure and externally applied positive end-expiratory pressure during controlled mechanical ventilation.

OBJECTIVE: To assess the interaction between intrinsic and externally applied positive end-expiratory pressure (intrinsic PEEP and administered PEEP) in mechanically ventilated patients. DESIGN: Prospective study. SETTING: Intensive care unit of a university hospital. PATIENTS: Twelve consecutive critically ill patients. INTERVENTIONS: Application of an external PEEP of the same value as the intrinsic PEEP. MEASUREMENTS AND MAIN RESULTS: We found that when the administered PEEP was increased from 0 to the baseline value of intrinsic PEEP, mean intrinsic PEEP decreased from 6.5 +/- 4.2 (SD) to 1.3 +/- 0.7 cm H2O (p = .001). The mean end-inspiratory pressure was increased from 20.3 +/- 4.6 to 23.1 +/- 6.1 cm H2O (p < .05). The difference between the modification of intrinsic PEEP and the change in the end-inspiratory pressure was not significantly > 0 cm H2O. Thus, the increase in end-inspiratory pressure may be directly attributable to the increase in total PEEP (administered PEEP plus intrinsic PEEP). None of the other measurements of pulmonary mechanics changed (peak pressure, inspiratory resistance, compliance, and trapped-gas volume). CONCLUSIONS: The administration of positive end-expiratory pressure equal to the intrinsic positive end-expiratory pressure causes the almost total disappearance of the intrinsic positive end-expiratory pressure. When the administered positive end-expiratory pressure does not exceed the intrinsic positive end-expiratory pressure, the former is applied almost in its entirety to the patient's external circuit. The administration of positive end-expiratory pressure without prior quantification of the intrinsic positive end-expiratory pressure results in an overestimation of the beneficial effects of the administered positive end-expiratory pressure on the quasi-static compliance.