Turbulence driven particle transport in Texas Helimak

We analyze the turbulence driven particle transport in Texas Helimak (K. W. Gentle and Huang He, Plasma Sci. and Technology, 10, 284 (2008)), a toroidal plasma device with one-dimensional equilibrium with magnetic curvature and shear. Alterations on the radial electric field, through an external voltage bias, change spectral plasma characteristics inducing a dominant frequency for negative bias values and a broad band frequency spectrum for positive bias values. For negative biased plasma discharges, the transport is high where the waves propagate with phase velocities near the plasma flow velocity, an indication that the transport is strongly affected by a wave particle resonant interaction. On the other hand, for positive bias the plasma has a reversed shear flow and we observe that the transport is almost zero in the shearless radial region, an evidence of a transport barrier in this region.Comment: 8 pages, 11 figure

Analysis of Electrostatic Turbulence Drive in Texas Helimak.

Plasma turbulence and particle transport in Texas Helimak change with the radial electric field profile modified by an external voltage bias. When the bias is positive, the turbulence shows enhanced level and broadband spectra with extreme events, similar to the turbulence in tokamak scrape-‐off layer. However, negative bias reduces the turbulence level and decreases the spectrum widths. Moreover, for negative biased shots, the particle transport is strongly affected by a wave particle resonant interaction. On the other hand, for positive bias values, the plasma presents a transport barrier in the reversed shear flow region

Factors associated to vascular pedicle width in ARDS

Introduction: In previous studies, vascular pedicle width (VPW) was the best radiographic sign of intravascular volume status in critically ill patients and may enhance implementation and acceptance of the conservative fluid strategy into routine clinical practice. Objective: Our aim was to find the relationship among VPW and parameters of mechanical ventilation (MV) and baseline data. The hypothesis was that pressures, tidal volume and baseline data, as age, could be related to VPW in acute respiratory distress syndrome (ARDS). Methodology: It was a retrospective cohort study enrolled in the Open Lung Approach trial performed in moderate-severe acute respiratory distress syndrome recruited in São Paulo, Brazil. VPW was measured by two investigators in chestradiographs taken at diagnosis and after 24 hours of mechanical ventilation adjustments. The relationship between VPW, age, predicted body weight (PBW), positive end-expiratory pressure (PEEP), plateau pressure and tidal volume adjusted by PBW were evaluated. Results: 26 patients were included in analysis, with a total of 52 chest radiography analyzed. There was a significant change in VPW between diagnosis and after 24hours from MV adjustments (r = 0.64, p < 0.01).  Age was related to VPW before and after adjustments in MV (r= 0.57, p < 0.01). No correlation was found between MV parameters (PEEP, plateau pressure and tidal volume) with VPW. Conclusions: There was no correlation among pressures and tidal volume applied during MV and PDW, reinforcing thismethod as an easy, wide available and noninvasive way to estimate intravascular volume status in ARDS patients. Age was related to VPW, suggesting that the measure of VPW could be improved after correction based in this parameter

Prevalência de infecção em unidades de terapia intensiva de um hospital escola terciário

OBJECTIVE: To determine the prevalence rates of infections among intensive care unit patients, the predominant infecting organisms, and their resistance patterns. To identify the related factors for intensive care unit-acquired infection and mortality rates. DESIGN: A 1-day point-prevalence study. SETTING:A total of 19 intensive care units at the Hospital das Clínicas - University of São Paulo, School of Medicine (HC-FMUSP), a teaching and tertiary hospital, were eligible to participate in the study. PATIENTS: All patients over 16 years old occupying an intensive care unit bed over a 24-hour period. The 19 intensive care unit s provided 126 patient case reports. MAIN OUTCOME MEASURES: Rates of infection, antimicrobial use, microbiological isolates resistance patterns, potential related factors for intensive care unit-acquired infection, and death rates. RESULTS: A total of 126 patients were studied. Eighty-seven patients (69%) received antimicrobials on the day of study, 72 (57%) for treatment, and 15 (12%) for prophylaxis. Community-acquired infection occurred in 15 patients (20.8%), non- intensive care unit nosocomial infection in 24 (33.3%), and intensive care unit-acquired infection in 22 patients (30.6%). Eleven patients (15.3%) had no defined type. The most frequently reported infections were respiratory (58.5%). The most frequently isolated bacteria were Enterobacteriaceae (33.8%), Pseudomonas aeruginosa (26.4%), and Staphylococcus aureus (16.9%; [100% resistant to methicillin]). Multivariate regression analysis revealed 3 risk factors for intensive care unit-acquired infection: age >; 60 years (p = 0.007), use of a nasogastric tube (p = 0.017), and postoperative status (p = 0.017). At the end of 4 weeks, overall mortality was 28.8%. Patients with infection had a mortality rate of 34.7%. There was no difference between mortality rates for infected and noninfected patients (p=0.088). CONCLUSION: The rate of nosocomial infection is high in intensive care unit patients, especially for respiratory infections. The predominant bacteria were Enterobacteriaceae, Pseudomonas aeruginosa, and Staphylococcus aureus (resistant organisms). Factors such as nasogastric intubation, postoperative status, and age ³60 years were significantly associated with infection. This study documents the clinical impression that prevalence rates of intensive care unit-acquired infections are high and suggests that preventive measures are important for reducing the occurrence of infection in critically ill patients.OBJETIVO: Determinar a prevalência de infecções em pacientes de Terapia Intensiva, os agentes infecciosos mais comuns e seus padrões de resistência. Identificar os fatores relacionados a infecção adquirida na Unidade de Terapia Intensiva e as taxas de mortalidade. DESENHO: Estudo de prevalência de um dia. LOCAL:Um total de 19 Unidades de Terapia Intensiva do Hospital das Clínicas da FMUSP (HC-FMUSP) participaram do estudo. PACIENTES: Todos os pacientes com idade superior a 16 anos internados em leitos de terapia intensiva por mais de 24 horas foram incluídos. As 19 Unidades de Terapia Intensiva forneceram 126 casos. VARIÁVEIS:Taxas de infecção, uso de antibióticos, padrões de resistência microbiológica, fatores relacionados à infecção adquirida na Unidade de Terapia Intensiva, taxas de mortalidade. RESULTADOS: Um total de 126 pacientes foi estudado. Oitenta e sete (69%) receberam antibióticos no dia do estudo, sendo 72 (57%) para tratamento e 15 (12%) para profilaxia. Baseado no tipo, observou-se que a infecção adquirida na comunidade ocorreu em 15 pacientes (20,8%), infecção hospitalar fora da Unidade de Terapia Intensiva em 24 (33,3%), e infecção adquirida na Unidade de Terapia Intensiva em 22 pacientes (30,6%). Para 11 pacientes (15,3%) não se definiu o tipo de infecção. Quanto ao sítio de infecção, as respiratórias foram as infecções mais comuns (58,5%). Os agentes mais freqüentemente isolados foram: Enterobacteriaceae (33,8%), Pseudomonas aeruginosa (26,4%) e Staphylococcus aureus (16,9%; 100% meticilina-resistentes). Análise multivariada identificou 3 fatores associados à infecção adquirida na Unidade de Terapia Intensiva: idade maior ou igual a 60 anos (p=0,007), uso de sonda nasogástrica (p=0,017) e pós-operatório (p=0,017). Ao final de quatro semanas, a taxa de mortalidade foi de 28,8%. Entre os infectados, a mortalidade foi de 34,7%. Não houve diferença entre as taxas de mortalidade para pacientes infectados e não-infectados (p=0,088). CONCLUSÃO: A taxa de infecção é alta entre os pacientes de terapia intensiva, especialmente as infecções respiratórias. As bactérias predominantes foram: Enterobacteriaceae. Pseudomonas aeruginosa e Staphylococcus aureus (agentes resistentes). Fatores como uso de sonda nasogástrica, pós-operatório e idade maior ou igual a 60 anos mostraram associação com infecção. Este estudo documenta a impressão clínica de que a prevalência de infecção adquirida na Unidade de Terapia Intensiva é alta e sugere que medidas preventivas são importantes para reduzir a ocorrência de infecção em pacientes críticos

Infection as an independent risk factor for mortality in the surgical intensive care unit

OBJECTIVES: Medical and surgical intensive care unit patients represent two different populations and require different treatment approaches. The aim of this study was to investigate the parameters associated with mortality in medical and surgical intensive care units. METHODS: This was a prospective cohort study of adult patients admitted to a medical and surgical intensive care unit teaching hospital over an 11-month period. Factors associated with mortality were explored using logistic regression analysis. RESULTS: In total, 827 admissions were observed, and 525 patients >;18 years old and with a length of stay >;24 h were analyzed. Of these patients, 227 were in the medical and 298 were in the surgical intensive care unit. The surgical patients were older (

Follow-up after acute respiratory distress syndrome caused by influenza a (H1N1) virus infection

BACKGROUND: There are no reports on the long-term follow-up of patients with swine-origin influenza A virus infection that progressed to acute respiratory distress syndrome. METHODS: Four patients were prospectively followed up with pulmonary function tests and high-resolution computed tomography for six months after admission to an intensive care unit. RESULTS: Pulmonary function test results assessed two months after admission to the intensive care unit showed reduced forced vital capacity in all patients and low diffusion capacity for carbon monoxide in two patients. At six months, pulmonary function test results were available for three patients. Two patients continued to have a restrictive pattern, and none of the patients presented with abnormal diffusion capacity for carbon monoxide. All of them had a diffuse ground-glass pattern on high-resolution computed tomography that improved after six months. CONCLUSIONS: Despite the marked severity of lung disease at admission, patients with acute respiratory distress syndrome caused by swine-origin influenza A virus infection presented a late but substantial recovery over six months of follow-up

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): study protocol for a randomized controlled trial

BACKGROUND: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). METHODS/DESIGN: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH2O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure 6430 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. DISCUSSION: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration metho

Ambulation capacity, age, immunosuppression, and mechanical ventilation are risk factors of in-hospital death in severe COVID-19: a cohort study

Importance: Despite ambulation capacity being associated with a decreased level of physical activity and survival may be influenced by the functional capacity, studies have not addressed the association between ambulation capacity and death in patients hospitalized by COVID-19. Objective: To verify the functional, clinical, and sociodemographic risk factors associated with in-hospital death in individuals with severe COVID-19. Methods: It is a cohort retrospective study performed at a large tertiary hospital. Patients 18 years of age or more, of both sexes, hospitalized due to severe COVID-19 were included. Cases with dubious medical records and/or missing essential data were excluded. Patients were classified according to their ambulation capacity before the COVID-19 infection. Information regarding sociodemographic characteristics, in-hospital death, total hospital stays, Intensive Care Unit (ICU) stays, and the necessity of Mechanical Ventilation (MV) were collected from medical records and registered in a RedCap database. Multiple logistic regression analysis was used to identify possible factors associated with the in-hospital death rate. Results: Data from 1110 participants were included in the statistical analysis. The median age of the patients was 57 (46‒66) years, 58.42% (n = 590) were male, and 61.73% (n = 602) were brown or black. The case fatality rate during hospitalization was 36.0% (n = 363). In-hospital death was associated with ambulation capacity; dependent ambulators (OR = 2.3; CI 95% = 1.2–4.4) and non-functional ambulation (OR = 1.9; CI 95% = 1.1–3.3), age [older adults (OR = 3.0; CI 95% = 1.9‒4.), ICU stays (OR = 1.4; CI 95% = 1.2‒1.4), immunosuppression (OR = 5.5 CI 95% = 2.3‒13.5) and mechanical ventilation (OR = 27.5; CI 95% = 12.0–62.9). Conclusion and relevance: Decreased ambulation capacity, age, length of ICU stay, immunosuppression, and mechanical ventilation was associated with a high risk of in-hospital death due to COVID-19