Spontaneous Breathing in Early Acute Respiratory Distress Syndrome: Insights From the Large Observational Study to UNderstand the Global Impact of Severe Acute Respiratory FailurE Study

OBJECTIVES: To describe the characteristics and outcomes of patients with acute respiratory distress syndrome with or without spontaneous breathing and to investigate whether the effects of spontaneous breathing on outcome depend on acute respiratory distress syndrome severity. DESIGN: Planned secondary analysis of a prospective, observational, multicentre cohort study. SETTING: International sample of 459 ICUs from 50 countries. PATIENTS: Patients with acute respiratory distress syndrome and at least 2 days of invasive mechanical ventilation and available data for the mode of mechanical ventilation and respiratory rate for the 2 first days. INTERVENTIONS: Analysis of patients with and without spontaneous breathing, defined by the mode of mechanical ventilation and by actual respiratory rate compared with set respiratory rate during the first 48 hours of mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: Spontaneous breathing was present in 67% of patients with mild acute respiratory distress syndrome, 58% of patients with moderate acute respiratory distress syndrome, and 46% of patients with severe acute respiratory distress syndrome. Patients with spontaneous breathing were older and had lower acute respiratory distress syndrome severity, Sequential Organ Failure Assessment scores, ICU and hospital mortality, and were less likely to be diagnosed with acute respiratory distress syndrome by clinicians. In adjusted analysis, spontaneous breathing during the first 2 days was not associated with an effect on ICU or hospital mortality (33% vs 37%; odds ratio, 1.18 [0.92-1.51]; p = 0.19 and 37% vs 41%; odds ratio, 1.18 [0.93-1.50]; p = 0.196, respectively ). Spontaneous breathing was associated with increased ventilator-free days (13 [0-22] vs 8 [0-20]; p = 0.014) and shorter duration of ICU stay (11 [6-20] vs 12 [7-22]; p = 0.04). CONCLUSIONS: Spontaneous breathing is common in patients with acute respiratory distress syndrome during the first 48 hours of mechanical ventilation. Spontaneous breathing is not associated with worse outcomes and may hasten liberation from the ventilator and from ICU. Although these results support the use of spontaneous breathing in patients with acute respiratory distress syndrome independent of acute respiratory distress syndrome severity, the use of controlled ventilation indicates a bias toward use in patients with higher disease severity. In addition, because the lack of reliable data on inspiratory effort in our study, prospective studies incorporating the magnitude of inspiratory effort and adjusting for all potential severity confounders are required

Identifying associations between diabetes and acute respiratory distress syndrome in patients with acute hypoxemic respiratory failure: an analysis of the LUNG SAFE database

Background: Diabetes mellitus is a common co-existing disease in the critically ill. Diabetes mellitus may reduce the risk of acute respiratory distress syndrome (ARDS), but data from previous studies are conflicting. The objective of this study was to evaluate associations between pre-existing diabetes mellitus and ARDS in critically ill patients with acute hypoxemic respiratory failure (AHRF). Methods: An ancillary analysis of a global, multi-centre prospective observational study (LUNG SAFE) was undertaken. LUNG SAFE evaluated all patients admitted to an intensive care unit (ICU) over a 4-week period, that required mechanical ventilation and met AHRF criteria. Patients who had their AHRF fully explained by cardiac failure were excluded. Important clinical characteristics were included in a stepwise selection approach (forward and backward selection combined with a significance level of 0.05) to identify a set of independent variables associated with having ARDS at any time, developing ARDS (defined as ARDS occurring after day 2 from meeting AHRF criteria) and with hospital mortality. Furthermore, propensity score analysis was undertaken to account for the differences in baseline characteristics between patients with and without diabetes mellitus, and the association between diabetes mellitus and outcomes of interest was assessed on matched samples. Results: Of the 4107 patients with AHRF included in this study, 3022 (73.6%) patients fulfilled ARDS criteria at admission or developed ARDS during their ICU stay. Diabetes mellitus was a pre-existing co-morbidity in 913 patients (22.2% of patients with AHRF). In multivariable analysis, there was no association between diabetes mellitus and having ARDS (OR 0.93 (0.78-1.11); p = 0.39), developing ARDS late (OR 0.79 (0.54-1.15); p = 0.22), or hospital mortality in patients with ARDS (1.15 (0.93-1.42); p = 0.19). In a matched sample of patients, there was no association between diabetes mellitus and outcomes of interest. Conclusions: In a large, global observational study of patients with AHRF, no association was found between diabetes mellitus and having ARDS, developing ARDS, or outcomes from ARDS. Trial registration: NCT02010073. Registered on 12 December 2013

Epidemiology and patterns of tracheostomy practice in patients with acute respiratory distress syndrome in ICUs across 50 countries

Background: To better understand the epidemiology and patterns of tracheostomy practice for patients with acute respiratory distress syndrome (ARDS), we investigated the current usage of tracheostomy in patients with ARDS recruited into the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG-SAFE) study. Methods: This is a secondary analysis of LUNG-SAFE, an international, multicenter, prospective cohort study of patients receiving invasive or noninvasive ventilation in 50 countries spanning 5 continents. The study was carried out over 4 weeks consecutively in the winter of 2014, and 459 ICUs participated. We evaluated the clinical characteristics, management and outcomes of patients that received tracheostomy, in the cohort of patients that developed ARDS on day 1-2 of acute hypoxemic respiratory failure, and in a subsequent propensity-matched cohort. Results: Of the 2377 patients with ARDS that fulfilled the inclusion criteria, 309 (13.0%) underwent tracheostomy during their ICU stay. Patients from high-income European countries (n = 198/1263) more frequently underwent tracheostomy compared to patients from non-European high-income countries (n = 63/649) or patients from middle-income countries (n = 48/465). Only 86/309 (27.8%) underwent tracheostomy on or before day 7, while the median timing of tracheostomy was 14 (Q1-Q3, 7-21) days after onset of ARDS. In the subsample matched by propensity score, ICU and hospital stay were longer in patients with tracheostomy. While patients with tracheostomy had the highest survival probability, there was no difference in 60-day or 90-day mortality in either the patient subgroup that survived for at least 5 days in ICU, or in the propensity-matched subsample. Conclusions: Most patients that receive tracheostomy do so after the first week of critical illness. Tracheostomy may prolong patient survival but does not reduce 60-day or 90-day mortality. Trial registration: ClinicalTrials.gov, NCT02010073. Registered on 12 December 2013

Percepção de exposição a cargas de trabalho e riscos de acidentes em Pelotas, RS (Brasil) Workers' perception of exposure to occupational hazards and the risk of accidents in a Southern Brazilian city

OBJETIVO: Investigar a associação entre a percepção de exposição às cargas de trabalho e o risco de acidentes. MÉTODOS: O delineamento do estudo foi o tipo de casos e controles. Os casos (n=264) incluíram os acidentes de trabalho típicos notificados no Instituto Nacional de Seguridade Social, de Pelotas, RS (Brasil), de janeiro a julho de 1996. Foram excluídos os óbitos (dois), os acidentes ocorridos na zona rural, e os que afastaram o trabalhador de suas atividades por menos de sete dias. Para cada caso foram selecionados três tipos de controles: um trabalhador da mesma empresa, um vizinho e um controle populacional. Os controles foram emparelhados com os casos por idade e sexo e precisavam ter vínculo empregatício formal e não ter sofrido acidente no último mês. Os dados foram analisados usando regressão logística condicional. RESULTADOS E CONCLUSÕES: Os trabalhadores que relatavam enfrentar situações de emergência, o trabalho em altura, perigo constante, ou ambientes ruidosos tinham cerca de duas vezes mais risco de acidentar-se. O trabalho em posições incômodas ou com esforço físico intenso aumentaram em 50% o risco de acidentes. As demais cargas de trabalho estudadas não se constituíram como fatores de risco para os acidentes. Os resultados foram ajustados para fatores de confusão.<br>OBJETIVE: The study of the association between workers' perceptions of occupational hazards and the risk of occupational accidents. DESIGN: Case control study. POPULATION: The cases were 264 workers who presented a "typical" occupational accident, registered at the National Institute of Social Security in the city of Pelotas, between January and July, 1996. Fatal accidents (two) were excluded, as were those leading to an absence of less than seven days from work. The cases were interviewed in their homes with a standard questionnaire. For each case, three controls were chosen: a fellow-work, a neighbor and a population control. Controls were matched to the cases by age (± 5 years) and sex; workers who had suffered an occupational accident in the preceding month were excluded from the control group. All cases and controls were formally employed and lived in the urban area. The data were analyzed using conditional logistic regression. RESULTS AND CONCLUSIONS: The risk of occupational accidents was found to double among workers who reported having faced emergency situations at work, working in high places, facing constant danger or noisy environments. Working in uncomfortable positions or intense physical activities were associated with a 50% increase in risk. The remaining occupational hazards under study were not significantly associated with the risk of accidents. All of the above results were adjusted for confounding factors

Efeito do índice glicêmico no gasto energético e utilização de substrato energético antes e depois de exercício cicloergométrico Effect of glycemic index on energy expenditure and energy substrate utilization before and after exercise on a stationary bicycle

OBJETIVO: No presente artigo, avaliou-se o efeito do consumo, durante cinco dias consecutivos, de refeições diferindo em índice glicêmico no gasto energético, na oxidação de substrato energético e no consumo excessivo de oxigênio após o exercício. MÉTODOS: Participaram do estudo 15 homens bem treinados, com idade de M=24,4, DP=3,70 anos e consumo máximo de oxigênio (VO2max) de M=70,00, DP=5,32mL (kg.min)-1. Após o consumo das refeições, os participantes permaneceram por noventa minutos no calorímetro indireto Deltatrac®, para a avaliação dos parâmetros metabólicos. A seguir, foi realizado um exercício de 85 a 95% da frequência cardíaca máxima, em três estágios de dez minutos. Os parâmetros metabólicos foram novamente avaliados durante os sessenta minutos pós-exercício. RESULTADOS: Os tratamentos aplicados no estudo não afetaram o gasto energético, o consumo excessivo de oxigênio e a oxidação lipídica após o exercício. Entretanto, a taxa de oxidação de gordura foi maior durante os noventa minutos no grupo que consumiu a refeição de alto índice glicêmico antes do exercício, em relação ao da refeição de baixo índice glicêmico. Além disso, a taxa de oxidação lipídica do período pós-prandial foi inferior àquela obtida no período pós-exercício. CONCLUSÃO: Os resultados sugerem que enquanto o consumo de refeições de baixo índice glicêmico pode não exercer efeito benéfico, a realização de exercício físico pode promover maior oxidação lipídica e consequentemente afetar a redução do teor de gordura corporal.<br>OBJECTIVE: The present study assessed, on 5 consecutive days, the effect of consuming meals with different glycemic indices on energy expenditure, energy substrate oxidation and excessive oxygen consumption after exercise. METHODS: A total of 15 well trained men aged M=24.4, SD=3.70 years with a mean body mass index of M=21.97, SD=1.46 kg/m² and maximum oxygen uptake (VO2max) of M=70.00, SD= 5.32 mL(kg.min)-1 participated in the study. After the meal, the participants remained 90 minutes in the indirect calorimeter Deltatrac® for assessment of the metabolic parameters. Next, they exercised at 85-95% of their maximum heart rate in three bouts of 10 minutes. The metabolic parameters were reassessed within the 60 minutes following the exercise. RESULTS: The study treatments did not affect energy expenditure, excessive oxygen consumption or fat oxidation after exercise. However, the rate of fat oxidation in the 90 minutes that followed the meal was higher in those who consumed the high-glycemic index meal than in those who consumed the low-glycemic index meal. Moreover, the postprandial fat oxidation rate was lower than that observed after the exercise. CONCLUSION: These results suggest that, while the consumption of low-glycemic index meals may not have beneficial effects, exercise can promote greater fat oxidation and, consequently, reduce body fat