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 cmH(2)O 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 <= 30 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 method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Morphological and chemical characterization of atmospheric particles PM10 in an urban site in Leon, Guanajuato, Mexico

Start PM10 concentrations and their trace metals content (Cd, Co, Cu, Fe and Zn) were determined in an urban site of Leon, Guanajuato during the rainy season 2018. PM10 exceeded the maximum permissible levels established by the Mexican Standards and WHO, constituting a potential risk to population health. Trace metals levels in PM10 were analyzed by Atomic Absorption Spectrometry, and in addition, morphology and elemental content were studied for some selected particles by Scanning Electronic Microscopy and Energy Dispersive Spectrometry. Chemical and morphological characterization revealed that Fe was the more abundant metal (0.986 µg m-3 ), followed in order of importance by Zn (0.243 µg m-3 ), due to theses metals are related to the crustal. Lower concentrations were found for Cu (0.140 µg m-3 ), Cd (0.119 µg m-3 ), Mn (0.070 µg m-3 ) and Co (0.043 µg m-3 ). Meteorological analysis showed that sources located at the SW and NE of the sampling site (industrial parks and facilities related to metals and mineral extraction) influenced the measured concentrations. Enrichment factors showed that all the measured metals were highly influenced by anthropogenic activity. Cancer Risk (CR) and Non-Cancer Risk Coefficients (cardiovascular and respiratory diseases) did not exceed the maximum permissible level established by EPA.The first section in your paper

Health risk assessment of the levels of BTEX in ambient air of one urban site located in leon, guanajuato, mexico during two climatic seasons

Levels of BTEX (benzene, toluene, ethylbenzene, and p-xylene) were determined in ambient air of an urban site located at the center of Mexico (Leon City in Guanajuato State) during two climatic seasons of 2018 (summer and autumn). Ethylbenzene (11.86 ug m~3) and toluene (11.85 ug m~3) showed the highest median concentrations during the study period. BTEX concentrations did not show a diurnal pattern but a seasonal trend was observed for benzene and toluene at a significant level of a = 0.05. Bi-variate and multivariate analysis showed significant positive correlations (at a = 0.05) among BTEX (excepting benzene), indicating common sources for toluene, ethylbenzene, and p-xylene and a different origin for benzene. A meteorological study was also conducted in order to determine the origin of air masses that could influence the BTEX concentrations in the study site. Finally, it was found that all BTEX species presented hazard quotient values (HQs) <1, indicating that there is no risk of non-cancer during the studied period. Lifetime cancer risk due to benzene exposure for the adult and child populations studied were estimated to be 7 in 1,000,000 and 1 in 100,000, respectively

Trace metal content and health risk assessment of PM10 in an urban environment of León, Mexico

Trace metal concentrations in PM10 were measured in an urban-industrial site in León, Mexico in three different seasons. PM10 were collected in quartz fiber filters of 47 mm diameter using low volume equipment operating with a controlled flow of 5 L min-1 over 24 h. Mass concentrations were gravimetrically determined and it was found that PM10 samples showed values in excess of the Mexican standard and the established values by WHO during cold dry and warm dry seasons. Morphology of selected particles was studied by SEM-EDS analysis, and the elemental composition was determined. Collected samples were analyzed by atomic absorption spectrometry in order to quantify ambient air concentrations of some trace metals (Cu, Co, Zn, Cd, Fe, Mg, and Mn). Median concentrations of trace metals showed the maximum value for iron (3.079 μgm-3) and the minimum value for Cd (0.050 μgm-3) over the entire period. From the meteorological analysis, it was found that sources located SW and ESE of the sampling site contributed to the levels of trace metals in PM10 in the studied site. The health risk assessment found that the population of León is at increased lifetime risk of experiencing cancer because of exposure to these concentrations of PM10 and their trace metal content

Atmospheric Levels of BTEX and Criteria Pollutants (CO, NO2, O3 and PM2.5) in an Urban Site Located in North Baja California, Mexico: Source Implications and Health Risk

Atmospheric levels of BTEX (benzene, toluene, ethylbenzene, p-xylene) and criteria air pollutants (O3, NO2, CO, PM2.5) were measured in urban air of one site located in North Baja California, Mexico during winter 2017. Diurnal variation was studied collecting samples at 1.5 h time intervals in different sampling periods: 07:30-09:00 h, 12:00-13:30 h, 15:00-16:30 h, and 18:00-19:30 h and then analyzed by gas chromatography with flame ionization detection. The highest concentrations of BTEX occurred during the morning (07:30-09:00h) and afternoon (18:00-19:30h) sampling periods. Mean concentrations of BTEX were 32.40 μg/m3 for benzene; 13.28 μg/m3 for toluene; 17.16 μg/m3 for p-xylene; and 7.02 μg/m3 for ethylbenzene. BTEX concentration ratios and meteorological analysis indicated that these compounds were influenced by local and fresh emissions. Pearson correlation and Principal Component Analysis were performed in order to correlate BTEX concentrations with criteria air pollutants and meteorological parameters to infer their possible sources. A health risk assessment showed that local exposure to benzene exceeded 1 x 10-6 for integrated lifetime cancer risk. It suggests that people living in Tijuana, Baja California, Mexico may have a probable risk of suffering cancer in their lifetime. These results indicate that changes in the existing environmental policies should therefore be applied to improve air quality in this region

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 cmH(2)O 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 <= 30 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 method.13Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt