Validación del método generador de hidruros por espectrometría de absorción atómica para la determinación de selenio en aguas naturales, de consumo y residuales

El objetivo fue la validación del método generador de hidruros asociado con espectrometría de absorción atómica para la determinación de selenio (Se) en aguas naturales, de consumo y residuales para el laboratorio Aqlab. Se realizó esta validación por la necesidad de disponer de métodos analíticos validados y acreditados por el Servicio de Acreditación Ecuatoriano (SAE), lo que permitirá ampliar el alcance de acreditación técnica basada en la norma INEN ISO IEC 17025:2017. Este trabajo inició con revisión del método normalizado para el análisis de metales en aguas SM 3114 C, 3500-Se. Se validó el método en el intervalo de trabajo de 0,01- 0,5 mg/l, en condiciones de repetibilidad y reproducibilidad. Las muestras de agua potable, fueron aciduladas con HCL al 10%, mientras que las muestras de agua residual fueron digestadas con H2SO4 2,5 N y K2S2O8 al 5%. Se utilizaron HCl al 10% v/v (9 ml/min) como solución de transporte, NaBH4 al 0,2% p/v (4 ml/min) diluido en NaOH al 0,05% como agente reductor y argón (120 ml/min) como gas de arrastre, a una temperatura de 900°C de la celda de cuarzo. Los parámetros de desempeño determinados, mediante análisis estadístico con un nivel de confianza del 95%, son: linealidad (0,005-0,01 mg/l), límite de detección (LD= 0,005 mg/l), límite de cuantificación (LC= 0,01 mg/l), precisión, exactitud (recuperación 94,80-102,00%), e incertidumbre (U±17%). Los cuales cumplen con los objetivos de validación predefinidos y con los criterios de rendimiento y aceptación tales como: coeficiente de variación de repetibilidad y reproducibilidad SDR <10% e incertidumbre U≤ 30%, el método proporcionó resultados válidos con un nivel de confianza aceptable, datos reproducibles y exactos bajo las condiciones controladas en las que se trabaja en el laboratorio, por lo que la declaración de validación fue aceptada.The purpose of the research was the validation of the hydride generator method associated with the atomic absorption spectroscopy for determining the selenium (Se) in drinking water for consumption, and sewage for Aqlab laboratory. This validation was carried out due to the need of having analytical methods which are validated and recognized by the Ecuadorian Accreditation Organization (SAE), this will allow widening the range of technical accreditation based on the INEN ISO IEC 17025:2017 norm. This research started with the revision of the standardized method for the analysis of metals in waters SM 3114 C, 3500-Se. The method was validated considering the work interval from 0,01 to 0,5 mg/l, in repetitiveness and reproducibility conditions. The drinking water samples were acidulated HCL at 10%, while sewage samples were digested H2SO4 2,5 N and K2 S2 O8 at 5%. HCI at 10% v/v (9ml/min) were used as transporting solution, NaBH4 at 0,2% p/v (4ml/min) diluted in NaOH at 0,5% as reducing agent and argon (120 ml/min) as carrier gas at a temperature of 900°C in the quartz cell. The performance parameters determined through a statistical analysis with a level of trust of 95% are: linearity (0,005-0,01 mg/l), detection limit (LD=0,005 mg/l), quantification limit (LC=0,01 mg/l), precision, accuracy (recovery 94,80-102,00%) and uncertainty (U±17%). This parameters fulfil the predefined validation objectives as well as the performance and acceptance criteria such as: repetitiveness variation coefficient and reproducibility SDR <10% and uncertainty U < 30%, the method reflected valid results with and acceptable level of trust reproducible and accurate data under controlled conditions in which the laboratory works; thus, the validation statement was accepted

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

International audienceBackground: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society