Байесовский подход к построению таблиц «затраты-выпуск»

Methods of updating, balancing, disaggregation of Input-Output Tables (IOT) are widely used in applied economic and statistical research (for example, for the calibration of computable general equilibrium models), as well as by statistical services for compilation of IOTs. As compared to the well-known popular methods (RAS, cross-entropy minimization, and their analogs), which provide point estimates of unknown tables, the proposed approach targets estimation of joint probability distribution of input-output (IO) coefficients. With this goal we develop a probabilistic model ofjoint distribution of the IO coefficients as a likelihood function of observed information (for example, output, value added, intermediate demand). This information from newly arrived data is being mixed with prior information of IO parameters (for example, known IOTs from former years) by Bayes rule. The resulting posterior joint distribution can be estimated using Markov chain Monte Carlo (MCMC) sampling methods. The sample of IOTs from the targeted distribution is a set of IO matrices consistent with the observed data, constrains, and also near to the prior information. In contrary to the point estimates, the stochastic IOTs naturally incorporate uncertain information of each estimated IO parameter, taking into account all the multivariate correlation between the cells. The proposed methodology can be applied to updating, interpolation, disaggregation, and balancing of IOTs, and more widely - national accounts. We test the methodology with experimental updating of IO table for the Russian economy for 2003 year, based on tables from 1998 to 2002 years. The results suggest adequacy and computational accessibility of the proposed methodology.С задачами обновления, балансировки, дезагрегации таблиц «затраты-выпуск» сталкиваются как исследователи в сфере экономики и статистики (например, для калибровки вычислимых моделей общего равновесия), так и статистические службы (при построении таблиц). В отличие от известных популярных методов (RAS, минимизации перекрестной энтропии и их аналогов) в предлагаемом подходе вместо точечных оценок коэффициентов прямых затрат оценивается их совместное вероятностное распределение. Для этого строится вероятностная модель совместного распределения ячеек, являющаяся функцией правдоподобия новой наблюдаемой информации (например, выпуск, добавленная стоимость, промежуточный спрос), которая с помощью формулы Байеса объединяется с априорной информацией о ячейках (например, известных таблиц предыдущих лет). Получаемая в итоге апостериорная совместная плотность вероятности оценивается методами сэмплирования Монте-Карло по схеме цепи Маркова. Характеристики апостериорного распределения определяются набором (выборкой) искомых таблиц из этого распределения. При этом каждая из полученных таблиц не противоречит имеющимся данным, ограничениям и не слишком далека от априорно заданной таблицы или любой другой информации о ячейках. В отличие от точечных оценок стохастические таблицы напрямую инкорпорируют информацию о неопределенности каждого оцененного коэффициента прямых затрат таблиц «затраты-выпуск», учитывая существующие между ними взаимосвязи. Предлагаемая методика может использоваться для экстраполяции, интерполяции, дезагрегации и балансировки таблиц «затраты-выпуск» и более широко - матриц социальных счетов. С целью апробации метода проводится экспериментальная оценка таблиц «затраты-выпуск» российской экономики за 2003 г. на основе таблиц 1998-2002 гг. Экспериментальное применение метода Байеса на реальных данных продемонстрировало адекватность и вычислительную доступность предлагаемой методики

Synthetic Analogue of Leu-Enkephalin Prevents Endothelial Dysfunction in vitro

The purpose of the study was to determine the efficacy of a synthetic leu-enkephalin stabilized analogue to prevent damage of endothelial cells monolayer in vitro caused by serum samples from septic shock patients.Materials and methods. The experiments were performed using the EaHy.926 endothelial cells monolayer. We studied the in vitro effect of synthetic leu-enkephalin analogue on the cell damage caused by serum samples from five septic shock patients. The status of endothelial intercellular junctions was estimated by immunofluorescence microscopy and western blot with antibodies against adherens junction protein, VE-cadherin, and against the tight junctions protein, claudin. Cell viability was determined by staining with propidium iodide.Results. Preconditioning with a synthetic leu-enkephalin analogue (10, 50 and 100 μg/ml) of endothelial cells in vitro prevented the destruction of both tight and adherens junction and partially prevented endothelial cell death.Conclusion. Preconditioning with a synthetic leu-enkephalin analogue partially prevents endothelial cell damage caused by exposure to septic patients’ sera in vitro. These data ensure the need for clinical trials on the effectiveness of a synthetic leu-enkephalin analogue for prevention of sepsis-associated endothelial dysfunction in clinics

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - An observational study in 29 countries

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (V T) size was 500 ml, or 7 to 9 ml kg−1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P ˂ 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P ˂ 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high V T and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome.</p

The Association of Intraoperative driving pressure with postoperative pulmonary complications in open versus closed abdominal surgery patients - a posthoc propensity score-weighted cohort analysis of the LAS VEGAS study

BackgroundIt is uncertain whether the association of the intraoperative driving pressure (Delta P) with postoperative pulmonary complications (PPCs) depends on the surgical approach during abdominal surgery. Our primary objective was to determine and compare the association of time-weighted average Delta P (Delta P-TW) with PPCs. We also tested the association of Delta P-TW with intraoperative adverse events.MethodsPosthoc retrospective propensity score-weighted cohort analysis of patients undergoing open or closed abdominal surgery in the 'Local ASsessment of Ventilatory management during General Anaesthesia for Surgery' (LAS VEGAS) study, that included patients in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs. The secondary endpoint was a composite of intraoperative adverse events.ResultsThe analysis included 1128 and 906 patients undergoing open or closed abdominal surgery, respectively. The PPC rate was 5%. Delta P was lower in open abdominal surgery patients, but Delta P-TW was not different between groups. The association of Delta P-TW with PPCs was significant in both groups and had a higher risk ratio in closed compared to open abdominal surgery patients (1.11 [95%CI 1.10 to 1.20], P &lt; 0.001 versus 1.05 [95%CI 1.05 to 1.05], P &lt; 0.001; risk difference 0.05 [95%CI 0.04 to 0.06], P &lt; 0.001). The association of &lt;Delta&gt;P-TW with intraoperative adverse events was also significant in both groups but had higher odds ratio in closed compared to open abdominal surgery patients (1.13 [95%CI 1.12- to 1.14], P &lt; 0.001 versus 1.07 [95%CI 1.05 to 1.10], P &lt; 0.001; risk difference 0.05 [95%CI 0.030.07], P &lt; 0.001).Conclusions&lt;Delta&gt;P is associated with PPC and intraoperative adverse events in abdominal surgery, both in open and closed abdominal surgery.Trial registrationLAS VEGAS was registered at clinicaltrials.gov (trial identifier NCT01601223)