Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Oxidative reforming of methane for hydrogen and synthesis gas production: Thermodynamic equilibrium analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A thermodynamic analysis of methane oxidative reforming was carried out by Gibbs energy minimization (at constant pressure and temperature) and entropy maximization (at constant pressure and enthalpy) methods, to determine the equilibrium compositions and equilibrium temperatures, respectively. Both cases were treated as optimization problems (non-linear programming formulation). The GAMS (R) 23.1 software and the CONOPT2 solver were used in the resolution of the proposed problems. The hydrogen and syngas production were favored at high temperatures and low pressures, and thus the oxygen to methane molar ratio (O-2/CH4) was the dominant factor to control the composition of the product formed. For O-2/CH4 molar ratios higher than 0.5, the oxidative reforming of methane presented autothermal behavior in the case of either utilizing O-2 or air as oxidant agent, but oxidation reaction with air possessed the advantage of avoiding peak temperatures in the system, due to change in the heat capacity of the system caused by the addition of nitrogen. The calculated results were compared with previously published experimental and simulated data with a good agreement between them.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.215571580Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Dimensional Analysis of the Parietal Bone in Areas of Surgical Interest and Relationship Between Parietal Thickness and Cephalic Index

Purpose: The aim of this study was to determine the thickness of the parietal bone in bone graft donor sites and to study the relationship between parietal bone thickness and gender or cephalic index. Materials and Methods: We studied 300 parietal bones from 150 human skulls (84 male and 66 female) from individuals aged 18 to 60 years at the time of death. On each parietal bone, 9 areas were drawn by use of reference anatomic landmarks (bregma, lambda, asterion, and pterion), and bone thickness was determined in the areas adjoining the sagittal suture-superior-anterior (Sa), superior-medial (Sm), and superior-posterior (Sp). Results: Mean thickness measurements ranged from 2.30 to 11.25 mm in the Sa area, from 3.08 to 13.32 mm in the Sm area, and from 2.88 to 12.26 in the Sp area. Smaller mean measurements were observed in the Sa area, with the smallest mean thickness being found in brachycephalic female specimens. The largest mean thickness was also found in female specimens in the Sin area. Statistically significant differences between genders were found only in the Sa area in dolichocephalic and mesocephalic specimens. Conclusion: Although the best bone graft donor site surgically is different in individuals of different genders and with different cephalic indexes, our findings suggest that harvesting from the anterosuperior area of the parietal bone should not be performed. (C) 2011 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 69:2930-2935, 201169112930293