The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Synergistic interaction of a protease and protease inhibitors from Russell's viper (Vipera russelli) venom

Synergistic interaction of a protease and protease inhibitors from Russell's viper (Vipera russelli) venom. Toxicon28, 65–74, 1990.—An acidic proteolytic enzyme, RVVX, was purified from Vipera russelli venom by successive chromatography on CM-Sephadex C-25, DEAE-cellulose and Sephadex G-100 columns. RVVX is a glycoprotein with a mol. wt of 79,000. It exhibited caseinolytic and factor X activating properties. Two trypsin inhibitors, TI-I and TI-II, were purified from V. russelli venom in a single step by CM-Sephadex C-25 column chromatography. The trypsin inhibitors interacted with the proteolytic enzyme RVVX. TI-I inhibited only the factor X activating property of RVVX while TI-II inhibited both, the caseinolytic and also factor X activating properties of RVVX. The edema inducing activity of RVVX increased markedly in the presence of non-edema inducing doses of TI-I and TI-II. RVVX, TI-I and TI-II were non-lethal in mice. The combination of RVVX and TI-II demonstrated enhanced toxicity

Caracterização individual do veneno de Bothrops alternatus Duméril, Bibron & Duméril em função da distribuição geográfica no Brasil (Serpentes,Viperidae) Individual characterization of Bothrops alternatus Duméril, Bibron & Duméril venoms, according to their geographic distribution in Brazil (Serpentes, Viperidae)

Bothrops alternatus Duméril, Bibron & Duméril, 1854 é uma serpente de importância em saúde pública, com ampla distribuição geográfica, desde o Mato Grosso do Sul até o sudeste do Brasil, chegando até a Argentina e Uruguai, ocupando vários domínios morfoclimáticos. Neste trabalho investigou-se a variação do veneno de adultos de Bothrops alternatus, em função de sua distribuição geográfica no Brasil, comparativamente ao veneno elaborado sob a forma de "pool" desta espécie (veneno referência), que inclui serpentes, em sua maioria, da região do estado de São Paulo. Foram analisadas as atividades letal, coagulante sobre o plasma, proteolítica sobre a caseína e miotóxica, bem como os padrões eletroforéticos de 61 amostras individuais de veneno contrapostas ao "pool". Os resultados mostraram que o veneno de B. alternatus é pouco ativo, comparativamente ao de outros Bothrops Wagler, 1824. A variação individual prevaleceu, não apresentando correlação com as áreas de distribuição geográfica e domínios morfoclimáticos, porém a atividade coagulante das amostras de veneno provenientes do nordeste da distribuição geográfica apresentaram-se menos ativas comparativamente às da porção central da distribuição. Os venenos provenientes das bordas da distribuição apresentaram ações proteolíticas e miotóxicas mais intensas, que estatisticamente não foram significativamente diferentes. As variações individuais prevaleceram.<br>Bothrops alternatus Duméril, Bibron & Duméril, 1854 snakebites are an important public health problem in Brazil. Such snakes are found from Mato Grosso do Sul (central Brazil) to southeastern Brazil, reaching even Argentina and Uruguay and thereby occupying different morphoclimatic domains. This work investigated venom variation occurring in adult specimens of B. alternatus specimens, according to their geographic distribution in Brazil. The standard venom pool (reference venom) produced by Instituto Butantan, which includes mostly venoms from B. alternatus specimens captured in São Paulo State, was also used for comparison. Lethal, myotoxic, proteolytic (on casein), and coagulant (on human plasma) activities, as well as the electrophoretic patterns of 61 individual venom samples, were evaluated and compared to those of the reference venom pool. Results showed that B. alternatus venom activities are less potent than those of other Bothrops Wagler, 1824 species. A great individual variation was noticed, which could not be correlated with either geographic distribution or morphoclimatic domains. Coagulant activity of venom samples obtained from specimens captured in the northeastern area of B. alternatus distribution was less intense if compared to those obtained from the central zone. Venoms from the peripheric area of B. alternatus distribution presented higher proteolytic and myotoxic activities, but no statistically significant difference was observed. In summary, individual variation predominated over geographic distribution

Probing surfaces with thermal He atoms: scattering and microscopy with a soft touch

Helium atom scattering (HAS) is a well established technique, particularly suited for the investigation of insulating and/or fragile materials and light adsorbates including hydrogen. In contrast to other beam techniques based on Xrays or electrons, low energy (typically less than 100 meV) He atoms are scattered by the tail of the electron density distribution which spill out from a surface, therefore HAS is strictly a nonpenetrating technique without any sample damage. HAS has been used to investigate structural properties of crystalline surfaces, including precise determination of atomic step heights, for monitoring thin film growth, to study surface transitions such as surface melting and roughening and for determining the presence and properties of adsorbates. Energy resolved HAS can provide information about surface vibrations (phonons) in the meV range and surface diffusion. This chapter provides a brief introduction to HAS with an outlook on a new, promising surface science technique: Neutral Helium Microscopy

Predicting the difficult laparoscopic cholecystectomy: development and validation of a pre-operative risk score using an objective operative difficulty grading system

Background: The prediction of a difficult cholecystectomy has traditionally been based on certain pre-operative clinical and imaging factors. Most of the previous literature reported small patient cohorts and have not used an objective measure of operative difficulty. The aim of this study was to develop a pre-operative score to predict difficult cholecystectomy, as defined by a validated intra-operative difficulty grading scale. Method: Two cohorts from prospectively maintained databases of patients who underwent laparoscopic cholecystectomy were analysed: the CholeS Study (8755 patients) and a single surgeon series (4089 patients). Factors potentially predictive of difficulty were correlated to the Nassar intra-operative difficulty scale. A multivariable binary logistic regression analysis was then used to identify factors that were independently associated with difficult laparoscopic cholecystectomy, defined as operative difficulty grades 3 to 5. The resulting model was then converted to a risk score, and validated on both internal and external datasets. Result: Increasing age and ASA classification, male gender, diagnosis of CBD stone or cholecystitis, thick-walled gallbladders, CBD dilation, use of pre-operative ERCP and non-elective operations were found to be significant independent predictors of difficult cases. A risk score based on these factors returned an area under the ROC curve of 0.789 (95% CI 0.773–0.806, p &lt; 0.001) on external validation, with 11.0% versus 80.0% of patients classified as low versus high risk having difficult surgeries. Conclusion: We have developed and validated a pre-operative scoring system that uses easily available pre-operative variables to predict difficult laparoscopic cholecystectomies. This scoring system should assist in patient selection for day case surgery, optimising pre-operative surgical planning (e.g. allocation of the procedure to a suitably trained surgeon) and counselling patients during the consent process. The score could also be used to risk adjust outcomes in future research

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (&gt; 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations &gt; 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p &lt; 0.001), with the proportions of operations lasting &gt; 90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care