Clinical spotlight review for the management of choledocholithiasis

Choledocholithiasis is a common presentation of symptomatic cholelithiasis that can result in biliary obstruction, cholangitis, and pancreatitis. A systematic English literature search was conducted in PubMed to determine the appropriate management strategies for choledocholithiasis. The following clinical spotlight review is meant to critically review the available evidence and provide recommendations for the work-up, investigations as well as the endoscopic, surgical and percutaneous techniques in the management of choledocholithiasis.     

Transfer of learning and patient outcome in simulated crisis resource management: a systematic review

Purpose

Simulation-based learning is increasingly used by healthcare professionals as a safe method to learn and practice non-technical skills, such as communication and leadership, required for effective crisis resource management (CRM). This systematic review was conducted to gain a better understanding of the impact of simulation-based CRM teaching on transfer of learning to the workplace and subsequent changes in patient outcomes.

Source

Studies on CRM, crisis management, crew resource management, teamwork, and simulation published up to September 2012 were searched in MEDLINE^®, EMBASE?, CINAHL, Cochrane Central Register of Controlled Trials, and ERIC. All studies that used simulation-based CRM teaching with outcomes measured at Kirkpatrick Level 3 (transfer of learning to the workplace) or 4 (patient outcome) were included. Studies measuring only learners’ reactions or simple learning (Kirkpatrick Level 1 or 2, respectively) were excluded. Two authors independently reviewed all identified titles and abstracts for eligibility.

Principal findings

Nine articles were identified as meeting the inclusion criteria. Four studies measured transfer of simulation-based CRM learning into the clinical setting (Kirkpatrick Level 3). In three of these studies, simulation-enhanced CRM training was found significantly more effective than no intervention or didactic teaching. Five studies measured patient outcomes (Kirkpatrick Level 4). Only one of these studies found that simulation-based CRM training made a clearly significant impact on patient mortality.

Conclusions

Based on a small number of studies, this systematic review found that CRM skills learned at the simulation centre are transferred to clinical settings, and the acquired CRM skills may translate to improved patient outcomes, including a decrease in mortality.     

Cholera transmission dynamic models for public health practitioners

Great progress has been made in mathematical models of cholera transmission dynamics in recent years. However, little impact, if any, has been made by models upon public health decision-making and day-to-day routine of epidemiologists. This paper provides a brief introduction to the basics of ordinary differential equation models of cholera transmission dynamics. We discuss a basic model adapted from Codeço (2001), and how it can be modified to incorporate different hypotheses, including the importance of asymptomatic or inapparent infections, and hyperinfectious V. cholerae and human-to-human transmission. We highlight three important challenges of cholera models: (1) model misspecification and parameter uncertainty, (2) modeling the impact of water, sanitation and hygiene interventions and (3) model structure. We use published models, especially those related to the 2010 Haitian outbreak as examples. We emphasize that the choice of models should be dictated by the research questions in mind. More collaboration is needed between policy-makers, epidemiologists and modelers in public health.     

REVIEW: The Zero-Stress State of the Gastrointestinal Tract:

The stresses and strains that remain in an organ when the external load is removed (the no-load state) are called residual stresses and strains. They can be relieved by cutting up the organ to obtain the zero-stress configuration. This phenomenon was demonstrated more than 15 years ago in cardiovascular research but until recently it was not realized by the gastrointestinal research community. The function of the gastrointestinal tract is to propel food by peristaltic motion, which is a result of the interaction of the tissue forces in the wall and the hydrodynamic forces in the food bolus. To understand the tissue forces, it is necessary to know the stress–strain relationships of the tissues that must be measured in reference to the zero-stress state. It has become clear that the zero-stress configuration of the gastrointestinal tract is very different from that of the no-load condition and that the zero-stress state is sensitive to structural and mechanical remodeling. The purpose of this review is to describe the basic theory and experiments of residual stress and to explore its physiological and pathophysiological implications in the gastrointestinal system.     

Photolyzed rhodopsin catalyzes the exchange of GTP for bound GDP in retinal rod outer segments.

We have studied the binding of guanyl nucleotides to retinal rod outer segment membranes to determine how light activates a cyclic GMP phosphodiesterase and a GTPase. We found that rod outer segment membranes contain tightly bound radioactive GDP after incubation in the dark with [3H]GDP or [alpha-32P]GTP. Reconstituted membranes containing only rhodopsin and phospholipid bind almost no GDP. More than 80% of the radioactive GDP bound to rod outer segment membranes could be released by subsequent illumination. At low light levels, the rate and extent of GDP release were markedly enhanced by the presence of GTP or p[NH]ppG, a nonhydrolyzable analog of GTP. The kinetics of binding of p[NH]ppG paralleled the kinetics of release of bound GDP, indicating that p[NH]ppG was exchanged for bound GDP. The maximal amount of bound p[NH]ppG was 1 per 30 rhodopsins when photolyzed membranes were incubated with 10 micro M nucleotide. Under these conditions, p[NH]ppG binding was half-maximal when only 1 in 90,000 rhodopsins was photolyzed. This corresponds to the catalyzed exchange of 500 p[NH]ppG for bound GDP per photolyzed rhodopsin. We propose a light-activated GTP-GDP amplification cycle involving a guanyl nucleotide binding protein with GTPase activity (E). The essence of this cycle is that photolyzed rhodopsin catalyzes the formation of E . GTP from E . GDP (the major species in the dark) by nucleotide exchange. The formation of several hundred E . GTP per photolyzed rhodopsin may be the first stage of amplification in visual excitation.