Anesthesiologists' skills in emergency cricothyroidotomy mandate a brush-up training after 3 months-A randomized controlled trial.

BACKGROUND: In the Difficult Airway Society's 2015 "cannot intubate, cannot oxygenate" guideline, the emergency cricothyroidotomy is the final option when managing an unanticipated difficult airway. How often training for maintenance of this skill is required for anesthesiologists remains unknown. We aimed to assess if specialist-trained anesthesiologists' skills improved from a brush-up intervention and if skills were retained after 3 months. METHODS: In this multicenter, randomized, controlled trial, participants were randomized to either a simulation-based brush-up or no brush-up. Both groups performed a mannequin-based technical skills emergency cricothyroidotomy test twice and were assessed by a blinded rater using a structured assessment tool that included time, positioning, palpation, appropriate employment of instruments, and stepwise progression. After 3 months of non-training, participants completed identical tests of retention. RESULTS: A total of 54 anesthesiologists were included from three hospitals in the Region of Southern Denmark. Thirty-seven percent of the participants had received skills training in emergency cricothyroidotomy in the prior 12 months. The intervention group (N = 27) performed better in the initial tests, with a mean time of 51.5 s (SD = 10.82), a total score per minute of 15.9 points (SD = 4.91), and 93% passing both initial tests compared to the control group (N = 27) with a mean time of 76.8 s (SD = 35.82), a total score per minute of 6.6 (SD = 4.68) and only 15% passing both initial tests. The intervention group managed to retain overall performance in retention tests in terms of performance time (48.9 s, p = .26), total score per minute (13.6 points, p = .094), and passing the tests (75%, p = .059). CONCLUSION: Exposure to simulation-based brush-up training in emergency cricothyroidotomy improved anesthesiologists' technical performance and was overall retained after 3 months. Some loss of skill concerning specific items was observed, highlighting the need for regular training in emergency cricothyroidotomy. Simulation-based training should be prioritized to improve and maintain technical skills in infrequent high-stakes procedures.

Consensus on technical procedures for simulation-based training in anaesthesiology: A Delphi-based general needs assessment.

BACKGROUND: Anaesthesiologists are expected to master an increasing number of technical procedures. Simulation-based procedural training can supplement and, in some areas, replace the classical apprenticeship approach during patient care. However, simulation-based training is very resource-intensive and must be prioritised and optimised. Developing a curriculum for simulation-based procedural training should follow a systematic approach, eg the Six-Step Approach developed by Kern. The aim of this study was to conduct a national general needs assessment to identify and prioritise technical procedures for simulation-based training in anaesthesiology. METHODS: A three-round Delphi process was completed with anaesthesiology key opinion leaders. In the first round, the participants suggested technical procedures relevant to simulation-based training. In the second round, a needs assessment formula was used to explore the procedures and produce a preliminary prioritised list. In the third round, participants evaluated the preliminary list by eliminating and re-prioritising the procedures. RESULTS: All teaching departments in Denmark were represented with high response rates in all three rounds: 79%, 77%, and 75%, respectively. The Delphi process produced a prioritised list of 30 procedure groups suitable for simulation-based training from the initial 138 suggestions. Top-5 on the final list was cardiopulmonary resuscitation, direct- and video laryngoscopy, defibrillation, emergency cricothyrotomy, and fibreoptic intubation. The needs assessment formula predicted the final prioritisation to a great extent. CONCLUSION: The Delphi process produced a prioritised list of 30 procedure groups that could serve as a guide in future curriculum development for the simulation-based training of technical procedures in anaesthesiology.

Developing and Gathering Validity Evidence for a Simulation-Based Test of Competencies in Lung Ultrasound.

BACKGROUND: Clinical lung ultrasound (LUS) is a fast bedside diagnostic tool which can assist clinicians in decisions regarding the treatment and monitoring of patients with respiratory symptoms. LUS training and education differ widely, and is often done in a clinical setting, with potential risks for patients if decisions are made based on the wrong interpretations. No clear guidelines or recommendations for objective and standardized assessment of LUS skills exist, and those that do are often based on a fixed time-frame or an arbitrary number of examinations performed; this does not ensure adequate competencies. OBJECTIVES: The study aimed to develop and gather validity evidence for a practical, simulation-based test in LUS. METHODS: Nine cases were developed in collaboration with 3D Systems Healthcare, Littleton, CO, USA, representing the most common diagnosis and sonographic findings in patients with respiratory symptoms. Thirty-six participants with different levels of competence in LUS, completed the test. The participants were divided into groups, i.e., novices, intermediates, and experienced, according to their experience with LUS, the number of examinations they had performed, and any research they had conducted. Their answers were used for item analyses. RESULTS: The intraclass correlation coefficient, Cronbachs' α, was 0.69 summarized, and there was a statistically significant difference (p < 0.001) between the novices and the trained participants (intermediates and experienced). A pass/fail score of 16 points was calculated according to the contrasting-groups method. CONCLUSION: We developed a test for the assessment of clinical competencies in LUS. The test proved solid validity evidence, and a pass/fail standard without any false-negatives, and only 2 explained false-positives.

Determining procedures for simulation-based training in radiology: a nationwide needs assessment.

OBJECTIVES: New training modalities such as simulation are widely accepted in radiology; however, development of effective simulation-based training programs is challenging. They are often unstructured and based on convenience or coincidence. The study objective was to perform a nationwide needs assessment to identify and prioritize technical procedures that should be included in a simulation-based curriculum. METHODS: A needs assessment using the Delphi method was completed among 91 key leaders in radiology. Round 1 identified technical procedures that radiologists should learn. Round 2 explored frequency of procedure, number of radiologists performing the procedure, risk and/or discomfort for patients, and feasibility for simulation. Round 3 was elimination and prioritization of procedures. RESULTS: Response rates were 67 %, 70 % and 66 %, respectively. In Round 1, 22 technical procedures were included. Round 2 resulted in pre-prioritization of procedures. In round 3, 13 procedures were included in the final prioritized list. The three highly prioritized procedures were ultrasound-guided (US) histological biopsy and fine-needle aspiration, US-guided needle puncture and catheter drainage, and basic abdominal ultrasound. CONCLUSION: A needs assessment identified and prioritized 13 technical procedures to include in a simulation-based curriculum. The list may be used as guide for development of training programs. KEY POINTS: • Simulation-based training can supplement training on patients in radiology. • Development of simulation-based training should follow a structured approach. • The CAMES Needs Assessment Formula explores needs for simulation training. • A national Delphi study identified and prioritized procedures suitable for simulation training. • The prioritized list serves as guide for development of courses in radiology.

Identifying Technical Procedures in Pulmonary Medicine That Should Be Integrated in a Simulation-Based Curriculum: A National General Needs Assessment.

BACKGROUND: Simulation training is a revolutionary addition to health care education. However, developing simulation-based training programs is often dictated by those simulators that are commercially available. Curriculum development requires deliberate planning and a standardized approach, including a 'general needs assessment'. OBJECTIVES: The aim of this study was to perform a national general needs assessment to identify technical procedures in pulmonary medicine that should be integrated in a simulation-based curriculum. METHODS: A three-round Delphi process was initiated among 62 key opinion leaders. Round 1 was an open-ended question to identify technical procedures pulmonologists should learn. Round 2 was a survey using a newly developed needs assessment formula to explore the frequency of procedures, number of operators, risk or discomfort when performed by an inexperienced doctor, and feasibility of simulation-based training. In round 3, results were reviewed and ranked according to priority. RESULTS: The response rates for the three rounds were 74, 63, and 60%, respectively. The Delphi process reduced the 30 procedures identified in round 1 to 11 prioritized technical procedures in round 3. These were: flexible bronchoscopy, pleurocentesis, endobronchial ultrasound, endoscopic ultrasound-guided fine-needle aspiration, noninvasive ventilation treatment, transthoracic biopsy of pleural or lung tumor, focused ultrasound scanning of the lungs, chest tube insertion, needle biopsy of visible lymph node/tumor of the skin, focused ultrasound scanning of the heart, and thoracoscopy. CONCLUSION: We performed a Delphi study using a needs assessment formula, which identified 11 technical procedures that are highly suitable for simulation-based training. Medical educators can use this list as a resource in planning simulation-based training programs for trainees in pulmonary medicine.

Safety, efficacy, and impact on gut microbial ecology of a Bifidobacterium longum subspecies infantis LMG11588 supplementation in healthy term infants: a randomized, double-blind, controlled trial in the Philippines.

Introduction: Bifidobacterium longum subspecies infantis (B. infantis) may play a key role in infant gut development. This trial evaluated safety, tolerability, and efficacy of B. infantis LMG11588 supplementation. Methods: This randomized, placebo-controlled, double-blind study conducted in the Philippines included healthy breastfed and/or formula-fed infants (14-21 days old) randomized for 8 weeks to a control group (CG; n = 77), or any of two B. infantis experimental groups (EGs): low (Lo-EG; 1*108 CFU/day; n = 75) or high dose (Hi-EG; 1.8*1010 CFU/day; n = 76). Primary endpoint was weight gain; secondary endpoints included stooling patterns, gastrointestinal symptoms, adverse events, fecal microbiome, biomarkers, pH, and organic acids. Results: Non-inferiority in weight gain was demonstrated for Hi-EG and Lo-EG vs. CG. Overall, probiotic supplementation promoted mushy-soft stools, fewer regurgitation episodes, and increased fecal acetate production, which was more pronounced in the exclusively breastfed infants (EBF) and positively correlated with B. infantis abundance. In EBF, fecal pro-inflammatory cytokines (IL-1 beta, IL-8) were reduced. Strain-level metagenomic analysis allowed attributing the increased abundance of B. infantis in EGs versus CG, to LMG11588 probiotic colonization. Colonization by autochthonous B. infantis strains was similar between groups. Discussion: B. infantis LMG11588 supplementation was associated with normal infant growth, was safe and well-tolerated and promoted a Bifidobacterium-rich microbiota driven by B. infantis LMG11588 colonization without disturbing the natural dispersal of autochthonous B. infantis strains. In EBF, supplementation stimulated microbial metabolic activity and beneficially modulated enteric inflammation.

Transcriptomes of the desiccation-tolerant resurrection plant Craterostigma plantagineum.

Studies of the resurrection plant Craterostigma plantagineum have revealed some of the mechanisms which these desiccation-tolerant plants use to survive environments with extreme dehydration and restricted seasonal water. Most resurrection plants are polyploid with large genomes, which has hindered efforts to obtain whole genome sequences and perform mutational analysis. However, the application of deep sequencing technologies to transcriptomics now permits large-scale analyses of gene expression patterns despite the lack of a reference genome. Here we use pyro-sequencing to characterize the transcriptomes of C. plantagineum leaves at four stages of dehydration and rehydration. This reveals that genes involved in several pathways, such as those required for vitamin K and thiamin biosynthesis, are tightly regulated at the level of gene expression. Our analysis also provides a comprehensive picture of the array of cellular responses controlled by gene expression that allow resurrection plants to survive desiccation.

Voluntary work for the physical and mental health of older volunteers: A systematic review.

Background: The increasing imbalance between the number of older adults not working and the number of adults in the age range of labour force participation (age range 20-64) has long been a fundamental public policy challenge in the Organization for Economic Co-operation and Development member countries. At a societal level, this growing imbalance raises serious concerns about the viability and funding of social security, pensions and health programmes. At an individual level, the concern is probably more that of aging well with the prospect of many years in retirement. Some research suggests that retiring for some carries the risk of a fast decline in health. Volunteering can play a significant role in people's lives as they transition from work to retirement, as it offers a "structured" means of making a meaningful contribution in society once the opportunity to do so through work has been cut off. Some older people consider voluntary work as a way to replicate aspects of paid work lost upon retirement, such as organisational structure and time discipline. In many countries, volunteering of the older adults is increasing and programmes designed specifically for this subpopulation are emerging. Volunteering may contribute to both individuals aging well and society aging well, as volunteering by the older adults at the same time relieves the societal burden if it helps maintain health and functionality for those who volunteer. It thus remains to be established to what extent volunteering impacts on the physical and mental health of those who volunteer. Objectives: The main objective of this review is to answer the following research question: what are the effects of volunteering on the physical and mental health of people aged 65 years or older? Search Strategy: Relevant studies were identified through electronic searches of bibliographic databases, governmental and grey literature repositories, hand search in specific targeted journals, citation tracking, contact to international experts and internet search engines. The database searches were carried out to December 2018 and other resources were searched in September 2019 and October 2019. We searched to identify both published and unpublished literature. The searches were international in scope. Reference lists of included studies and relevant reviews were also searched. Selection Criteria: The intervention of interest was formal volunteering which can be described as voluntary, on-going, planned, helping behaviour that intend to increase the well-being of strangers, offers no monetary compensation and typically occurs within an organisational context. We included older people aged 65 or over who are engaged in formal voluntary work. The primary focus was on measures of physical and mental health. All study designs that used a well-defined control group were eligible for inclusion. Studies that utilised qualitative approaches were not included. Data Collection and Analysis: The total number of potential relevant studies constituted 17,046 hits. A total of 90 studies, met the inclusion criteria and were critically appraised by the review authors. The 90 studies analysed 47 different populations. Only 26 studies (analysing 19 different populations) could be used in the data synthesis. Forty-six studies could not be used in the data synthesis as they were judged to have too high risk of bias and, in accordance with the protocol, were excluded from the meta-analysis on the basis that they would be more likely to mislead than inform. Eighteen studies did not provide enough information enabling us to calculate an effects size and standard error or did not provide results in a form enabling us to use it in the data synthesis. Finally, of the 26 studies that could be used in the data synthesis, two pairs of studies used the same two data sets and reported on the same outcome(s), thus in addition two studies were not used in the data synthesis.Meta-analysis of both physical health outcomes and mental health outcomes were conducted on each metric separately. All analyses were inverse variance weighted using random effects statistical models that incorporate both the sampling variance and between study variance components into the study level weights. Random effects weighted mean effect sizes were calculated using 95% confidence intervals (CIs).Sensitivity analysis was carried out by restricting the meta-analysis to a subset of all studies included in the original meta-analysis and was used to evaluate whether the pooled effect sizes were robust across components of risk of bias. Results: The 24 studies (analysing 19 different populations), used for meta analysis were from Australia, Ireland, Israel, Japan, Korea and United States, three were a randomised controlled trial and 21 were NRS. The baseline time period (the year the voluntary work that was analysed was measured) spanned by the included studies is 30 years, from 1984 to 2014 and on average the baseline year was 2001. On average the number of follow up years was 5, although with great variation from 0 to 25 years. The average number of volunteers analysed (not reported in four studies) was 2,369, ranging from 15 to 27,131 and the average number of controls was 13,581, ranging from 13 to 217.297. In total the average number of participants analysed was 14,566, ranging from 28 to 244.428.Ten studies analysed the effect of voluntary work on mortality, however, eight studies reported a hazard ratio and two studies reported an odds ratio. We analysed these two types of effect sizes separately. A hazard ratio <1 indicates that the treated, the volunteers is favoured. That is, the conditional mortality rate is lower for volunteers. All reported results indicated an effect favouring the volunteers, primary study effect sizes lied in the range 0.67-0.91. The random effects weighted mean hazard ratio was 0.76 (95% CI, 0.72-0.80) and statistically significant. The two studies that reported odds ratios of mortality supported this result. There was no heterogeneity between the studies in either of the meta analyses.Three studies analysed the effect of voluntary work on incident functional disability, using a hazard ratio as effect measure. All reported results indicated an effect favouring the volunteers, primary study effect sizes lied in the range 0.70-0.99. The random effects weighted mean hazard ratio was 0.83 (95% CI, 0.72-0.97) and statistically significant. There was a small amount of heterogeneity between the studies.Two studies analysed the effect of voluntary work on decline in instrumental activities of daily living, using an odds ratio as effect measure. Both reported results indicated an effect favouring the volunteers (0.63 and 0.83). The random effects weighted mean odds ratio was 0.73 (95% CI, 0.53-1.01) and not statistically significant. There is no heterogeneity between the two studies.Three studies analysed the effect of voluntary work on maintenance of functional competence, using an odds ratio as effect measure. All reported results indicated an effect favouring the volunteers, primary study effect sizes lied in the range 0.67-0.83. The random effects weighted mean odds ratio was 0.81 (95% CI, 0.70-0.94) and statistically significant. There is no heterogeneity between the studies.In addition a number of other physical outcomes were reported in a single study only.Three studies analysed the effect of voluntary work on depression, and reported results that enabled the calculation of standardised mean difference (SMD) and variance. The effect sizes are measured such that a positive effect size favours the volunteers. All reported results indicated an effect favouring the volunteers, primary study effect sizes lied in the range 0.05-0.66. The random effects weighted SMD was 0.12 (95% CI, 0.00-0.23) and statistically significant. There is a very small amount of heterogeneity between the studies.In addition, a number of other mental health outcomes were reported in a single study only.We did not find any adverse effects.There were no appreciable changes in the results across components of risk of bias as indicated by the sensitivity analysis. Authors' Conclusions: The review aimed to examine effects on all types of physical and mental health outcomes. With the exception of mortality, there was insufficient evidence available. The available evidence, however, does suggest that there is an effect on the mortality of volunteers, although the effect is small. We found evidence that voluntary work reduces the mortality hazard of the volunteers aged 65 and above. The effect corresponds to a 43% chance of the volunteers dying first which should be compared to a fifty-fifty chance (50%) of dying first if the intervention had no effect. The evidence seems robust in the sense that we did not find any heterogeneity between the studies. As the intervention, unlike most other interventions in the social welfare area, is not costly, it could be prescribed to more older adults. In fact as the intervention in contrary to carrying a cost is a productive activity contributing directly to community well-being and has a positive effect on the volunteers it probably should be prescribed universally. However, due to the very nature of the intervention, it is voluntary and it cannot be prescribed. But more people could be encouraged to take up voluntary work if the opportunity was immediately available and visible.

Calcium and the role of motoneuronal doublets in skeletal muscle control.

This work presents a novel structural model of skeletal muscle activation, providing a physiologically based account of frequency-dependent muscle responses like the catch-like effect. Numerous Ca2+ reservoirs within muscle fibers are considered, and a simplified analysis of the allocation of Ca2+ resources and the dynamics of calcium transport is proposed. The model correctly accounts for catch-like effects in slow and fast-twitch fibers during long-train stimulations and force-frequency relations in different muscle types. Results obtained from the model compare favorably to experiments showing that prolonged increases in force characteristic of the catch-like effect are not accompanied by sustained increases in free myoplasmic Ca2+. Also, in agreement with early experiments, the interspike interval in catch-inducing doublets is seen to be an important parameter for regulating the precise onset amplitude of the catch-like effect. This suggests that a plausible physiological function for the inclusion of doublets or the exclusion of individual spikes within a regular motor-neuronal spike-train is to rapidly bring skeletal muscles to predefined target forces according to prespecified motor programs in the central nervous system. This is a potentially very useful property directly mediated by the catch-like process modeled here. One further prediction of the model is that the slope of the frequency-tension profile of a given muscle is highly sensitive to changes in the efficiency and temporal characteristics of the dihydropyridine-ryanodine receptor complex. Interestingly, this is consistent with findings made on cardiac muscles, and might incidentally explain some instances of cardiac failure.

Small class sizes for improving student achievement in primary and secondary schools: a systematic review.

This Campbell systematic review examines the impact of class size on academic achievement. The review summarises findings from 148 reports from 41 countries. Ten studies were included in the meta-analysis. Included studies concerned children in grades kindergarten to 12 (or the equivalent in European countries) in general education. The primary focus was on measures of academic achievement. All study designs that used a well-defined control group were eligible for inclusion. A total of 127 studies, consisting of 148 papers, met the inclusion criteria. These 127 studies analysed 55 different populations from 41 different countries. A large number of studies (45) analysed data from the Student Teacher Achievement Ratio (STAR) experiment which was for class size reduction in grade K-3 in the US in the eighties. However only ten studies, including four of the STAR programme, could be included in the meta-analysis. Overall, the evidence suggests at best a small effect on reading achievement. There is a negative, but statistically insignificant, effect on mathematics. For the non-STAR studies the primary study effect sizes for reading were close to zero but the weighted average was positive and statistically significant. There was some inconsistency in the direction of the primary study effect sizes for mathematics and the weighted average effect was negative and statistically non-significant. The STAR results are more positive, but do not change the overall finding. All reported results from the studies analysing STAR data indicated a positive effect of smaller class sizes for both reading and maths, but the average effects are small. Plain language summary: Small class size has at best a small effect on academic achievement: Reducing class size is seen as a way of improving student performance. But larger class sizes help control education budgets. The evidence suggests at best a small effect on reading achievement. There is a negative, but statistically insignificant, effect on mathematics, so it cannot be ruled out that some children may be adversely affected.What is this review about?: Increasing class size is one of the key variables that policy makers can use to control spending on education.But the consensus among many in education research is that smaller classes are effective in improving student achievement which has led to a policy of class size reductions in a number of US states, the UK, and the Netherlands. This policy is disputed by those who argue that the effects of class size reduction are only modest and that there are other more cost-effective strategies for improving educational standards.Despite the important policy and practice implications of the topic, the research literature on the educational effects of class-size differences has not been clear.This review systematically reports findings from relevant studies that measure the effects of class size on academic achievement.What are the main findings of this review?: What studies are included?: Included studies concerned children in grades kindergarten to 12 (or the equivalent in European countries) in general education. The primary focus was on measures of academic achievement. All study designs that used a well-defined control group were eligible for inclusion.A total of 127 studies, consisting of 148 papers, met the inclusion criteria. These 127 studies analysed 55 different populations from 41 different countries. A large number of studies (45) analysed data from the Student Teacher Achievement Ratio (STAR) experiment which was for class size reduction in grade K-3 in the US in the eighties. However only ten studies, including four of the STAR programme, could be included in the meta-analysis.What are the main results?: Overall, the evidence suggests at best a small effect on reading achievement. There is a negative, but statistically insignificant, effect on mathematics.For the non-STAR studies the primary study effect sizes for reading were close to zero but the weighted average was positive and statistically significant. There was some inconsistency in the direction of the primary study effect sizes for mathematics and the weighted average effect was negative and statistically non-significant.The STAR results are more positive, but do not change the overall finding. All reported results from the studies analysing STAR data indicated a positive effect of smaller class sizes for both reading and maths, but the average effects are small.What do the findings of this review mean?: There is some evidence to suggest that there is an effect of reducing class size on reading achievement, although the effect is very small. There is no significant effect on mathematics achievement, though the average is negative meaning a possible adverse impact on some students cannot be ruled out.The overall reading effect corresponds to a 53 per cent chance that a randomly selected score of a student from the treated population of small classes is greater than the score of a randomly selected student from the comparison population of larger classes. This is a very small effect.Class size reduction is costly. The available evidence points to no or only very small effect sizes of small classes in comparison to larger classes. Moreover, we cannot rule out the possibility that small classes may be counterproductive for some students. It is therefore crucial to know more about the relationship between class size and achievement in order to determine where money is best allocated.How up-to-date is this review?: The review authors searched for studies published up to February 2017. This Campbell systematic review was published in 2018. Executive Summary/Abstract: BACKGROUND: Increasing class size is one of the key variables that policy makers can use to control spending on education. Reducing class size to increase student achievement is an approach that has been tried, debated, and analysed for several decades. Despite the important policy and practice implications of the topic, the research literature on the educational effects of class-size differences has not been clear.The consensus among many in education research, that smaller classes are effective in improving student achievement has led to a policy of class size reductions in a number of U.S. states, the United Kingdom, and the Netherlands. This policy is disputed by those who argue that the effects of class size reduction are only modest and that there are other more cost-effective strategies for improving educational standards.OBJECTIVES: The purpose of this review is to systematically uncover relevant studies in the literature that measure the effects of class size on academic achievement. We will synthesize the effects in a transparent manner and, where possible, we will investigate the extent to which the effects differ among different groups of students such as high/low performers, high/low income families, or members of minority/non-minority groups, and whether timing, intensity, and duration have an impact on the magnitude of the effect.SEARCH METHODS: Relevant studies were identified through electronic searches of bibliographic databases, internet search engines and hand searching of core journals. Searches were carried out to February 2017. We searched to identify both published and unpublished literature. The searches were international in scope. Reference lists of included studies and relevant reviews were also searched.SELECTION CRITERIA: The intervention of interest was a reduction in class size. We included children in grades kindergarten to 12 (or the equivalent in European countries) in general education. The primary focus was on measures of academic achievement. All study designs that used a well-defined control group were eligible for inclusion. Studies that utilized qualitative approaches were not included.DATA COLLECTION AND ANALYSIS: The total number of potential relevant studies constituted 8,128 hits. A total of 127 studies, consisting of 148 papers, met the inclusion criteria and were critically appraised by the review authors. The 127 studies analysed 55 different populations from 41 different countries.A large number of studies (45) analysed data from the STAR experiment (class size reduction in grade K-3) and its follow up data.Of the 82 studies not analysing data from the STAR experiment, only six could be used in the data synthesis. Fifty eight studies could not be used in the data synthesis as they were judged to have too high risk of bias either due to confounding (51), other sources of bias (4) or selective reporting of results (3). Eighteen studies did not provide enough information enabling us to calculate an effects size and standard error or did not provide results in a form enabling us to use it in the data synthesis.Meta-analysis was used to examine the effects of class size on student achievement in reading and mathematics. Random effects models were used to pool data across the studies not analysing STAR data. Pooled estimates were weighted using inverse variance methods, and 95% confidence intervals were estimated. Effect sizes were measured as standardised mean differences (SMD). It was only possible to perform a meta-analysis by the end of the treatment year (end of the school year).Four of the studies analysing STAR data provided effect estimates that could be used in the data synthesis. The four studies differed in terms of both the chosen comparison condition and decision rules in selecting a sample for analysis. Which of these four studies' effect estimates should be included in the data synthesis was not obvious as the decision rule (concerning studies using the same data set) as described in the protocol could not be used. Contrary to usual practice we therefore report the results of all four studies and do not pool the results with the studies not analysing STAR data except in the sensitivity analysis. We took into consideration the ICC in the results reported for the STAR experiment and corrected the effect sizes and standard errors using ρ = 0.22. No adjustment due to clustering was necessary for the studies not analysing STAR data.Sensitivity analysis was used to evaluate whether the pooled effect sizes were robust across components of methodological quality, in relation to inclusion of a primary study result with an unclear sign, inclusion of effect sizes from the STAR experiment and to using a one-student reduction in class size in studies using class size as a continuous variable.RESULTS: All studies, not analysing STAR data, reported outcomes by the end of the treatment (end of the school year) only. The STAR experiment was a four year longitudinal study with outcomes reported by the end of each school year. The experiment was conducted to assess the effectiveness of small classes compared with regular-sized classes and of teachers' aides in regular-sized classes on improving cognitive achievement in kindergarten and in the first, second, and third grades. The goal of the STAR experiment was to have approximately 100 small classes with 13-17 students (S), 100 regular classes with 22-25 students (R), and 100 regular with aide classes with 22-25 students (RA).Of the six studies not analysing STAR, only five were used in the meta-analysis as the direction of the effect size in one study was unclear. The studies were from USA, the Netherlands and France, one was a RCT and five were NRS. The grades investigated spanned kindergarten to 3. Grade and one study investigated grade 10. The sample sizes varied; the smallest study investigated 104 students and the largest study investigated 11,567 students. The class size reductions varied from a minimum of one student in four studies, a minimum of seven students in another study to a minimum of 8 students in the last study.All outcomes were scaled such that a positive effect size favours the students in small classes, i.e. when an effect size is positive a class size reduction improves the students' achievement.Primary study effect sizes for reading lied in the range -0.08 to 0.14. Three of the study-level effects were statistically non-significant. The weighted average was positive and statistically significant. The random effects weighted standardised mean difference was 0.11 (95% CI 0.05 to 0.16) which may be characterised as small. There is some inconsistency in the direction of the effect sizes between the primary studies. Primary study effect sizes for mathematics lies in the range -0.41 to 0.11. Two of the study-level effects were statistically non-significant. The weighted average was negative and statistically non-significant. The random effects weighted standardised mean difference was -0.03 (95% CI -0.22 to 0.16). There is some inconsistency in the direction as well as the magnitude of the effect sizes between the primary studies.All reported results from the four studies analysing STAR data indicated a positive effect favouring the treated; all of the study-level effects were statistically significant. The study-level effect sizes for reading varied between 0.17 and 0.34 and the study-level effect sizes for mathematics varied between 0.15 and 0.33.There were no appreciable changes in the results when we included the extremes of the range of effect sizes from the STAR experiment. The reading outcome lost statistical significance when the effect size from the primary study reporting a result with an unclear direction was included with a negative sign and when the results from the studies using class size as a continuous variable were included with a one student reduction in class size instead of a standard deviation reduction in class size.Otherwise, there were no appreciable changes in the results.AUTHORS' CONCLUSIONS: There is some evidence to suggest that there is an effect of reducing class size on reading achievement, although the effect is very small. We found a statistically significant positive effect of reducing the class size on reading. The effect on mathematics achievement was not statistically significant, thus it is uncertain if there may be a negative effect.The overall reading effect corresponds to a 53 per cent chance that a randomly selected score of a student from the treated population of small classes is greater than the score of a randomly selected student from the comparison population of larger classes. The overall effect on mathematics achievement corresponds to a 49 per cent chance that a randomly selected score of a student from the treated population of small classes is greater than the score of a randomly selected student from the comparison population of larger classes.Class size reduction is costly and the available evidence points to no or only very small effect sizes of small classes in comparison to larger classes. Taking the individual variation in effects into consideration, we cannot rule out the possibility that small classes may be counterproductive for some students. It is therefore crucial to know more about the relationship between class size and achievement and how it influences what teachers and students do in the classroom in order to determine where money is best allocated.

Lung ultrasound training: a systematic review of published literature in clinical lung ultrasound training.

BACKGROUND: Clinical lung ultrasound examinations are widely used in the primary assessment or monitoring of patients with dyspnoea or respiratory failure. Despite being increasingly implemented, there is no international consensus on education, assessment of competencies, and certification. Today, training is usually based on the concept of mastery learning, but is often unstructured and limited by bustle in a clinical daily life. The aim of the systematic review is to provide an overview of published learning studies in clinical lung ultrasound, and to collect evidence for future recommendations in lung ultrasound education and certification. METHODS: According to PRISMA guidelines, three databases (PubMed, Embase, Cochrane Library) were searched, and two reviewers examined the results for eligibility. Included publications were described and assessed for level of evidence and risk of bias according to guidelines from Oxford Centre for Evidence-Based Medicine and Cochrane Collaboration Tool for Risk of Bias assessment. RESULTS: Of 7796 studies screened, 16 studies were included. Twelve pre- and post-test studies, three descriptive studies and one randomized controlled trial were identified. Seven studies included web-based or online modalities, while remaining used didactic or classroom-based lectures. Twelve (75%) studies provided hands-on sessions, and of these, 11 assessed participants' hands-on skills. None of the studies used validated neither written nor practical assessment. The highest level of evidence score was 2 (n = 1), remaining scored 4 (n = 15). Risk of bias was assessed high in 11 of 16 studies (68.75%). CONCLUSION: All educational methods proved increased theoretical and practical knowledge obtained at the ultrasound courses, but the included studies were substantial heterogeneous in setup, learning-, and assessment methods, and outcome measures. On behalf of current published studies, it was not possible to construct clear guidelines for the future education and certification in clinical lung ultrasound, but the use of different hands-on training facilities tends to contribute to different aspects of the learning process. This systematic review proves a lack of learning studies within this content, and research with validated theoretical and practical tests for assessment is desired.

Consensus on procedures to include in a simulation-based curriculum in ophthalmology: a national Delphi study.

PURPOSE: The number of available simulation-based models for technical skills training in ophthalmology is rapidly increasing, and development of training programmes around these procedures should follow a structured approach. The aim of this study was to identify all technical procedures that should be integrated in a simulation-based curriculum in ophthalmology. METHODS: Key opinion leaders involved in the education of ophthalmologists in Denmark including heads of departments, heads of clinical education, professors and board members of the society were invited to participate in a three-round Delphi process. Round 1 aimed at identifying technical procedures that physicians should be able to perform competently when completing specialty training; round 2 involved characterization of each procedure including frequency, number of operators, risk and/or discomfort for patients associated with an inexperienced physician, and feasibility of simulation-based training; round 3 included a priority ranking of procedures. RESULTS: The response rate for each round was 71%, 64% and 64%, respectively. Sixty-five procedures were reduced to 25 prioritized procedures during the three rounds. Two-thirds of the procedures that were identified and highly prioritized were therapeutic procedures such as intravitreal injection therapy, yttrium-aluminium-garnet laser iridotomy/capsulotomy, minor ocular surface procedures and retinal argon laser therapy. The diagnostic procedures that were prioritized were ocular ultrasound, superficial keratectomy and optical coherence tomography (OCT). CONCLUSION: The Delphi process identified and prioritized 25 procedures that should be practised in a simulation-based environment to achieve competency before working with patients. The list may be used to guide the development of future training programmes for ophthalmologists.

Influence of endotoxin-induced sepsis on the requirements of propofol-fentanyl infusion rate in pigs.

Endotoxin-induced sepsis in pigs is a recognized experimental model for the study of human septic shock. Generally, pigs are brought into general anaesthesia before sepsis is induced. It is our experience that drug dosages of propofol and fentanyl need to be reduced during endotoxin-induced sepsis, in order to prevent respiratory and cardiovascular depression, but the scientific evidence for this observation is lacking. Therefore, we measured the consumption of propofol and fentanyl at equal level of anaesthesia in pigs with (n = 5) and without (n = 5) endotoxin-induced sepsis, using the cerebral state index (CSI) as measure of anaesthetic depth. Infusion rates of propofol (P < 0.01) and fentanyl (P < 0.05) were significantly lower in septic pigs. Pigs with endotoxin-induced sepsis had an infusion rate of 2.2 mg/kg/hr (S.D. 0.5) for propofol and 12 microg/kg/hr (S.D. 2) for fentanyl, whereas healthy pigs had infusion rates of 3.5 mg/kg/hr (S.D. 0.6) and 17 microg/kg/hr (S.D. 4), respectively. CSI was equal in both groups throughout the experiment, and had a lowest average value of 47 (S.D. 10) at t = 30 in healthy pigs and reached a highest average value of 67 (S.D. 19) at t = 240 in pigs with endotoxin-induced sepsis. Anaesthetic depth was sufficient, assessed clinically, throughout the experiment in both groups. We concluded that the consumption of propofol and fentanyl was significantly reduced in pigs with endotoxin-induced sepsis. In the present study, we adjusted the level of anaesthesia according to clinical signs, and found good agreement with CSI.

On the possibility for computing the transmembrane potential in the heart with a one shot method: an inverse problem.

We analyze the possibility for using body surface potential maps (BSPMs), a priori information about the voltage distribution in the heart and the bidomain equations to compute the transmembrane potential throughout the myocardium. Our approach is defined in terms of an inverse problem for elliptic partial differential equations (PDEs). More precisely, we formulate it in terms of an output least squares framework in which a goal functional is minimized subject to suitable PDE constraints. The problem is highly unstable and, even under optimal recording conditions, it does not have a unique solution. We propose a methodology for stabilizing and enforcing uniqueness for this inverse problem. Moreover, a fully implicit method for solving the involved minimization problem is presented. In other words, we show how one may solve it in terms of a system consisting of three linear elliptic PDEs, i.e. we derive a so-called one shot method (also commonly referred to as an all-at-once method). Finally, our theoretical findings are illuminated by a series of numerical experiments. These examples indicate that, in the presence of regional ischemia, it might be possible to approximately recover the transmembrane potential during the resting and plateau phases of the heart cycle. This is probably due to the fact that rather accurate a priori information is available during these time intervals. The problem of computing the transmembrane potential at an arbitrary time instance during a heart beat is still an open problem.

A linear system of partial differential equations modeling the resting potential of a heart with regional ischemia.

Ischemic ST-segment shift has been modeled using scalar stationary approximations of the bidomain model. Here, we propose an alternative simplification of the bidomain equations: a linear system modeling the resting potential, to be used in determining ischemic TP shift. Results of 2D and 3D simulations show that the linear system model is much more accurate than the scalar model. This improved accuracy is important if the model is to be used for solving the inverse problem of determining the size and location of an ischemic region. Furthermore, the model can provide insight into how the resting potential depends on the variations in the extracellular potassium concentration that characterize ischemic regions.

Regularization of Ill-Posed Point Neuron Models.

Point neuron models with a Heaviside firing rate function can be ill-posed. That is, the initial-condition-to-solution map might become discontinuous in finite time. If a Lipschitz continuous but steep firing rate function is employed, then standard ODE theory implies that such models are well-posed and can thus, approximately, be solved with finite precision arithmetic. We investigate whether the solution of this well-posed model converges to a solution of the ill-posed limit problem as the steepness parameter of the firing rate function tends to infinity. Our argument employs the Arzelà-Ascoli theorem and also yields the existence of a solution of the limit problem. However, we only obtain convergence of a subsequence of the regularized solutions. This is consistent with the fact that models with a Heaviside firing rate function can have several solutions, as we show. Our analysis assumes that the vector-valued limit function v, provided by the Arzelà-Ascoli theorem, is threshold simple: That is, the set containing the times when one or more of the component functions of v equal the threshold value for firing, has zero Lebesgue measure. If this assumption does not hold, we argue that the regularized solutions may not converge to a solution of the limit problem with a Heaviside firing function.

Identifying content for simulation-based curricula in urology: a national needs assessment.

OBJECTIVE: Simulation-based training is well recognized in the transforming field of urological surgery; however, integration into the curriculum is often unstructured. Development of simulation-based curricula should follow a stepwise approach starting with a needs assessment. This study aimed to identify technical procedures in urology that should be included in a simulation-based curriculum for residency training. MATERIALS AND METHODS: A national needs assessment was performed using the Delphi method involving 56 experts with significant roles in the education of urologists. Round 1 identified technical procedures that newly qualified urologists should perform. Round 2 included a survey using an established needs assessment formula to explore: the frequency of procedures; the number of physicians who should be able to perform the procedure; the risk and/or discomfort to patients when a procedure is performed by an inexperienced physician; and the feasibility of simulation training. Round 3 involved elimination and reranking of procedures according to priority. RESULTS: The response rates for the three Delphi rounds were 70%, 55% and 67%, respectively. The 34 procedures identified in Round 1 were reduced to a final prioritized list of 18 technical procedures for simulation-based training. The five procedures that reached the highest prioritization were cystoscopy, transrectal ultrasound-guided biopsy of the prostate, placement of ureteral stent, insertion of urethral and suprapubic catheter, and transurethral resection of the bladder. CONCLUSION: The prioritized list of technical procedures in urology that were identified as highly suitable for simulation can be used as an aid in the planning and development of simulation-based training programs.

Computing the size and location of myocardial ischemia using measurements of ST-segment shift.

It is well known that the presence of myocardial ischemia can be observed as a shift in the ST segment of an electrocardiogram (ECG) recording. The question we address in this paper is whether or not ST shift can be used to compute approximations of the size and location of the ischemic region. We begin by investigating a cost functional (measuring the difference between synthetic recorded data and simulated values of ST shift) for a parameter identification problem to locate the ischemic region. We then formulate a more flexible representation of the ischemia using a level set framework and solve the associated minimization problem for the size and position of the ischemia. We apply this framework to a set of ECG data generated by the Bidomain model using the cell model of Winslow et al. Based on this data, we show that values of ST shift recorded at the body surface are capable of identifying the position and (roughly) the size of the ischemia.

Ill-Posed Point Neuron Models.

We show that point-neuron models with a Heaviside firing rate function can be ill posed. More specifically, the initial-condition-to-solution map might become discontinuous in finite time. Consequently, if finite precision arithmetic is used, then it is virtually impossible to guarantee the accurate numerical solution of such models. If a smooth firing rate function is employed, then standard ODE theory implies that point-neuron models are well posed. Nevertheless, in the steep firing rate regime, the problem may become close to ill posed, and the error amplification, in finite time, can be very large. This observation is illuminated by numerical experiments. We conclude that, if a steep firing rate function is employed, then minor round-off errors can have a devastating effect on simulations, unless proper error-control schemes are used.

Computing ischemic regions in the heart with the bidomain model--first steps towards validation.

We investigate whether it is possible to use the bidomain model and body surface potential maps (BSPMs) to compute the size and position of ischemic regions in the human heart. This leads to a severely ill posed inverse problem for a potential equation. We do not use the classical inverse problems of electrocardiography, in which the unknown sources are the epicardial potential distribution or the activation sequence. Instead we employ the bidomain theory to obtain a model that also enables identification of ischemic regions transmurally. This approach makes it possible to distinguish between subendocardial and transmural cases, only using the BSPM data. The main focus is on testing a previously published algorithm on clinical data, and the results are compared with images taken with perfusion scintigraphy. For the four patients involved in this study, the two modalities produce results that are rather similar: The relative differences between the center of mass and the size of the ischemic regions, suggested by the two modalities, are 10.8% ± 4.4% and 7.1% ± 4.6%, respectively. We also present some simulations which indicate that the methodology is robust with respect to uncertainties in important model parameters. However, in contrast to what has been observed in investigations only involving synthetic data, inequality constraints are needed to obtain sound results.