Alpha2 Antagonist Vatinoxan Does Not Abolish the Preconditioning Effect of Dexmedetomidine on Experimental Ischaemia-Reperfusion Injury in the Equine Small Intestine.

Pharmacological preconditioning with dexmedetomidine has been shown to ameliorate intestinal ischaemia reperfusion injury in different species, including horses. However, it remains unknown if this effect is related to alpha2 adrenoreceptor activity. Therefore, the aim of this study was to determine the effect of dexmedetomidine preconditioning with and without the administration of the peripheral alpha2 antagonist vatinoxan. This prospective randomized experimental trial included 12 horses equally divided between two treatment groups. Horses in group Dex received a bolus of dexmedetomidine followed by a continuous rate infusion (CRI), while group DexV additionally received vatinoxan as bolus and CRI. A median laparotomy was performed under general anaesthesia, and jejunal ischaemia was applied for 90 min, followed by 30 min of reperfusion. Mucosal damage was evaluated in full thickness biopsies by use of a semiquantitative mucosal injury score and by determining the apoptotic cell counts with immunohistochemical staining for cleaved caspase-3 and TUNEL. Comparisons between the groups and time points were performed using non-parametric tests (p < 0.05). During pre-ischaemia and ischaemia, no differences could be found in mucosal injury between the groups. After reperfusion, group DexV showed lower mucosal injury scores compared to group Dex. The apoptotic cell counts did not differ between the groups. In conclusion, antagonizing the peripheral alpha2 adrenoreceptors did not negatively affect dexmedetomidine preconditioning.

Pharmacodynamics and plasma concentrations of dexmedetomidine with or without vatinoxan as a constant-rate infusion in horses anaesthetized with isoflurane-A pilot study.

The aim was to determine the effects of vatinoxan on dexmedetomidine plasma concentrations and effects on cardiovascular and intestinal tissue pharmacodynamics. In a prospective randomized study, six horses were premedicated intravenously with dexmedetomidine 3.5 µg kg-1 followed by a constant-rate infusion of 7 µg kg-1  h-1 (group DEX) and six horses with dexmedetomidine of the same dose (bolus and constant-rate infusion) combined with vatinoxan 130 µg kg-1 followed by 40 µg kg-1  h-1 (group VAT). Anaesthesia was induced with ketamine and diazepam and maintained with isoflurane. Venous blood samples were withdrawn before and at predefined points in time after drug application. During sedation and anaesthesia, cardiopulmonary variables, gastrointestinal tissue perfusion and oxygenation were recorded. Data were analysed using two-way-ANOVA, unpaired-t-test and Dunnett's-t-test (p < 0.05). Group VAT had significantly higher oxygen delivery and lower oxygen extraction ratio, venous admixture, alveolar dead space and alveolar-arterial-oxygen difference. Tissue perfusion of buccal mucosa was reduced during anaesthesia in group DEX. Plasma concentrations of dexmedetomidine in group VAT (n = 6) and group DEX (n = 5) were comparable between groups. In the present pilot study, co-administration of vatinoxan with dexmedetomidine did not alter plasma concentrations of dexmedetomidine but ameliorated tissue perfusion and global oxygenation variables.

Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses.

BACKGROUND: Strangulating small intestinal lesions in the horse have increased morbidity and mortality compared to nonstrangulating obstructions due to mucosal barrier disruption and subsequent endotoxaemia. OBJECTIVES: To investigate protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in the horse. STUDY DESIGN: Randomised, controlled, experimental study. METHODS: Eighteen systemically healthy horses were randomly assigned to three groups: control, preconditioning, and post-conditioning. During isoflurane anaesthesia, complete ischaemia was induced in a 1-m segment of jejunum for 90 minutes. Horses in the preconditioning and post-conditioning groups received dexmedetomidine (3.5 µg/kg followed by 7 µg/kg/h) before (preconditioning) or after beginning ischaemia (post-conditioning), and during reperfusion. Jejunal biopsies were collected before ischaemia (baseline-1), at the end of the ischaemic period (ischaemia), and 30 minutes after reperfusion (reperfusion-1). Additional biopsies were taken 24 hours after reperfusion from ischaemia-reperfusion-injured jejunum (reperfusion-2). Epithelial injury was scored histologically, and morphometric analyses were used to calculate villus surface area (VSA) denuded of epithelium. Data were analysed using analysis of variance, Kruskal-Wallis and Wilcoxon two-sample tests. RESULTS: In the control group, epithelial injury scores and percentage of VSA denudation for ischaemia-reperfusion-injured jejunum were higher compared to baseline-1 at all time points. The ischaemia and both reperfusion samples from the pre- and post-conditioning groups had lower epithelial injury scores and percentage of VSA epithelial denudation compared to the control group, with no difference from baseline-1 at any time point for the preconditioning group. MAIN LIMITATIONS: Preconditioning has limited application in the clinical setting with naturally occurring strangulating small intestinal lesions. CONCLUSIONS: Dexmedetomidine was protective for small intestinal ischaemia-reperfusion injury in the horse when administered before or during ischaemia.

High-fidelity simulation increases obstetric self-assurance and skills in undergraduate medical students.

OBJECTIVE: Teaching intrapartum care is one of the most challenging tasks in undergraduate medical education. High-fidelity obstetric simulators might support students' learning experience. The specific educational impact of these simulators compared with traditional methods of model-based obstetric teaching has not yet been determined. STUDY DESIGN: We randomly assigned 46 undergraduate medical students to be taught using either a high-fidelity simulator or a scale wood-and-leather phantom. Their self-assessments were evaluated using a validated questionnaire. We assessed obstetric skills and asked students to solve obstetric paper cases. MAIN OUTCOME MEASURES: Assessment of fidelity-specific teaching impact on procedural knowledge, motivation, and interest in obstetrics as well as obstetric skills using high- and low-fidelity training models. RESULTS: High-fidelity simulation specifically improved students' feeling that they understood both the physiology of parturition and the obstetric procedures. Students in the simulation group also felt better prepared for obstetric house jobs and performed better in obstetric skills evaluations. However, the two groups made equivalent obstetric decisions. CONCLUSION: This study provides first data on the impact of high-fidelity simulation in an undergraduate setting.

Pick-N multiple choice-exams: a comparison of scoring algorithms.

To compare different scoring algorithms for Pick-N multiple correct answer multiple-choice (MC) exams regarding test reliability, student performance, total item discrimination and item difficulty. Data from six 3rd year medical students' end of term exams in internal medicine from 2005 to 2008 at Munich University were analysed (1,255 students, 180 Pick-N items in total). Scoring Algorithms: Each question scored a maximum of one point. We compared: (a) Dichotomous scoring (DS): One point if all true and no wrong answers were chosen. (b) Partial credit algorithm 1 (PS(50)): One point for 100% true answers; 0.5 points for 50% or more true answers; zero points for less than 50% true answers. No point deduction for wrong choices. (c) Partial credit algorithm 2 (PS(1/m)): A fraction of one point depending on the total number of true answers was given for each correct answer identified. No point deduction for wrong choices. Application of partial crediting resulted in psychometric results superior to dichotomous scoring (DS). Algorithms examined resulted in similar psychometric data with PS(50) only slightly exceeding PS(1/m) in higher coefficients of reliability. The Pick-N MC format and its scoring using the PS(50) and PS(1/m) algorithms are suited for undergraduate medical examinations. Partial knowledge should be awarded in Pick-N MC exams.

Do worked examples foster medical students' diagnostic knowledge of hyperthyroidism?

OBJECTIVES: In an initial experimental study in the domain of learning about hypertension, a case-based, worked example approach was found to be most effective when erroneous examples and elaborated feedback were provided. However, combining erroneous examples with knowledge of correct result (KCR) feedback impaired learning. This study was designed to establish whether these findings could be replicated in the domain of learning about hyperthyroidism. METHODS: A total of 124 medical students were randomly assigned to the four conditions of a 2 x 2 design (with errors versus without errors; elaborated feedback versus KCR feedback). Diagnostic knowledge was operationalised by a multiple-choice test, key feature problems and problem-solving tasks. Acceptance and subjective learning outcomes were assessed on three rating scales. RESULTS: The combination of erroneous examples and elaborated feedback was the most effective learning condition, whereas erroneous examples with KCR feedback impaired knowledge acquisition. These effects were independent of differences in prior knowledge and time on task and replicated key findings of the study on hypertension diagnostics. Additionally, results showed that students in conditions with elaborated feedback assessed their learning outcomes as significantly higher than students receiving KCR feedback only. CONCLUSIONS: By providing erroneous examples in combination with elaborated feedback in a computer-based learning environment, diagnostic knowledge was fostered. The approach of 'learning from worked examples' was successfully adapted to a complex domain and was found to support the acquisition of complex competencies.

Fostering diagnostic knowledge through computer-supported, case-based worked examples: effects of erroneous examples and feedback.

OBJECTIVES: A case-based, worked example approach was realised in a computer-based learning environment with the intention of facilitating medical students' diagnostic knowledge. In order to enhance the effectiveness of the approach, two additional measures were implemented: erroneous examples and elaborated feedback. In the context of an experimental study, the two measures were varied experimentally. METHODS: A total of 153 medical students were randomly assigned to four experimental conditions of a 2 x 2-factor design (errors versus no errors, elaborated feedback versus knowledge of correct result [KCR]). In order to verify the sustainability of the effects, a subgroup of subjects (n = 52) was compared with a control group of students who did not participate in the experiment (n = 145) on a regular multiple-choice question (MCQ) test. RESULTS: Results show that the acquisition of diagnostic knowledge is mainly supported by providing erroneous examples in combination with elaborated feedback. These effects were independent from differences in time-on-task and prior knowledge. Furthermore, the effects of the learning environment proved sustainable. CONCLUSIONS: Our results demonstrate that the case-based, worked example approach is effective and efficient.

[Candidate selection in internal medicine regarding the new licensing regulation for doctors]. / Einstellungskriterien in der Inneren Medizin im Lichte der neuen AAppO.

BACKGROUND AND PURPOSE: Since October 2003, a new licensing regulation for doctors exists in Germany. Due to this reform medical students obtain individual grades for each clinical subject. At the end of 2006, these grades appeared in the students' leaving certificates for the first time. As the significance of these grades concerning their influence on selection criteria is still very uncertain, the aim of this study was to further investigate criteria for residency selection focusing on the evaluation of the new grades. METHODS: The importance of selection criteria was assessed by an electronic questionnaire based on a five-point Likert scale (1 = unimportant; 5 = critical). The questionnaire was sent to 7,766 members of the German Society of Internal Medicine in May 2006. 897 questionnaires were returned (11.6%): 133 heads of department, 158 senior physicians, 269 specialists, and 337 residents. 43% of the respondents were involved in the selection process. RESULTS: Factors ranking as most important for respondents involved in residency selection included personally knowing an applicant, e.g., after a rotation (mean 4.1; standard deviation 1.3), and personal recommendations from colleagues (3.8 +/- 1.2). High emphasis was also placed on social commitment and additional skills. Concerning the grades given according to the old licensing regulation for doctors, the final grade of the Medical Licensing Examination (3.5 +/- 1.1) and the grade of the Medical Licensing Examination step 3 (3.4 +/- 1.1) were ranked as important. Regarding the new licensing regulation for doctors, 38% of the respondents (3.0 +/- 1.2) considered the individual grades more important than the results of the Medical Licensing Examination step 2. 49% of the respondents stated, that the grade D ("sufficient") in internal medicine would be an exclusion criterion when selecting residents (3.3 +/- 1.3). CONCLUSION: Whether the results are representative of all physicians involved in the selection process has to remain open taking a response rate of 11.6% into account. Personal knowledge of applicants, personal recommendations and additional skills were considered more important than the grades in the Medical Licensing Examination when selecting residents. The new individual grades were evaluated heterogeneously, but there is a tendency toward ranking the grades of their own clinical subject as important; especially minor grades are considered an exclusion criterion.

Answer changing in multiple choice assessment change that answer when in doubt--and spread the word!

BACKGROUND: Several studies during the last decades have shown that answer changing in multiple choice examinations is generally beneficial for examinees. In spite of this the common misbelief still prevails that answer changing in multiple choice examinations results in an increased number of wrong answers rather than an improved score. One suggested consequence of newer studies is that examinees should be informed about this misbelief in the hope that this prejudice might be eradicated. This study aims to confirm data from previous studies about the benefits of answer changing as well as pursue the question of whether students informed about the said advantageous effects of answer changing would indeed follow this advice and change significantly more answers. Furthermore a look is cast on how the overall examination performance and mean point increase of these students is affected. METHODS: The answer sheets to the end of term exams of 79 3rd year medical students at the University of Munich were analysed to confirm the benefits of answer changing. Students taking the test were randomized into two groups. Prior to taking the test 41 students were informed about the benefits of changing answers after careful reconsideration while 38 students did not receive such information. Both groups were instructed to mark all answer changes made during the test. RESULTS: Answer changes were predominantly from wrong to right in full accordance with existing literature resources. It was shown that students who had been informed about the benefits of answer changing when in doubt changed answers significantly more often than students who had not been informed. Though students instructed on the benefits of changing answers scored higher in their exams than those not instructed, the difference in point increase was not significant. CONCLUSION: Students should be informed about the benefits of changing initial answers to multiple choice questions once when in reasonable doubt about these answers. Furthermore, reconsidering answers should be encouraged as students will heed the advice and change more answers than students not so instructed.

Answering multiple-choice questions in high-stakes medical examinations.

OBJECTIVES: To examine whether changing initial answers during a multiple-choice question (MCQ) test in medicine brings about better overall test results, as has been shown in other academic fields. METHODS: A total of 36 answer books from the German Second National Medical Board Examination, with 580 MCQs (where 1 answer out of 5 must be selected), were used for analysis. RESULTS: We confirmed that high-stakes MCQ test scores in medicine did indeed improve when students changed their answers once. Further changes of answers did not improve the scores. CONCLUSIONS: In written, high-stakes medical examinations, we recommend that students be encouraged, after further reflection, to change their answers in MCQ tests for questions for which they had previously had doubts about the answers.

A modified electronic key feature examination for undergraduate medical students: validation threats and opportunities.

The purpose of our study was the development and validation of a modified electronic key feature exam of clinical decision-making skills for undergraduate medical students. Therefore, the reliability of the test (15 items), the item difficulty level, the item-total correlations and correlations to other measures of knowledge (40 item MC-test and 580 items of German MC-National Licensing Exam, Part II) were calculated. Based on the guidelines provided by the Medical Council of Canada, a modified electronic key feature exam for internal medicine consisting of 15 key features (KFs) was developed for fifth year German medical students. Long menu (LM) and short menu (SM) question formats were used. Acceptance was assessed through a questionnaire. Thirty-seven students from four medical schools voluntarily participated in the study. The reliability of the key feature exam was 0.65 (Cronbach's alpha). The items' difficulty level scores were between 0.3 and 0.8 and the item-total correlations between 0.0 and 0.4. Correlations between the results of the KF exam and the other measures of knowledge were intermediate (r between 0.44 and 0.47) as well as the learners' level of acceptance. The modified electronic KF examination is a feasible and reliable evaluation tool that may be implemented for the assessment of clinical undergraduate training.