External Quality Assessment of Absorbance Measurements on Spectral and Spectral-Line Photometers

Peer Reviewe

Diagnosis of obstructive coronary artery disease using computed tomography angiography in patients with stable chest pain depending on clinical probability and in clinically important subgroups: meta-analysis of individual patient data

OBJECTIVE: To determine whether coronary computed tomography angiography (CTA) should be performed in patients with any clinical probability of coronary artery disease (CAD), and whether the diagnostic performance differs between subgroups of patients. DESIGN: Prospectively designed meta-analysis of individual patient data from prospective diagnostic accuracy studies. DATA SOURCES: Medline, Embase, and Web of Science for published studies. Unpublished studies were identified via direct contact with participating investigators. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Prospective diagnostic accuracy studies that compared coronary CTA with coronary angiography as the reference standard, using at least a 50% diameter reduction as a cutoff value for obstructive CAD. All patients needed to have a clinical indication for coronary angiography due to suspected CAD, and both tests had to be performed in all patients. Results had to be provided using 2×2 or 3×2 cross tabulations for the comparison of CTA with coronary angiography. Primary outcomes were the positive and negative predictive values of CTA as a function of clinical pretest probability of obstructive CAD, analysed by a generalised linear mixed model; calculations were performed including and excluding non-diagnostic CTA results. The no-treat/treat threshold model was used to determine the range of appropriate pretest probabilities for CTA. The threshold model was based on obtained post-test probabilities of less than 15% in case of negative CTA and above 50% in case of positive CTA. Sex, angina pectoris type, age, and number of computed tomography detector rows were used as clinical variables to analyse the diagnostic performance in relevant subgroups. RESULTS: Individual patient data from 5332 patients from 65 prospective diagnostic accuracy studies were retrieved. For a pretest probability range of 7-67%, the treat threshold of more than 50% and the no-treat threshold of less than 15% post-test probability were obtained using CTA. At a pretest probability of 7%, the positive predictive value of CTA was 50.9% (95% confidence interval 43.3% to 57.7%) and the negative predictive value of CTA was 97.8% (96.4% to 98.7%); corresponding values at a pretest probability of 67% were 82.7% (78.3% to 86.2%) and 85.0% (80.2% to 88.9%), respectively. The overall sensitivity of CTA was 95.2% (92.6% to 96.9%) and the specificity was 79.2% (74.9% to 82.9%). CTA using more than 64 detector rows was associated with a higher empirical sensitivity than CTA using up to 64 rows (93.4% v 86.5%, P=0.002) and specificity (84.4% v 72.6%, P<0.001). The area under the receiver-operating-characteristic curve for CTA was 0.897 (0.889 to 0.906), and the diagnostic performance of CTA was slightly lower in women than in with men (area under the curve 0.874 (0.858 to 0.890) v 0.907 (0.897 to 0.916), P<0.001). The diagnostic performance of CTA was slightly lower in patients older than 75 (0.864 (0.834 to 0.894), P=0.018 v all other age groups) and was not significantly influenced by angina pectoris type (typical angina 0.895 (0.873 to 0.917), atypical angina 0.898 (0.884 to 0.913), non-anginal chest pain 0.884 (0.870 to 0.899), other chest discomfort 0.915 (0.897 to 0.934)). CONCLUSIONS: In a no-treat/treat threshold model, the diagnosis of obstructive CAD using coronary CTA in patients with stable chest pain was most accurate when the clinical pretest probability was between 7% and 67%. Performance of CTA was not influenced by the angina pectoris type and was slightly higher in men and lower in older patients. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42012002780

Diagnosis of obstructive coronary artery disease using computed tomography angiography in patients with stable chest pain depending on clinical probability and in clinically important subgroups: Meta-analysis of individual patient data

Objective To determine whether coronary computed tomography angiography (CTA) should be performed in patients with any clinical probability of coronary artery disease (CAD), and whether the diagnostic performance differs between subgroups of patients. Design Prospectively designed meta-analysis of individual patient data from prospective diagnostic accuracy studies. Data sources Medline, Embase, and Web of Science for published studies. Unpublished studies were identified via direct contact with participating investigators. Eligibility criteria for selecting studies Prospective diagnostic accuracy studies that compared coronary CTA with coronary angiography as the reference standard, using at least a 50% diameter reduction as a cutoff value for obstructive CAD. All patients needed to have a clinical indication for coronary angiography due to suspected CAD, and both tests had to be performed in all patients. Results had to be provided using 2×2 or 3×2 cross tabulations for the comparison of CTA with coronary angiography. Primary outcomes were the positive and negative predictive values of CTA as a function of clinical pretest probability of obstructive CAD, analysed by a generalised linear mixed model; calculations were performed including and excluding non-diagnostic CTA results. The no-treat/treat threshold model was used to determine the range of appropriate pretest probabilities for CTA. The threshold model was based on obtained post-test probabilities of less than 15% in case of negative CTA and above 50% in case of positive CTA. Sex, angina pectoris type, age, and number of computed tomography detector rows were used as clinical variables to analyse the diagnostic performance in relevant subgroups. Results Individual patient data from 5332 patients from 65 prospective diagnostic accuracy studies were retrieved. For a pretest probability range of 7-67%, the treat threshold of more than 50% and the no-treat threshold of less than 15% post-test probability were obtained using CTA. At a pretest probability of 7%, the positive predictive value of CTA was 50.9% (95% confidence interval 43.3% to 57.7%) and the negative predictive value of CTA was 97.8% (96.4% to 98.7%); corresponding values at a pretest probability of 67% were 82.7% (78.3% to 86.2%) and 85.0% (80.2% to 88.9%), respectively. The overall sensitivity of CTA was 95.2% (92.6% to 96.9%) and the specificity was 79.2% (74.9% to 82.9%). CTA using more than 64 detector rows was associated with a higher empirical sensitivity than CTA using up to 64 rows (93.4% v 86.5%, P=0.002) and specificity (84.4% v 72.6%, P<0.001). The area under the receiver-operating-characteristic curve for CTA was 0.897 (0.889 to 0.906), and the diagnostic performance of CTA was slightly lower in women than in with men (area under the curve 0.874 (0.858 to 0.890) v 0.907 (0.897 to 0.916), P<0.001). The diagnostic performance of CTA was slightly lower in patients older than 75 (0.864 (0.834 to 0.894), P=0.018 v all other age groups) and was not significantly influenced by angina pectoris type (typical angina 0.895 (0.873 to 0.917), atypical angina 0.898 (0.884 to 0.913), non-anginal chest pain 0.884 (0.870 to 0.899), other chest discomfort 0.915 (0.897 to 0.934)). Conclusions In a no-treat/treat threshold model, the diagnosis of obstructive CAD using coronary CTA in patients with stable chest pain was most accurate when the clinical pretest probability was between 7% and 67%. Performance of CTA was not influenced by the angina pectoris type and was slightly higher in men and lower in older patients. Systematic review registration PROSPERO CRD42012002780

External Quality Control in the Determination of Neonatal Bilirubin. An Approach to the Improvement of Results

Peer Reviewe

Comparison of Five Routine Methods with the Candidate Reference Method for the Determination of Bilirubin in Neonatal Serum

Peer Reviewe

Praktische Lehre im Medizinstudium in Zeiten von COVID-19. Bericht über die COVID-19-bedingte Umgestaltung der peergestützten Lehre im Skills Lab mithilfe eines Inverted-Classroom-Formats

Objective: Drastic restrictions were imposed due to the COVID-19 pandemic, especially relating to the practical training part of the undergraduate human and dental medical training. During emergency mode teaching in the summer semester of 2020, a pilot project on practical classroom teaching under COVID-19 conditions was undertaken the Skills Lab Dresden, the Interprofessional Medical Training Centre (MITZ). Students were able to continue learning basic communication and manual skills. This project report presents the adaptations needed for this teaching concept and discusses their feasibility as well as selected evaluation results of the trial run.Description of the project: In normal teaching, students rotate to complete training sessions in small groups. Teaching is provided in a peer-teaching format. An Inverted Classroom Model was implemented as a teaching concept during emergency operation with preparation through digital learning and classroom teaching. Organisational and teaching adjustments were carried out for the concept and to comply with containment regulations. The concept was evaluated by the students using a standardised online questionnaire.Results: 1012 students completed their training during emergency operation at the university. The containment regulations meant that there were a higher number of training sessions and a higher workload. Only one of the alternative dates provided had to be used for COVID-19-related reasons. Infection chains could be tracked. The majority of students found the communication of information via Moodle to be sufficient and did not experience any technical problems. An analysis of the students' evaluation revealed a high level of overall satisfaction with the adapted teaching concept. Conclusion: The MITZ will once again use the concept in a modified form should there be renewed or continued emergency operation. The Inverted Classroom Model will also be established as an integral part of regular teaching. The findings may be of interest to other Skills Labs to develop concepts for emergency operation teaching to efficiently utilise site-specific resources.Zielsetzung: Bedingt durch die COVID-19-Pandemie entstanden insbesondere für die praktische Ausbildung des Human- und Zahnmedizinstudiums drastische Einschränkungen. Während der Notbetriebslehre im Sommersemester 2020 fand im Skills Lab Dresden, dem Medizinischen Interprofessionellen Trainingszentrum (MITZ), ein Pilotprojekt zur Umsetzung von praktischer Präsenzlehre unter COVID-19-Bedingungen statt. Studierende konnten weiterhin kommunikative und manuelle Basisfertigkeiten trainieren. Dieser Projektbericht stellt die nötigen Anpassungen für dieses Lehrkonzept vor und diskutiert deren Durchführbarkeit sowie ausgewählte Auswertungsergebnisse des Probedurchlaufs.Projektbeschreibung: In der regulären curricularen Lehre absolvieren die Studierenden in Kleingruppen Trainingsstationen im Rotationsprinzip. Die Lehre findet im Peer-Teaching-Format statt. Für den Notbetrieb wurde als Lehrkonzept ein Inverted-Classroom-Modell mit Vorbereitung durch digitales Lernen und Präsenzlehre implementiert. Für das Konzept und die Einhaltung der Eindämmungsbestimmungen wurden organisatorische und didaktische Anpassungen vorgenommen. Mit Hilfe eines standardisierten Online-Fragebogens wurde die Studierendenevaluation durchgeführt.Ergebnisse: Im Notbetrieb absolvierten 1012 Studierende die Trainings. Durch die Eindämmungsbestimmungen kam es zu einer höheren Anzahl an Trainingsterminen und einem erhöhten Arbeitsaufwand. Nur einer der bereitgestellten Ausweichtermine musste COVID-19-bedingt genutzt werden. Infektionsketten wären nachvollziehbar gewesen. Der Großteil der Studierenden empfand die Bereitstellung von Informationen über Moodle als ausreichend und sah keine technischen Probleme. Die Auswertung der Studierendenevaluation zeigte eine hohe Gesamtzufriedenheit mit dem angepassten Lehrkonzept. Schlussfolgerung: Im erneuten oder fortzusetzenden Notbetrieb wird das MITZ das Konzept modifiziert wieder nutzen. Zudem wird das Inverted-Classroom-Modell als fester Bestandteil der regulären Lehre etabliert. Die Erkenntnisse können für andere Skills Labs zur Erarbeitung von Konzepten für die Notbetriebslehre von Interesse sein, um die standortindividuellen Ressourcen effizient zu nutzen