The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.

The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.

The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.

The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.

Contexte: Le pronostic des neutropénie fébrile (NF) post-chimiothérapie de l’enfant a été amélioré par une antibiothérapie à large spectre systématique. Cependant des infections sévères ne surviennent que dans 15-25% des cas. Il a été recommandé en 2012 de faire évoluer la prise en charge en tenant compte du risque infectieux en utilisant des règles de décision clinique (RDC). Nous avions montré que les outils publiés pour distinguer ce risque étaient peu performants, non validés ou non applicables sur notre population. Une nouvelle RDC (score) permettant de distinguer les épisodes de NF à bas risque d’infection sévère a été construite. Cette RDC a été validée en interne. Compte tenu des différences mises en évidence dans les populations de tumeurs solides et d’hémopathies, il pourrait être pertinent d’utiliser un arbre de décision clinique pour classer le risque infectieux dont la première division serait le type de cancer et de valider cette nouvelle RDC.L’objectif de ce travail était de calibrer cette RDC sous forme d’arbre et de la valider sur un échantillon multicentrique pour distinguer les enfants avec NF à bas risque d’infection sévère. Méthodes: La première étape a été d’évaluer la méthodologie de développement des RDC déjà publiées pour identifier d’éventuelles limites méthodologiques. Ensuite, nous avons décrit les différences entre les hémopathies ou avec les tumeurs solides. Puis, la nouvelle RDC a été calibrée sous forme d’un arbre de décision à l’aide du logiciel Sipina. Sa performance a été évaluée en termes de sensibilité (Se), spécificité (Sp), et rapport de vraisemblance négatif (RVN).En parallèle, un protocole de validation multicentrique prospectif a été monté, avec pour objectif une Se proche de 100% et un RVN inférieur à 0,1. Il a été validé par le CCTIRS et par la CNIL. Il a été financé par la Ligue Contre le Cancer (72 000 euros). Trente et un centres ont été recrutés. La RDC n’a été appliquée qu’a posteriori ; la prise en charge de cette population n’a donc pas été modifiée. La performance de la RDC entre la population de validation et construction a été analysée en termes de Se, Sp, RVN. L’évaluation des pratiques de prise en charge des NF post-chimiothérapie de l’enfant a été faite en parallèle sous la forme d’une enquête nationale, dans la perspective d’une étude d’impact ultérieure.Résultats: L’étude de la méthodologie des RDC déjà publiées a montré que les critères de développement d’une RDC étaient respectés dans 71% des cas (médiane). Une RDC avait atteint le plus haut niveau d’évidence, mais sa population de construction était différente de la nôtre et cette RDC n’était pas reproductible sur notre population. Il existait 2 à 3 fois plus d’infection sévère chez les patients atteints d’une hémopathie maligne. Deux arbres de décision ont donc été construits pour différencier le risque d’infection sévère. Pour les patients avec une tumeur solide il avait des Se de 96%, Sp de 59% et RVN à 0,07, pour ceux avec une hémopathie maligne, il avait des Se de 99%, Sp de 52% et RVN à 0,03. Les inclusions de la validation multicentrique se sont déroulées de janvier 2012 à mai 2016. 1806 épisodes ont été inclus (333 infections sévères, 18,4%). L’application de la RDC a été faite a posteriori(en cours). L’enquête nationale menée en parallèle sur la prise en charge faite en pratique dans les centres français a montré une grande variabilité de prise en charge notamment dans les définitions de la neutropénie et de la fièvre. Un travail doit être initié avec la Société Française des Cancers de l’Enfant pour uniformiser la prise en charge des NF et déterminer le type d’allègement thérapeutique à proposer en vue de l’étude d’impact, en utilisant cette RDC. Conclusion: Les étapes de construction et de validation de cette nouvelle RDC ont été réalisées en respectant les standards méthodologiques. Une étude d’évaluation de l’impact de la RDC devra être mise en place pour atteindre le plus haut niveau d’évidence. / Purpose: Chemotherapy-induced febrile neutropenia (FN) is known to be a risk for severe infection and death in the absence of prompt and appropriate antibiotic therapy. Immediate hospitalization for rapid institution of empirical broad-spectrum intravenous antibiotic therapy has led to reduce the mortality. However, documented or severe infections occur in only 15-25% of cases. In 2012 paediatric guidelines suggested to adapt the management of FN episodes to the infectious risk. In a previous work, none of the published clinical decision rules (CDRs) to rule out severe infections have been validated and have only rarely been tested in an external set of children. The methodological standards used to derive and validate these CDRs were a real concern. A new CDR was previously derived as a scoring system in Lille to classify the patients at high or low risk of severe infection, with a dataset collected in 2 centers in Lille, in following methodological standards. Differences between solid tumours and blood cancers were observed in children with FN for numbers and types of infections. As a result, we considered relevant to build a decision tree model to predict the low risk for severe infection with a first division that could be the type of cancer. This new decision rule was already validated in an internal set of data, but required an external validation.The aim of this project was to calibrate the CDR as a decision tree and validate its performance a posteriori in an external set of patients, using prospectively collected data from multiple centers.Methods: the methodological standards of available CDRs were first analysed. The new CDR derived on a bicentric dataset was reused to calibrate the CDR as a decision tree, using Sipina software. A prospective multicentric observational protocol funded by 72000€ provided by “la Ligue Contre le Cancer” was developed for an external validation of the CDR to expect near 100% sensitivity (Se) and a negative likelihood ratio (LR) below 0.1. The ethical regulation was followed. Thirty-one centers were recruited in France (27/30 referent centers for management of children with cancer, and 4 proximity centers fit to manage children with FN). The CDR was not applied to the included patients, and remained confidential. The data were collected on an e-CRF “capture system”. The data were captured by an assistant of clinical research and controlled by a physician researcher after the monitoring of the data in all centers. The CDR was a posteriori applied on the dataset. The performance of the CDR between validation and derivation sets of patients was analysed in terms of Se, specificity (Sp) and negative LR.Results: the methodological standards of development of a CDR were not always followed for the development of the published CDR predicting infection for FN in children. Only one CDR followed all criteria and reached the highest level of evidence, but this CDR was built in a very different population from our and was not reproducible. A decision tree model of the CDR was built to distinguish children with FN at low risk of severe infection. For children with solid tumours, the CDR had 96% Se, 59% Sp, and a negative LR at 0.07. For children with blood cancers, the CDR had 99% Se, 52% Sp, and a negative LR at 0.03.For external validation, inclusions started in 2012 until May 2016. Of the 31 centers, 23 included 1806 cases (333 severe infections [18.4%]). The retrospective application of the CDR on all included case in ongoing. A national survey was also conducted as the same time to analyse the real management of children with FN in France in order to determine the type of management that could be proposed for low risk patients when the CDR will be tested in an impact study.Conclusion: the different steps for the construction and validation of the new CDR were conducted following standards. This CDR is in progress to reach the highest level of evidence.

Clinical decision rules improve health care fidelity, benefit patients, physicians and healthcare systems, without reducing patient safety or satisfaction, while promoting cost-effective practice standards. It is critical to appropriately and consistently apply clinical decision rules to realize these benefits. The objective of this thesis was to understand how physicians use the Ottawa Ankle Rules to guide radiography decision-making. The study employed a clinical judgment survey targeting members of the Canadian Association of Emergency Physicians. Statistical analyses were informed by the Brunswik Lens Model and Social Judgment Analysis. Physicians’ overall agreement with the ankle rule was high, but can be improved. Physicians placed greatest value on rule-based cues, while considering non-rule-based cues as moderately important. There is room to improve physician agreement with the ankle rule and use of rule-based cues through knowledge translation interventions. Further development of this Lens Modeling technique could lend itself to a valuable cognitive behavioral intervention.

Clinical decision rules improve health care fidelity, benefit patients, physicians and healthcare systems, without reducing patient safety or satisfaction, while promoting cost-effective practice standards. It is critical to appropriately and consistently apply clinical decision rules to realize these benefits. The objective of this thesis was to understand how physicians use the Ottawa Ankle Rules to guide radiography decision-making. The study employed a clinical judgment survey targeting members of the Canadian Association of Emergency Physicians. Statistical analyses were informed by the Brunswik Lens Model and Social Judgment Analysis. Physicians’ overall agreement with the ankle rule was high, but can be improved. Physicians placed greatest value on rule-based cues, while considering non-rule-based cues as moderately important. There is room to improve physician agreement with the ankle rule and use of rule-based cues through knowledge translation interventions. Further development of this Lens Modeling technique could lend itself to a valuable cognitive behavioral intervention.

Clinical decision rules improve health care fidelity, benefit patients, physicians and healthcare systems, without reducing patient safety or satisfaction, while promoting cost-effective practice standards. It is critical to appropriately and consistently apply clinical decision rules to realize these benefits. The objective of this thesis was to understand how physicians use the Ottawa Ankle Rules to guide radiography decision-making. The study employed a clinical judgment survey targeting members of the Canadian Association of Emergency Physicians. Statistical analyses were informed by the Brunswik Lens Model and Social Judgment Analysis. Physicians’ overall agreement with the ankle rule was high, but can be improved. Physicians placed greatest value on rule-based cues, while considering non-rule-based cues as moderately important. There is room to improve physician agreement with the ankle rule and use of rule-based cues through knowledge translation interventions. Further development of this Lens Modeling technique could lend itself to a valuable cognitive behavioral intervention.

Background: Diagnosis of acute coronary syndromes (ACS) in the Emergency Department (ED) is a topical and contentious issue. Current diagnostic techniques rely on hospital admission for troponin testing. Only a minority of those admitted prove to have ACS while unacceptable proportions of those discharged have unrecognised ACS. Aims: We aimed to evaluate the diagnostic and prognostic value of individual clinical findings and novel biomarkers in ED patients with suspected cardiac chest pain. We then aimed to derive a clinical decision rule (CDR) to potentially enable safe, immediate discharge of a proportion of patients from the ED while risk stratifying others to facilitate triage to an appropriate level of in-patient care. Methods: We recruited patients who presented to the ED with suspected cardiac chest pain. Variables that have previously been shown to predict diagnosis of acute myocardial infarction (AMI) or to predict outcome were prospectively recorded. Blood was drawn at presentation for levels of eight biomarkers. Patients underwent 12-hour troponin testing and were followed up for the composite primary outcome of AMI, death or urgent coronary revascularisation for six months. Variables that were univariate predictors (p<0.05) of outcome were entered into a multivariate analysis using recursive partitioning. Results: While many clinical findings and levels of all eight novel biomarkers were found to be significant predictors of outcome, none could be used individually to confirm or exclude ACS in the ED. We derived a nine-point CDR that combined clinical findings with biomarker levels to effectively stratify patients into four risk groups. 14.2% of patients were identified as being at ‘no risk’ and had a 0.0% outcome rate. The rule performed significantly better than two commonly used risk scores and may improve on triage decisions made in actual clinical practice. Conclusion: ACS remains a difficult diagnosis to confidently confirm or refute in the ED. Our CDR may help to avoid unnecessary hospital admissions while improving on triage decisions made for the remaining in-patients. Prospective validation of our findings is warranted.

No description available.