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Increasingly often, the surgeon operates remotely. More and more, he/she does neither see nor touch the patient directly but acts with miniaturized systems, such as catheters and robotic instruments. This reduces intervention time and accelerates the patient’s recovery. This paper reports the ergonomic contribution to the design of a device for the resection of stenosed aortic valves and the implantation of a new aortic bioprosthesis. In high-risk contexts as in cardiac surgery, high fidelity prototypes are necessary to allow clinical trials. An association between engineers and ergonomists becomes essential, because the prototype becomes a key stage of the design process. We suggest a triangulation of methods (heuristic inspection, task analysis and usability testing) to produce a high-fidelity prototype reliable for clinical trials. The clinical trials themselves then constitute a preliminary step for further improving the device.

Aortic stenosis is the most important acquired heart disease, with a prevalence of 4.8% in patients aged more than 75 years and represent more than 60% of the indications for cardiac surgery in elderly patients. Regardless of the good results reported with conventional aortic valve replacements (AVRs) in elderly patients, still many patients are denied surgery by the high operative risk. In this frail population, Transcatheter Aortic Valve Implantation (TAVI) can be a good compromise to achieve good results and minimize morbidity and mortality. This technique allows implanting a balloon-expandable bioprosthesis, without resecting the native aortic valve. Several complications are described as consequence of the residual, highly calcified valve squeezed between the aortic wall and the stent of the implant. In this perspective, the concept of endovascular resection of the aortic valve, before TAVI, was developed and enhanced by Astarci, Glineur, Elkhoury, and Raucent.

This article is part of the design of a surgical device in cardiology for circular cutting of the aortic valve. In this context of future use, the consequences of device misuse can be critical but it is impossible to perform user tests for every design iteration. The authors present the methods they applied to circumvent the evaluation in real-life situations and to develop the usability of a prototype. The methods used are known (heuristic inspection, task modelling and artificial situation testing), the interest is in their combined uses at this stage of device design. Overall, the results tend to show that triangulation of methods is really interesting if it crosses artificial and real data collection methods.

We bring different theories together to develop a theoretical framework that helps to understand how early warning messages about (new) dangerous drugs can influence the public's perception of substance use. We bring together the agenda setting theory, framing theory, dual processing theory, social learning theory, health belief model, theory of planned behavior, and cultivation theory in order to explain how warning messages diffused through the mass media can have an impact on the receivers' perceptions. Based on these insights we construct the Integrated Media Effect Framework (IMFE) that takes into account the role of cultural and structural contexts in the realm of early warning systems (EWS). Ultimately, this framework provides valuable guidelines for conceptualizing EWS and for developing applications by governments. (C) 2008 Elsevier Inc. All rights reserved.

This research forms a part of the design of a system for the resection and implantation of an aortic valve. Four transapical endovalve implantations are analyzed with a view to characterizing the exceptional criticality of this surgical procedure. We demonstrate that the surgeon’s activity is largely cognitive, operational and social and requires mastery of a critical task, i.e. the performance and supervision of a risky, deliberately initiated procedure with an uncertain outcome. The concept of “critical task” is used to describe tasks combining potentially extreme seriousness and potential success, risk-taking with cure. The task is critical as its criticality is intentionally generated by the surgical team. In short, this paper defines the concept of critical task according to ten characteristics: Deliberate, Uniqueness, Learning restriction, Planning, Expertise, Preparation, Collective, Hazardous, Rigidity and Uncertain outcome; and supplies a number of ergonomic recommendations with a view to improvement.