Fig. 1

The concept of devices’ global evaluation. In order to assess ‘efficacy’ of a device, we considered that a global ergonomics evaluation required evaluating concomitantly ‘efficiency’, ‘engagement’, ‘ease of use’ and ‘tolerance to error’, as these four dimensions may be considered as interdependent. Tolerance to error was evaluated through the objective tasks completion scenarios. While considering that an easy-to-use device should be easily managed by a skilled physician, but not familiar to that specific device, we took particular attention to included naive subjects in the evaluation. Bench testings do explore the most important technical determinants of the efficiency of a device (tidal volume accuracy, triggering, etc.). Efficiency assessment might also include interfaces’ performance evaluation. For such sake, we used pupillary diameter variation which can be considered as a determinant of stress. Other eye-tracking tools such as blinking measurements or heat mapping may also have been used. Engagement during use of the device was evaluated through the use of psycho-cognitive scales, combined with physiological parameters measurements. Heart rate variability (HRV) may also have been measured for such sake