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With the increasing use of artificial organs, blood damage has been raising ever more clinical concern. Blood trauma is in fact a major complication resulting from the implantation of medical devices and the use of life support apparatuses. Red blood cells damage predictive models furnish critical information on both the design and the evaluation of artificial organs, because their correct usage and implementation are thought to provide clear and rational guidance for the improvement of safety and efficacy. The currently adopted power-law shear-induced haemolysis prediction model lacks sensitivity with respect to the cumulative effect of previously applied stress magnitudes. An alternative model is proposed where a mechanical quantity was defined, able to describe the blood damage sustained by red cells under unsteady stress conditions, taking into account the load history. The proposed formulation predicted the same trend as the available experimental data. The obtained results have to be considered a preliminary validation of the basic hypothesis of this modified red blood cell damage prediction model. To date, the necessity to design further experiments to validate the proposed damage function clashes with the limitations inherent to current systems to get the time-varying shear stress completely under control.

This paper aims at delivering a structured overview of telerehabilitation literature by analysing the entire set of articles under the search terms "telerehabilitation" or "tele-rehabilitation" to portray "state of the art" ten years after the publication of the first scientific article on the topic. A structured study has been conducted by considering all those articles containing the word "telerehabilitation" or "telerehabilitation". Medline, Embase, Cochrane, UK Centre for Reviews and Dissemination, Canadian Agency for Drugs and Technologies in Health databases have been interrogated for articles between 1998 and 2008. 146 scientific articles were found. 56 articles focus on patient treatment, 23 are reviews, 3 are to be considered as both patient treatment papers and reviews, 53 are either technical reports, system descriptions or analyses of new approaches; 8 are general discussion on telerehabilitation. The present paper draw the scenario of the first ten years of telerehabilitation, focussing on clinical applications and technologies. Basically, it confirms the lack of comprehensive studies providing evidence for supporting decision and policy-makers in adopting telerehabilitation technologies in the clinical practice. An overall lack of standardisation in the used terminology also results from the analysis of keywords, which is typical of quite recent fields of application.

Blood trauma caused by medical devices is a major concern. Complications following the implantation/application of devices such as prosthetic heart valves, cannulae, blood pumps, tubing, and throttles lead to sublethal and lethal damage to platelets and erythrocytes. This damage is provided by the alterations in fluid dynamics, providing a mechanical load on the blood corpuscle's membrane by means of the shear stress. An appropriate quantification of the shear-induced hemolysis of artificial organs is thought to be useful in the design and development of such devices in order to minimize device-induced blood trauma. To date, a power-law mathematical relationship using the time of exposure of a blood corpuscle to a certain mechanical load and the shear stress itself (derived under the peculiar condition of uniform shear stress) has served as a basic model for the estimation of the damage to blood, investigated by means of numerical and/or experimental fluid dynamical techniques. The aim of the present article is to highlight the effect of a time-varying mechanical loading acting on blood cells based on the usual power-law model; furthermore, the effect of the loading history of a blood particle is discussed, showing how the past history of the shear acting on a blood corpuscle is not taken into account, as researchers have done until now. The need for a reassessment of the power-law model for potential blood trauma assessment is discussed by using a mathematical formulation based on the hypotheses of the existence of damage accumulation for blood with respect to time and with respect to shear stress, to be applied in complex flow fields such as the ones established in the presence of artificial organs.