Évaluation externe de la qualitéQuality control.

Since ten years, the immunohaematology working group of the French Society of Blood Transfusion has organized a quality control. Tests concern essentially the screening and identification of irregular antibodies, direct antiglobulin tests and elutions.     

Étude de dosimétrie en radiologie interventionnelle et radiodiagnostic

L'objectif de l'étude menée au Centre Hospitalier de Troyes était d'estimer les équivalents de dose reçus par le corps médical lors d'actes nécessitant l'utilisation de rayons X et ainsi d'optimiser sa protection. Le choix des interventions médicales étudiées s'est fait sur deux critères : la durée d'utilisation des rayons X et la fréquency d'occurrence de ce type d'actes. Le protocole de mesure a consisté en l'estimation des doses reçues au niveau des différents organes ou tissus les plus exposés ou les plus sensibles au moyen de dosimètres thermoluminescents (TLD) pour les actes de radiologie interventionnelle (artériographie, chimionucléolyse, angioplastie), et en l'utilisation d'un dosimètre opérationnel pour d'autres interventions (radiographie au lit des patients, etc.). Les résultats obtenus sont comparables à ceux trouvés dans la littérature. Ils permettent d'observer que clans la plupart des cas, la surveillance par dosimètre radiographique et dosimètre opérationnel portés sous toute protection ne reflète pas la réalité. Des mesures sont proposées pour réduire les doses reçues au corps de ces actes. L'étude reste une étude initiale et doit être complétée par des études complémentaires qui permettront d'approfondir les mesures réalisées et d'aboutir à une politique de protection optimale.     

Évolution des pratiques transfusionnelles pour la chirurgie

The context of transfusion has changed in recent years. Some data could lead to an increased demand: the risk of viral transmission has significantly decreased; a national survey has revealed that the mortality related to an insufficient or delayed transfusion was higher to the side effects of the transfusion itself. Some other data could decrease the demand: the preoperative use of EPO is now easier; the intraoperative use of antifibrinolytic has been shown to be efficient. The number of allogenic red blood cells units (RBCs) transfused each year in France regularly increases, while the transfusion of predeposited autologous blood is in sharp decline. However, in hospitals still using but reducing this technique, the consumption of allogenic RBCs does not increase and the transfusion of any blood (allogenic and/or autologous) decreases. The strategy is based on preoperative evaluation of usual blood loss and tolerable blood loss by accepting a reasonable risk of allogenic blood transfusion. Advances in public health seem to be found above all in the analysis of system failures.     

Étude de la polymérisation du styrène en émulsion inverse

The polymerization of reversed emulsions water in styrene prepared with polystyrene-polyethyleneoxide block copolymers (Cop PS-POE) has been studied. The kinetics of this polymerization has been studied as a function of the parameters: type and concentration of initiator, phase ratio water/styrene, concentration of Cop PS-POE, molecular characteristics of Cop PS-POE. The type of the emulsion can be regulated by the characteristics of the Cop PS-POE and by the phase ratio water/styrene. The initiation of the polymerizations can be achieved by water soluble initiators (K₂S₂O₈). Correlations could be established between the rate of polymerization and the initiator concentration, the amount of water in the reversed emulsions and the concentration of Cop PS-POE. It was shown furthermore that the rate of polymerization increases with the POE content of two-block copolymers and that three-block copolymers are more appropriate for the polymerization in reversed emulsions. Finally the main influence of the water/styrene interface was demonstrated which regulates the transfer of radicals from the aqueous into the organic phase.     

Étude comparative des caractéristiques physicochimiques de substituts osseux phosphocalciques

Bone substitutes are more and more used in bone surgery for their biologic safety, clinic efficiency and facility to synthesize. However many devices are actually marketed which are not similar according to their theoretical composition. We did not find any comparative physicochemical or clinical study which allows to evaluate them. The aim of this study is to compare with the same analysis methods the physicochemical properties of 14 marketed materials (blocs and granules). X-ray diffraction and infrared spectroscopy were used for components determination. Secondary electron microscopy (SEM) was performed for porosity measurements and micro-indentation method was applied to determine the elastic limits. At last a dissolution test was performed. The results have shown that the composition is likely those claimed by manufacturers excepted for one material. However mineral impurities were detected in some substitutes. All materials are not macroporous (some of them have macroporosity less than 30%). Moreover we observed a large diversity between materials (macroporosity comprised between 30 and 60%). Micro-indentation method allowed to characterize three groups of substitutes (elastic limit lower than 10 MPa, comprised between 30 and 40 MPa, upper 100 MPA). Results from dissolution experiments did not show any correlation with theoretical composition. This study shows that all materials have a nearby composition. The macroporosity and mechanical properties are not similar according the several studied substitutes. However these last properties have a great influence on the osseous integration and it would be on interest to perform some clinical comparative study with these bone substitutes.     

Élaboration d''une politique nationale de maintenance des dispositifs médicaux. L''exemple du Bénin

National regulation medical device maintenance. The Benin example.The development of a country is measured by the good health of its populations. To achieve this goal, the Republic of Benin has built a network of hospitals equipped with medical devices to meet the demand in health care for the public. But one of the obstacles is to keep them under operation because of the absence of a national policy for maintenance. Approaches of solutions are proposed through the development of a national policy for maintenance. That policy will be implemented over the period 2002 to 2006. The question of the management of equipment grants is tackled and it shows the possibility for the broad outline of the charter of gifts. The concern is to control the cost of maintenance and to propose a logical step for the implementation of this policy.     

Préprogramme d'équipement médical d'un plateau technique : l'exemple de l'hôpital Édouard-Herriot

The 2007 hospital plan increases the number of modernisation projects in health establishments. One of the goals of those projects is to reduce the working costs. It can be done by grouping together similar technical departments. Édouard-Herriot Hospital is a good example of this phenomenon. Indeed, its scattered architecture will be abandoned for the project of new hospital planed for 2013. Within the framework of a project of a new hospital, the first stage consists to well define the functional courses, the capacity, specifications and a financial valuation of the new buildings, before the architectural project. During this first stage, the biomedical department was asked to elaborate an equipment program in order to foresee the financial amount of medical devices purchases which must be planned. First, we develop a general method for the elaboration and financial valuation of an equipment program. This procedure is based on the use of a software called “Key Data”. This software is used by the “hospices civils de Lyon” to establish their equipment programs. Secondly, this method is applied to the new critical care unit.     

Étude de la copolymérisation de monomères acryliques fluorés avec le méthacrylate de morpholinoéthyle

The copolymerization of 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl acrylate (AC8), methacrylate (MAC8) and α-acetoxyacrylate (αAC8) with morpholinoethyl methacrylate (MEMA) is presented. For these three systems, the values of the reactivity ratios (r_i) of both comonomers were determined by means of four methods (Jaacks, Macret, Fineman-Ross and Tidwell-Mortimer) usually used, and these results were compared. In each case, the copolymer obtained exhibits a structure with a higher content of the fluorinated base unit. A reactivity scale in the radical copolymerization with MEMA is proposed and shows that αAC8 and MAC8 are more reactive than AC8, contrary to their homopolymerization behaviour. An explanation of such a tendency was suggested taking into account the Q-e scheme of Alfrey and Price of hydrocarbon homologues.     

Étude cinétique de la polymérisation anionique du styrène en présence d'un contre-ion baryum

The anionic polymerization of styrene in tetrahydrofuran initiated by a bifunctional organo-barium derivative shows a remarkable property: for a given temperature the propagation rate does not depend on carbanion concentration in the range from 3.10^?5 to 5.10^?3 mol/l. This corresponds to a linear relationship between the rate constant of propagation k_p and the reciprocal of active sites concentration. The activation energy of propagation is equal to 4,1 kcal/mol (17,1±1,3 kJ/mol). Our experimental results were interpreted assuming that “living” polymer molecules form rings, their two anionic ends being associated through a divalent cation, and that they constitute aggregates with a “rosace” type structure. The validity of this assumption is supported by spectral and viscosimetric studies of living polymer solutions.     

Étude de la microstructure de polyéthylènes de basse densité chlorés en solution et en suspension

High resolution NMR analysis of polyethylenes of low density chlorinated in suspension or in solution shows a fundamental difference of the microstructure between these two kinds of products. The products prepared in suspension with up to 65% chlorine can schematically be considered as semicrystalline copolymers with polyethylene-poly(vinyl chloride) sequences and beyond 65% chlorine as amorphous copolymers of vinyl chloride, 1,1-dichloroethylene, 1,2-dichloroethylene, and 1,2,3-trichloroethylene. The products prepared in solution are practically chlorinated statistically and become very quickly amorphous. At the beginning of their chlorination the formation of dichloromethylene groups dominates. At higher chlorine contents vinyl chloride sequences appear which become predominant at 60% chlorine. Beyond 60% chlorine 1,2-dichloroethylene units appear.